benzofurans and dibenzofuran

It is well established that for non-occupationally exposed populations, dietary intake is, by far, the main way of human exposure to polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-p-furans (PCDD/Fs), a family of environmental POPs with a well-known potential toxicity -including carcinogenicity-in humans. We here summarize the results of recent studies (2010-2021) (databases: Scopus and PubMed), focused on determining the levels of PCDD/Fs in food samples of different origins, as well as the dietary intake of these pollutants. We have revised studies conducted in various Asian, American and European countries. However, information is rather limited, with no recent data for most countries over the world. Due to the enormous differences in the methodologies of the studies, to conduct a detailed comparison of the results for the different regions and countries has not been possible. Notwithstanding, where data over time are available, important reductions have been observed. These reductions have been linked to the decreases in the environmental emissions of PCDD/Fs noted in recent years. Interestingly, reductions in the levels of PCDD/Fs in biological tissues are also occurring in parallel. In general, the tolerable daily/weekly/monthly dietary intakes of PCDD/Fs are not being currently exceeded where data are available.

Topics: Asia, Eastern; Benzofurans; Diet; Europe; Food; Food Analysis; Food Contamination; Humans; North America; Polychlorinated Dibenzodioxins

Reports from the past ten years describing the isolation and/or synthesis of bioactive dibenzofurans possessing three or more oxygen-containing substituents are reviewed. Dibenzofuranoquinones are included in the review.

Topics: Animals; Benzofurans; Humans; Oxygen

This paper reviews the levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in different environmental media, human body burdens and health risk assessment results at e-waste recycling sites in China. To provide an indication of the seriousness of the pollution levels in the e-waste recycling sites in China, the data are compared with guidelines and available existing data for other areas. The comparison clearly shows that PCDD/Fs derived from the recycling processes lead to serious pollution in different environmental compartments (such as air, soil, sediment, dust and biota) and heavy body burdens. Of all kinds of e-waste recycling operations, open burning of e-waste and acid leaching activities are identified as the major sources of PCDD/Fs. Deriving from the published data, the estimated total exposure doses via dietary intake, inhalation, soil/dust ingestion and dermal contact are calculated for adults, children and breast-fed infants living in two major e-waste processing locations in China. The values ranged from 5.59 to 105.16 pg WHO-TEQ/kg bw/day, exceeding the tolerable daily intakes recommended by the WHO (1-4 pg WHO-TEQ/kg bw/day). Dietary intake is the most important exposure route for infants, children and adults living in these sites, contributing 60-99% of the total intakes. Inhalation is the second major exposure route, accounted for 12-30% of the total exposure doses of children and adults. In order to protect the environment and human health, there is an urgent need to control and monitor the informal e-waste recycling operations. Knowledge gaps, such as comprehensive dietary exposure data, epidemiological and clinical studies, body burdens of infants and children, and kinetics about PCDD/Fs partitions among different human tissues should be addressed.

Topics: Benzofurans; Body Burden; China; Electrical Equipment and Supplies; Environmental Pollutants; Humans; Polychlorinated Dibenzodioxins; Recycling; Refuse Disposal; Risk Assessment; Waste Disposal Facilities

A comprehensive worldwide literature review of blood levels of dioxins and dioxin-like compounds in non-exposed adult general populations was performed. The studies published in 1989-2010 reporting information on polychlorinated dibenzo-para-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), non-ortho-PCBs (nPCBs), mono-ortho-PCBs (mPCBs) levels and Toxic Equivalencies (TEQs, a summary weighted measure of their combined toxicity) were reviewed. TEQs were calculated using as standard the most recent WHO 2005 reevaluation of Toxic Equivalency Factors (TEFs). Weighted multiple regression analyses adjusted for year, subject's age, type of sample analyzed, method used for values below detection limit, and central tendency measure used were performed for each congener and standardized TEQs (log-transformed). We identified 187 studies regarding 29,687 subjects of 26 countries. Year of blood collection ranged from 1985 to 2008. The studies reporting congener levels 161. In adjusted analyses, European countries showed higher levels of most dioxin-like congeners and TEQs. A strong positive association of subjects' age with most congeners and with TEQ values was found, confirming previous findings. Significant decreases over time (1985-2008) were documented for PCCDs, PCDFs, and TEQs including their contributions. No significant decrease was found for non-ortho-PCBs, notably PCB 126. Only some mono-ortho-PCBs showed clear significant declines. Accordingly, TEQs including only PCB contribution did not decrease over time. In interpreting these findings, it should be considered that for dioxin-like PCBs the analysis period was shorter (17 years), since these compounds were first measured in 1992.

Topics: Benzofurans; Dioxins; Environmental Exposure; Environmental Pollutants; Humans; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins

Photocatalysis is applied increasingly in addressing and solving environmental and energy-related problems. Especially the TiO₂-derived catalysts attract attention because of their catalytic efficiency, wide range of applications, ease in use, and low cost (it costs about 150 Yuan a kilogram in China). This review first describes the principles of photocatalytic destruction by semiconductors and then focuses on degradation rates and reaction mechanisms in a variety of photocatalytic uses of modified TiO(2). Finally, these concepts are illustrated by selected examples relating to the photocatalytic degradation of organic persistent pollutants, such as polychlorinated benzenes (PCBz), biphenyls (PCB) and dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). And some approaches towards industrial application are analyzed.

Topics: Benzofurans; Catalysis; Environmental Pollutants; Environmental Restoration and Remediation; Hydrocarbons, Cyclic; Hydroxyl Radical; Metal Nanoparticles; Photochemical Processes; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Semiconductors; Titanium

Thyroid hormones play a critical role in the proper development of brain function and cell growth. Several epidemiological studies have been conducted to assess potential associations between pre- and post-natal exposure to dioxins or dioxin-like compounds (DLCs) and the levels of circulating thyroid hormones during early development. Dioxins and DLCs include chlorinated dibenzo-p-dioxins, chlorinated dibenzofurans, and mono- and non-ortho polychlorinated biphenyls (PCBs). We identified a total of 23 relevant epidemiological studies (21 cohort studies and 1 case-control study) that measured exposures to various types of dioxins and DLCs as well as markers of thyroid function, such as thyroid stimulating hormone (TSH), total thyroxine (T4), free T4, total triiodothyroxine (T3), free T3, and thyroid-binding globulin concentrations in cord blood or circulation. While some of the studies reported associations between concentrations of dioxins and/or DLCs and some biomarkers of thyroid function, the majority of the observed associations were not statistically significant. Moreover, there were no clear and consistent effects across studies for any of the hormone levels examined, and while a number of studies showed a statistically significant association with exposure for a given marker of thyroid function, other studies showed either no change or changes in the opposite direction for the same thyroid function marker. Similarly, when the results were analyzed considering developmental stage, there generally were no clear and consistent effects at any age from birth through 12 years of age. The absence of a clear correlation between background exposures to dioxins and DLCs and thyroid function biomarkers during development is not consistent with the hypothesis that background exposures to these chemicals cause effects on thyroid function during development.

Topics: Benzofurans; Biomarkers; Dioxins; Environmental Exposure; Humans; Infant, Newborn; Polychlorinated Biphenyls; Thyroid Gland; Thyroid Hormones; Thyrotropin

Polychlorinated dibenzo-p-dioxins and -furans (PCDD/Fs) are among the most harmful environmental contaminants. Their widespread distribution due to unintentional or unknown release coincides with environmental persistence, acute and chronic toxicity to living organisms, and long-term effects due to the compounds' tendency for bioaccumulation and biomagnification. While microbial aerobic degradation of PCDD/Fs is mainly reported for the turnover of low chlorinated congeners, this review focuses on anaerobic reductive dehalogenation, which may constitute a potential remediation strategy for polychlorinated compounds in soils and sediments. Microorganisms in sediments and in microcosms or enrichment cultures have been shown to be involved in the reductive dechlorination of dioxins. Bacteria related to the genus Dehalococcoides are capable of the reductive transformation of dioxins leading to lower chlorinated dioxins including di- and monochlorinated congeners. Thus, reductive dehalogenation might be one of the very few mechanisms able to mediate the turnover of polychlorinated dioxins by reducing their toxicity and paving the way for a subsequent breakdown of the carbon skeleton.

Topics: Anaerobiosis; Benzofurans; Biodegradation, Environmental; Biotechnology; Chloroflexi; Geologic Sediments; Oxidation-Reduction; Polychlorinated Dibenzodioxins; Soil Microbiology; Soil Pollutants

Once they have been generated, polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) and other persistent organic pollutants (POPs) can persist in soils and sediments and in waste repositories for periods extending from decades to centuries. In 1994, the US EPA concluded that contaminated sites and other reservoirs are likely to become the major source of contemporary pollution problems with these substances. With this in mind, this article is the first in a new series in ESPR under the title 'Case Studies on Dioxin and POP Contaminated Sites--Contemporary and Future Relevance and Challenges', which will address this important issue. The series will document various experiences from sites contaminated with PCDD/F and other POPs. This article provides an overview of the content of the articles comprising the series. In addition, it provides a review of the subject in its own right and identifies the key issues arising from dioxin/POP-contaminated sites. Additionally, it highlights the important conclusions that can be drawn from these examples. The key aim of this article and of the series as a whole is to provide a comprehensive overview of the types of PCDD/F contaminated sites that exist as a result of historical activities. It details the various processes whereby these sites became contaminated and attempts to evaluate their contemporary relevance as sources of PCDD/Fs and other POPs. It also details the various strategies used to assess these historical legacies of contamination and the concepts developed, or which are under development, to effect their remediation.. Special sessions on 'Contaminated sites--Cases, remediation, risk and policy' were held at the DIOXIN conferences in 2006 and 2007, and this theme will be continued at DIOXIN 2008 to be held in Birmingham. Selected cases from the approximately 70 contributions made to these sessions, together with some additional invited case studies are outlined together with the key issues they raise. By evaluating these cases and adding details of experiences published in the current literature, an overview will be given of the different features and challenges of dioxin and POP-contaminated sites.. This article provides a systematic categorisation of types of PCDD/F and POP-contaminated sites. These are categorised according to the chemical or manufacturing process, which generated the PCDD/Fs or POPs and also includes the use and disposal aspects of the product life cycle in question. The highest historical PCDD/F and dioxin-like polychlorinated biphenyl (PCB) contamination burdens have arisen as a result of the production of chlorine and of chlorinated organic chemicals. In particular, the production of chlorinated pesticides, PCBs and the related contaminated waste streams are identified being responsible for historical releases of toxic equivalents (TEQs) at a scale of many tonnes. Along with such releases, major PCDD/F contaminated sites have been created through the application or improper disposal of contaminated pesticides, PCBs and other organochlorine chemicals, as well through the recycling of wastes and their attempted destruction. In some extreme examples, PCDD/F contaminated sites have also resulted from thermal processes such as waste incinerators, secondary metal industries or from the recycling or deposition of specific waste (e.g. electronic waste or car shredder wastes), which often contain chlorinated or brominated organic chemicals. The examples of PCDD/F and dioxin-like PCB contamination of fish in European rivers or the impact of contaminated sites upon fishing grounds and upon other food resources demonstrate the relevance of these historical problems to current and future human generations. Many of the recent food contamination problems that have emerged in Europe and elsewhere demonstrate how PCDD/F and dioxin like PCBs from historical sources can directly contaminate human and animal feedstuffs and indeed highlight their considerable contemporary relevance in this respect. Accordingly, some key experiences and lessons learnt regarding the production, use, disposal and remediation of POPs from the contaminated sites are summarised.. An important criterion for evaluating the significance and risks of PCDD/Fs and other POPs at contaminated sites is their present or future potential for mobility. This, in turn, determines to a large degree their propensity for off-site transport and environmental accessibility. The detailed evaluation of contaminated site cases reveals different site-specific factors, which influence the varied pathways through which poor water-soluble POPs can be mobilised. Co-contaminants with greater water solubility are also typically present at such sites. Hence, pumping of groundwater (pump and treat) is often required in addition to attempting to physically secure a site. At an increasing number of contaminated sites, securing measures are failing after relatively short time spans compared to the time horizon, which applies to persistent organic pollutant contamination. Due to the immense costs and challenges associated with remediation of contaminated sites 'monitored natural attenuation' is increasingly gaining purchase as a conceptual remediation approach. However, these concepts may well prove limited in their practical application to contaminated sites containing persistent organic pollutants and other key pollutants like heavy metals.. It is inevitable, therefore, that dioxin/POP-contaminated sites will remain of contemporary and future relevance. They will continue to represent an environmental issue for future generations to address. The securing and/or remediation of dioxin/POP-contaminated sites is very costly, generally in the order of tens or hundreds of millions of dollars. Secured landfills and secured production sites need to be considered as constructions not made for 'eternity' but built for a finite time scale. Accordingly, they will need to be controlled, supervised and potentially repaired/renewed. Furthermore, the leachates and groundwater impacted by these sites will require ongoing monitoring and potential further remediation. These activities result in high maintenance costs, which are accrued for decades or centuries and should, therefore, be compared to the fully sustainable option of complete remediation. The contaminated site case studies highlight that, while extensive policies and established funds for remediation exist in most of the industrialised western countries, even these relatively well-regulated and wealthy countries face significant challenges in the implementation of a remediation strategy. This highlights the fact that ultimately only the prevention of contaminated sites represents a sustainable solution for the future and that the Polluter Pays Principle needs to be applied in a comprehensive way to current problems and those which may emerge in the future.. With the continuing shift of industrial activities in developing and transition economies, which often have poor regulation (and weak self-regulation of industries), additional global challenges regarding POPs and other contaminated sites may be expected. In this respect, a comprehensive application of the "polluter pays principle" in these countries will also be a key to facilitate the clean-up of contaminated areas and the prevention of future contaminated sites. The threats and challenges of contaminated sites and the high costs of securing/remediating the problems highlight the need for a comprehensive approach based upon integrated pollution prevention and control. If applied to all polluting (and potentially polluting) industrial sectors around the globe, such an approach will prove to be both the cheapest and most sustainable way to underpin the development of industries in developing and transition economies.

Topics: Benzofurans; Environmental Monitoring; Environmental Pollution; Environmental Restoration and Remediation; International Cooperation; Polychlorinated Dibenzodioxins; Social Responsibility; Soil Pollutants; Waste Management

The Myxomycetes (true slime molds) are an unusual group of primitive organisms that may be assigned to one of the lowest classes of eukaryotes. As their fruit bodies are very small and it is very difficult to collect much quantity, few studies have been made on the chemistry of myxomycetes. We studied spore germination experiments of hundreds of field-collected myxomycetes collected in Japan, and succeeded in laboratory culture of plasmodia of several myxomycetes in a practical scale for natural products chemistry studies. Pyrroloiminoquinones, polyene yellow pigments, and a peptide lactone were isolated from cultured plasmodia of myxomycetes, while new naphthoquinone pigments, cycloanthranilylprolines, tyrosine-kinase inhibitory bisindoles, a cytotoxic triterpenoid aldehyde lactone, a dibenzofuran glycoside, and sterols possessing an unprecedented 2,6-dioxabicyclo[2.2.2] octan-3-one ring system, were also isolated from field-collected fruit bodies of myxomycetes.

Topics: Animals; Benzofurans; Drug Design; Glycosides; Lactones; Myxomycetes; Naphthoquinones; Polyenes; Proline; Pyrroloiminoquinones; Sterols

Humans are exposed to many environmental chemicals, some of which can potentially affect neurodevelopment. Fetuses, infants, and young children are the most susceptible to the effects of these chemicals. As part of the National Health and Examination Survey, 1999-2000, the Centers for Disease Control and Prevention analyzed biological samples for many of these chemicals in a representative sampling of the U.S. population. Concentration data of selected metals, persistent organic pollutants, organophosphorus and carbamate insecticides, and cotinine are presented. For example, the 95th percentile estimates for serum total PCBs (whole weight) in the population aged 20 years and older is about 2.7 ng/g. The 95th percentile estimates for serum dioxin total toxic equivalence in the U.S. population aged 20 years and older is between 40 and 50 pg/g lipid basis. In general, human levels of these chemicals are decreasing over time in the U.S. population. This reflects the effects of legislation, industry efforts, and changes in lifestyle/activity patterns in the U.S. population. These data will continue to be collected in 2-year cycles and thus allow changes in human levels to be followed.

Topics: Adolescent; Adult; Age Factors; Benzofurans; Child; Child, Preschool; Cotinine; Environmental Monitoring; Environmental Pollutants; Epidemiological Monitoring; Female; Humans; Hydrocarbons, Chlorinated; Infant; Lead; Lipids; Male; Mercury; Metals; Middle Aged; Nervous System; Neurotoxicity Syndromes; Pesticides; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Polymers; Tobacco Smoke Pollution; United States

Thermal treatment of plastics flame retarded with brominated compounds often lead to the formation of PBDD/F, especially if polybrominated diphenyl ethers are used. By the presence of antimony(III) oxide, water and some other metals, the amounts of PBDD/F increase. Even during the production and recycling processes of plastics, PBDD/F can be found in considerable amounts. By the use of flame retardants, which are not direct precursors of PBDD/F, the amounts can significantly be decreased. An incomplete and uncontrolled incineration, occurring in fire accidents in private residences, can form high amounts of PBDD/F, which can endanger the environment and persons in contact with fire residues. Complete and controlled incineration of bromine-containing compounds as usually conducted in municipal waste incinerators, however, show no raised risk. An overview about the formation of PBDD/F primarily during combustion and also during production and recycling processes of flame-retarded plastic materials is given in this paper.

Topics: Benzofurans; Conservation of Natural Resources; Dioxins; Flame Retardants; Hydrocarbons, Brominated; Incineration; Models, Chemical; Plastics; Thermodynamics

This article reviews the state of the science regarding the health effects of polybrominated dibenzo-p-dioxins (PBDDs) and dibenzofurans (PBDFs). While thousands of articles have been published on the health effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin and related polychlorinated dibenzodioxins (PCDDs) and dibenzofurans (PCDFs), little is know about the brominated and mixed chloro/bromo homologs. Available literature suggests that brominated compounds have similar toxicity profiles to their chlorinated homologs. However, further research investigating health effects will only be useful if exposure scenarios truly exist. Current exposure data is extremely limited, posing a major data gap in assessing potential risk of these chemicals. The rapid increase in the use of brominated flame retardants has raised the level of environmental concern regarding PBDDs/PBDFs as it is likely that human, as well as wildlife, exposure to brominated dioxins and furans will increase with their use.

Topics: Benzofurans; Dioxins; Environmental Exposure; Hydrocarbons, Brominated; Public Health

Microbially mediated dehalogenation processes contribute to the global cycling of both biogenic and anthropogenic halogenated organic compounds. Detailed information on biodegradation mechanisms for a variety of organohalides and on the microorganisms mediating these processes has greatly increased our understanding of the cycling and fate of these unique and widespread compounds in our environment. The marine environment appears to be a particularly rich source of dehalogenating microorganisms. It is well established by laboratory and field studies that anaerobic dehalogenation of sediment contaminants, such as PCBs, pesticides, and dioxins, occurs intrinsically and can be enhanced via various methods. Specific dehalogenating bacterial populations can be enriched on various organohalides. Biodehalogenation processes are likely to be significantly affected by the prevailing terminal electron-accepting condition, and thus, biotransformation of organohalide contaminants in marine and estuarine environments will vary as a function of the redox conditions within the sediment profile. Fundamental knowledge of the activities and interactions of dehalogenating microorganisms is providing a strong basis for development of new bioremediation technologies for removal of harmful halogenated compounds from our environment.

Topics: Anaerobiosis; Benzofurans; Biodegradation, Environmental; Dioxins; Geologic Sediments; Hydrocarbons, Halogenated; Oxidation-Reduction; Water Pollutants, Chemical

Phytoremediation is already regarded as an efficient technique to remove or degrade various pollutants in soils, water and sediments. However, hydrophobic organic molecules such as PAHs, PCBs and PCDD/Fs are much less responsive to bioremediation strategies than, for example, BTEX or LAS. PCDD/Fs and PCBs represent 3 prominent groups of persistent organic pollutants that share common chemical, toxicological and environmental properties. Their widespread presence in the environment may be explained by their chemical and biological stability. This review considers their fate and dissipation mechanisms. It is then possible to identify major sinks and to understand biological activities useful for remediation. Public health and economic priorities lead to the conclusion that alternative techniques to physical treatments are required. This review focuses on particular problems encountered in biodegradation and bioavailability of PCDD/Fs and PCBs. It highlights the potential and limitations of plants and micro-organisms as bioremediation agents and summarises how plants can be used to augment bacterial activity. Phytoremediation is shown to provide some new possibilities in reducing risks associated with dioxins and PCBs.

Topics: Benzofurans; Biodegradation, Environmental; Biological Availability; Plants; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Soil Pollutants

Lichen metabolites exert a wide variety of biological actions including antibiotic, antimycobacterial, antiviral, antiinflammatory, analgesic, antipyretic, antiproliferative and cytotoxic effects. Even though these manifold activities of lichen metabolites have now been recognized, their therapeutic potential has not yet been fully explored and thus remains pharmaceutically unexploited. In this mini-review, particular attention is paid to the most common classes of small-molecule constituents of lichens, from both the chemical viewpoint and with regard to possible therapeutic implications. In particular, aliphatic acids, pulvinic acid derivatives, depsides and depsidones, dibenzofuans, anthraquinones, naphthoquinones as well as epidithiopiperazinediones are described. An improved access to these lichen substances in drug discovery high-throughput screening programs will provide impetus for identifying novel lead-compounds with therapeutic potential and poses new challenges for medicinal chemistry.

Topics: 4-Butyrolactone; Anthraquinones; Benzofurans; Depsides; Hydroxybenzoates; Lactones; Lichens; Naphthoquinones

None of the publications reviewed provide clinical evidence that PCBs (polychlorinated biphenyls) and related chemicals adversely affect weight, immune, or thyroid function in infants or children born to healthy mothers. Birth weights of term infants fell within the normal range in all studies. The greatest difference between comparison groups was reported by G. G. Fein et al. (1984a, Intrauterine Exposure of Humans to PCBs: Newborn Effects, EPA-600/3-84-060, Environmental Protection Agency; 1984b, J. Pediatr. 105, 315-320). P. R. Taylor et al. (1989, Am. J. Epidemiol. 129, 395-406) reported smaller differences in occupationally exposed women and E. Dar et al. (1992, Environ. Res. 59, 189-201) found that women with higher PCB serum levels had larger babies. S. Patandin et al. (1998, Pediatr Res. 44, 538-545) found a negative association of PCB concentrations in maternal or cord plasma and birth weight of breast and formula-fed infants combined but not when breast-fed infants were analyzed separately. L. Rylander et al. (1995, Scand. J. Work Environ. Health 21, 368-375) reported decreased birth weights with higher dietary intake of contaminated fish. Thus, correlations between PCB exposure or polluted fish ingestion and birth weight were inconsistent. Thyroid and immune function were also within the normal range. In none of the papers were normal laboratory reference values provided and overall the statistically significant differences accounted for little of the variance.

Topics: Benzofurans; Birth Weight; Child; Child, Preschool; Food Contamination; Humans; Immune System; Infant; Infant, Newborn; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Thyroid Gland

Fluorene and its three heteroatomic analogs, dibenzofuran, dibenzothiophene, and carbazole, are environmental contaminants in areas impacted by spills of creosote. In addition, dibenzofuran has been used as an insecticide, and it is formed from the photolysis of chlorinated biphenyl ethers. Many biodegradation studies of dibenzofuran have considered it as a model for chlorinated dibenzofurans, which are of greater environmental concern. This paper reviews the bacterial degradation of fluorene and its analogs. These compounds are susceptible to three different modes of initial oxidation: (i) the naphthalene-like attack, in which one of the aromatic rings is oxidized to a dihydrodiol; (ii) an angular dioxygenase attack, in which the carbon bonded to the methylene group in fluorene or to the heteroatoms in the analogs, and the adjacent carbon in the aromatic ring are both oxidized; and (iii) the five-membered ring attack, in which the methylene carbon atom in fluorene or the sulfur atom in dibenzothiophene is oxidized. The metabolites, enzymology, and genetics of these transformation are summarized. Literature data are presented, indicating that the electronegativity of the atom connecting the two aromatic rings influences the attack of the angular dioxygenase. In dibenzofuran and carbazole, the connecting atoms, O and N respectively, have high electronegativities, and these compounds serve as substrates for angular dioxygenases. In contrast, the connecting atoms in dibenzothiophene and fluorene, S and C respectively, have lower electronegativities, and these atoms must be oxidized before the angular dioxygenases attack these compounds.

Topics: Bacteria; Benzofurans; Biodegradation, Environmental; Carbazoles; Fluorenes; Thiophenes

Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans are toxic compounds formed during natural processes and human activities. The extraction and clean-up for these compounds from various environmental and biological sources has been described. The gas chromatographic analysis of polychlorinated dibenzo dioxins/furans with different columns and detectors has been reviewed. The advantages of using a mass detector in the analysis are discussed.

Topics: Air Pollutants; Benzofurans; Chromatography, Gas; Environmental Pollutants; Polychlorinated Dibenzodioxins; Soil Pollutants; Water Pollutants

One of the major goals of the Great Lakes Action Plan is to actively accumulate and assess toxicological information on persistent toxic substances found in the Great Lakes basin. As part of Health Canada's commitment to this plan, a review of biomarkers for the environmental contaminants polychlorinated biphenyls (PCBs) and polychlorinated dibenzodioxins/dibenzofurans (PCDDs/PCDFs) was conducted. In general, while food consumption was identified as the major source of human exposure to both contaminant groups, certain commodities, such as fish, milk and dairy products, and meat, were found to predominate. Due to the ubiquitous nature of these environmental contaminants and their propensity to bioaccumulate, all humans will have detectable body burdens, which in certain cases can be positively associated with the consumption of particular foods (i.e., PCBs and freshwater fish from the Great Lakes). When dealing with environmental exposure only, relating specific effect biomarkers to contaminant exposure or tissue levels was difficult, due in part to the complex nature of the exposure and the nonspecific nature of the effect. For PCBs, the most likely biomarkers of effect included some form of alteration in lipid metabolism (serum triglyceride/cholesterol levels) and elevation of hepatic-related enzymes, aspartate aminotransferase (AST) and gamma-glutamyltransferase (GGT). Cross-species extrapolation also indicates the potential for neurotoxicologic effects to occur in humans. For PCDDs/PCDFs, dermatologic lesions (chloracne) and indications of hepatic enzyme induction have been documented, but primarily due to occupational or high acute accidental exposures. Recent evidence suggests that neonates may represent a potential at-risk population due to relatively high exposure to PCDDs/PCDFs, as with PCBs, during breast feeding as compared to standard adult dietary intake. Future areas of potential benefit for biomarker development include immunologic and endocrine effects, primarily based on biologic plausibility from experimental animal research.

Topics: Adipose Tissue; Adult; Benzofurans; Biomarkers; Canada; Child; Environmental Exposure; Female; Food Contamination; Great Lakes Region; Humans; Infant; Male; Milk, Human; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Water Pollutants, Chemical

With substantial improvements in analytic techniques over the past decade, it has become possible to measure polychlorinated dioxins (PCDDs) and dibenzofurans (PCDFs) in human tissue in a congener-specific fashion down to the low parts per trillion level. This paper reviews findings using these new techniques from a number of recent medical and environmental case studies. These studies include those of workers exposed to a polychlorinated biphenyl (PCB) transformer fire in the United States, German chemical workers exposed to 2,3,7,8-tetrachlorodibenzodioxin (2,3,7,8-TCDD) while cleaning up after an explosion, workers at a municipal incinerator in New York City, a chemist exposed to brominated and chlorinated dioxins, U.S. veterans and also Vietnamese civilians exposed to Agent Orange contaminated with TCDD in Vietnam, and victims of the polychlorinated dibenzofuran and PCB contaminated rice oil (Yusho) incident in Japan.

Topics: Adipose Tissue; Adult; Benzofurans; Environmental Exposure; Female; Humans; Japan; Male; Milk, Human; New York; Occupational Exposure; Polychlorinated Dibenzodioxins; Vietnam

During the past decade a considerable amount of data has been generated concerning polychlorinated dibenzodioxin (PCDD) and polychlorinated dibenzofuran (PCDF) levels in humans from many geographical locations. To organize these data in a useful fashion for environmental purposes and for consideration of human toxicity, selected portions of our data are presented in a somewhat atypical fashion, by percentage contribution of individual congeners to total PCDD/Fs in human tissue, and to the total dioxin equivalents (TEq). This is done to better characterize congener contributions from environmental contamination in various geographical regions at this time and health-related levels. To present the findings in a global perspective, data from widely different locations are presented including the United States, Germany, Vietnam, the former Soviet Union, Thailand, Cambodia, China, South Africa, and Guam.

Topics: Adipose Tissue; Adult; Benzofurans; Humans; Infant, Newborn; Milk, Human; Polychlorinated Dibenzodioxins

Polybrominated dibenzo-p-dioxins (PBDDs) and dibenzofurans (PBDFs) occur as trace (ppb) contaminants in brominated flame retardants and are produced during combustion of these chemicals. They are also formed when organics are incinerated in the presence of bromine, e.g., in municipal and industrial incinerators and in internal-combustion engines. Combustion of organics in the presence of both bromine and chlorine results in the formation of mixed (i.e., bromo, bromo/chloro and chloro) halogenated dibenzo-p-dioxins and dibenzofurans (HDDs and HDFs). There are 4600 potential mixed congeners. The biological effects of PBDDs and PBDFs are similar, if not identical, to those of PCDDs and PCDFs. Both groups of compounds induce hepatic aryl hydrocarbon hydroxylase (AHH) and ethoxyresorufin-o-deethylase (EROD) in rats and cause wasting and thymic atrophy in rats and guinea pigs. Tetrabrominated dinenzo-p-dioxin (TBDD) and dibenzofuran (TBDF) are reproductive toxins in mice and produce skin lesions in the rabbit-ear acnegenic test. The brominated compounds appear to bind to the same cytosolic receptors believed to mediate the toxicities of the chlorinated analogs. When compared on a molar-concentration basis, the brominated compounds are equipotent to the chlorinated analogs. TBDD is absorbed after oral, dermal, or intratracheal administration in rats, stored in the liver and adipose tissue, and eliminated in the feces through biliary excretion. The biological half-lives of the brominated compounds appear to be somewhat shorter than those of the corresponding chlorinated species. The brominated compounds, like their chlorinated congeners, have the potential to cause dermal, hepatic, and gastrointestinal toxicities in humans.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Benzofurans; Dioxins; Female; Humans; Male; Tissue Distribution

The experimental and theoretical data available concerning the gas- and particle-phase reactions of polychlorodibenzo-p-dioxins (PCDDs) and polychlorodibenzofurans (PCDFs) are discussed. These data lead to the expectation that the dominant tropospheric loss processes of gas-phase PCDDs and PCDFs will be photolysis and reaction with the OH radical, with the OH radical reaction being the most important for the less chlorinated species. The estimated tropospheric lifetimes of gas-phase PCDFs increase significantly more rapidly with the degree of chlorination than is the case for PCDDs. For particle-associated PCDDs and PCDFs, the dominant tropospheric removal processes are expected to be photolysis and wet and dry deposition, with wet and dry deposition of the host particles being the most important. The estimated lifetimes in the lower troposphere range from less than 1 day for dibenzo-p-dioxin, the mono-, di- and trichlorodibenzo-p-dioxins, dibenzofuran and the monochlorodibenzofurans present in the gas phase, to greater than or equal to 10 days for particle-associated PCDDs and PCDFs, with a general increase in the tropospheric lifetime with the degree of chlorination. While long-range transport of PCDDs is expected to occur for those PCDDs which are totally or mainly particle associated, gas- and particle-phase PCDFs containing four or more chlorine atoms are also expected to have sufficiently long tropospheric lifetimes to undergo long-range transport.

Topics: Air Pollutants; Atmosphere; Benzofurans; Dioxins; Drug Stability; Molecular Structure; Photolysis; Polychlorinated Dibenzodioxins; Polymers

Topics: Animals; Benzofurans; Dioxins; Humans; Risk Factors; Soil Pollutants; Water Pollutants, Chemical

Toxic polychlorinated dioxins and dibenzofurans have been identified in effluents and products from pulp and paper mills using chlorine bleaching. The amounts and levels depend on the bleaching technique used and the product quality. The same compounds have also been identified in sediment samples and aquatic organisms collected in the vicinity of pulp mills. The highest levels were found in hepatopancreas from crustaceans. Much higher levels of alkyl-substituted polychlorodibenzofurans have been found in sediment and sludge samples.

Topics: Animals; Benzofurans; Crustacea; Dioxins; Environmental Pollutants; Industry; Liver; Pancreas; Paper

Chloracne, an acneform eruption resulting from poisoning by halogenated aromatic compounds, has been a considerable problem over the last 40 years. The condition is always a symptom of systemic poisoning and should be familiar to all practitioners, particularly dermatologists. It is difficult to treat and can last for long periods without known additional exposure to chloracnegens. Some chloracnegens are capable of causing a variety of systemic signs and symptoms and may be oncogenic. Although there are probably fewer than 4,000 persons with chloracne worldwide, those found with the disorder should be evaluated medically on a regular basis and followed, if possible, throughout their lives.

Topics: 2,4-Dichlorophenoxyacetic Acid; 2,4,5-Trichlorophenoxyacetic Acid; Acne Vulgaris; Agent Orange; Aniline Compounds; Animals; Azo Compounds; Benzofurans; Biphenyl Compounds; Chemical Phenomena; Chemistry; Dibenzofurans, Polychlorinated; Dioxins; Drug Contamination; Halogens; Humans; Hydrocarbons, Chlorinated; Naphthalenes; Neoplasms; Polychlorinated Dibenzodioxins

Apple replant disease (ARD) is a severe soil-borne disease frequently observed in apple tree nurseries and orchards worldwide. One of the responses of apple trees to ARD is the formation of biphenyl and dibenzofuran phytoalexins in their roots. However, there is no information on whether or not these phytoalexins are exuded into the soil. To answer this open question, a model system was established using the ARD-sensitive apple rootstock M26 (Malus × domestica Borkh. Rosaceae) and GC-MS analysis in combination with an in-house GC-MS database including retention indices. We have detected a total of 35 phytoalexins, i.e. 10 biphenyls and 25 dibenzofurans in root samples, thereby adding eight compounds to the previously reported 27 phytoalexins of Malinae species. When in vitro cultured M26 plantlets were treated with yeast extract, all the 35 phytoalexins were formed in the roots and 85.2% of the total phytoalexin amount was exuded into the culture medium. In roots of M26 plants grown in ARD soil in pot, 26 phytoalexins were detected and their exudation was demonstrated using two independent approaches of collecting root exudates. In a modified dipping experiment and a soil-hydroponic hybrid setup, the exudation rate was 39.5% and 20.6%, respectively. The exudation rates for individual phytoalexins differed, indicating controlled exudation processes. The exuded phytoalexins may play an important role in shaping the soil microbiome, which appears to greatly influence the development and severity of ARD.

Topics: Benzofurans; Biphenyl Compounds; Dibenzofurans; Malus; Phytoalexins; Plant Roots; Sesquiterpenes; Soil

Five new compounds, eupatodibenzofuran A (

Topics: Acetophenones; Antineoplastic Agents, Phytogenic; Apoptosis; Benzofurans; Cell Proliferation; Chromones; Eupatorium; Humans; Molecular Structure; Neoplasms; Phytochemicals; Plant Extracts; Structure-Activity Relationship; Tumor Cells, Cultured

The formation of dibenzofuran (DF), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and environmentally persistent free radicals (EPFRs) from 1,2,3-trichlorobenzene (1,2,3-TrCBz) over metal oxide / silica surface were investigated using a tubular furnace. PCDD/Fs increased exponentially from 250 to 550 °C over copper oxide / silica surface and PCDD/Fs had the maximum growth from 400 to 450 °C. The ratio of PCDD / PCDF was much less than 1, especially when the temperature raised from 450 to 550 °C. Pentachlorianated dibenzo-p-furan (PeCDF) dominated among the homologues, which contributed 45-61% to the total PCDD/Fs. Two peaks of the yield of DF occurred at 400 °C and 500 °C respectively. Furthermore, the oxygen contents have different effects for PCDD and PCDF formation, and low oxygen could promote PCDD production, especially for tetrachlorinated dibenzo-p-dioxin (TCDD). More PCDF were formed on the oxygen rich condition, indicating that the oxygen promoted the chlorination of DF. Iron oxides are better than copper oxides to catalyze the formation of PCDD/Fs from 1,2,3-TrCBzs at 350 °C, especially for PCDF. The major EPFRs on the catalysts were formed with g values in the range of 2.0040 to 2.0049, which were phenoxy radicals and semiquinone occurred with higher g value of 2.0075 when the temperature increased to 550 °C, and more EPFRs were produced with the temperature increasing. The addition of iron oxides reduced the spins concentrations of oxygen-centered radicals but increase the spins concentrations of signals with lower g values. The different possible formation pathways of PCDD and PCDF from 1,2,3-TrCBz over metal oxide surface were also proposed.

Topics: Benzofurans; Chlorobenzenes; Dibenzofurans; Dibenzofurans, Polychlorinated; Free Radicals; Oxides; Polychlorinated Dibenzodioxins; Silicon Dioxide

BACKGROUND Osteosarcoma (OS) is a highly aggressive, metastatic bone tumor with a poor prognosis, and occurs more commonly in children and adolescents. Therefore, new drugs and treatments are urgently needed. In this study, we investigated the effect and potential mechanisms of C₁₈H₁₇NO₆ on osteosarcoma cells. MATERIAL AND METHODS Human MNNG osteosarcoma cells were treated with different concentrations of C₁₈H₁₇NO₆. The proliferation of the MNNG cells was examined via CCK-8 assay. Cell migration and invasion were tested via wound-healing assay and Transwell migration and invasion assays. ELISA was used to detect MMP-2, MMP-9, and VEGF secretion. Finally, Western blotting and qRT-PCR were used to detect protein and mRNA expressions, respectively. RESULTS C₁₈H₁₇NO₆ inhibited MNNG proliferation in a dose- and time-dependent manner and inhibited MMP-2, MMP-9, and VEGF secretion. C₁₈H₁₇NO₆ treatment significantly downregulated N-cadherin and Vimentin expression levels and upregulated E-cadherin expression levels in vitro and in vivo. C₁₈H₁₇NO₆ inhibited tumor growth in a MNNG xenograft. We also found that C₁₈H₁₇NO₆ can significantly reduce the phosphorylation of the PI3K/AKT signaling pathway in vivo and in vitro. However, 740Y-P (a PI3K agonist) had the opposite effect on proliferation, migration and invasion of MNNG cells treated with C₁₈H₁₇NO₆. LY294002 (a PI3K inhibitor) downregulated p-PI3K and p-AKT could mimic the inhibitory effect of C₁₈H₁₇NO₆. CONCLUSIONS Our results suggest that C₁₈H₁₇NO₆ can inhibit human MNNG osteosarcoma cell invasion and migration via the PI3K/AKT signaling pathway both in vivo and in vitro. C₁₈H₁₇NO₆ may be a highly effective and low-toxicity natural drug for the prevention or treatment of OS.

Topics: Animals; Apoptosis; Benzofurans; Cell Line, Tumor; Cell Movement; Cell Proliferation; Drugs, Chinese Herbal; Female; Humans; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Medicine, Chinese Traditional; Mice; Neoplasm Invasiveness; Osteosarcoma; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Signal Transduction; Usnea; Xenograft Model Antitumor Assays

Topics: Benzofurans; Carbazoles; Cyclopentanes; Free Radicals; Gases; Indoles; Kinetics; Models, Chemical; Models, Molecular; Molecular Structure; Polycyclic Aromatic Hydrocarbons; Thiophenes

Rhizosphere microorganisms play an important role in the interactions of many species in the rhizosphere, including soil nematodes. One hundred strains of rhizosphere actinomycetes were screened in vitro for their effects on the chemotactic behavior of the root-knot nematode, Meloidogyne incognita. Volatile compounds produced by the strain Streptomyces plicatus G demonstrated both strong attractant and repellent activities towards M. incognita. The compound dibenzofuran attracted M. incognita nematodes strongly, while compound benzothiazole repelled them. The chemotaxis of M. incognita was also tested under controlled conditions in pot experiments. Cultures of S. plicatus G and volatile dibenzofuran attracted M. incognita while volatile benzothiazole repelled them. The results showed that volatile compounds produced by rhizosphere actinomycetes could influence the chemotaxis of nematodes to a host. This study provides new information about the interrelationship between rhizosphere actinomycetes and nematodes that may be useful in preventing nematode parasitism of agricultural crops.

Topics: Actinobacteria; Animals; Benzofurans; Chemotaxis; Crops, Agricultural; Rhizosphere; Streptomyces; Tylenchoidea; Volatile Organic Compounds

Dibenzofuran (DBF) derivatives have caused serious environmental problems, especially those produced by paper pulp bleaching and incineration processes. Prominent for its resilient mutagenicity and toxicity, DBF poses a major challenge to human health. In the present study, a new strain of Pseudomonas aeruginosa, FA-HZ1, with high DBF-degrading activity was isolated and identified. The determined optimum conditions for cell growth of strain FA-HZ1 were a temperature of 30 °C, pH 5.0, rotation rate of 200 rpm and 0.1 mM DBF as a carbon source. The biochemical and physiological features as well as usage of different carbon sources by FA-HZ1 were studied. The new strain was positive for arginine double hydrolase, gelatinase and citric acid, while it was negative for urease and lysine decarboxylase. It could utilize citric acid as its sole carbon source, but was negative for indole and H

Topics: Bacterial Proteins; Benzofurans; Biodegradation, Environmental; Dioxygenases; Environmental Pollutants; Escherichia coli; Industrial Waste; Metabolic Networks and Pathways; Proteomics; Pseudomonas aeruginosa

An experimental protocol to achieve the Meerwein-Ponndorf-Verley (MPV) reduction of ketones under mildly basic conditions is reported. The transformation is tolerant of a range of ketone substrates, including

Topics: Benzofurans; Benzophenones; Catalysis; Heterocyclic Compounds; Ketones; Molecular Structure; Oxidation-Reduction; Stereoisomerism

Studies on the formation of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) during the electrolysis of sodium chloride solution (brine) using graphite or titanium electrodes were carried out at a laboratory scale. High concentrations of PCDFs but no PCDDs were formed in tests using graphite electrodes. With titanium electrodes, PCDFs were only formed when tar pitch was added and mainly originated from the dibenzofuran present in the tar. For the first time, a detailed assessment of the formation of mono- to octachlorinated PCDD/PCDF from tar pitch was investigated. The assessment included of the chlorination steps proved that PCDFs were formed by successive lateral chlorinated from dibenzofuran to MonoCDFs, DiCDFs, and TriCDFs to form the typical known "chlorine pattern" of TetraCDF to OctaCDF with a dominance of 1,2,7,8- and 2,3,7,8-TetraCDFs, 1,2,3,7,8-PentaCDF, and 1,2,3,4,7,8-HexaCDF as marker congeners. The final homologue distributions depended on reaction time and reaction temperature. In addition, electrolysis with non-chlorinated dibenzo-p-dioxins, dibenzofuran, and biphenyl was carried out. As a result, PCDDs, PCDFs, and PCB were formed at comparable yields. Congener patterns in soil samples from a PCDD/F-contaminated site where chlor-alkali electrolysis had been operated for decades in Japan had identical isomer distribution demonstrating the source and contamination potential and risk of these processes. Therefore, sites where in the past 120 years chlor-alkali electrolysis has been operated or where residues from chlor-alkali production or other chlorine using industries have been disposed should be assessed for their pollution level and exposure relevance. The assessment of total organohalogen content revealed that PCDF is only a small fraction of organohalogens in the contaminated soils. For an appropriate risk assessment, also other chlorinated aromatic compounds such as PCBs or PCNs need to be considered.

Topics: Alkalies; Benzofurans; Chlorine; Dibenzofurans, Polychlorinated; Environmental Pollution; Japan; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Soil Pollutants

Polychlorinated naphthalenes (PCNs) have been found widely in the aquatic environment and can be transferred through food chains, which can magnify or dilute their toxic effects on humans. In this study, PCNs were analyzed in samples of 17 species of fish with different dietary habits collected in the Bohai coastal area in China. Dichloronaphthalenes, which have rarely been quantified in previous studies, were determined. The total PCN concentrations were from 7.3 to 214 pg/g wet weight, and the highest concentration was found in ditrema. The trichloronaphthalenes were the most abundant PCNs, followed by the dichloronaphthalenes and pentachloronaphthalenes. The relatively high contributions of the less-chlorinated homologs to the total PCN concentrations indicated that the main PCN sources around the Bohai were industrial thermal process emissions rather than technical PCN formulations. The trophic magnification factors of the PCN homologs were from 3.1 to 9.9, indicating that PCNs were biomagnified by fish. The trophic magnification factor of dichloronaphthalene and trichloronaphthalenes was 5.8 and 6.4, respectively, indicating for the first time that dichloronaphthalene and trichloronaphthalenes can undergo trophic magnification by fish. The two highest trophic magnification factors were for the pentachloronaphthalenes and hexachloronaphthalenes, probably because these PCNs having fewer vicinal carbon atoms without chlorine atoms attached are less easily biotransformed than the other homologs. The dioxin-like toxicities of the PCNs in the samples, expressed as potential toxic equivalences (TEQs), were assessed. The highest total TEQ was 0.0090 pg/g ww, in Pacific herring, and the hexachloronaphthalenes were the dominant contributors to the total TEQs in the fish samples. The PCN TEQs were much lower than the polychlorinated dibenzo-p-dioxin and dibenzofuran and dioxin-like polychlorinated biphenyl TEQs found in fish from the Bohai in previous studies, and made marginal contributions to overall human exposure to dioxin-like TEQs, suggesting that PCNs pose no toxicological concerns.

Topics: Animals; Benzofurans; China; Dioxins; Fishes; Naphthalenes; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Seafood; Water Pollutants, Chemical

Herein described the design, synthesis and antitubercular evaluation of novel series of dibenzofuran, dibenzothiophene and N-methyl carbazole tethered 2-aminothiazoles and their cinnamamide analogs. One pot condensation of N-methyl carbazole, dibenzofuran and dibenzothiophene methyl ketones with thiourea in the presence of Iodine and CuO gave respective 2-aminothiazoles 4-6 in very good yields. Aminothiazoles were further coupled with substituted cinnamic acids using acid-amine coupling conditions to give desired cinnamamide analogs 8a-e, 9a-e and 10a-e. All the newly synthesized compounds were fully characterized by their NMR and mass spectral analysis. In vitro screening of new derivatives against Mycobacterium tuberculosis H37Rv (Mtb) resulted 8c, 10d and 10e (MIC: 0.78 µg/mL) and 2-aminothiazoles 5 and 6 (MIC: 1.56 µg/mL) as potent compounds with lower cytotoxicity profile.

Topics: Anti-Bacterial Agents; Benzofurans; Carbazoles; Cell Survival; Cinnamates; Dose-Response Relationship, Drug; HEK293 Cells; Humans; Microbial Sensitivity Tests; Molecular Structure; Mycobacterium tuberculosis; Structure-Activity Relationship; Thiazoles; Thiophenes

There is great concern about decreasing the amounts of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) that are formed and emitted during the chlorine bleaching of pulp. The formation of PCDD/Fs during non-woodpulp chlorine bleaching was investigated in the study described here. Wheat straw was separated into three components, cellulose, hemicellulose, and lignin. Chlorination experiments were performed, and lignin and hemicellulose contributed more than cellulose to PCDD/F formation when the pulp was bleached using chlorine. The chemical components of lignin were identified by gas chromatography mass spectrometry, and nine possible PCDD/F precursors were quantified by gas chromatography tandem mass spectrometry. Spiked chlorination experiments were performed to investigate the effects of these compounds on PCDD/F formation. 4-Ethyl-2-methoxyphenol had the strongest effect on PCDD/F formation, followed by p-chlorophenol, and guaiacol. All the test compounds promoted polychlorinated dibenzofuran formation but had limited effects on polychlorinated dibenzo-p-dioxin formation. The results allowed mechanisms for the formation of PCDD/Fs from phenol, chlorophenol, catechol, and guaiacol to be proposed.

Topics: Benzofurans; Bleaching Agents; Chlorine; Dibenzofurans, Polychlorinated; Polychlorinated Dibenzodioxins

Comamonas sp. JB was used to investigate the cometabolic degradation of dibenzofuran (DBF) and dibenzothiophene (DBT) with naphthalene as the primary substrate. Dehydrogenase and ATPase activity of the growing system with the presence of DBF and DBT were decreased when compared to only naphthalene in the growing system, indicating that the presence of DBF and DBT inhibited the metabolic activity of strain JB. The pathways and enzymes involved in the cometabolic degradation were tested. Examination of metabolites elucidated that strain JB cometabolically degraded DBF to 1,2-dihydroxydibenzofuran, subsequently to 2-hydroxy-4-(3'-oxo-3'H-benzofuran-2'-yliden)but-2-enoic acid, and finally to catechol. Meanwhile, strain JB cometabolically degraded DBT to 1,2-dihydroxydibenzothiophene and subsequently to the ring cleavage product. A series of naphthalene-degrading enzymes including naphthalene dioxygenase, 1,2-dihydroxynaphthalene dioxygenase, salicylaldehyde dehydrogenase, salicylate hydroxylase, and catechol 2,3-oxygenase have been detected, confirming that naphthalene was the real inducer of expression the degradation enzymes and metabolic pathways were controlled by naphthalene-degrading enzymes.

Topics: Benzofurans; Biotransformation; Catechols; Comamonas; Enzymes; Metabolic Networks and Pathways; Naphthalenes; Thiophenes

A series of symmetric polyoxygenated dibenzofurans with 2-methylbutyril moieties at C-4 and C-6 were obtained from commercial phloroglucinol through a sequence of reactions that include monoacylation, iodination, Suzuki-Miyaura coupling, oxidative dimerization and cyclization. Some of the compounds obtained were active against Gram-positive bacteria, including multiresistant Staphylococcus aureus clinical isolates. The dibenzofuran 28 with propyl chains at C-2 and C-8 exhibited the best antibacterial activity with values comparable to those of the natural dibenzofuran achyrofuran. From the obtained results some structure-activity relationships were outlined.

Topics: Anti-Bacterial Agents; Benzofurans; Dose-Response Relationship, Drug; Enterococcus faecalis; Microbial Sensitivity Tests; Molecular Structure; Staphylococcus aureus; Structure-Activity Relationship

(+)-Usnic acid ((R)-2,6-diacetyl-7,9-dihydroxy-8,9b-dimethyl-1,3(2H,9bH)-dibenzo-furandione), a dibenzofuran isolated from the lichen Usnea longissima, has been chemically transformed to synthesize a series of sixteen novel triazole analogs by click chemistry approach. The synthesized compounds were tested for their anti-inflammatory potential against the cytokines TNF-[Formula: see text] and IL-1[Formula: see text] in U937 cell lines. The bromo enamines (2a, 2b), azido enamines (3a, 3b) and triazole analogs (4f, 4g, 4h, 5f, 5g and 5h) exhibited promising anti-inflammatory activity against TNF-[Formula: see text] with [Formula: see text] values ranging from 1.40 to 5.70 [Formula: see text]M. Most significantly, the [Formula: see text] values of compounds 5f (1.40 [Formula: see text]M) and 5h (1.88 [Formula: see text]M) are the lowest among the compounds tested and found close to that of standard prednisolone. Hence, these two compounds can be considered as lead molecules for further fine tuning to make highly potent anti-inflammatory therapeutic agents.

Topics: Anti-Inflammatory Agents; Benzofurans; Click Chemistry; Humans; Interleukin-1beta; Triazoles; Tumor Necrosis Factor-alpha; U937 Cells; Usnea

(+)-Usnic acid (1) is a common bioactive lichen-derived secondary metabolite with a characteristic dibenzofuran scaffold. It displayed low micromolar antiproliferative activity levels and, notably, induced autophagy in a panel of diverse breast cancer cell lines, suggesting the mechanistic (formerly "mammalian") target of rapamycin (mTOR) as a potential macromolecular target. The cellular autophagic markers were significantly upregulated due to the inhibition of mTOR downstream effectors. Additionally, 1 showed an optimal binding pose at the mTOR kinase pocket aided by multiple interactions to critical amino acids. Rationally designed benzylidene analogues of 1 displayed excellent fitting into a targeted deep hydrophobic pocket at the core of the kinase cleft, through stacking with the phenolic side chain of the Tyr2225 residue. Several potent analogues were generated, including 52, that exhibited potent (nM concentrations) antiproliferative, antimigratory, and anti-invasive activities against cells from multiple breast cancer clonal lines, without affecting the nontumorigenic MCF-10A mammary epithelial cells. Analogue 52 also exhibited potent mTOR inhibition and autophagy induction. Furthermore, 52 showed potent in vivo antitumor activity in two athymic nude mice breast cancer xenograft models. Collectively, usnic acid and analogues are potential lead mTOR inhibitors appropriate for future use to control breast malignancies.

Topics: Animals; Apoptosis; Autophagy; Benzofurans; Benzylidene Compounds; Breast Neoplasms; Cell Proliferation; Crystallography, X-Ray; Disease Models, Animal; Female; Humans; Lichens; Mice; Mice, Nude; Models, Molecular; Molecular Conformation; Molecular Structure; Protein Kinase Inhibitors; Sirolimus; TOR Serine-Threonine Kinases; Xenograft Model Antitumor Assays

Dioxin-like compounds of varying toxicities are found in complex mixtures. The toxic equivalency factor (TEF) approach was developed based on the potency of a dioxin-like compound relative to the potency of 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD) to streamline risk assessment. One limitation of the TEF approach is uncertainty regarding differences in the relative potency of dioxin-like compounds among different species. Relative potencies among fishes are limited, relative to relative potencies among birds and mammals, and TEFs for fishes are based entirely on the model species, rainbow trout (Oncorhynchus mykiss). An in vitro liver explant assay was used to characterize species-specific responses with regard to up-regulation of CYP1A transcript after exposure to 6 dioxin-like compounds in rainbow trout, white sturgeon (Acipenser transmontanus), lake sturgeon (Acipenser fulvescens), and northern pike (Esox lucius). Differences in sensitivities were observed among species after exposure to dioxin-like compounds. The relative potencies developed from liver explants of rainbow trout were comparable to relative potencies developed from embryo toxicity assays. Differences in relative potencies between species with the least and greatest relative potencies were up to 40-fold. To compare relative potencies among species, concentrations of dioxin-like compounds in fish eggs in the Fraser River and in Lake Ontario were used to calculate toxic equivalency quotients (TEQs) determined from TEFs or TCDD equivalents determined from relative potencies. The TEQs underestimated TCDD equivalents for white sturgeon, lake sturgeon, and northern pike, indicating uncertainty in application of TEFs to diverse fishes.

Topics: Animal Testing Alternatives; Animals; Benzofurans; Cytochrome P-450 CYP1A1; Dioxins; Esocidae; Fishes; In Vitro Techniques; Oncorhynchus mykiss; Polychlorinated Biphenyls; Risk Assessment; Rivers; Species Specificity; Water Pollutants, Chemical

The formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) was explored during de novo tests designed to compare the catalytic activity of copper (II) chloride (CuCl2) with that of iron (III) oxide (Fe2O3) and to test some synergistic effect between these two catalytic compounds. Both copper chloride (CuCl2) and iron oxide (Fe2O3) were earlier proposed as catalysts to explain the PCDD/F emissions from, e.g. municipal solid waste incineration (MSWI). In addition, haematite (Fe2O3) is the main iron ore and could be responsible for the typical iron ore sintering plant fingerprint. A total of nine model fly ash (MFA) samples were prepared by mixing and grinding of sodium chloride (NaCl), activated carbon and a powder matrix of silica (SiO2) with the selected metal compound(s). The conditions of these de novo tests were 1 h in duration, 350 °C in a flow of synthetic combustion gas (10 vol.% oxygen in nitrogen). The effect of Fe-Cu catalyst concentration on yield and distribution pattern of PCDD/F was systematically explored; three strongly differing ratios of [Fe]:[Cu] were considered (1:1, 10:1 and 100:1) to study the potential interactions of Fe2O3 and CuCl2 suggested earlier. The results show some slight rise of PCDD/F formed with raising iron concentration from 0 to 10.1 wt% (no Cu added; 0.1 wt% Cu), as well as strong surging of both amount and average chlorination level of PCDD/F when rising amounts of copper (0 to 1.1 wt%) are introduced. The resulting fingerprints are compared with those from sintering and from MSWI.

Topics: Benzofurans; Catalysis; Coal Ash; Copper; Dioxins; Ferric Compounds; Incineration; Polychlorinated Dibenzodioxins

In the present paper, a novel series of dibenzofuran-piperazine derivatives were synthesized via the treatment of N-(2-methoxy-3-dibenzofuranyl)-2-chloroacetamide with substituted piperazine derivatives. The chemical structures of the compounds were elucidated by (1)H NMR, (13)C NMR, mass spectral data; elemental analysis and HPLC analysis. Each derivative was evaluated for antiplatelet activity and anticholinesterase activity. Compound 2 m with 2-furoyl moiety exhibited high percentage inhibition as much as standard drug aspirin on arachidonic acid (AA)-induced platelet aggregation. None of the compounds presented significant inhibitor effect on collagen-induced platelet aggregation. Furthermore, the anticholinesterase activity of the compounds was determined and they did not show promising inhibitor activity compared with standard drug donepezil.

Topics: Benzofurans; Piperazine; Piperazines; Platelet Aggregation Inhibitors

Levels and profiles of polychlorinated dibenzo-p-dioxin and dibenzofurans (PCDD/Fs) were analyzed for the first time in raw and treated water from five water treatment plants in Shenzhen, South China. The average PCDD/Fs concentrations were 32.93 pg/L (0.057 pg international toxic equivalent quantity (I-TEQ)/L) and 0.64 pg/L (0.021 pg I-TEQ/L) in raw and treated water, respectively. The removal rate of PCDD/Fs in terms of mass concentration varied from 93.4% to 98.8%, whereas a negative removal rate was observed in one plant in terms of TEQ concentration. The PCDD/Fs concentration in raw water was lower than most of the published data from other countries and regions, and the PCDD/Fs concentration in treated water was below the Maximum Contaminants Level (MCL) of 30 pg/L for dioxin in drinking water set by the US EPA. Historical pentachlorophenol usage, local waste incineration and industrial emissions, as well as surface runoff or even soil erosion, might be the main sources for PCDD/F pollution in water. The daily intake of PCDD/Fs for local residents from drinking water was estimated to be 0.69 fg I-TEQ/kg/day, which is negligible compared with that from food consumption (1.23 pg WHO-TEQ/kg/day) in the local area.

Topics: Benzofurans; China; Dibenzofurans, Polychlorinated; Dioxins; Drinking Water; Environmental Monitoring; Fresh Water; Polychlorinated Dibenzodioxins; Water Pollutants, Chemical; Water Purification

Polybrominated dibenzofurans (PBDFs) are a class of highly toxic environmental contaminants which comprises 135 structurally different congeners. While the gas chromatographic separation and analysis of the most polychlorinated dibenzofurans (PCDFs) are well-documented, comparably little data is currently available in the case of PBDFs. In this study dibenzofuran was brominated to give a mixture of ∼40 PBDFs with one to seven bromine atoms. This synthesis mixture was fractionated by both countercurrent chromatography (CCC) with the solvent system n-hexane/toluene/acetonitrile and non-aqueous reversed-phase high performance liquid chromatography (RP-HPLC) with acetonitrile as the mobile phase. All together 80 consecutive CCC fractions and 40 HPLC fractions were taken and analyzed for PBDFs by gas chromatography coupled to mass spectrometry (GC/MS). CCC and RP-HPLC offered orthogonal separation of the PBDF mixture. As a consequence, selected CCC fractions were further fractionated by RP-HPLC. In this way, eight PBDFs could be isolated and the structures of twelve PBDFs were elucidated by proton magnetic resonance spectroscopy ((1)H NMR).

Topics: Benzofurans; Chemical Fractionation; Chromatography, High Pressure Liquid; Countercurrent Distribution; Dibenzofurans, Polychlorinated; Environmental Monitoring; Environmental Pollutants; Gas Chromatography-Mass Spectrometry; Hexanes; Solvents; Toluene

Co-processing municipal solid waste incinerator (MSWI) fly ash in cement kilns is challenging because the unintentional production of persistent organic pollutants (POPs) during the process is not well understood. The distributions, profiles and formation mechanisms of polychlorinated naphthalenes (PCNs) as new POPs covered under Stockholm Convention in two cement kilns co-processing MSWI fly ash were studied. The average concentrations of PCNs in stack gas samples were 710 ng m(-3). The PCN concentration in particle samples collected from different process stages in the cement kilns ranged from 1.1 to 84.7 ng g(-1). Three process sites including suspension pre-heater boiler, humidifier tower, and the kiln back-end bag filter were identified to be the major formation sites of PCNs in cement kilns co-processing MSWI fly ash. The PCN distribution patterns were similar to that of polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/Fs), which indicates the possibility for simultaneous control of PCNs and PCDD/Fs in cement kilns co-processing fly ash. Chlorination was suggested to be an important formation mechanism of PCNs, and chlorination pathways of PCN congeners are proposed based on the congener profiles. Thermodynamic calculations, including relative thermal energies (ΔE) and standard free energy of formation (ΔG), and the charge densities of the carbon atoms in PCN supported the proposed chlorination mechanisms for PCN formation. The results presented in this study might provide helpful information for developing techniques and strategies to control PCN emissions during cement kilns co-processing MSWI fly ash.

Topics: Benzofurans; Carbon; Coal Ash; Dioxins; Environmental Monitoring; Hazardous Substances; Incineration; Naphthalenes; Polychlorinated Dibenzodioxins; Solid Waste; Waste Products

Magnetically immobilized cells of Comamonas sp. JB coupling with electrode reaction was developed to enhance the treatment efficiency of coking wastewater containing phenol, carbazole (CA), dibenzofuran (DBF), and dibenzothiophene (DBT). The pair of graphite plate-stainless iron mesh electrodes was chosen as the most suitable electrodes. Magnetically immobilized cells coupling with graphite plate-stainless iron mesh electrodes (coupling system) exhibited high degradation activity for all the compounds, which were significantly higher than the sum by single magnetically immobilized cells and electrode reaction at the optimal voltage. Recycling experiments demonstrated that the degradation activity of coupling system increased gradually during eight recycles, indicating that there was a coupling effect between the biodegradation and electrode reaction. Phenol hydroxylase and qPCR assays confirmed that appropriate electrical stimulation could improve phenol hydroxylase activity and promote cells growth. Toxicity assessment suggested the treatment of the coking wastewater by coupling system led to less toxicity than untreated wastewater.

Topics: Benzofurans; Biodegradation, Environmental; Carbazoles; Cells, Immobilized; Coke; Comamonas; Electrodes; Graphite; Iron; Magnetics; Mixed Function Oxygenases; Phenol; Thiophenes; Waste Disposal, Fluid; Wastewater

A series of novel dibenzofuran tethered thiazolyl-1,2,3-triazolyl acetamides, designed by assembling antitubercular pharmacophoric fragments, dibenzofuran, 2-aminothiazole and substituted triazoles in one molecular architecture, were evaluated against Mycobacterium tuberculosis. The new analogues 6a-p accomplished in four step synthetic sequence utilizing click chemistry in the penultimate step, was fully characterized by their NMR and mass spectral data. Among the compounds 6a-p screened for in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv, three compounds 6j (MIC: 1.56μg/mL); 6a and 6p (MIC: 3.13μg/mL) was found to be most active and exhibited lower cytotoxicity. Among these three, 6j could be a candidate to consider as a drug like hit analogue for further development.

Topics: Acetamides; Animals; Antitubercular Agents; Benzofurans; Cell Proliferation; Click Chemistry; Dose-Response Relationship, Drug; Mice; Microbial Sensitivity Tests; Molecular Structure; Mycobacterium tuberculosis; RAW 264.7 Cells; Structure-Activity Relationship

The efficacy of inoculation of single pure bacterial cultures into complex microbiomes, for example, in order to achieve increased pollutant degradation rates in contaminated material (that is, bioaugmentation), has been frustrated by insufficient knowledge on the behaviour of the inoculated bacteria under the specific abiotic and biotic boundary conditions. Here we present a comprehensive analysis of genome-wide gene expression of the bacterium Sphingomonas wittichii RW1 in contaminated non-sterile sand, compared with regular suspended batch growth in liquid culture. RW1 is a well-known bacterium capable of mineralizing dibenzodioxins and dibenzofurans. We tested the reactions of the cells both during the immediate transition phase from liquid culture to sand with or without dibenzofuran, as well as during growth and stationary phase in sand. Cells during transition show stationary phase characteristics, evidence for stress and for nutrient scavenging, and adjust their primary metabolism if they were not precultured on the same contaminant as found in the soil. Cells growing and surviving in sand degrade dibenzofuran but display a very different transcriptome signature as in liquid or in liquid culture exposed to chemicals inducing drought stress, and we obtain evidence for numerous 'soil-specific' expressed genes. Studies focusing on inoculation efficacy should test behaviour under conditions as closely as possible mimicking the intended microbiome conditions.

Topics: Benzofurans; Biodegradation, Environmental; Cell Survival; Environmental Pollutants; Gene Expression Profiling; Genome, Bacterial; Humans; RNA, Bacterial; Soil Microbiology; Sphingomonas; Transcriptome

A high-throughput analytical method has been developed for the determination of seventeen 2,3,7,8-substituted congeners of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in aqueous samples. A recently introduced octadecyl (C18) disk for semi-automated solid-phase extraction of PCDD/Fs in water samples with a high level of particulate material has been tested for the analysis of dioxins. A new type of C18 disk specially designed for the analysis of hexane extractable material (HEM), but never previously reported for use in PCDD/Fs analysis. This kind of disk allows a higher filtration flow, and therefore the time of analysis is reduced. The solid-phase extraction technique is used to change samples from liquid to solid, and therefore pressurized liquid extraction (PLE) can be used in the pre-treatment. In order to achieve efficient purification, extracts from the PLE are purified using an automated Power-prep system with disposable silica, alumina, and carbon columns. Quantitative analyses of PCDD/Fs were performed by GC-HRMS using multi-ion detection (MID) mode. The method was successfully applied to the analysis of water samples from the wastewater treatment system of a vinyl chloride monomer plant. The entire procedure is in agreement with EPA1613 recommendations regarding the blank control, MDLs (method detection limits), accuracy, and precision. The high-throughput method not only meets the requirements of international standards, but also shortens the required analysis time from 2 weeks to 3d.

Topics: Benzofurans; Chemical Industry; High-Throughput Screening Assays; Industrial Waste; Liquid-Liquid Extraction; Polychlorinated Dibenzodioxins; Solid Phase Extraction; Wastewater; Water Pollutants, Chemical

Decades after phasing out their production and use, especially in the formulations of brominated flame retardants (BFRs), polybrominated biphenyls (PBBs) still pose serious environmental and health problems. The oxidation of PBB has been hypothesised as a pathway for the formation of the notorious polybrominated dibenzofurans (PBDFs) and their dispersion in the environment. However, the exact reaction corridor remains misunderstood, with the existing mechanisms predicting the reaction to proceed via a high energy process that involves the breakage of C-C linkage (∼118.0 kcal mol(-1)) and the subsequent formation of bromophenols molecules, where the latter are supposed to act as precursors for the formation of PBDFs (∼40.0-60.0 kcal mol(-1)). Herein, we show that PBBs produce PBDFs in a facile mechanism through a series of highly exothermic reactions (i.e., overall barriers reside 8.2-10.0 kcal mol(-1) below the entrance channel). Whilst the fate of the ROO-type intermediates in oxidation of all aromatics is to emit CO or CO2, PBDFs constitute the dominant products from the oxidation of PBBs. Initially formed R-OO adduct evolves in a very exoergic mechanism to yield PBDFs. In view of the facile oxidative transformation of PBBs into PBDFs, we conclude that, it is unsafe to dispose BFRs in oxidation processes, as this practice generates high yields of toxic PBDFs.

Topics: Benzofurans; Environmental Pollutants; Flame Retardants; Kinetics; Molecular Structure; Oxidation-Reduction; Polybrominated Biphenyls

This study was launched to establish comprehensive environmental monitoring on the levels and patterns of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and polycyclic aromatic hydrocarbons (PAHs) both in soil and ambient air around a thermal desorption plant in China. All 209 congeners of PCBs, 136 congeners of PCDD/Fs (P = 4 to 8) and 16 EPA priority PAHs were analyzed. The concentration of PCBs ranged from 20.0 to 536 ng g(-1) (or 0.077-5.27 pg WHO-TEQ g(-1)) in soil and from 972 to 991 ng Nm(-3) (or 0.245-0.374 pg WHO-TEQ Nm(-3)) in air samples, much higher than the levels in cities. A single soil sampling point could have been affected by some transfer of PCBs from the untreated soil by the fingerprint characteristics and the statistical analysis. Establishing blank values prior to the start-up of new plant is a safe and sure method to establish subsequent impacts on the environment. During the treatment of hazardous waste, strict control of all waste materials and all emissions is required.

Topics: Air Pollutants; Benzofurans; China; Dioxins; Environmental Monitoring; Environmental Pollution; Polychlorinated Biphenyls; Polycyclic Aromatic Hydrocarbons; Soil; Soil Pollutants

We present, in this study, mechanistic and kinetic accounts of the formation of dibenzofuran (DF), dibenzo-p-dioxin (DD) and their hydroxylated derivatives (OHs-DF/OHs-DD) from the catechol (CT) molecule, as a model compound for phenolic constituents in biomass. Self-condensation of two CT molecules produces predominantly a DD molecule via open- and closed-shell corridors. Coupling modes involving the o-semiquinone radical and the CT molecule (o-SQ/CT) generate two direct structural blocks for the formation of OHs-DF/OHs-DD structures, ether-type intermediates and di-keto moieties. The calculated reaction rate constants indicate that the fate of ether-type intermediates is to make hydroxylated diphenyl ethers rather than to undergo cyclisation reactions leading to the formation of preDF structures. Unimolecular loss of a H or OH moiety from a pivotal carbon in these hydroxylated diphenyl ethers then produces hydroxylated and non-hydroxylated DD molecules. Formation of OHs-DF initiated by o(C)-o(C) cross-linkages involving o-SQ/o-SQ and o-SQ/CT reactions incurs very similar reaction and activation enthalpies encountered in the formation of chlorinated DFs from chlorophenols.

Topics: Benzofurans; Catechols; Dioxins; Hydroxylation; Molecular Structure

A major part of sheep livers contains levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) above the former but to some extent also the new maximum levels (MLs) in the EU. In order to investigate the relationship between the intake of these contaminants and their accumulation in livers, kidney fat and meat, young blackhead sheep were fed with grass pellets containing PCDD/Fs at 2.5 times the maximum level. Levels of PCDD/Fs in livers were already quite high at the start of the exposure but increased 3-fold within 56d, exceeding the new product based MLs. Levels in meat and fat also increased but did not exceed the MLs. Although less elevated in the grass, both dl- and ndl-PCB levels also increased in liver and fat. Their kinetics in the tissues was less clear, potentially caused by increased levels in the straw given to the sheep during the whole experimental period. There was a clear difference in the behavior of the various congeners, the PCDFs and especially the higher chlorinated PCDFs and PCDDs showing a higher accumulation in the liver. In the case of the PCBs, this was particularly true for PCB 126. When switched to clean grass after 56d, the levels in livers and other tissues decreased to about the levels in the control sheep within 56d. This offers a potential solution for decreasing the intake of consumers.

Topics: Animal Feed; Animals; Benzofurans; Dioxins; Kidney; Liver; Muscle, Skeletal; Netherlands; Organ Size; Poaceae; Polychlorinated Biphenyls; Sheep; Tissue Distribution

In this study the occurrence of polychlorinated biphenyls (PCBs), polychlorinated dibenzodioxins and polychlorinated dibenzofurans (PCDDs/PCDFs) in street dust samples was investigated using pressurized liquid extraction and gas chromatography coupled to mass spectrometry. Street dust samples were taken from rural, urban, industrial and industrially influenced urban areas. PCB6 concentrations ranged from 5090±2200 μg/kg (average±standard error of mean) in dusts from industrial premises to 29±8.7 μg/kg in rural areas. Concentration ranges were for dioxin-like PCB toxicity equivalents (dl-PCB TEQ) from 362±164 ng/kg (industrial premises) to 6.5±1.8 ng/kg (rural areas), and for PCDD/PCDF TEQ from 503±448 ng/kg to 2.4±0.13 ng/kg, respectively. Area concentrations of PCB6 (0.040 μg/m2-22 μg/m2), dl-PCB TEQ (0.0038 ng/m2-2.6 ng/m2) and PCDD/PCDF TEQs (14 pg/m2-1980 pg/m2) were estimated. Furthermore, particle size related concentrations of PCBs and PCDD/PCDFs in street dusts were analysed showing throughout almost all samples a distinctive trend of increasing concentrations with decreasing particle sizes. Characterization of homologue patterns of PCBs and PCDDs/PCDFs in street dusts was performed showing a dependence of homologue patterns on different area types, especially for PCBs. It could be demonstrated that the analysis of concentrations in combination with specific homologue patterns of PCBs and PCDDs/PCDFs in street dust samples enables allocation of potential emission sources.

Topics: Air Pollutants; Benzofurans; Dioxins; Dust; Environmental Monitoring; Germany; Polychlorinated Biphenyls

We compared polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) concentrations [expressed as toxic equivalent quantities (TEQs)] in agricultural soil samples from Chongming Island (Shanghai, China) determined using two analytical approaches, an enzyme-linked immunoassay (EIA) method and a high resolution gas chromatography-high resolution mass spectrometry (HRGC/HRMS) method. The PCDD/F concentrations in all 31 soil samples were at background levels (7.30-16.7 pg EIA-TEQ/g from the EIA analysis and 0.526-1.99 pg WHO-TEQ/g from the HRGC/HRMS analysis). Although, the EIA method overestimated the PCDD/F concentrations compared with the concentrations determined using the HRGC/HRMS method. The absence of false-negatives showed by the EIA analysis verified that this method is useful for preliminary sample screening (prior to HRGC/HRMS analysis) and the preliminary characterization of potentially contaminated sites.

Topics: Agriculture; Benzofurans; China; Dioxins; Environmental Monitoring; Gas Chromatography-Mass Spectrometry; Islands; Soil

In order to better understand the fate and activity of bacteria introduced into contaminated material for the purpose of enhancing biodegradation rates, we constructed Sphingomonas wittichii RW1 variants with gene reporters interrogating dibenzofuran metabolic activity. Three potential promoters from the dibenzofuran metabolic network were selected and fused to the gene for enhanced green fluorescent protein (EGFP). The stability of the resulting genetic constructions in RW1 was examined, with plasmids based on the broad-host range vector pME6012 being the most reliable. One of the selected promoters, upstream of the gene Swit_4925 for a putative 2-hydroxy-2,4-pentadienoate hydratase, was inducible by growth on dibenzofuran. Sphingomonas wittichii RW1 equipped with the Swit_4925 promoter egfp fusion grew in a variety of non-sterile sandy microcosms contaminated with dibenzofuran and material from a former gasification site. The strain also grew in microcosms without added dibenzofuran but to a very limited extent, and EGFP expression indicated the formation of consistent small subpopulations of cells with an active inferred dibenzofuran metabolic network. Evidence was obtained for competition for dibenzofuran metabolites scavenged by resident bacteria in the gasification site material, which resulted in a more rapid decline of the RW1 population. Our results show the importance of low inoculation densities in order to observe the population development of the introduced bacteria and further illustrate that the limited availability of unique carbon substrate may be the most important factor impinging growth.

Topics: Benzofurans; Biotransformation; Environmental Microbiology; Genes, Reporter; Green Fluorescent Proteins; Metabolic Networks and Pathways; Promoter Regions, Genetic; Soil Pollutants; Sphingomonas

Many studies involving polychlorinated dibenzo-p-dioxins and dibenzofurans (Cl4-Cl8) are limited to the 17 2,3,7,8-substituted congeners, which are used for the computation of the toxic equivalent concentration (TEQ) and often are the basis for regulatory actions. The values determined for total homolog groups may also be reported in some cases, e.g., Total Tetra-Dioxins, and such results provide some additional information but do not reveal the subtle details that can be derived from the study of individual congeners. There are 136 possible structures for tetra- through octa-chlorinated dibenzo-p-dioxins and dibenzofurans, including the 17 2,3,7,8-substituted congeners. In this work, the valuable role that inclusion of the other 119 congeners plays in understanding emission deviations (upsets) compared to normal operating conditions for a secondary aluminum smelter facility is illustrated. An exponential correlation was observed between the concentrations of specific non-2,3,7,8-substituted tetrachlorinated congeners (e.g., 2,3,6,7/3,4,6,7-TCDFs vs. 1,3,6,8-TCDD and 1,3,7,9-TCDD) and the TEQ-based emissions at the outlet of a baghouse pollution control device. The correlation possibly points to the additional and occasionally essential role played by metal-catalyzed stereoselective chlorination reactions taking place during the melting-purification process, as well as (conceivably) inside the air pollution control device. This chlorination in turn highlights not only the importance of the chlorine addition step and the kinetics involved with regard to regulating emission levels but also the role of measuring all 136 PCDD/F congeners.

Topics: Air Pollutants; Air Pollution; Benzofurans; Environmental Monitoring; Halogenation; Kinetics; Metallurgy; Polychlorinated Dibenzodioxins; Temperature

Are the levels of biologically active and the most toxic dioxin-like substances in adipose tissue of patients with deep infiltrating endometriosis (DIE) higher than in a control group without endometriosis?. DIE patients have higher levels of dioxins and polychlorinated biphenyls (PCBs) in adipose tissue compared with controls without endometriosis.. Some studies have investigated the levels of dioxin-like substances, in serum samples, in patients with endometriosis, with inconsistent results.. Case-control study including two groups of patients. The study group (DIE group) consisted of 30 patients undergoing laparoscopic surgery because of DIE. In all patients, an extensive preoperative work-up was performed including clinical exploration, magnetic resonance imaging (MRI) and transvaginal sonography. All patients with DIE underwent a confirmatory histological study for DIE after surgery. The non-endometriosis control group (control group), included the next consecutive patient undergoing laparoscopic surgery in our center due to adnexal benign gynecological disease (ovarian or tubal procedures other than endometriosis) after each DIE patient, and who did not present any type of endometriosis.. During the surgical procedure 1-2 g of adipose tissue from the omentum were obtained. Dioxin-like substances were analyzed in adipose tissue in DIE patients and controls without endometriosis.. The total toxic equivalence and concentrations of both dioxins and PCBs were significantly higher in patients with DIE in comparison with the control group (P < 0.05), mainly due to the significantly higher values of the two most toxic dioxins (2,3,7,8-tetrachlorodibenzo-p-dioxin [2,3,7,8-TCDD] and 1,2,3,7,8-pentachlorodibenzo-p-dioxin [1,2,3,7,8-PeCDD]) (P < 0.01 for each compound). The levels of furan 2,3,4,7,8-PeCDF were statistically higher in the DIE group compared with controls. Only four congeners of PCBs had toxic equivalence values and concentrations that were statistically higher in patients with DIE, but these included the most toxic and carcinogenic PCB-126 (PCB-114 P < 0.05; PCB-156 P < 0.05; PCB-189 P = 0.04; PCB-126 P < 0.01).. Since few patients were recruited, the study is only exploratory. Our results need to be confirmed in larger and more heterogeneous population studies since environmental and even genetic factors involved in determining dioxins and PCBs widely vary in different countries. Furthermore, the strict eligibility criteria used may preclude generalization of the results to other populations and the surgery-based sampling frame may induce a selection bias. Finally, adipose tissue was obtained only from the omentum, and not from other adipose tissue of the body.. Our results suggest a potential role of dioxin-like substances in the pathogenesis of DIE. Further studies are warranted to confirm our findings.. None.. Not applicable.

Topics: Adipose Tissue; Adolescent; Adult; Benzofurans; Body Mass Index; Case-Control Studies; Dioxins; Endometriosis; Female; Humans; Laparoscopy; Limit of Detection; Magnetic Resonance Imaging; Polychlorinated Biphenyls; Ultrasonography; Vagina; Young Adult

We carried out molecular orbital theory calculations for the homogeneous gas-phase formation of dibenzofuran from phenanthrene, fluorene, 9-methylfluorene and 9-fluorenone. Dibenzofuran will be formed if ∙OH adds to C8a, and the order of reactivity follows as 9-fluorenone > 9-methylfluorene > fluorene > phenanthrene. The oxidations initiated by ClO∙ are more favorable processes, considering that the standard reaction Gibbs energies are at least 21.63 kcal/mol lower than those of the equivalent reactions initiated by ∙OH. The adding of ∙OH and then O2 to phenanthrene is a more favorable route than adding ∙OH to C8a of phenanthrene, when considering the greater reaction extent. The reaction channel from fluorene and O2 to 9-fluorenone and H2O seems very important, not only because it contains only three elementary reactions, but because the standard reaction Gibbs energies are lower than -80.07 kcal/mol.

Topics: Benzofurans; Fluorenes; Gases; Hydroxyl Radical; Oxidation-Reduction; Phenanthrenes; Quantum Theory; Thermodynamics

The formation and environmental release of highly toxic organohalogen compounds associated with informal recycling of waste electric and electronic equipment (e-waste) is a growing problem at e-waste dumps/recycling sites (EWRSs) in many developing countries worldwide. We chose a cross-sectional study design to measure the internal exposure to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) as well as polychlorinated biphenyls (PCBs) of individuals working on one of the largest EWRSs of Africa, located at Agbogbloshie, Accra, Ghana, and in controls from a suburb of Accra without direct exposure to EWRS activities. In whole blood samples of 21 age matched male exposed individuals (mean age: 24.7 years, SD 6.0) and 21 male controls (mean age: 24.4 years, SD 5.7) 17 PCDD/F congeners were determined. Moreover three indicator PCB congeners (#138, #153 and #180) were measured in blood of 39 exposed (mean age: 27.5 years, SD 11.7) and 19 non-exposed (mean age: 26.8 years, SD 9.7) patients. Besides a health examination, biometric and demographic data, residential and occupational history, occupational exposures and working conditions were recorded using a standardized questionnaire. In the exposed group, median PCDD/F-concentrations were 6.18 pg/g lipid base WHO2005-TEq (range: 2.1-42.7) and significantly higher compared to the control group with 4.60 pg/g lipid base WHO2005-TEq (range: 1.6-11.6). Concentrations were different for 2,3,7,8-TetraCDD, three HexaCDD and all 10 PCDF congeners, indicating a combustion pattern. Using a multivariate regression analysis exposure to EWRS activities was the most important determinant for PCDD/F exposure. Median PCB levels for the indicator congeners #138, #153 and #180 were 0.011, 0.019 and 0.008 μg/l whole blood (ranges: 0.002-0.18, 0.003-0.16, 0.002-0.078) in the exposed group and, surprisingly, significantly higher in the controls (0.037, 0.062 and 0.022; ranges: 0.005-0.46, 0.010-0.46, 0.004-0.21). In a multivariate regression approach e-waste related activities had no positive influence on internal PCB exposure, but rather the time living in Accra. The internal PCB exposure is in particular notable for a country where PCBs have historically never been produced or used. The impact of EWRS activities on organohalogen compound exposure of individuals working at and living in the surroundings of the Agbogbloshie EWRS, and the surprisingly high PCB exposure of people living in Accra not involved in e-waste act

Topics: Adult; Benzofurans; Biphenyl Compounds; Case-Control Studies; Cross-Sectional Studies; Dioxins; Electronic Waste; Environmental Pollutants; Female; Ghana; Humans; Male; Middle Aged; Multivariate Analysis; Occupational Exposure; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Recycling; Young Adult

Quantum chemical calculations were carried out to investigate the homogeneous gas-phase formation of mixed polybrominated/chlorinated dibenzo-p-dioxins/benzofurans (PBCDD/Fs) from the cross-condensation of 2-chlorophenoxy radical (2-CPR) with 2-bromophenoxy radical (2-BPR), 2,4-dichlorophenoxy radical (2,4-DCPR) with 2,4-dibromophenoxy radical (2,4-DBPR), and 2,4,6-trichlorophenoxy radical (2,4,6-TCPR) with 2,4,6-tribromophenoxy radical (2,4,6-TBPR). The geometrical parameters and vibrational frequencies were calculated at the MPWB1K/6-31+G(d,p) level, and single-point energy calculations were performed at the MPWB1K/6-311+G(3df,2p) level of theory. The rate constants of the crucial elementary reactions were evaluated by the canonical variational transition-state (CVT) theory with the small curvature tunneling (SCT) correction over a wide temperature range of 600-1200K. Studies show that the substitution pattern of halogenated phenols not only determines the substitution pattern of the resulting PBCDD/Fs, but also has a significant influence on the formation mechanism of PBCDD/Fs, especially on the coupling of the halogenated phenoxy radicals.

Topics: Benzofurans; Chlorophenols; Computer Simulation; Phenols; Polychlorinated Dibenzodioxins

Biphenyls and dibenzofurans are the phytoalexins of the Malinae involving apple and pear. Biosynthesis of the defence compounds includes two O-methylation reactions. cDNAs encoding the O-methyltransferase (OMT) enzymes were isolated from rowan (Sorbus aucuparia) cell cultures after treatment with an elicitor preparation from the scab-causing fungus, Venturia inaequalis. The preferred substrate for SaOMT1 was 3,5-dihydroxybiphenyl, supplied by the first pathway-specific enzyme, biphenyl synthase (BIS). 3,5-Dihydroxybiphenyl underwent a single methylation reaction in the presence of S-adenosyl-l-methionine (SAM). The second enzyme, SaOMT2, exhibited its highest affinity for noraucuparin, however the turnover rate was greater with 5-hydroxyferulic acid. Both substrates were only methylated at the meta-positioned hydroxyl group. The substrate specificities of the OMTs and the regiospecificities of their reactions were rationalized by homology modeling and substrate docking. Interaction of the substrates with SAM also took place at a position other than the sulfur group. Expression of SaOMT1, SaOMT2 and SaBIS3 was transiently induced in rowan cell cultures by the addition of the fungal elicitor. While the immediate SaOMT1 products were not detectable in elicitor-treated cell cultures, noraucuparin and noreriobofuran accumulated transiently, followed by increasing levels of the SaOMT2 products aucuparin and eriobofuran. SaOMT1, SaOMT2 and SaBIS3 were N- and C-terminally fused with the super cyan fluorescent protein and a modified yellow fluorescent protein, respectively. All the fluorescent reporter fusions were localized to the cytoplasm of Nicotiana benthamiana leaf epidermis cells. A revised biosynthetic pathway of biphenyls and dibenzofurans in the Malinae is presented.

Topics: Amino Acid Sequence; Benzofurans; Biphenyl Compounds; Malus; Molecular Sequence Data; Protein O-Methyltransferase; Pyrus; RNA, Messenger; Sequence Homology, Amino Acid; Substrate Specificity

Dibenzofuran is a direct precursor of extremely toxic compounds such as dioxins. It is widely distributed persistent organic pollutant in environment that potentiate oxidative stress, apoptosis, and necrosis through bioactivation in HepG2 cells. An alkalotolerent Pseudomonas strain ISTDF1 can metabolize dibenzofuran as a sole source of carbon and energy through diverse dioxygenation. However, there is a paucity of information about the potential toxic effects of the intermediary metabolites that are formed during treatment with dibenzofuran. We have assessed and discovered the potential mechanism of toxicity induced by metabolites of dibenzofuran that were formed at 18 and 36 h. Cell viability, CYP1A2 induction, ROS activity, Superoxide production, mitochondrial NADPH oxidase activity, and mitochondrial trans-membrane potential were studied using different assays such as 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), confocal laser scanning microscopy, and flow cytometry. Analysis revealed formation of 2-(1-carbonyl methylidine)-2,3-dihydrobenzofuranlidene after 18 h of bacterial treatment due to oxygenation at carbon (C3-C4). This compound induces higher mitochondrial NADPH oxidase-dependent superoxide production that makes it more toxic than the parent compound. It was evident that after 36 h of bacterial treatment, toxicity induced by dibenzofuran and its metabolites was completely removed. This study highlights the fact that despite of efficient biodegradation of toxicants, bioactive toxic intermediates can be formed. Therefore, it is necessary to assess the toxicity of each intermediary for complete mitigation of associated risk.

Topics: Benzofurans; Biodegradation, Environmental; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Survival; Cytochrome P-450 CYP1A2; Hep G2 Cells; Humans; Membrane Potential, Mitochondrial; Mitochondria, Liver; NADPH Oxidases; Pseudomonas; Reactive Oxygen Species; Superoxides

An efficient method for the synthesis of dibenzofuran from o-iododiaryl ether using reusable Pd/C under ligand-free conditions has been developed. Synthesis of o-iododiaryl ether was achieved in one pot through sequential iodination and O-arylation of phenol under mild reaction conditions.

Topics: Benzofurans; Catalysis; Ether; Hydrocarbons, Iodinated; Hydrogen Bonding; Ligands; Molecular Structure; Palladium; Stereoisomerism

Dysregulation of dual-specificity tyrosine-phosphorylation-regulated kinase 1A (DYRK1A) has been demonstrated in several pathological conditions, including Alzheimer's disease and cancer progression. It has been recently reported that a gain of function-mutation in the human DYRK1B gene exacerbates metabolic syndrome by enhancing obesity. In the previous study, we developed an inhibitor of DYRK family kinases (INDY) and demonstrated that INDY suppresses the pathological phenotypes induced by overexpression of DYRK1A or DYRK1B in cellular and animal models. In this study, we designed and synthesized a novel inhibitor of DYRK family kinases based on the crystal structure of the DYRK1A/INDY complex by replacing the phenol group of INDY with dibenzofuran to produce a derivative, named BINDY. This compound exhibited potent and selective inhibitory activity toward DYRK family kinases in an in vitro assay. Furthermore, treatment of 3T3-L1 pre-adipocytes with BINDY hampered adipogenesis by suppressing gene expression of the critical transcription factors PPARγ and C/EBPα. This study indicates the possibility of BINDY as a potential drug for metabolic syndrome.

Topics: 3T3-L1 Cells; Adipogenesis; Animals; Benzofurans; Benzothiazoles; Binding Sites; CCAAT-Enhancer-Binding Protein-alpha; Drug Design; Dyrk Kinases; Humans; Mice; Molecular Docking Simulation; PPAR gamma; Protein Kinase Inhibitors; Protein Serine-Threonine Kinases; Protein Structure, Tertiary; Protein-Tyrosine Kinases

In this study, the removal efficiency of 136 tetra- to octa-chlorinated dibenzo-p-dioxin (CDD)/furan (F) congeners from a nitrogen + oxygen carrier gas was studied using a laboratory-scale, fixed bed adsorption system. Two kinds of activated carbon with dissimilar pore structures were used as adsorbents. The total concentration of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) in the source gas was 541 ng/Nm(3) and that of the 17 toxic 2,3,7,8-substituted PCDD/Fs 96.35 ng/Nm(3), accounting for 17.8% of the total original weight amount. Their toxic equivalent quantity (TEQ) was 8.31 ng I-TEQ/Nm(3). For both activated carbons, the removal efficiencies of the ten PCDD/F homologue groups rise with chlorine substitution number. The removal efficiencies vary approximately as a power function of vapor pressure (correlation coefficients r(2) = 0.93 and 0.81, respectively). Competitive adsorption and desorption occur as adsorption time went on, causing elution of the lower chlorinated homologues, i.e. tetra-CDD/F and Penta-CDD/F congeners. In addition, there are significantly different concentration distributions for isomers in the same homologue groups. However, their removal efficiencies have weak correlation with their initial concentrations. The correlation coefficients are from -0.47 to 0.32 and from -0.57 to 0.46 respectively for the two kinds of activated carbons.

Topics: Adsorption; Benzofurans; Charcoal; Dioxins; Environmental Pollutants; Polychlorinated Dibenzodioxins

This contribution investigates mechanistic and kinetic parameters pertinent to formation of mixed dibenzo-p-dioxins and dibenzofurans (PXDD/Fs) from the condensation reactions involving 2-chlorophenoxy (2-CPxy) and 2-bromophenoxy (2-BPxy) radicals. Keto-ether structures act as direct intermediates for the formation of DD, 1-MCDD, 1-MBDD, 1-B,6-CDD and 1-B,9-CDD molecules. Likewise, diketo adducts initiate the formation of 4-MCDF, 4-MBDF and 4-B,6-CDF compounds through interconversion and rearrangement reactions. As formation mechanisms of halogenated dibenzo-p-dioxins and dibenzofurans from precursors of brominated and chlorinated phenols are insensitive to substitution at meta and para sites, our mechanistic and kinetic analysis of reactions involving 2-BPxy and 2-CPxy should also apply to higher halogenated phenoxy radicals.

Topics: Benzofurans; Dioxins; Environmental Pollutants; Halogenation; Hydrocarbons, Halogenated; Kinetics; Models, Chemical; Molecular Structure; Phase Transition; Phenols

This study provides, for the first time, a baseline evaluation of dioxin-like biological activity in sediments and fish sampled in- and adjacent to anchorages along the Mediterranean and Red Sea coasts of Israel. It indicates the effect of past pollution, still present in the sediments of older Israeli harbors, with putative contribution of still existing sources of pollution. A commercial reporter gene bioassay was used to evaluate the biological activity of dioxin-like compounds extracted from the samples. HRGC/HRMS analysis of several samples contributed a profile of dioxin-like compounds in sediments and fish. The results point out 1,2,3,4,6,7,8-HeptaCDD, 2,3,4,6,7,8-HexaCDF, 1,2,3,4,6,7,8-HeptaCDF, РСВ-126 and РСВ-118 as major contributors to the dioxin-like activity in sediments. It indicates polychlorinated biphenyls non-selective absorption in fish livers, in contrary to a biased accumulation of poorly chlorinated and more potent dibenzodioxins and dibenzofurans.

Topics: Animals; Benzofurans; Biological Assay; Dioxins; Environmental Monitoring; Fishes; Genes, Reporter; Geologic Sediments; Indian Ocean; Israel; Liver; Mediterranean Sea; Polychlorinated Biphenyls; Tissue Extracts; Water Pollutants, Chemical

Concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were estimated for different particle size distributions in a carbon black feeding process at a tire manufacturing plant on 15 days in March and April of 2014. A total of 75 integrated air samples were collected using a micro-orifice uniform deposition impactor (MOUDI). Particle-bound PCDD/Fs were analyzed using a high-resolution gas chromatograph/high-resolution mass spectrometer (HRGC/HRMS). Concentrations of thoracic particles and total particles produced in the carbon black feeding process of a tire manufacturing plant were measured in ranges of 0.19-2.61 and 0.28-4.22 mg/m(3), respectively. On all sampling days, the three most abundant species of PCDD/Fs were OCDD, 1,2,3,4,6,7,8-HpCDF, and OCDF. The mean concentrations of total PCDD/Fs were 0.74-6.83 pg/m(3) within five particle size ranges. Total I-TEQ in particulate matter (PM)<1.0 was 2.2 and 3.2 times higher than those in PM>18 and PM2.5-10, respectively. However, the total I-TEQ of thoracic PM contributed approximately 74 % of the total I-TEQ of total PM. The assessment of health risk indicates that exposure to fractions of thoracic PM by inhalation poses a significant cancer risk (>10(-6)).

Topics: Air Pollutants; Air Pollution; Benzofurans; Dioxins; Gas Chromatography-Mass Spectrometry; Industry; Particulate Matter; Soot

The concentrations and formation pathways of mono- to octa-chlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were investigated in main organochemical industries. High levels of PCDDs and PCDFs were detected. The total concentrations of 27 PCDD/F congeners in chloranil, 2,4-D, and 1,4-dichlorobenzene were 5302397 ± 8944449, 20963 ± 15908, and 242 ± 67 pg g(-1), respectively, and the less-chlorinated PCDD/F levels were 12006 ± 20155, 9536 ± 5594, and 195 ± 94 pg g(-1), respectively. The distribution trends of less and more chlorinated PCDD/Fs were similar in different chemical plants because of their similar formation pathways, which may also be related to the degree of chlorination of chemical products and purification processes. 1,2,3,4-TeCDF and 2,4,8-TrCDF were selected as model molecules to calculate the bond dissociation energy, showing that 2-MCDF, 3-MCDF, and 2,8-DCDF are more easily formatted as shown by the analytical results. The formation pathways of less to more chlorinated PCDFs are proposed to explain why 2-MoCDF, 2,8-DiCDF, 2,4,8-TrCDF, and 2,3,4,7,8-PeCDF are the dominant congeners and to explain why 2,3,4,7,8-PeCDF is the largest contributor of I-TEQs in most studies.

Topics: Benzofurans; Halogenation; Industry; Polychlorinated Dibenzodioxins; Thermodynamics

During this study wipe sampling was applied to various impervious surfaces for the determination of polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDFs) area concentrations. To that end, a wipe sampling method based on solvent wetted cotton wipes was evaluated and transfer efficiencies of PCBs and PCDD/PCDFs in particulate films (PFs) and oily liquid films (OFs) during sampling were investigated. For PFs sufficient transfer efficiencies of low concentrated PCB and PCDD/PCDF congeners in 1g/m(2) spiking surrogate were achieved after the first wipe using n-hexane as wetting solvent. Transfer efficiencies for OFs were the highest in the first wipe if n-hexane or n-heptane were used rather than toluene. The spiking experiments of OFs showed a log-linear correlation between the number of wiping procedures and transfer efficiency which indicates that transfer efficiencies were constant in subsequent wipes. Furthermore, it was successfully demonstrated that pressurized liquid extraction is a suitable tool for the extraction of wipe samples. Finally, the feasibility of this wipe sampling method was demonstrated on various impervious surfaces of different origin, and concentration levels of PCBs and PCDD/PCDFs in wipe samples are discussed. Hereby, remarkably high ∑CB6 concentrations of up to 1400μg/m(2) (taken at a transformer recycling site) were detected.

Topics: Air Pollutants; Benzofurans; Dioxins; Environmental Monitoring; Polychlorinated Biphenyls

Plastics from cathode ray tube (CRT) casings were sampled in Nigeria and analysed for their polybrominated dibenzo-p-dioxin and dibenzofuran (PBDD/F) content. PBDD/Fs, consisting mainly of PBDFs, were detected in BFR containing plastic with a median (mean) concentration of 18,000 ng/g (41,000 ng/g). The PBDD/Fs levels were highest in samples containing PBDEs, but the levels of PBDFs were two orders of magnitude higher than the levels reported in the technical PBDE mixtures and where frequently exceeding 1000 μg/g of PBDE content. These higher levels are likely to arise from additional transformation of PBDEs during production, use, recycling, or storage, but the processes responsible were not identified in this study. PBDD/Fs in CRT casings containing1,2-bistribromophenoxyethane (TBPE) were dominated by tetrabrominated dibenzo-p-dioxin (TBDDs) with concentrations around 10 μg/g of the TBPE content. The PBDD/Fs in CRT casings containing tetrabromobisphenol A (TBBPA) were found at concentrations around 0.1 μg/g of TBBPA levels. Casings treated with TBPE or TBBPA often contained PBDEs (and PBDF) as impurities-probably originating from recycled e-waste plastics. It was estimated that the 237,000 t of CRT casings stockpiled in Nigeria contain between 2 and 8 t of PBDD/Fs. The total PBDD/F contamination in polymers arising from total historic PBDE production/use is estimated in the order of 1000 t. TEQ values of CRT samples frequently exceeded the Basel Convention's provisional low POPs content of 15 ng TEQ/g. Due to the significant risks to health associated with PBDD/Fs, more detailed studies on the exposure routes from PBDD/Fs in stockpiles are needed.

Topics: Benzofurans; Dioxins; Electronic Waste; Environmental Monitoring; Environmental Pollutants; Halogenation; Humans; Nigeria; Plastics

To explore the levels and congener profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in airborne fine particulate matter (PM25) in Shenzhen and roughly discuss its correlations between PM25 concentration and meteorological factors.. The high volume air samplers were used to collect the samples in six sampling sites in respective winter and spring phase and summer and autumn phase. Referring to the US EPA TO-9A for dioxins detection methods, the concentrations of the 17 polychlorinated dibenzo-p-dioxins and dibenzofurans in airborne fine particulate matter were determined by HRGC/HRMS.. The total concentrations of PCDD/Fs ranged from 0.32 to 9.35 pg/m3, with average of 2.45 pg/ m3. The TEQ concentrations ranged from 0.006 to 0.388 pg I-TEQ/m3, with average of 0.095 pg I-TEQ/m3. The four abundant congeners were found to be OCDD (36.49%), 1, 2, 3, 4, 6, 7, 8-HpCDF (14.89%), OCDF (13.34%) and 1, 2, 3, 4, 6, 7, 8-HpCDD (10.92%). 2, 3, 4, 7, 8-PeCDF was the dominant contributor to toxicity equivalent (TEQ), accounting for 34.65%. Positive relationship was found between the levels of fine particle-bound PCDD/Fs and PM2.5 concentration (r(s) = 0.794, P = 0.006), whereas no correlation was observed for temperature, humidity and atmospheric pressure. Inhalation exposure to PCDD/Fs were 0. 023 pg I-TEQ/(kg · d) for adult and 0.035 pg I-TEQ/(kg · d) for children during winter and spring and relatively higher than those during summer and autumn (0.014 pg I-TEQ/(kg · d). for adult and 0.021 pg I-TEQ/(kg · d) for children respectively).. The levels of PCDD/Fs in airborne fine particle-bound samples collected in Shenzhen were lower than those in Hangzhou and Beijing.

Topics: Adult; Benzofurans; Child; China; Dioxins; Humans; Particulate Matter; Polychlorinated Dibenzodioxins; Risk Assessment

To analyze the contamination levels and profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in fish samples in Shenzhen areas of China, and to reveal the status of PCDD/Fs pollution for fish samples in a decade.. The fish samples including freshwater and saltwater fishes, were collected and analyzed from 2004 to 2013, and PCDD/Fs were detected by isotope dilution HRGC/HRMS using multiple ion detection mode (MID), which was an advanced and authority technique referenced US EPA1613 method.. The average concentration of PCDD/Fs in fish was 0.90 pg/(g wet weight), and the average total toxicity equivalency factor (TEQ) calculated on the basis of the toxic equivalency factor (TEF) published by the World Health Organization (WHO) in 2005 was 0.088 pg WHO-TEQ/(g, wet weight). PCDD/Fs levels in fishes varied widely depending on the species. The PCDD/Fs average contamination levels of fish in 10 years did not exceeded the limit standards of European Commission. The evaluation dietary intake of PCDD/Fs from fish for local residents was 4.80 pg WHO-TEQ/(kg · BW · m).. The PCDD/Fs levels in fish in a decade was less than the maximum limit standards set by European Commission 2011.

Topics: Animals; Benzofurans; Biological Assay; China; Dibenzofurans, Polychlorinated; Dioxins; Environmental Monitoring; Environmental Pollution; Fishes; Food Analysis; Fresh Water; Nutrition Assessment; Water Pollutants, Chemical

Bivalve samples from 142 sites were analyzed to determine the concentration and toxicity equivalents (TEQ) of dioxins and furans (D/F) as part of the NOAA National Status and Trends Program. The total concentration of 17 D/F ranged from not detected to 203 pg/g wet weight of tissue. Octachlorinated dibenzo-p-dioxin, OCDD, had a concentration range from not detected to 189 pg/g and a mean concentration of 8.65 pg/g. OCDD was the dominant D/F compound detected and accounted for, on average, over 70% of the total D/F concentration. The TEQ (compared to 2,3,7,8-TCDD) ranged from 0.12 to 7.32 pg TEQ/g. The TEQ for 39% of the bivalves analyzed were below 0.238 pg TEQ/g. TEQ above human consumption advisory concentration of 1.2 pg TEQ/g were found in 9.3% of the samples analyzed. TEQ for D/F indicate very limited human health concerns from consumption of bivalves at most of the locations sampled.

Topics: Animals; Benzofurans; Bivalvia; Dioxins; Humans; Polychlorinated Dibenzodioxins; Water Pollutants, Chemical; Water Pollution, Chemical

The Seveso Women's Health Study (SWHS) is a historical cohort study of the female population residing near Seveso, Italy, on 10 July 1976, when a chemical explosion resulted in the highest known residential exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Individual TCDD concentration was measured in serum collected near the time of the explosion, and in 1996, we collected adequate blood for TCDD and total dioxin toxic equivalent (TEQ) measurement. Polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls were measured in 1996 serum for a sample (n=225, 23%) of the SWHS cohort and WHO 2005 TEQs were calculated. We examined characteristics that predict 1996 TCDD concentrations and estimated TCDD elimination half-life over the 20-year period since the explosion. Median lipid-adjusted TCDD and total TEQ concentrations in 1996 serum were 7.3 and 26.2 p.p.t., respectively. Initial 1976 TCDD and age at explosion were the strongest predictors of 1996 TCDD. The TCDD elimination half-life was 7.1 years for women older than 10 years in 1976, but was shorter in those who were younger. Twenty years after the explosion, TCDD concentrations in this SWHS sample, the majority of who were children in 1976, remain elevated relative to background. These data add to the limited data available on TCDD elimination half-life in children.

Topics: Adult; Age Factors; Benzofurans; Dioxins; Environmental Exposure; Environmental Pollutants; Female; Half-Life; Humans; Italy; Longitudinal Studies; Middle Aged; Polychlorinated Dibenzodioxins; Regression Analysis; Risk Factors; Seveso Accidental Release; Smoking; Women's Health; Young Adult

To demonstrate the biodegradation of dibenzofuran (DF) and its structural analogs by a newly isolated Agrobacterium sp. PH-08.. To assess the biodegradation potential of newly isolated Agrobacterium sp. PH-08, various substrates were evaluated as sole carbon sources in growth and biotransformation experiments. ESI LC-MS/MS analysis revealed the presence of angular degrading by-products as well as lateral dioxygenation metabolites in the upper pathway. The metabolites in the lower pathway also were detected. In addition, the cometabolically degraded daughter compounds of DF-related compounds such as BP and dibenzothiophene (DBT) in dual substrate degradation were observed. Strain PH-08 exhibited the evidence of meta-cleavage pathway as confirmed by the activity and gene expression of catechol-2,3-dioxygenase.. Newly isolated bacterial strain, Agrobacterium sp. PH-08, grew well with and degraded DF via both angular and lateral dioxygenation as demonstrated by metabolites identified through ESI LC-MS/MS and GC-MS analyses. The other heterocyclic pollutants were also cometabolically degraded.. Few reports have described the complete degradation of DF by a cometabolic lateral pathway. Our study demonstrates the novel results that the newly isolated strain utilized the DF as a sole carbon source and mineralized it via multiple dioxygenation.

Topics: Agrobacterium; Benzofurans; Biodegradation, Environmental; Catechol 2,3-Dioxygenase; Tandem Mass Spectrometry; Thiophenes

A series of novel dibenzo[b,d]furan-1,2,3-triazole conjugates, rationally designed by reorientation of dibenzo[b,d]furan pharmacophore and alkyl/aryl groups appended on 1,2,3-triazole core, were synthesized using click chemistry. The required key intermediate, 2-ethynyl dibenzo[b,d]furan 3 was prepared from dibenzofuran-2-carboxaldehyde using Corey-Fuchs reaction. Further reaction of 3 with various alkyl/aryl azides in the presence of copper catalyst produced 1,2,3-triazole conjugates in excellent yields. Evaluation of all the new compounds for in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv (ATCC27294), resulted 5a (MIC: 1.56 μg/mL), 5d (MIC: 0.78 μg/mL) and 5f (MIC: 0.78 μg/mL) as promising lead analogues. Among these three compounds, 1-(4-bromobenzyl)-4-(dibenzo[b,d]furan-2-yl)-1H-1,2,3-triazole (5f) emerged as the most promising antitubercular agent with lowest cytotoxicity (selectivity index: ≫25) against the HEK-293T cell line.

Topics: Antitubercular Agents; Benzofurans; Click Chemistry; HEK293 Cells; Humans; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Structure-Activity Relationship; Triazoles; Tuberculosis

The pollution trend of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the Baltic Sea region was studied based on depth profiles of PCDD/Fs in sediment cores collected from six offshore areas, eight coastal sites impacted by industrial/urban emissions, and one coastal reference site. A general trend was observed for the offshore and coastal reference sites with substantial increase in PCDD/F concentrations in the mid-late 1970s and peak levels during 1985-2002. The overall peak year for PCDD/Fs in Baltic Sea offshore areas was estimated (using spline-fit modeling) to 1994 ± 5 years, and a half-life in sediments was estimated at 29 ± 11 years. For the industrial/urban impacted coastal sites, the temporal trend was more variable with peak years occurring 1-2 decades earlier compared to offshore areas. The substantial reductions from peak levels (38 ± 11% and 81 ± 12% in offshore and coastal areas, respectively) reflect domestic and international actions taken for reduction of the release of PCDD/Fs to the environment. The modeled overall half-life and reductions of PCDD/Fs in offshore Baltic Sea sediment correspond well to both PCDD/F trends in European lakes without any known direct PCDD/F sources (half-lives 30 and 32 years), and previously modeled reduction in atmospheric deposition of PCDD/Fs to the Baltic Sea since 1990. These observations support previous findings of a common diffuse source, such as long-range air transport of atmospheric emissions, as the prime source of PCDD/Fs to the Baltic Sea region. The half-life of PCDD/Fs in Baltic Sea offshore sediments was estimated to be approximately 2 and 4-6 times longer than in semirural and urban European air, respectively. This study highlights the need for further international actions to reduce the levels of PCDD/Fs in Baltic Sea air specifically and in European air in general.

Topics: Air Pollutants; Benzofurans; Geography; Geologic Sediments; Half-Life; History, 20th Century; Oceans and Seas; Plants; Polychlorinated Dibenzodioxins; Time Factors; Water Pollutants, Chemical

Although chlorophenols (CPs) are considered to be the most important and direct precursors of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), our understanding of the formation mechanism of PCDD/Fs is exclusively limited to an invariable idea that chlorophenoxy radicals (CPRs) are only necessary intermediates. The present work presents a systematic theoretical study that aims at providing new insight into the homogeneous formation of PCDD/Fs from CPs. Two different types of radicals from CPRs, i.e., substituted phenyl radicals and phenoxyl diradicals, are proposed to serve as potential sources contributing to the formation of PCDD/Fs. The thermodynamic and kinetic properties of reactions of 2-chlorophenol (2-CP), as a representative of CP congeners, with atomic H to produce various potential radicals forming PCDD/Fs are studied by performing density functional theory calculations and direct kinetics studies. The newly proposed radicals, especially substituted phenoxyl diradicals (the most direct intermediates of PCDD/Fs), can be formed via reactions of 2-CP with atomic H with small barriers and large reaction energies. They should be expected to be responsible for the homogeneous formation of PCDD/Fs under high temperature. Several typical PCDD/F products are predicated through direct self- and cross-couplings of the newly proposed radicals. The radical coupling patterns proposed in the present work expand our understanding of the formation mechanism of PCDD/Fs from CP precursors.

Topics: Benzofurans; Chlorophenols; Kinetics; Polychlorinated Dibenzodioxins; Quantum Theory

We measured serum concentrations of seven dibenzo-p-dioxin congeners (PCDDs), ten dibenzofurans (PCDFs), four non-ortho polychlorinated biphenyls (noPCBs) and six mono-ortho polychlorinated biphenyls (moPCBs) in 1950 veterans of the Vietnam War. The veterans were participants in the Air Force Health Study (AFHS) who attended the final medical examination in 2002. Blood samples were collected from 777 Ranch Hands involved in the aerial spraying of herbicides in Vietnam and a comparison group of 1173 veterans ("Comparisons") who served in Southeast Asia during the same time period. Results for moPCBs were based on a random subsample of 800 veterans. The median 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) concentrations in 2002 were 5.0 pg g(-1) lipid in Ranch Hands and 2.2 pg g(-1) lipid in Comparisons. No substantial differences were found in measured concentrations of other PCDDs, PCDFs, and noPCBs. Similarly, no substantial differences were found for moPCBs in the subsample. The median total dioxin toxic equivalent (TEQ) in Ranch Hands was 18.7 pg g(-1) lipid for PCDDs, 3.4 pg g(-1) lipid for PCDFs, and 3.2 pg g(-1) lipid for noPCBs. Median TEQs in Comparisons were 14.4 pg g(-1) lipid for PCDDs, 3.5 pg g(-1) lipid for PCDFs, and 3.3 pg g(-1) lipid for noPCBs. These TEQs, with the exception of PCDD TEQ in Ranch Hands (primarily due to elevated TCDD), were similar to or lower than those reported for similar age and gender groups in the 2001-2002 National Health and Nutrition Examination Survey (NHANES). These findings support the assumption that the Ranch Hand veterans were not more highly exposed to dioxin-like compounds other than TCDD than were Comparison veterans or the general US population.

Topics: Aged; Aged, 80 and over; Benzofurans; Dioxins; Herbicides; Humans; Male; Middle Aged; Military Personnel; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Veterans; Vietnam; Vietnam Conflict

In developing countries such as China, there is a strong need for simple and rapid bioassays for the determination of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in environmental samples; i.e., flue gas and fly ash from waste incinerators. In this study, we applied the DR-EcoScreen cell (DR-cell) assay to determination of PCDD/Fs in 78 flue gas samples obtained from various waste incinerators in China between 2009 and 2011. The flue gas samples were obtained from four kinds of incinerators, classified into hazardous, medical and municipal-solid waste, and iron ore sintering, and the flue gas extracts were cleaned up using an SPD-600 automated-sample preparation device for DR-cell assay. The PCDD/Fs values obtained from the DR-cell assay were compared with those obtained from conventional high resolution gas chromatography-high resolution mass spectrometry (HRGC-HRMS) analysis. The bioanalytical equivalent (BEQ) values obtained from the DR-cell assay were very closely correlated with the international toxicity equivalent (I-TEQ) values from HRGC-HRMS analysis (r2=0.98, n=78), while the BEQ values were 5.52-fold higher than the I-TEQ values, as the PCDFs, which account for 80% of the total I-TEQ value, were overestimated by DR cell-assay. Therefore, we multiplied the BEQ values from the DR-cell assay by a conversion coefficient (0.181, the reciprocal of 5.52), and could approximate the TEQ values from the HRGC-HRMS analysis. These results suggest that the DR-cell assay combined with SPD-600 cleanup provides a promising method for the simple and rapid screening of PCDD/Fs levels in flue gas samples, such as those from various waste incinerators in China.

Topics: Animals; Benzofurans; Biological Assay; Cell Line; China; Dibenzofurans, Polychlorinated; Dioxins; Environmental Monitoring; Gas Chromatography-Mass Spectrometry; Gases; Humans; Incineration; Mice; Polychlorinated Dibenzodioxins

A total of 126 food samples, categorised into three groups (seafood and seafood products, meat and meat products, as well as milk and dairy products) from Malaysia were analysed for polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). The concentration of PCDD/Fs that ranged from 0.16 to 0.25 pg WHO05-TEQ g(-1) fw was found in these samples. According to the food consumption data from the Global Environment Monitoring System (GEMS) of the World Health Organization (WHO), the dietary exposures to PCDD/F from seafood and seafood products, meat and meat products, as well as milk and dairy products for the general population in Malaysia were 0.064, 0.183 and 0.736 pg WHO05-TEQ kg(-1) bw day(-1), respectively. However, the exposure was higher in seafood and seafood products (0.415 pg WHO05-TEQ kg(-1) bw day(-1)) and meat and meat products (0.317 pg WHO05-TEQ kg(-1) bw day(-1)) when the data were estimated using the Malaysian food consumption statistics. The lower exposure was observed in dairy products with an estimation of 0.365 pg WHO05-TEQ kg(-1) bw day(-1). Overall, these dietary exposure estimates were much lower than the tolerable daily intake (TDI) as recommended by WHO. Thus, it is suggested that the dietary exposure to PCDD/F does not represent a risk for human health in Malaysia.

Topics: Benzofurans; Dioxins; Eating; Environmental Pollutants; Food; Food Analysis; Food Contamination; Humans; Malaysia

Sediment cores from Xingyun Lake close to the pulp mill region of Jiangchuan (China), earlier found to be highly contaminated by pulping at least from the 1990s, were analyzed by HRGC/HRMS for the concentrations of 17 polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs). Regarding the contribution of individual congeners, PCDD/F levels ranged from ND (non-detectable) to 82.05 pg g(-1) dw (from ND to 0.16 pg WHO-TEQ g(-1) dw) in 0-20 cm of sediment and from ND to 45.61 pg g(-1) dw (from ND to 0.67 WHO-TEQ g(-1) dw) in 20-40 cm of sediment for 17 PCDD/Fs (WHO-TEQ: WHO-endorsed toxic equivalents). Major PCDD/Fs identified and confirmed were high-chlorinated congeners including OCDD/Fs and HpCDD/Fs in the two depths. For high-chlorinated PCDD/Fs such as O, Hp-CDD/Fs across the depth of sediment, sediment had a higher proportion in 0-20 cm than that in 20-40 cm. On the contrary, for low-chlorinated PCDD/Fs such as T, Pe, Hx-CDD/Fs, the lower proportion was found in 0-20 cm. The results demonstrated that PCDD/Fs loads in the sediment of Xingyun Lake were very low compared to loads in the other regions about 8 years after closedown of a majority of pulp production with chlorine, which indicated that pulp production was an important emission source of dioxins.

Topics: Benzofurans; China; Dibenzofurans, Polychlorinated; Dioxins; Environmental Monitoring; Geologic Sediments; Lakes

The levels and specific profiles of polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in Mytilus galloprovincialis from the Mar Grande and the Mar Piccolo of Taranto were determined during the extensive monitoring plan of Local Health Authority to assess PCDD/Fs and DL-PCBs contamination in food and farm products, within 20 km from the industrial areas of Taranto, between March and December 2011. The average Total Toxicity Equivalence (TEQ) values for the sum of PCDD/F and DL-PCBs ranged from 1.61 to 5.63 pg WHO2005-TEQ g(-1) wet weight basis, with the highest in the first inlet of the Mar Piccolo. In particular, DL-PCBs were the dominant chemicals in all samples, followed by PCDFs and PCDDs. Congener patterns in mussels were similar, indicating a homogeneous behavior in studied areas and, probably, the same type of source. The seasonal concentrations trend showed a relevant increase of dioxin and dioxin-like PCBs TEQs during the summer months, exceeding the limits set by the European Community for food and foodstuff. Reducing PCDD/Fs and PCBs is necessary to decrease contamination levels in order to safeguard marine ecosystem and human health in the Taranto area.

Topics: Animals; Benzofurans; Dioxins; Food Contamination; Humans; Italy; Mediterranean Sea; Mytilus; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Seasons

Fire blight is a devastating disease of Rosaceae plants, such as apple and pear trees. It is characterized by necrosis of plant tissue, caused by the phytopathogenic bacterium Erwinia amylovora. The plant pathogen produces the well-known antimetabolite 6-thioguanine (6TG), which plays a key role in fire blight pathogenesis. Here we report that YcfR, a member of the LTTR family, is a major regulator of 6TG biosynthesis in E. amylovora. Inactivation of the regulator gene (ycfR) led to dramatically decreased 6TG production. Infection assays with apple plants (Malus domestica cultivar Holsteiner Cox) and cell cultures of Sorbus aucuparia (mountain ash, rowan) revealed abortive fire blight pathogenesis and reduced plant response (biphenyl and dibenzofuran phytoalexin production). In the presence of the ΔycfR mutant, apple trees were capable of activating the abscission machinery to remove infected tissue. In addition to unveiling the regulation of 6TG biosynthesis in a major plant pathogen, we demonstrate for the first time that this antimetabolite plays a pivotal role in dysregulating the plant response to infection.

Topics: Bacterial Outer Membrane Proteins; Base Sequence; Benzofurans; Biphenyl Compounds; Erwinia amylovora; Molecular Sequence Data; Multigene Family; Mutation; Phytoalexins; Plant Cells; Plant Diseases; Rosaceae; Sesquiterpenes; Thioguanine

The paper aims at investigating the contribution of a steel plant located in a rural area in northwestern Italy (700,000 tons of steel/year) to the deposition fluxes of Polychorinated Dibenzo-p-dioxins and Polychorinated dibenzofurans (PCDD/PCDFs) at local level through the analysis of sampling data, literature data, and air dispersion model (AERMOD)output data. Total measured deposition fluxes of PCDD/PCDFs in three monitoring stations were consistent with other studies carried out in Italy in urban and suburban areas and in rural European areas; while these were lower than those measured in other European urban/suburban areas or in sites influenced by industrial sources. Furthermore, the measured fluxes were also compared with the pattern of PCDD/Fs in ambient air sampled at the same sites in a previous study. This comparison showed a similarity between air concentration and deposition patterns of the samples collected at the three monitoring stations and a clear distinction of these from the source. The study was completed with AERMOD simulations, conducted with a mass mean particle diameter of 0.5 μm, according to the particle size distribution of the samples collected at the source. AERMOD calculated deposition fluxes of two to three orders of magnitude lower than those measured in two monitoring points; while in the most distant monitoring station, the deposition fluxes were too low to be calculated by the model. The simulations confirmed that the most distant monitoring station was not subject to emissions from the steel plant. The analysis highlighted the limited influence of the source in the local PCDD/F deposition fluxes.

Topics: Air Pollutants; Air Pollution; Benzofurans; Environmental Monitoring; Italy; Metallurgy; Polychlorinated Dibenzodioxins; Steel

Dioxin levels in the breast milk of mothers residing near a contaminated former airbase in Vietnam remain much higher than in unsprayed areas, suggesting high perinatal dioxin exposure for their infants. The present study investigated the association of perinatal dioxin exposure with autistic traits in 153 3-year-old children living in a contaminated area in Vietnam. The children were followed up from birth using the neurodevelopmental battery Bayley-III. The high-2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposed groups (⩾3.5 pg per g fat) showed significantly higher Autism Spectrum Rating Scale (ASRS) scores for both boys and girls than the mild-TCDD exposed groups, without differences in neurodevelopmental scores. In contrast, the high total dioxin-exposed group, indicated by polychlorinated dibenzo-p-dioxins/furans (PCDDs/Fs)--the toxic equivalents (TEQ) levels⩾17.9 pg-TEQ per g fat, had significantly lower neurodevelopmental scores than the mild-exposed group in boys, but there was no difference in the ASRS scores. The present study demonstrates a specific impact of perinatal TCDD on autistic traits in childhood, which is different from the neurotoxicity of total dioxins (PCDDs/Fs).

Topics: Autistic Disorder; Benzofurans; Child Development; Child, Preschool; Cohort Studies; Dioxins; Dose-Response Relationship, Drug; Female; Follow-Up Studies; Humans; Male; Maternal Exposure; Milk, Human; Polychlorinated Dibenzodioxins; Psychiatric Status Rating Scales; Sex Factors; Vietnam

Fluorine-containing halogenated fluorophenol may have effect as intermediate species involved in the formation of polyfluorinated dibenzo-p-dioxin/dibenzofurans (PFDDs/Fs). The mechanism for the atomic H initiated reactions with complete series of nineteen fluorophenol congeners was studies using the density functional theory. At the MPWB1K/6-31+G(d,p) level, the geometries and frequencies of reactants, transition states, and products were obtained, and the accurate energetic values were acquired at the MPWB1K/6-311+G(3df,2p) level. The rate constants were evaluated by the canonical variational transition-state theory with the small curvature tunneling contribution over a wide temperature range of 600-1000 K. The study shows that the intramolecular hydrogen-bond in the ortho-substituted FPs as well as the inductive effect of the electron-withdrawing fluorine and steric repulsion of multiple substitutions may ultimately be responsible for the relative strength of the O-H bonds in FPs. The results can be used for further studies on PFDD/Fs formation mechanism.

Topics: Benzofurans; Chlorophenols; Dioxins; Hydrocarbons, Fluorinated; Hydrogen; Kinetics; Phenols

Unintentionally produced persistent organic pollutants (UP-POPs) including polychlorinated dibenzo-p-dioxins, and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), and polychlorinated naphthalenes (PCNs) were characterized and quantified in stack gas and fly ash from the second ventilation systems in five typical converters in five different steelmaking plants. The 2378-substituted PCDD/Fs (2378-PCDD/Fs) and dioxin-like PCB (dl-PCBs) toxic equivalents (TEQs) were 1.84-10.3 pg WHO-TEQ Nm(-3) in the stack gas and 5.59-87.6 pg WHO-TEQ g(-1) in the fly ash, and the PCN TEQs were 0.06-0.56 pg TEQ Nm(-3) in the stack gas and 0.03-0.08 pg TEQ g(-1) in the fly ash. The concentrations of UP-POPs in the present study were generally lower than those in other metallurgical processes, such as electric arc furnaces, iron ore sintering, and secondary metallurgical processes. Adding scrap metal might increase UP-POP emissions, indicating that raw material composition was a key influence on emissions. HxCDF, HpCDF, OCDF, HpCDD, and OCDD were the dominant PCDD/Fs in the stack gas and fly ash. TeCB and PeCB were dominant in the stack gas, but HxCB provided more to the total PCB concentrations in the fly ash. The lower chlorinated PCNs were dominant in all of the samples. The 2378-PCDD/F, dl-PCB, and PCN emission factors in stack gases from the steelmaking converter processes (per ton of steel produced) were 1.88-2.89, 0.14-0.76, and 229-759 μg t(-1), respectively.

Topics: Air Pollutants; Benzofurans; Coal Ash; Dioxins; Environmental Monitoring; Gases; Hazardous Substances; Metallurgy; Naphthalenes; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins

We determined the distribution of polychlorinated biphenyls (PCBs), pentachlorobenzene (PeCBz), hexachlorobenzene (HxCBz), and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in surface sediments at 21 sites inside and outside Muroran Port, Japan. The concentration ranges and geometric means of PCBs (Σ209PCB), PeCBz, HxCBz, and PCDD/Fs and toxicity equivalence quantity (total TEQ) of dioxins inside Muroran Port were 1,100-65,000 (mean, 17,000) pg/g dw, 37-220 (100) pg/g dw, 31-810 (84) pg/g dw, 69-410 (170) pg/g dw, and 0.51-6.2 (2.3) pg TEQ/g dw, respectively. Their corresponding inventories inside Muroran Port were estimated to be 76, 0.31, 0.32, 0.55, and 7.8 g TEQ, respectively. The amounts of these pollutants were higher inside the port than outside the port and especially large in the inner part of the port. Most PCBs were homologues and congeners of penta- to hepta-chlorinated compounds, and the PCBs around Muroran Port were derived from technical PCBs, especially KC500 and KC600. As for PCDD/Fs, the influence of pentachlorophenol was significant, although pollution due to chloronitrofen and combustion was detected. The congeners of PCDD/Fs predominantly contributed to total TEQ. The concentration distributions of PeCBz, HxCBz, and PCDD/Fs and total TEQ were highly correlated with one another. This indicates that they are derived from the same combustion process.

Topics: Benzofurans; Chlorobenzenes; Dioxins; Environmental Monitoring; Environmental Pollutants; Geologic Sediments; Hexachlorobenzene; Japan; Polychlorinated Biphenyls

We present a new multimedia chemical fate model (SESAMe) which was developed to assess chemical fate and behaviour across China. We apply the model to quantify the influence of environmental parameters on chemical overall persistence (POV) and long-range transport potential (LRTP) in China, which has extreme diversity in environmental conditions. Sobol sensitivity analysis was used to identify the relative importance of input parameters. Physicochemical properties were identified as more influential than environmental parameters on model output. Interactive effects of environmental parameters on POV and LRTP occur mainly in combination with chemical properties. Hypothetical chemicals and emission data were used to model POV and LRTP for neutral and acidic chemicals with different KOW/DOW, vapour pressure and pKa under different precipitation, wind speed, temperature and soil organic carbon contents (fOC). Generally for POV, precipitation was more influential than the other environmental parameters, whilst temperature and wind speed did not contribute significantly to POV variation; for LRTP, wind speed was more influential than the other environmental parameters, whilst the effects of other environmental parameters relied on specific chemical properties. fOC had a slight effect on POV and LRTP, and higher fOC always increased POV and decreased LRTP. Example case studies were performed on real test chemicals using SESAMe to explore the spatial variability of model output and how environmental properties affect POV and LRTP. Dibenzofuran released to multiple media had higher POV in northwest of Xinjiang, part of Gansu, northeast of Inner Mongolia, Heilongjiang and Jilin. Benzo[a]pyrene released to the air had higher LRTP in south Xinjiang and west Inner Mongolia, whilst acenaphthene had higher LRTP in Tibet and west Inner Mongolia. TCS released into water had higher LRTP in Yellow River and Yangtze River catchments. The initial case studies demonstrated that SESAMe performed well on comparing POV and LRTP of chemicals in different regions across China in order to potentially identify the most sensitive regions. This model should not only be used to estimate POV and LRTP for screening and risk assessments of chemicals, but could potentially be used to help design chemical monitoring programmes across China in the future.

Topics: Benzo(a)pyrene; Benzofurans; China; Decision Support Techniques; Environment; Environmental Monitoring; Environmental Pollutants; Geography; Models, Chemical; Multimedia; Rain; Risk Assessment; Rivers; Soil; Wind

A naphthalene-utilizing bacterium, Arthrobacter sp. W1, was used to investigate the cometabolic degradation of carbazole (CA), dibenzofuran (DBF) and dibenzothiophene (DBT) using naphthalene as the primary substrate. Both the growing and washed cells of strain W1 could degrade CA, DBF, DBT, and naphthalene simultaneously and quickly. Inhibition kinetics confirmed that the presence of CA, DBF and DBT in the growing system would inhibit the cells growth and biodegradability of strain W1. The relationship between ln(C/C0) and time, and specific degradation rate and CA, DBF and DBT concentration could be described well by First-order and Michaelis-Menten kinetics. The treatment of real coking wastewater containing high concentration of phenol, naphthalene, CA, DBF, DBT and NH3-N was shown to be highly efficient by naphthalene-grown W1 coupling with activation zeolite. Toxicity assessment indicated the treatment of the coking wastewater by strain W1 coupling with activation led to less toxicity than untreated wastewater.

Topics: Arthrobacter; Benzofurans; Biodegradation, Environmental; Carbazoles; Coke; Kinetics; Naphthalenes; Thiophenes; Time Factors; Toxicity Tests; Vibrio; Wastewater; Water Pollutants, Chemical

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were analyzed in 25 background and 80 agricultural soil samples collected from 21 sites in Beijing, China. The levels of PCDD/Fs in the north agricultural soils were low (0.15-0.58 ng international toxic equivalent quantity [I-TEQ]/kg), which were comparable with those of the background soils (0.091-0.35 ng I-TEQ/kg). In the southern agricultural soils, however, concentrations were several times higher (0.27-3.3 ng I-TEQ/kg). Comparison of PCDD/Fs congener compositions between possible sources and samples indicated that agricultural soils in Beijing had not been contaminated by the 3 main PCDD/F contamination sources in China--ferrous and nonferrous metal, waste incineration, and power generation. They had, however, been slightly contaminated by the impurities of some organochlorine pesticides, such as sodium pentachlorophenate, and by open burning of biomass, vehicle exhaust, atmospheric deposition, sediment, and sewage sludge. These results have been supported by the principal components analysis.

Topics: Agriculture; Benzofurans; China; Dioxins; Environmental Monitoring; Hydrocarbons, Chlorinated; Incineration; Pesticides; Soil; Soil Pollutants

Municipal solid waste incinerators (MSWIs) have long been the major contributors of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) to ambient air in Taiwan. After stringent MSWI emission standards were introduced in 2001, the long-term continuous monitoring of flue gas and ambient air quality became necessary to ensure the effectiveness of the related control strategies. Three MSWIs and the surrounding ambient air were investigated in the current study for PCDD/F characteristics during 2006 to 2011. The average concentrations in the flue gas ranged from 0.008 ~ 0.0488 ng I-TEQ/Nm(3), which is much less than the emission standard in Taiwan (0.1 ng I-TEQ/Nm(3)) (I-TEQ is the abbreviation of International Toxic Equivalent). This led to extremely low levels in the ambient air, 0.0255 pg I-TEQ/Nm(3), much less than the levels seen in most urban areas around the world. Additionally, the results obtained using the Industrial Source Complex Short-Term Dispersion Model (ISCST3) indicate that the PCDD/F contributions from the three MSWIs to the ambient air were only in the range from 0.164 ~ 0.723 %. Principal component analysis (PCA) showed that the PCDD/Fs in the air samples had very similar characteristics to those from mobile sources. The results thus show that stringent regulations have been an effective control strategy, especially for urban areas, such as Taipei City.

Topics: Air Pollutants; Benzofurans; Dioxins; Environmental Monitoring; Incineration; Models, Theoretical; Solid Waste; Taiwan

In this study, the cometabolic degradation of carbazole (CA), dibenzofuran (DBF), and dibenzothiophene (DBT) by immobilized Arthrobacter sp. W1 cells pregrown with naphthalene was investigated. Four kinds of polymers were evaluated as immobilization supports for strain W1. After comparison with agar, alginate, and κ-carrageenan, gellan gum was selected as the optimal immobilization support. Furthermore, magnetic Fe₃O₄ nanoparticle was selected as most suitable nanoparticle for immobilization and the optimal concentration was 80 mg/L. The relationship between specific degradation rate and the initial concentration of CA, DBF and DBT was described well by Michaelis-Menten kinetics. The recycling experiments demonstrated that the magnetically immobilized cells coupling with activation zeolite showed highly bioremediation activity on the coking wastewater containing high concentration of phenol, naphthalene, CA, DBF and DBT during seven recycles. Toxicity assessment indicated the treatment of the coking wastewater by magnetically immobilized cells with activation zeolite led to less toxicity than untreated wastewater.

Topics: Arthrobacter; Benzofurans; Biodegradation, Environmental; Carbazoles; Cells, Immobilized; Coke; Kinetics; Nanoparticles; Polysaccharides, Bacterial; Thiophenes; Waste Disposal, Fluid; Wastewater; Water Pollutants, Chemical

On the basis of laboratory experiments with model mixtures (active carbon+CuBr2 at different loads), this work studies the formation of polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) by de novo synthesis. For the different samples, the temperature of the maximum carbon oxidation rate was determined by thermogravimetric analysis, and a kinetic model was proposed for the degradation of the materials in an oxidizing atmosphere (synthetic air). The effect of the addition of different amounts of CuBr2 was studied, finding that its presence accelerates the degradation of the carbonaceous structure in the presence of oxygen. The thermal degradation of the samples in air is satisfactorily described by a first-order single-reaction model. In addition, combustion runs of one of the mixtures (consisting of activated carbon+50 wt % CuBr2, pyrolyzed at 700 °C) were performed in a quartz horizontal laboratory furnace. The analysis of the emissions and the solid residue proved the formation of brominated dioxins and furans at 300, 400, and 500 °C, with a maximum yield at 300 °C (91.7 ng/g of total PBDD/Fs) and a higher bromination degree with increasing temperature.

Topics: Benzofurans; Bromides; Charcoal; Copper; Dioxins; Halogenation; Kinetics; Oxidation-Reduction; Temperature

Effective management of contaminated sediments is important for long-term human and environmental health, but site-management decisions are often made under high uncertainty and without the help of structured decision support tools. Potential trade-offs between remedial costs, environmental effects, human health risks, and societal benefits, as well as fundamental differences in stakeholder priorities, complicate decision making. Formal decision-analytic tools such as multicriteria decision analysis (MCDA) move beyond ad hoc decision support to quantitatively and holistically rank management alternatives and add transparency and replicability to the evaluation process. However, even the best decisions made under uncertainty may be found suboptimal in hindsight, once additional scientific, social, economic, or other details become known. Value of information (VoI) analysis extends MCDA by systematically evaluating the impact of uncertainty on a decision. VoI prioritizes future research in terms of expected decision relevance by helping decision makers estimate the likelihood that additional information will improve decision confidence or change their selection of a management plan. In this study, VoI analysis evaluates uncertainty, estimates decision confidence, and prioritizes research to inform selection of a sediment capping strategy for the dibenzo-p-dioxin and -furan contaminated Grenland fjord system in southern Norway. The VoI model extends stochastic MCDA to model decisions with and without simulated new information and compares decision confidence across scenarios with different degrees of remaining uncertainty. Results highlight opportunities for decision makers to benefit from additional information by anticipating the improved decision confidence (or lack thereof) expected from reducing uncertainties for each criterion or combination of criteria. This case study demonstrates the usefulness of VoI analysis for environmental decisions by predicting when decisions can be made confidently, for prioritizing areas of research to pursue to improve decision confidence, and for differentiating between decision-relevant and decision-irrelevant differences in evaluation perspectives, all of which help guide meaningful deliberation toward effective consensus solutions.

Topics: Benzofurans; Decision Making; Decision Support Techniques; Dioxins; Environment; Geologic Sediments; Humans; Information Dissemination; Norway; Probability; Public Health; Stochastic Processes; Uncertainty; Water Pollutants, Chemical; Water Pollution

Treatment and disposal of fly ash in China are becoming increasingly difficult, since its production has steadily risen and its features are uncertain. The excess pollutant components of fly ash are the key factor affecting its treatment and resource utilization. In this study, fly ash samples collected from a power plant with circulating fluidized incinerators of municipal solid waste (MSW) located in Shandong Province (eastern China) were studied. The results showed that there were no obvious seasonal differences in properties of fly ash. The content of total salt, Zn, and pH exceeded the national standards and low-ring polycyclic aromatic hydrocarbons (PAHs) and polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (Fs) were the main organic components of fly ash for this power plant, which posed great threats to the surrounding environment. The amount of Zn of fly ash was higher than other heavy metals, which should be due to alkaline batteries of MSW. The leachate of fly ash had low concentrations of heavy metals and the main soluble components were sulfates and chlorides. The major mineral crystals of fly ash were SiO2, CaSO4, and Fe2O3. The main organic pollutants were low-ring PAHs, polychlorinated PCDDs, and low-chlorinated PCDFs, and concentrations were lower than the limiting values of the national regulations. Additionally, the distribution of PCDD/Fs had either a positive or a negative linear correlation with fly ash and flue gas, which was associated with the chlorinated degree of PCDD/Fs. The analysis was conducted to fully understand the properties of fly ash and to take appropriate methods for further comprehensive utilization.

Topics: Benzofurans; Calcium Sulfate; Coal Ash; Environmental Pollutants; Ferric Compounds; Hydrogen-Ion Concentration; Incineration; Metals, Heavy; Polychlorinated Dibenzodioxins; Polycyclic Aromatic Hydrocarbons; Silicon Dioxide; Solid Waste

Unintentionally produced persistent organic pollutants (UP-POPs) were determined in ambient air from around five secondary non-ferrous metal processing plants in China, to investigate the potential impacts of the emissions of these plants on their surrounding environments. The target compounds were polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (dl-PCBs), and polychlorinated naphthalenes (PCNs). The PCDD/F, dl-PCB, and PCN concentrations in the ambient air downwind of the plants were 4.70-178, 8.23-7520 and 152-4190 pg/m(3), respectively, and the concentrations upwind of the plants were lower. Clear correlations were found between ambient air and stack gas concentrations of the PCDD/Fs, dl-PCBs, and PCNs among the five plants, respectively. Furthermore, the UP-POPs homolog and congener patterns in the ambient air were similar to the patterns in the stack gas samples. These results indicate that UP-POPs emissions from the plants investigated have obvious impacts on the environments surrounding the plants.

Topics: Air Pollutants; Aluminum; Benzofurans; China; Copper; Dioxins; Gases; Metallurgy; Naphthalenes; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) belong to the group of persistent organic pollutants, highly toxic environmental pollutants that include hydrophobic compounds with the tendency to bioaccumulate. Earthworms (Eisenia andrei) were exposed to PCDD/Fs-contaminated soil, and changes in their lipophilic structures and the gene expression of their defense molecules were followed. Damage to the intestinal wall and adjacent chloragogenous tissue was observed. Further, the up-regulation of the expression of several genes was detected. On the basis of these results, the mechanism of the impact of PCDD/Fs on earthworms has been proposed. Dioxins that accumulate in the lipophilic structures cause an increase in reactive oxidative species that triggers oxidative stress followed by the gene expression of two molecules that play a role in protection against oxidant toxicity, calreticulin (CRT) and Hsp70. Moreover, the effect of microbial biomass on the expression of coelomic cytolytic factor (CCF), a pattern recognition receptor, was also observed.

Topics: Animals; Benzofurans; Dioxins; Gene Expression Regulation; Oligochaeta; Soil; Soil Pollutants

During 2009-2011 a monitoring programme for 17 polychlorinated dibenzo-p-dioxins (PCDDs)/polychlorinated dibenzofurans (PCDFs) and 12 dioxin-like polychlorinated biphenyls (DL-PCBs) was conducted in the Latvian food and feed market. Using ISO 17025-accredited analytical methodology, investigation of 121 food (milk, dairy products, meat, eggs, fish, fish products) and 66 feed samples (fish meal and oil, compound and mineral feed, vegetable and animal fats) was performed. Most samples showed contamination below the European Commission (EC) Regulation No. 1881/2006 and Commission Directive 2006/13/EC limits. Average total toxicological equivalent (total-TEQ(1998)) concentrations within the food sample groups, except fish and fish products, ranged between 0.41 and 15.1 pg total-TEQ(1998) g(-1) fat. Fish and fish products showed contamination levels from 0.18 to 46.0 pg total-TEQ(1998) g(-1) fresh weight (f.w.). Fifty-seven per cent of cod liver samples were non-compliant. The most contaminated feed samples were fish meal and fish oil. A comparison with WHO-TEF(2005) data is given.

Topics: Animal Feed; Animals; Benzofurans; Dairy Products; Eggs; Environmental Pollutants; Fish Oils; Fish Products; Fishes; Food Contamination; Latvia; Meat; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins

The remote oceans are among the most pristine environments in the world, away from sources of anthropogenic persistent organic pollutants (POP), but nevertheless recipients of atmospheric deposition of POPs that have undergone long-range atmospheric transport (LRAT). In this work, the background occurrence of gas and aerosol phase polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin like polychlorinated biphenyls (dl-PCB) is evaluated for the first time in the atmosphere of the tropical and subtropical Atlantic, Pacific, and Indian oceans. Thirty-nine air samples were collected during the eight-month Malaspina circumnavigation cruise onboard the R/V Hespérides. The background levels of dioxins and dl-PCBs remained very low and in many cases very close to or below the limit of detection. Expectedly, the levels of PCBs were higher than dioxins, PCB#118 being the most abundant compound. In the particular case of dioxins, octachlorodibenzo-p-dioxin (OCDD) was the most abundant PCDD/F congener. Distribution of dl-PCB is dominated by the gas phase, while for PCDD/F the aerosol phase concentrations were higher, particularly for the more hydrophobic congeners. The Atlantic Ocean presented on average the highest PCDD/F and dl-PCB concentrations, being lower in the southern hemisphere. The assessment of air mass back trajectories show a clear influence of continental source regions, and lower concentrations when the air mass has an oceanic origin. In addition, the samples affected by an oceanic air mass are characterized by a lower contribution of the less chlorinated dioxins in comparison with the furans, consistent with the reported higher reaction rate constants of dibenzo-p-dioxins with OH radicals than those of dibenzofurans. The total dry atmospheric deposition of aerosol-bound ∑PCDD/F and ∑dl-PCB to the global oceans was estimated to be 354 and 896 kg/year, respectively.

Topics: Aerosols; Air; Air Pollutants; Atlantic Ocean; Atmosphere; Benzofurans; Biphenyl Compounds; Gases; Geography; Indian Ocean; Oceans and Seas; Pacific Ocean; Polychlorinated Dibenzodioxins; Ships

This study investigated the cytotoxicity, genotoxicity, and growth inhibition effects of four different inorganic nanoparticles (NPs) such as aluminum (nAl), iron (nFe), nickel (nNi), and zinc (nZn) on a dibenzofuran (DF) degrading bacterium Agrobacterium sp. PH-08. NP (0-1,000 mg L(-1)) -treated bacterial cells were assessed for cytotoxicity, genotoxicity, growth and biodegradation activities at biochemical and molecular levels. In an aqueous system, the bacterial cells treated with nAl, nZn and nNi at 500 mg L(-1) showed significant reduction in cell viability (30-93.6 %, p < 0.05), while nFe had no significant inhibition on bacterial cell viability. In the presence of nAl, nZn and nNi, the cells exhibited elevated levels of reactive oxygen species (ROS), DNA damage and cell death. Furthermore, NP exposure showed significant (p < 0.05) impairment in DF and catechol biodegradation activities. The reduction in DF biodegradation was ranged about 71.7-91.6 % with single NPs treatments while reached up to 96.3 % with a mixture of NPs. Molecular and biochemical investigations also clearly revealed that NP exposure drastically affected the catechol-2,3-dioxygenase activities and its gene (c23o) expression. However, no significant inhibition was observed in nFe treatment. The bacterial extracellular polymeric materials and by-products from DF degradation can be assumed as key factors in diminishing the toxic effects of NPs, especially for nFe. This study clearly demonstrates the impact of single and mixed NPs on the microbial catabolism of xenobiotic-degrading bacteria at biochemical and molecular levels. This is the first study on estimating the impact of mixed NPs on microbial biodegradation.

Topics: Agrobacterium; Aluminum; Benzofurans; Biodegradation, Environmental; Iron; Nanoparticles; Nickel; Zinc

The occurrence of nineteen mixed halogenated (bromo-chloro) dibenzo-p-dioxins, dibenzofurans (PXDD/Fs) and biphenyls (PXBs) in a range of foods (n>100) was investigated. The analytical methodology used dual activated carbon column fractionation with high resolution mass spectrometric measurement (13,500-15,000 res). Occurrence was observed in most commonly consumed foods but the most frequent detections of these environmental contaminants were made in shellfish and offal. The concentrations of the individual compounds were condensed into toxic equivalents (TEQs) using recently reported relative potency values. Although representing only a small subset of the full range of toxic PXDD/Fs and PXBs, the TEQs estimated for these compounds ranged from 0.2% to approximately 15% (depending on the food matrix) of the corresponding TEQ for the fully chlorinated analogues. This finding is of great toxicological importance as it implies that a potentially greater magnitude of TEQ could be associated with the full range of toxic PXDD/Fs and PXBs, thus making a significant contribution to dioxin-like toxicity from the diet, to human exposure.

Topics: Benzofurans; Biphenyl Compounds; Dioxins; Environmental Pollutants; Food Contamination; Furans; Humans; Hydrocarbons, Brominated; Hydrocarbons, Chlorinated; Polychlorinated Dibenzodioxins

Chicken and duck eggs collected from three different areas in Vietnam were examined for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). These regions included a background area, an area sprayed with Agent Orange and the Bien Hoa airbase area where Agent Orange was handled by the US Army. The latter area now is inhabited and people keep their own laying hens. Egg samples were first screened with an in vitro reporter gene bioassay and a selection was analyzed by GC/HRMS. Samples from Bien Hoa airbase showed very high PCDD/F levels, up to 249 pg dioxin-equivalents (TEQ)/g fat, mainly due to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). In the sprayed areas, levels (3.2-8.2 pg TEQ g(-1)) were comparable to those observed in background areas (3.2-8.2 pg TEQ g(-1) fat). The estimated average consumption of 22 g d(-1) of the highly contaminated eggs will result in a 2-fold exceedance of the current exposure limits for adults and 5-fold for children, even without considering other contaminated food sources. This indicates a potential health risk from consumption of these highly contaminated eggs, which were not yet considered as a source for exposure to PCDD/Fs of people living in the highly contaminated areas.

Topics: 2,4-Dichlorophenoxyacetic Acid; 2,4,5-Trichlorophenoxyacetic Acid; Adult; Agent Orange; Animals; Benzofurans; Chickens; Child; Ducks; Eggs; Food Contamination; Humans; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Vietnam

This work assesses the influence of the operating conditions H2O2 dose (20 or 100% of the stoichiometric amount), temperature (20 or 70°C), and the presence of chloride in the oxidation medium in the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) during Fenton treatment of aqueous samples of 2-chlorophenol, 2-CP, one of the strongest precursor of PCDD/Fs. After 4h of oxidation in the experiments carried out with 20% H2O2 chlorinated phenoxyphenols and biphenyls, which are intermediates in PCDD/Fs formation, as well as PCDD/Fs were observed, resulting in concentrations 11 times higher than in the untreated sample. Additionally, when NaCl was also present in the reaction medium, PCDD/Fs were formed at higher extent, with a total concentration 74.4 times higher than in the untreated 2-CP solution. Results depicted a preferential formation of PCDFs over PCDDs, with dominance of lower chlorinated PCDD/Fs (tetra and penta-PCDD/Fs). Besides, the formation of the most toxic PCDD/Fs congeners (2,3,7,8-PCDD/Fs) was not favored under the operating conditions used in this work.

Topics: Benzofurans; Chlorides; Chlorophenols; Hydrogen Peroxide; Iron; Oxidation-Reduction; Polychlorinated Dibenzodioxins; Temperature

In Taiwan, a food safety crisis involving a presence of high concentrations of dioxin residues in duck eggs occurred in 2004. The dioxin content in duck meat sampled from supermarkets was also reported to be substantially higher than in products from other farm animals. Despite increased awareness of the potential for contamination and exposure to dioxins, the accumulation and elimination of dioxins in ducks have not been well characterized. In the present study, mule ducks were fed capsules containing polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) for 14 days and the trial was continued for another 28 days without PCDD/Fs supplementation. Ducks were sacrificed on the 14th, 28th, and 42nd days from the beginning of administration and samples of abdominal fat, breast, and liver tissue were obtained. The concentrations of PCDD/Fs were analyzed in the samples to investigate their distribution and elimination in various duck tissues. The bioaccumulation of PCDD/Fs in ducks was found to be tissue-dependent. In the abdominal fat, the bioconcentration factor was negatively correlated with the degree of chlorination. Conversely, more chlorinated PCDD/Fs (hexa- or hepta-congeners) were associated with higher bioconcentration in the liver and breast tissue. In terms of the efficiency of PCDD/Fs elimination, the liver was found to be the fastest, followed by the breast and the abdominal fat. The clearance rate positively correlated with the degree of chlorination, as determined by comparing the apparent elimination rate constant (k) of PCDD/Fs in various tissues. Overall, lower k values observed in this study imply that mule ducks have a reduced clearance of PCDD/Fs in comparison with layer and broiler chickens.

Topics: Animals; Benzofurans; Dioxins; Ducks; Environmental Pollutants; Taiwan

Between July 9-12, 1997, at least 400 tonnes of polyvinyl chloride (PVC) were consumed in a fire at the Plastimet Inc. plastics recycling facility in Hamilton, Ontario, Canada. This led to the release of contaminants, including highly toxic polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF). This study re-examines a composite soil sample collected shortly after the fire using state-of-the-art FT-ICR (Fourier transform ion cyclotron resonance) and GC × GC-TOF (comprehensive two-dimensional gas chromatography-time-of-flight) mass spectrometry. The FT-ICR experiments led to the identification of approximately 150 molecular formulas, corresponding to chlorinated and mixed chloro/bromo compounds. The majority of these are halogenated polycyclic aromatic hydrocarbons (halo-PAHs), including highly substituted (e.g., C14HCl9 and C16HCl9) and high molecular weight (e.g., C28H12Cl4) Cl-PAHs that have not been reported previously in environmental samples. Complementary GC × GC-TOF experiments resolved individual halo-PAHs, some of which were confirmed with available standards. The concentrations of the most abundant halo-PAH groups, C14H8Cl2 (22 μg/g) and C16H8Cl2 (20 μg/g) are much higher than reported dioxin values and comparable to the corresponding PAH groups C14H10 (12 μg/g) and C16H10 (19 μg/g). The high abundance of the halo-PAHs identified in this study highlights the need for further investigation into their environmental occurrence and risk.

Topics: Benzofurans; Environmental Monitoring; Environmental Pollutants; Fires; Fourier Analysis; Gas Chromatography-Mass Spectrometry; Hydrocarbons, Halogenated; Ontario; Polychlorinated Dibenzodioxins; Polycyclic Aromatic Hydrocarbons

The concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in 35 soil samples collected from Fildes Peninsula in the Antarctic, Ny-Ålesund in the Arctic, and Zhangmu-Nyalam in the Tibetan Plateau were reported in this study. A comparison of the total concentration and TEQ of PCDD/Fs at the Three Poles was conducted. Both the total concentration and TEQ of PCDD/Fs demonstrates a decreasing trend in the order of Zhangmu-Nyalam (mean: 26.22 pg/g, 0.37 pg I-TEQ/g)>Ny-Ålesund (mean: 9.97 pg/g, 0.33 pg I-TEQ/g)>Fildes Peninsula (mean: 2.18 pg/g, 0.015 pg I-TEQ/g) (p<0.05). In all samples, the congener and homologue profiles dominated with higher (seven and eight) chlorinated PCDD/Fs (more than 85% of the total mass percentage of PCDD/Fs) at the Three Poles. Finally, a FLEXPART backward simulation was used to preliminarily identify the potential local and regional anthropogenic sources of PCDD/Fs. The results imply that the air masses passing over surrounding regions with significant PCDD/F emissions might contribute to the occurrence of PCDD/Fs in both the Arctic and Tibetan Plateau.

Topics: Antarctic Regions; Arctic Regions; Benzofurans; Environmental Monitoring; Polychlorinated Dibenzodioxins; Soil; Soil Pollutants; Tibet

Due to its geographical peculiarities, the Republic of Maldives represents a case study of great interest for the investigation of persistent organic pollutants, from both a socio-economic and an ecological perspective. Thus, we conducted a first survey to assess the current status of polychlorinated dibenzo-p-dioxin (PCDD), polychlorinated dibenzofuran (PCDF) and dioxin-like polychlorinated biphenyl (DL-PCB) concentrations in Maldivian soils. The range for PCDD/F and DL-PCB soil concentrations was 0.01-49.3 pg WHO2005-TEQ g(-1) and 0.01-3.69 pg WHO2005-TEQ g(-1) dw respectively. PCDD/F concentrations exceeding several international soil guidelines were found in samples from locations in the proximity of local waste combustion sources. DL-PCB concentrations were lower than PCDD/Fs and comparable to those in previous reports from background areas and in areas with developing industrial and agricultural activities. PCDD/F and DL-PCB levels (expressed as WHO2005-TEQ) in soils were strongly correlated (r=0.89), which suggests that, in most of the sites, they are originated from the same emission sources. Results indicate that PCDD/F soil concentrations (expressed as WHO2005-TEQ) tend to decrease with the distance from the local pollution sources. Principal component analysis (PCA) showed that PCDD/Fs in the most polluted locations are mainly generated by waste combustion. These findings highlight the need for immediate changes in waste management policies in the Archipelago, in order to reduce the release of Persistent Organic Pollutants (POPs) in the fragile local environment.

Topics: Benzofurans; Environmental Monitoring; Environmental Pollution; Human Activities; Humans; Indian Ocean Islands; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Soil Pollutants; Waste Management

The World Health Organization recently proposed the inclusion of brominated congeners in addition to chlorinated congeners when computing the toxic equivalency (TEQ) of dioxin-like compounds (DLCs) in assessments of human health risks. In the present study, 12 polybrominated dibenzo-p-dioxins and furans (PBDD/Fs) were analyzed by gas chromatography/high resolution mass spectrometry in the composited, archived biosolids that were collected in 32 U.S. states and the District of Columbia from 94 wastewater treatment plants by the United States Environmental Protection Agency in its 2001 national sewage sludge survey. Two PBDDs and five PBDFs were detected in the biosolids composites at varying frequencies (40-100%) with a total mean concentration of 10,000 ng/kg dry weight (range: 630-42,800), of which 1,2,3,4,6,7,8-hepta-BDF constituted about 95% by mass. Relative to commercial polybrominated diphenyl ether (PBDE) formulations, the ratio of PBDD/Fs to PBDEs in biosolids was 55-times higher (∼ 0.002% vs ∼ 0.11%), which indicates potential PBDE transformation or possibly additional sources of PBDD/Fs in the environment. The TEQ contribution of PBDD/Fs was estimated at 162 ng/kg 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) (range: 15-672), which is equivalent to 75% (range: 12-96%) of the total TEQ in biosolids. The TEQ of DLCs released annually to U.S. soils as a result of the land application of biosolids was estimated at 720 g (range: 530-1600 g). Among all known DLCs determined in biosolids, brominated analogs contributed 370% more TEQ than did chlorinated congeners, which indicates the need to include brominated DLCs in the exposure and risk assessment of land-applied biosolids.

Topics: Benzofurans; Data Collection; Dioxins; Halogenated Diphenyl Ethers; Sewage; United States; United States Environmental Protection Agency

Increased electronic waste (e-waste) has raised public concerns regarding exposure to numerous toxic contaminants, particularly polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). In China, the body burdens of PCBs, PBDEs and PCDD/Fs are associated with thyroid hormones in populations from e-waste dismantling sites; however, it is unclear whether this association occurs in children. In this study, we determined the serum levels of PCBs, PBDEs and PCDD/Fs and the endocrine hormones including free triiodothyronine (FT3), total triiodothyronine (TT3), free thyroxine (FT4), total thyroxine (TT4), thyroid-stimulating hormone (TSH), adrenocorticotropic hormone (ACTH), cortisol and growth hormone (GH) in 21 children from an e-waste dismantling area and 24 children from a control area. The results showed that the mean levels of ∑PCBs and ∑PBDEs in the exposure group were significantly higher than in the control group (40.56 and 32.09 ng g(-1) lipid vs. 20.69 and 8.43 ng g(-1) lipid, respectively, p<0.01 for each), and the mean level of ∑PCDD/Fs in the exposure group was higher than in the control group, but the difference was not significant (206.17 vs. 160.27 pg g(-1) lipid, p>0.05). For the endocrine hormones, we did not find significant differences between the exposed and control groups, although the mean levels of FT3, TT3, TT4, ACTH, cortisol and GH were higher, whereas the mean levels of FT4 and TSH were lower in the exposed group. The mean level of ∑PBDEs was positively correlated with the mean levels of ∑PCBs (r=0.60, p<0.05) and ∑PCDD/Fs (r=0.61, p<0.05). Furthermore, the mean level of ∑PBDEs was positively correlated with ACTH (r=0.61, p<0.05). In conclusion, our data suggested that exposure to e-waste dismantling environment increased the body burdens of PCBs and PBDEs in local children and that these contaminants released from the e-waste might contribute to abnormal changes in hormone levels.

Topics: Benzofurans; Child; China; Dioxins; Electronic Waste; Endocrine Disruptors; Environmental Exposure; Environmental Pollutants; Female; Halogenated Diphenyl Ethers; Hormones; Humans; Male; Polychlorinated Biphenyls

A comprehensive approach was taken to characterize the polyhalogenated dibenzo-p-dioxin and dibenzofuran contents of fire debris. Household and electronics fire simulations were performed to create samples representative of those firefighters most typically come in contact with. Sample analysis was performed using GC×GC-TOFMS to provide a comprehensive profile of the halogenated dioxins and furans present among the two types of fire debris. Both the household fire and electronics fire simulations produced a significant amount of polybrominated dibenzofurans. Only the electronics rich fire simulation produced mixed halogenated (Br/Cl) dibenzofurans in amounts above the limit of detection of the analytical method. Of the mixed halogenated dibenzofurans identified, a majority were those having no commercially available standard to allow for specific congener identification. GC×GC-TOFMS was extremely beneficial for the identification of compound classes due to the manner in which compounds classify in the two-dimensional chromatographic plane, thus aiding data reduction for these materials.

Topics: Air Pollutants; Benzofurans; Dioxins; Electrons; Fires; Gas Chromatography-Mass Spectrometry; Halogenation

The European Water Framework Directive (WFD) establishes a framework for the protection and improvement of all water bodies including transitional waters; its final objective is to achieve at least 'good status' by 2015. In the present work, a hierarchical sampling design was applied to analyze the influence of anthropogenic inputs on the spatial distribution of metals, polychlorinated dibenzo-p-dioxins (PCDDs) dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in sediment at four areas in Pialassa Baiona coastal lagoon. In order to assess the chemical status, levels of priority substances and other pollutants were compared with the recently developed national Environmental Quality Standards (EQS) and site specific background levels for metals. Levels of mercury and PCBs were particularly high and exceeded their national EQS values at all sampled areas, thus not contributing to the achievement of a good chemical status of this transitional water body according to the WFD classification.

Topics: Benzofurans; Dioxins; Environmental Monitoring; Environmental Pollutants; Geologic Sediments; Halogenated Diphenyl Ethers; Italy; Metals, Heavy; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins

The bromophenoxy radicals (BPRs) are key intermediate species involved in the formation of polybrominated dibenzo-p-dioxin/dibenzofurans (PBDD/Fs). In this work, the formation of BPRs from the complete series reactions of 19 bromophenol (BP) congeners with H and OH radicals were investigated theoretically by using the density functional theory (DFT) method and the direct dynamics method. The geometries and frequencies of the reactants, transition states, and products were calculated at the MPWB1K/6-31+G(d,p) level, and the energetic parameters were further refined by the MPWB1K/6-311+G(3df,2p) method. The rate constants were evaluated by the canonical variational transition-state (CVT) theory with the small curvature tunneling (SCT) contribution over a wide temperature range of 600-1200K. The present study indicates that the reactivity of the O-H bonds in BPs as well as the formation potential of BPRs from BPs is strongly related to the bromine substitution pattern. The obtained results can be used for future estimates of PBDD/F emissions quantity based on the well estimated PCDD/F inventory.

Topics: Benzofurans; Bromine; Dioxins; Hydrocarbons, Brominated; Hydrogen; Hydroxyl Radical; Kinetics; Phenols; Temperature

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (DL-PCBs), polybrominated diphenyl ethers (PBDEs), and hexachlorobenzene (HCB) concentrations were determined in abdominal fat samples from 30 cattle. The relationships between chemicals, age, and gender were investigated. The concentration of PCDD/Fs ranged from 0.01 to 1.36 pg TEQ g(-1) fat, DL-PCBs ranged from 0.17 to 1.64 pg TEQ g(-1) fat, PBDEs ranged from 135 to 725 pgg(-1) fat, and HCB ranged from 25.5 to 2061 pgg(-1) fat. A comparison between cattle's age and gender vs. the concentration of contaminants revealed higher concentrations of PCDD/Fs and DL-PCBs in cattle aged more than 3 years; no difference between genders was apparent. Moreover, the concentrations of PBDEs in cattle fat did not correspond with the age of cattle. Relative to cattle 1.5-2.5 years of age, cattle aged 3 and 4 years had higher concentration of HCB but the concentration difference was not clear at age 5. Human exposures to these compounds from beef sources were calculated based on beef consumption.

Topics: Animals; Benzofurans; Cattle; Environmental Exposure; Environmental Pollutants; Fats; Female; Food Contamination; Gas Chromatography-Mass Spectrometry; Halogenated Diphenyl Ethers; Hexachlorobenzene; Humans; Male; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Republic of Korea

Rhodococcus sp. strain p52, a previously isolated dibenzofuran degrader, could effectively inhibit the growth of cyanobacteria, including species of Microcystis, Anabaena, and Nodularia. When strain p52 was inoculated at the concentration of 7.7×10(7) CFU/ml, 93.5% of exponentially growing Microcystis aeruginosa (7.3×10(6) cells/ml initially) was inhibited after 4 day. The threshold concentration for its algicidal activity against M. aeruginosa was 7.7×10(6) CFU/ml. Strain p52 exerted algicidal effect by synthesizing extracellular substances, which were identified as trans-3-indoleacrylic acid, DL-pipecolic acid, and L-pyroglutamic acid. The effective concentrations of trans-3-indoleacrylic acid and DL-pipecolic acid against M. aeruginosa were tested to be 0.5 mg/l and 5 mg/l, respectively.

Topics: Anabaena; Anti-Bacterial Agents; Antibiosis; Benzofurans; DNA, Bacterial; Indoles; Microcystis; Molecular Sequence Data; Nodularia; Pipecolic Acids; Pyrrolidonecarboxylic Acid; Rhodococcus; Sequence Analysis, DNA

The construction in Constantí (Tarragona County, Catalonia) of the first, and up till now the only hazardous waste incinerator (HWI) in Spain, finished in 1999. In this study, we measured the concentrations of a number of organic substances determined in blood and urine of the HWI workers. Samples of 18 men and 9 women, classified according to their respective workplaces, were collected in 2011, after approximately 12 years of regular operations in the facility. The current results were compared with those of the baseline survey, as well as with the most recent surveys performed in 2008, 2009 and 2010. Plasma analyses were carried out for hexachlorobenzene (HCB), polychlorinated biphenyls (PCBs 28, 52, 101, 138, 153, and 180) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), while the levels of 2,4- and 2,5-dichlorophenol (DCP), 2,4,5- and 2,4,6-trichlorophenol (TCP), pentachlorophenol (PCP) and 1-hydroxypyrene (1-HP) were measured in urine samples. In plasma, the mean concentrations were the following: 10.8μg/kg lipid for HCB; 0.8μg/kg lipid for PCB28; 0.3μg/kg lipid for PCB52; 0.5μg/kg lipid for PCB101; 42.2μg/kg lipid for PCB138; 18.5μg/kg lipid for PCB153, and 51.2μg/kg lipid for PCB180. For PCDD/Fs, the mean concentration was 4.6ng I-TEQ/kg lipid (4.7ng WHO-TEQ/kg lipid). These levels, as well as those found in urine samples, are in agreement with the data of previous surveys performed in the same area. The current results in HWI workers do not show any evident sign of occupational exposure to PCDD/Fs and other organic substances. However, these results must be considered only as an indication of potential exposure, as the study presents notable limitations, such as the reduced number of participants and the lack of data relative to the air concentrations of chemicals. Consequently, general conclusions cannot be derived and the results should not be used as a basis for the implementation of industrial hygiene measures in other HWIs.

Topics: Benzene Derivatives; Benzofurans; Body Burden; Chlorophenols; Dioxins; Environmental Monitoring; Environmental Pollutants; Female; Hazardous Waste; Hexachlorobenzene; Humans; Incineration; Male; Occupational Exposure; Polychlorinated Biphenyls; Pyrenes; Refuse Disposal; Spain

In 2011, a joint World Health Organization (WHO) and United Nations Environment Programme (UNEP) expert consultation took place, during which the possible inclusion of brominated analogues of the dioxin-like compounds in the WHO Toxicity Equivalency Factor (TEF) scheme was evaluated. The expert panel concluded that polybrominated dibenzo-p-dioxins (PBDDs), dibenzofurans (PBDFs), and some dioxin-like biphenyls (dl-PBBs) may contribute significantly in daily human background exposure to the total dioxin toxic equivalencies (TEQs). These compounds are also commonly found in the aquatic environment. Available data for fish toxicity were evaluated for possible inclusion in the WHO-UNEP TEF scheme (van den Berg et al., 1998). Because of the limited database, it was decided not to derive specific WHO-UNEP TEFs for fish, but for ecotoxicological risk assessment, the use of specific relative effect potencies (REPs) from fish embryo assays is recommended. Based on the limited mammalian REP database for these brominated compounds, it was concluded that sufficient differentiation from the present TEF values of the chlorinated analogues (van den Berg et al., 2006) was not possible. However, the REPs for PBDDs, PBDFs, and non-ortho dl-PBBs in mammals closely follow those of the chlorinated analogues, at least within one order of magnitude. Therefore, the use of similar interim TEF values for brominated and chlorinated congeners for human risk assessment is recommended, pending more detailed information in the future.

Topics: Animals; Benzofurans; Dioxins; Dose-Response Relationship, Drug; Environmental Exposure; Environmental Monitoring; Humans; Polybrominated Biphenyls; Risk Assessment; Soil Pollutants; Toxicity Tests

A total synthesis of the proposed structures of fulicineroside and its aglycone fulicinerine is reported. The tetrasubstituted dibenzofuran substructure was accessible either through a Pd-mediated ortho-metalation or by an Ir-catalyzed meta-borylation. The synthesis of the β,β,α-linked trisaccharide consisting of D-olivose, L-rhodinose, and L-rhamnose was challenged by the unprecedented β-linked rhodinose. A Pd-catalyzed β-selective glycosylation of a 4-epi-rhodinose and a subsequent Mitsunobu inversion provided selectively the β-linked L-rhodinose-L-rhamnose disaccharide. Comparison with the reported data for the natural product and the aglycone suggests a misassignment of the structure of the natural product.

Topics: Benzofurans; Biological Products; Deoxy Sugars; Disaccharides; Glycosides; Glycosylation; Trisaccharides

This study presents a detailed mechanistic and kinetic investigation that explains the experimentally observed high yields of formation of polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) from the polybrominated diphenyl ethers (PBDEs), commonly deployed in brominated flame retardants (BFRs). Theoretical calculations involved the accurate meta hybrid functional of M05-2X. The previously suggested pathways of debromination and generation of bromophenols/bromophenoxys/bromobenzenes were found to be unimportant corridors for the formation of PBDD/Fs. A loss of an ortho Br or H atom from PBDEs, followed by a ring-closure reaction, is the most accessible pathway for the production of PBDFs via modest reaction barriers. The initially formed peroxy-type adduct (RO₂) is found to evolve in a complex, nevertheless very exoergic, mechanism to produce PBDDs. Results indicate that, degree and pattern of bromination, in the vicinity of the ether oxygen bridge, has a minor influence on governing mechanisms and that even fully brominated isomers of BFRs are capable of forming PBDD/Fs. We thoroughly discuss bimolecular reactions of PBDEs with Br and H, as well as the Br-displacement reaction by triplet oxygen. The rate of the Br-displacement reaction significantly exceeds that of the unimolecular inititiation reactions due to loss of ortho Br or H. Results presented herein address conclusively the intriguing question of how PBDEs form PBDD/Fs, a matter that has been in the center of much debate among environmental chemists.

Topics: Benzofurans; Bromine; Dioxins; Halogenated Diphenyl Ethers; Kinetics

Two cross-bridged cyclen-based macrocycles with two trans-N-acetic acid arms, one having a dibenzofuran (DBF) moiety as the bridge, H2L1, and the other a diphenyl ether (DPE) one, H2L2, were synthesized. Both compounds behave as "proton sponges." The thermodynamic stability constants for the Cu(2+), Zn(2+), Al(3+), and Ga(3+) complexes of both compounds were determined. They exhibit an excellent thermodynamic selectivity for copper(II), ensuring that metal ions largely present in the human body do not interfere with the copper(II) chelates. All complexes are very slow to form, and [CuL2] and [CuL1] are extremely inert to demetallate, especially [CuL2]. The acid-assisted dissociation of [CuL1] led to a half-life of 4.28 h in 5 M HCl at 363.2 K, while [CuL2] needed harsher conditions of 12 M HCl at 363.2 K with a half-life of 30.8 days. To the best of our knowledge, [CuL2] exhibits the highest half-life value for a copper(II) complex of a polyazamacrocycle derivative reported in the literature until now. Single crystal X-ray diffraction determined for [Cu(H2L1)](ClO4)2 showed the copper center in a distorted octahedral environment bound to the N4O donors of the macrobicycle and one oxygen atom from a carboxylic arm, while for [CuL2] it showed the copper center in a trigonal bipyramid geometry only bound to the donors of the macrobicycle and leaving the carboxylate arms away from the coordination sphere. UV-vis-NIR and X-band EPR spectra showed that in [CuL1] the copper center adopts a distorted compressed octahedral environment, which is the only structure found in solution for this complex, while in [CuL2] a similar environment was found in the first stages of its slow formation but reached a square-pyramidal geometry upon stabilization. The acetate arms play therefore an important role during the formation of the complex, as revealed by the comparison of its complexation behavior with the corresponding parent compounds.

Topics: Acetates; Benzofurans; Chelating Agents; Coordination Complexes; Copper; Crystallography, X-Ray; Cyclams; Heterocyclic Compounds; Macrocyclic Compounds; Models, Molecular; Phenyl Ethers; Spectrum Analysis; Thermodynamics

Hyperuricemia (too much uric acid in the blood) is the predisposing condition for gout and is associated with hypertriglyceridemia, diabetes mellitus, and coronary artery disease. Polychlorinated dibenzo-p-dioxins and dibenzo-furans (PCDD/Fs) cause renal toxicity and elevate uric acid. The aim of this analysis was to investigate and clarify the effect of moderate-to-high PCDD/F exposure on hyperuricemia risk.. In this cross-sectional study, we recruited 1531 healthy participants living near a deserted pentachlorophenol factory. We measured serum levels of 17 2,3,7,8-substituted PCDD/Fs, and then examined associations between the main predictor variable, serum TEQ(DF-2005) (total PCDD/Fs 2005 World Health Organization [WHO] toxic equivalency [TEQ]), and dependent variables such as uric acid, glomerular filtration rates, and hyperuricemia risk.. We observed a strong monotonic inverse relationship between serum TEQ(DF-2005) quartiles and the estimated glomerular filtration rate after adjusting for confounding factors (Men: β were 0, -4.7, -6.2, and -14.8; Women: β were 0, -6.7, -12.9, and -21.5). In addition, we observed a suggestive positive trend between serum TEQDF-2005 quartiles and uric acid only in men after adjusting for confounding factors (Men: β were 0, 0.40, 0.36, and 0.59; P for trend <0.05). Men with serum TEQ(DF-2005) higher than the reference group's (<7.4 pg WHO(2005)-TEQ(DF/g) lipid) had a higher hyperuricemia risk after adjusting for confounding factors (25th to <50th percentile, adjusted odds ratio [AOR] = 2.20 [95% confidence interval {CI} = 1.30-3.73]; 50th to <75th percentile, AOR = 1.86 [95% CI = 1.08-3.22]; ≥ 75th percentile, AOR = 3.00 [95% CI = 1.69-5.31]).. We conclude that serum TEQ(DF-2005) is an important determinant of serum uric acid levels and heightens the risk of hyperuricemia in general populations.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Benzofurans; Cross-Sectional Studies; Environmental Exposure; Environmental Pollutants; Female; Humans; Hyperuricemia; Male; Middle Aged; Polychlorinated Dibenzodioxins; Risk Assessment; Sex Factors; Young Adult

Rhodium-catalyzed intramolecular C-H arylation of 2-aryloxybenzoic acids proceeded accompanied by decarbonylation to give dibenzofuran derivatives in high yields. The present reaction is widely applicable to substrates bearing various functionalities.

Topics: Benzoates; Benzofurans; Catalysis; Hydrogen Bonding; Molecular Structure; Rhodium; Stereoisomerism

Photolytic transformation profiles of technical hexabromocyclododecane (HBCD) and technical decabromodiphenyl ether (DecaBDE) in flame-retarded textiles exposed to natural sunlight were compared. Textiles that contained approximately 4% HBCDs by weight showed no substantial loss of any of the HBCD diastereomers during the entire exposure period (371 days), indicating that they were resistant to sunlight, that is, that debromination and isomerization of HBCD diastereomers did not occur under the experimental conditions. Exposure of a textile treated with technical DecaBDE resulted in the formation of polybrominated dibenzofurans (PBDFs) as products of photodecomposition of polybrominated diphenyl ethers present in the technical DecaBDE. After 329 days of exposure, the total PBDF concentration reached a maximum of 27 000 ng g(-1), which was approximately 10 times the initial concentration. During the experiment, di- to hexa-BDF congener concentrations increased continuously. Although the concentrations of PBDFs in the textiles were 4–5 orders of magnitude lower than the concentrations of polybrominated diphenyl ethers, it is important to note that PBDFs were formed as a result of sunlight exposure during normal use of products treated with technical DecaBDE.

Topics: Benzofurans; Flame Retardants; Halogenated Diphenyl Ethers; Halogenation; Hydrocarbons, Brominated; Isomerism; Photolysis; Sunlight; Textiles

Some substances are mixtures of very large number of constituents which vary widely in their properties, and thus also in terms of their environmental fate and the hazard that they may pose to humans and the environment. Examples of such substances include industrial chemicals such as the chlorinated paraffins, technical pesticides such as toxaphene, and unintended combustion side products, such as mixed halogenated dibenzo-p-dioxins and dibenzofurans. Here we describe a simple graphical superposition method that could precede a more detailed hazard assessment for such substances. First, partitioning and degradation properties for each individual constituent of a mixture are estimated with high-throughput quantitative structure-property relationships. Placed in a chemical partitioning space, i.e. a coordinate system defined by two partitioning coefficients, the mixtures appear as 'clouds'. When model-derived hazard assessment metrics, such as the potential for bioaccumulation and long range transport, are superimposed on these clouds, the resulting maps identify the constituents with the highest value for a particular parameter and thus potentially the greatest hazard. The maps also indicate transparently how the potential for long range transport and bioaccumulation is dependent on structural attributes, such as chain length, and the degree and type of halogenation. In contrast to previous approaches, in which the mixture is represented by a single set of properties or those of a few selected constituents, the whole range of environmental fate behaviors displayed by the constituents of a mixture are being considered. The approach is illustrated with three sets of chemical substances.

Topics: Animals; Benzofurans; Complex Mixtures; Dioxins; Environmental Monitoring; Environmental Pollutants; Halogenation; Humans; Models, Biological; Models, Chemical; Paraffin; Toxaphene

The contamination profiles of polybrominated dibenzo-p-dioxins (PBDDs), dibenzofurans (PBDFs), diphenyl ethers (PBDEs), and mixed monobromo/chloro dibenzo-p-dioxins (PXDDs) and dibenzofurans (PXDFs) were determined in the tissue of Baltic wild salmon and compared with those of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs). Out of the analyzed PXDD/DFs, only the 3-B-2,7,8-triCDF was detected (in the concentration range of 0.039-0.075 pg g(-1) fresh weight (f.w.)). The toxic equivalents (TEQs) for analyzed PBDD/DFs (0.074-0.142 pg TEQ g(-1) f.w.) were found to contribute on average 2.1% to the total PCDD/DF-PBDD/DF-TEQ. The total concentrations of 27 PBDE congeners were in the range of 1.3-5.6 ng g(-1) f.w., with an average of 3.3 ng g(-1) f.w. The levels of PCDD/DFs and PCBs were found to be in the range of 4.53-14.6 pg WHO(2005)-PCDD/DF-PCB-TEQ g(-1) f.w., and concentrations of these compounds in most of the analyzed samples were above the maximum levels specified in Commission Regulation (EU) No. 1259/2011. Good correlation was observed between WHO(2005)-PCDD/DF-TEQ and WHO(2005)-PCB-TEQ (r(2) = 0.98), and these parameters were well correlated with the total sum of PBDE concentrations (r(2) = 0.91 and r(2) = 0.94, respectively). The results suggest that the consumption of Baltic wild salmon has no crucial impact on the average POP intake for typical Latvians.

Topics: Animals; Benzofurans; Diet; Environmental Pollutants; Female; Male; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Salmo salar

This is the first to elucidate the distribution and sources of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDFs), and dioxin-like polychlorinated biphenyls in the waters from Kanzaki River, which is one of the most heavily polluted rivers in Japan. The World Health Organization (WHO)-toxic equivalent quantities (TEQs) in waters from the mainstream exceeded the Japanese environmental standard (1.0 pg-TEQ/L). The PCDD/PCDFs were dominated by highly chlorinated DFs, which predominantly contributed to the WHO-TEQs, suggesting that the main causes would be the incineration-related wastes. To find the sources, the dioxin congener concentrations in water and sediment samples from its tributary small waterways were determined. Abnormally high WHO-TEQs were detected in a water (50 pg-TEQ/L) and a sediment sample (41,000 ng-TEQ/kg dry weight) near the industrial solid waste incinerators (ISWIs). The PCDD/PCDF characteristics agreed well with those of the incinerator-related wastes as seen in the mainstream. These facts indicate that the dioxin pollution in the mainstream could be largely related to the industrial wastes from the ISWIs. Here, a TEQ apportionment method was used to understand the contribution of the pyrogenic sources to the WHO-TEQs. The average contribution ratios of the pyrogenic sources to WHO-TEQs were more than 80% for river waters from the mainstream, indicating that the elevated WHO-TEQs in the mainstream had been largely caused by the ISWIs.

Topics: Benzofurans; Cities; Geography; Geologic Sediments; Incineration; Industrial Waste; Japan; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Rivers; Solid Waste; Water; Water Pollutants, Chemical; Water Pollution

A study was conducted to observe the changes in polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F) levels and congener profiles in the flue gas of a hazardous waste incinerator during two start-up periods. Flue gas samplings were performed simultaneously through Air Pollution Control Devices (APCDs) (including boiler outlet, electrostatic precipitator (ESP) outlet, wet scrubbers (WS) outlet, and activated carbon (AC) filter outlet) in different combustion temperatures during a planned cold (long) start-up and an unplanned warm (short) start-up. The results showed that PCDD/F concentrations could be elevated during the start-up periods up to levels 3-4 times higher than those observed in the normal operation. Especially lower combustion temperatures in the short start-ups may cause high PCDD/F concentrations in the raw flue gas. Assessment of combustion temperatures and Furans/Dioxins values indicated that surface-catalyzed de novo synthesis was the dominant pathway in the formation of PCDD/Fs in the combustion units. PCDD/F removal efficiencies of Air Pollution Control Devices suggested that formation by de novo synthesis existed in ESP also when in operation, leading to increase of gaseous phase PCDD/Fs in ESP Particle-bound PCDD/Fs were removed mainly by ESP and WS, while gaseous phase PCDD/Fs were removed by WS, and more efficiently by AC filter.. This paper evaluates PCDD/F emissions and removal performances of APCDs (ESP, wet scrubbers, and activated carbon) during two start-up periods in an incinerator. The main implications are the following: (1) start-up periods increase PCDD/F emissions up to 2-3 times in the incinerator; (2) low combustion temperatures in start-ups cause high PCDD/F emissions in raw gas; (3) formation of PCDD/Fs by de novo synthesis occurs in ESP; (4) AC is efficient in removing gaseous PCDD/Fs, but may increase particle-bound ones; and (5) scrubbers remove both gaseous and particle-bound PCDD/Fs efficiently.

Topics: Air Pollutants; Air Pollution; Benzofurans; Environmental Monitoring; Gas Chromatography-Mass Spectrometry; Hazardous Waste; Incineration; Polychlorinated Dibenzodioxins; Turkey

Two artificial wastes (A and B) whose contents reflect regional differences in municipal solid waste composition, were used to investigate the thermal formation of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), biphenyls (PCBs), and naphthalenes (PCNs) during incineration. Flue gas samples were simultaneously collected at three ports in the post-combustion zone corresponding to flue gas temperatures of 400, 300, and 200 °C. The combustion of Waste B, which had a higher chlorine and metal content than Waste A, produced greater levels of highly-chlorinated homologues, as demonstrated by a higher degree of chlorination. The total concentrations of PCDDs, PCDFs, PCBs, and PCNs formed in the combustion of both wastes increased as temperature decreased along the convector. There were no significant differences in total concentrations between Waste A and Waste B combustion at specific temperatures, with exception of PCDFs at 400 °C. Orthogonal Projections to Latent Structures Discriminant Analysis (OPLS-DA) modeling, used to evaluate the data for all compound groups, suggest that during flue gas quenching at temperatures of 400 °C low-chlorinated homologues are preferentially formed in the presence of copper, which is known to be a very active catalyst for this process. At 300 and 200 °C, the formation of highly-chlorinated homologues is favored.

Topics: Air Pollutants; Benzofurans; Dioxins; Environmental Monitoring; Hot Temperature; Incineration; Naphthalenes; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins

Exposure to environmental pollutants such as dibenzofurans and furans is linked to the pathophysiology of several diseases. Dibenzofuran (DBF) is listed as a pollutant of concern due to its persistence in the environment, bioaccumulation and toxicity to humans, being associated with the development of lung diseases and cancers, due to its extremely toxic properties such as carcinogenic and teratogenic. Mitochondria play a key role in cellular homeostasis and keeping a proper energy supply for eukaryotic cells is essential in the fulfillment of the tissues energy-demand. Therefore, interference with mitochondrial function leads to cell death and organ failure. In this work, the effects of DBF on isolated rat liver mitochondria were analyzed. DBF exposure caused a markedly increase in the lag phase that follows depolarization induced by ADP, indicating an effect in the phosphorylative system. This was associated with a dose-dependent decrease in ATPase activity. Moreover, DBF also increased the threshold to the induction of the mitochondrial permeability transition (MPT) by calcium. Pretreatment of mitochondria with DBF also increased the concentration of carboxyatractyloside (CAT) necessary to abolish ADP phosphorylation and to induce the MPT, suggesting that DBF may interfere with mitochondria through an effect on the adenine nucleotide translocase (ANT). By co-immunoprecipitating ANT and Cyclophilin D (CypD) following MPT induction, we observed that in the presence of DBF, the ratio CypD/ANT was decreased. This demonstrates that DBF interferes with the ANT and so prevents CypD binding to the ANT, causing decreased phosphorylative capacity and inhibiting the MPT, which is also reflected by an increase in calcium retention capacity. Clarifying the role of pollutants in some mechanisms of toxicity, such as unbalance of bioenergetics status and mitochondrial function, may help to explain the progressive and chronic evolution of diseases derived from exposure to environmental pollutants.

Topics: Adenosine Triphosphatases; Animals; Benzofurans; Cyclophilins; Environmental Pollutants; Male; Membrane Potential, Mitochondrial; Mitochondria, Liver; Mitochondrial ADP, ATP Translocases; Oxygen; Peptidyl-Prolyl Isomerase F; Rats; Rats, Wistar

This article presents the results of the most recent estimation of polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) atmospheric emissions in Portugal, which has covered the period 2004-2009 and includes 27 emission sources types. The results are compared with previous emissions inventories published for Portugal. The main objective of this work is to provide relevant information about the amounts of the compounds that are released into the atmosphere in Portugal, and identify their major sources and trends. The methodology involved the identification of relevant sources, the collection of information to characterize these sources, the selection of appropriate emission factors and their application to estimate the emissions. Furthermore, several studies conducted in Portugal were considered, namely reports from PCDD/PCDF measurements performed in some industrial facilities. The inventory covered 27 emission sources types. However the results show that only 8 were relevant, i.e. with emission amounts greater than 1 g I-TEQ year(-1). The total emissions of PCDD/PCDF in Portugal reached between 40 and 105 g I-TEQ year(-1), for the period of 2004-2009. The largest emission source and at same time with greater variation is forest fires, with emissions between 3 g I-TEQ year(-1) and 67 g I-TEQ year(-1) in 2008 and 2005, respectively. Excluding the emissions from forest fires, the total emission is more or less constant over the years and around 37 g I-TEQ year(-1).

Topics: Air Pollutants; Air Pollution; Atmosphere; Benzofurans; Dioxins; Environmental Monitoring; Industry; Portugal

Mercury levels were measured in colonial waterbird eggs collected from two sites in northern Alberta and one site in southern Alberta, Canada. Northern sites in the Peace-Athabasca Delta and Lake Athabasca were located in receiving waters of the Athabasca River which drains the oil sands industrial region north of Fort McMurray, Alberta. Temporal trends in egg mercury (Hg) levels were assessed as were egg stable nitrogen isotope values as an indicator of dietary change. In northern Alberta, California and Ring-billed Gulls exhibited statistically significant increases in egg Hg concentrations in 2012 compared to data from the earliest year of sampling. Hg levels in Caspian and Common Tern eggs showed a nonstatistically significant increase. In southern Alberta, Hg concentrations in California Gull eggs declined significantly through time. Bird dietary change was not responsible for any of these trends. Neither were egg Hg trends related to recent forest fires. Differences in egg Hg temporal trends between northern and southern Alberta combined with greater Hg levels in eggs from northern Alberta identified the likely importance of local Hg sources in regulating regional Hg trends. Hg concentrations in gull and Common Tern eggs were generally below generic thresholds associated with toxic effects in birds. However, in 2012, Hg levels in the majority of Caspian Tern eggs exceeded the lower toxicity threshold. Increasing Hg levels in eggs of multiple species nesting downstream of the oil sands region of northern Alberta warrant continued monitoring and research to further evaluate Hg trends and to conclusively identify sources.

Topics: Air Pollutants; Alberta; Animals; Benzofurans; Birds; Charadriiformes; Environmental Monitoring; Geography; Mercury; Nitrogen Isotopes; Oil and Gas Fields; Ovum; Polychlorinated Dibenzodioxins; Silicon Dioxide

Aucuparin is the most widely distributed biphenyl phytoalexin in the rosaceous subtribe Pyrinae, which includes the economically important fruit trees apple and pear. The biphenyl scaffold is formed by biphenyl synthase, which catalyzes biosynthesis of 3,5-dihydroxybiphenyl. Conversion of this precursor to aucuparin (3,5-dimethoxy-4-hydroxybiphenyl) was studied in cell cultures of Sorbus aucuparia after treatment with an elicitor preparation from the scab-causing fungus Venturia inaequalis. The sequence of the biosynthetic steps detected was O-methylation - 4-hydroxylation - O-methylation. The two alkylation reactions were catalyzed by distinct methyltransferases, which differed in pH and temperature optima as well as stability. Biphenyl 4-hydroxylase was a microsomal cytochrome P450 monooxygenase, whose activity was appreciably decreased by the addition of established P450 inhibitors. When fed to V. inaequalis-treated S. aucuparia cell cultures, radioactively labeled 3,5-dihydroxybiphenyl was not only incorporated into aucuparin but also into the dibenzofuran eriobofuran, the accumulation of which paralleled that of aucuparin. However, biphenyl 2'-hydroxylase activity proposed to be involved in dibenzofuran formation was detected in neither microsomes nor cell-free extracts in the presence of NADPH and 2-oxoglutarate, respectively. Nevertheless, a basis for studying biphenyl biosynthesis at the gene level is provided.

Topics: Ascomycota; Benzofurans; Biphenyl Compounds; Cells, Cultured; Cytochrome P-450 Enzyme System; Ketoglutaric Acids; Malus; Multienzyme Complexes; Phytoalexins; Pyrus; Sesquiterpenes; Sorbus

Temporal trends of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in mothers' milk are still quite rare. Data are particularly scarce when it comes to concentrations from the last decade, 2000 and onwards. The aims of the present study were to assess temporal trends of PCDD, PCDF and DL-PCB in mothers' milk from Stockholm, 1972-2011 and to compare the results with previous analysis of some of the older samples. The samples were analyzed by high resolution GC/MS and results were statistically evaluated for the periods, 1972-2011 and 2002-2011. The rate of which ∑PCDDs, ∑DL-PCBs and the ∑TEQ are decreasing (on pg/g fat WHO-TEQ2005) is higher in the last decade compared to the 40year period, 1972-2011. A similar trend is indicated, but not confirmed, for ∑TEQ of PCDFs, probably due to too many PCDF congeners below LOQ in the period 2002-2011. Concentrations of ∑PCDDs, ∑PCDFs, ∑DLPCBs and ∑TEQ, all expressed as pg/g fat on TEQ-WHO2005-basis, show a statistically significant decline over time, 5.8-6.8% per year, 1972-2011. The last ten years the annual declines for ∑PCDDs, ∑DL-PCBs and ∑TEQ are 9.2-11% and for ∑PCDF, 5.4%. Congener specific trend analysis, 2002-2001, of PCDDs and DL-PCBs showed the same pattern, while the PCDF congeners showed no such general trend. The results from the re-analysis showed good agreement with slightly lower ∑TEQ1998 pg/g fat concentrations in six out of seven samples and mean difference of 13% in ∑TEQ1998. The study shows that time series can be elongated from previous studies, as long as the sample population remains the same.

Topics: Adult; Benzofurans; Environmental Monitoring; Environmental Pollutants; Female; Gas Chromatography-Mass Spectrometry; Humans; Maternal Exposure; Milk, Human; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Sweden; Time Factors

The electrochemical degradation of 2-chlorophenol (2-CP) on boron-doped diamond (BDD) anodes was carried out using two electrolytes, NaCl and Na2SO4. Both electrolytes supported complete mineralization of 2-CP, but faster rates of degradation were observed in NaCl. After 4 h of oxidation, the total organic carbon (TOC) balance neared 100% with Na2SO4 for identifiable compounds, whereas 4 mM of TOC remained unidentified with NaCl. Since chlorophenols are known to be precursors of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), a rigorous assessment of intermediate products was carried out. When near complete mineralization was achieved, the use of NaCl resulted in the concentration of total PCDD/Fs increasing 2.68 × 10(4) times compared to the untreated sample, and to toxicity values several times higher than the maximum level established by U.S. Environmental Protection Agency for water ingestion. When Na2SO4 was used, the increase in total PCDD/Fs concentration was 134 times lower than with NaCl and there was no significant 2,3,7,8-PCDD/Fs formation. Thus, we emphasize the importance of electrolyte selection in electro-oxidation processes, especially when PCDD/Fs precursors are initially present or may be formed in the treated water samples.

Topics: Benzofurans; Chlorophenols; Electrochemistry; Electrolytes; Kinetics; Oxidation-Reduction; Polychlorinated Dibenzodioxins; Sodium Chloride; Solutions; Sulfates

A Rh-catalyzed tandem annulation and (5 + 1) cycloaddition was realized. 3-Hydroxy-1,4-enyne served as the new 5-carbon component for the (5 + 1) cycloaddition. Substituted carbazoles, dibenzofurans, and tricyclic compounds containing a cyclohexadienone moiety could be prepared efficiently. The identification of a byproduct suggests that metal carbene and ketene intermediates may be involved in the (5 + 1) cycloaddition.

Topics: Benzofurans; Carbazoles; Carbon; Catalysis; Cycloaddition Reaction; Cyclohexenes; Rhodium

A total of 84 samples of wild and farmed fish, cephalopods and fish oils for animal feeding, traded in Spain, were analysed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in 2009-2012, by gas chromatography-ion trap tandem mass spectrometry (GC-MS-MS). The method was optimised for screening at moderate costs, allowing PCDD/Fs determination at 1 pg World Health Organization-toxic equivalent quantities (WHO-TEQ) g⁻¹ wet weight (w w) and dl-PCBs at 0.02 pg WHO-TEQ g⁻¹ w w. Concentrations in fish and cephalopods ranged from values below the limit of detection to 1.7 pg g⁻¹ WHO-TEQ sum PCDD/Fs and dl-PCBs, considered as safe with regard to EU legislation. Higher levels were found in cod livers (5.4-54.2) and fish oils (3.3-30.7), with one noncompliant sample in each group.

Topics: Animals; Animals, Wild; Aquaculture; Benzofurans; Cephalopoda; Environmental Pollutants; European Union; Fish Oils; Fish Products; Fishes; Food Contamination; Food Inspection; Food, Preserved; Frozen Foods; Guideline Adherence; Health Policy; Health Promotion; Humans; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Seafood; Shellfish; Spain

This study investigated dioxins and dioxin-like polychlorinated biphenyls in gasses emitted from waste incinerators and thermal processes in central and western parts of India. The concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/DFs) ranged from 0.0070 to 26.8140 ng toxicity equivalent (TEQ)/Nm(3), and those of dioxin-like polychlorinated biphenyls (PCBs) ranged from 0.0001 × 10(-1) to 0.0295 ng TEQ/Nm(3). The characteristics of mean PCDD/F I-TEQ concentration and congener profiles were studied over all the samples of air. In particular, a pattern consisting of a low proportion of dioxin-like PCBs and high proportion of PCDDs/DFs was common for all the samples from incinerators and high-temperature processes.

Topics: Air Pollutants; Air Pollution; Benzofurans; Environmental Monitoring; Incineration; India; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins

Prenatal exposure to dioxins may result in many adverse health effects. However, the mechanisms by which dioxins are transferred from mother to fetus through the placenta are not well understood. The aim of this study was to investigate the differences in dioxin concentrations between maternal blood, the placenta, and cord blood in normal pregnant women, and to identify which individual congeners of these compounds are transferred from mother to fetus through the placenta.. Samples were collected from 19 pregnant Japanese women. Specific congeners of seven polychlorinated dibenzo-p-dioxins (PCDDs), 10 polychlorinated dibenzofurans (PCDFs), and four non-ortho polychlorinated biphenyls (PCBs) were analyzed.. The TEQ concentrations of PCDDs, PCDFs, and non-ortho PCBs were 8.03, 3.39, and 3.95 pg TEQ/g lipid, respectively, in the maternal blood; 8.78, 3.61, and 0.87 pg TEQ/g lipid in the placenta; and 4.33, 1.25, 1.08 pg TEQ/g lipid in the cord blood. Among specific congeners, 1,2,3,7,8-PentaCDD and 2,3,4,7,8-PentaCDF exhibited a placenta to maternal blood ratio greater than 1.0, while OctaCDD exhibited the greatest cord blood to placenta ratio. The cord blood to maternal blood ratio of total PCDDs was significantly higher than that of total PCDFs and total non-ortho PCBs.. The dioxin concentration in cord blood was approximately half of the amount in maternal blood, despite congeners showing a high toxic equivalency factor accumulating in the placenta. PCDDs were transferred more readily than PCDFs and non-ortho PCBs from maternal blood to the fetus through the placenta.

Topics: Adult; Benzofurans; Female; Fetal Blood; Humans; Japan; Maternal-Fetal Exchange; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Pregnancy

Dietary exposure to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) via fish consumption in two major electronic (e) waste sites: Guiyu (GY), Guangdong Province and Taizhou (TZ), Zhejiang Province, and dioxin-like activity in fish determined by H4IIE-luc bioassay. In the present study, all fish were below EU's maximum allowable concentration in muscle of fish (4 pg WHO-TEQ/g wet wt), except crucian (4.28 pg WHO-TEQ/g wet wt) and silver carps (7.49 pg WHO-TEQ/g wet wt) collected from GY rivers. Moreover, the residual concentration in bighead carp collected from GY (2.15 pg WHO-TEQ/g wet wt) was close to the EU's action level (3 pg WHO-TEQ/g wet wt) which gives "early warning" to the competent authorities and operators to take measures to eliminate contamination. In addition, results indicated that the maximum human intake of PCDD/Fs via freshwater fish consumption in GY was 4.31 pg WHO-TEQ/kg bw/day, which exceeds the higher end of the tolerable daily intake recommended by the WHO, EC-SCF and JECFA (1-4, 2 and 2.3 pg WHO-TEQ/kg bw/day respectively). Furthermore, H4IIE-luc cell bioassay provides a very sensitive and cost-efficient screening tool for assessing the overall dioxin-like toxicity in the study, and is therefore valuable for high-throughput environmental monitoring studies.

Topics: Animals; Benzofurans; Biological Assay; Carps; China; Dibenzofurans, Polychlorinated; Diet; Dioxins; Environmental Exposure; Fishes; Humans; Maximum Allowable Concentration; Muscle, Skeletal; Polychlorinated Dibenzodioxins; Tilapia

Previous studies reported that exposure to dioxins was associated with an increased risk of various diseases in general populations.. The aim of this study was to examine the association between levels of dioxins in blood and allergic and other diseases.. We conducted a cross-sectional study on 1,063 men and 1,201 women (aged 15-76 years), who were living throughout Japan and not occupationally exposed to dioxins, during 2002-2010. In fasting blood samples, polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like PCBs (DL-PCBs) were analyzed by isotope dilution high-resolution gas chromatography/mass spectrometry. We obtained information on life style and self-reported history of diseases using a questionnaire. Blood pressure, blood levels of hemoglobin A1c, and serum lipids were also measured. Multiple logistic regression models were used to analyze the association between dioxin levels in blood and various diseases.. Toxic equivalents of PCDDs/PCDFs and total dioxins showed significant inverse dose-response relationships with atopic dermatitis, after adjustments for potential confounders. The highest quartile for total dioxins had an adjusted odds ratio of 0.26 (95 % confidence interval 0.08-0.70) compared to the reference group (first quartile). The odds ratios for hypertension, diabetes mellitus, hyperlipidemia, gout in men, and gynecologic diseases in women significantly increased with increasing toxic equivalents of PCDDs/PCDFs, DL-PCBs, and total dioxins in blood.. The present findings suggest that background exposure to dioxins was associated with reduced risk of atopic dermatitis. The results also support the idea that low-level exposure to dioxins is associated with an increased risk of diabetes, hypertension, and hyperlipidemia.

Topics: Adolescent; Adult; Aged; Benzofurans; Cross-Sectional Studies; Dermatitis, Atopic; Diabetes Mellitus; Environmental Exposure; Female; Humans; Hyperlipidemias; Hypertension; Japan; Life Style; Male; Middle Aged; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Surveys and Questionnaires; Young Adult

In 1979, approximately 2,000 people in central Taiwan were accidentally exposed to polychlorinated biphenyls and dibenzofurans due to ingestion of contaminated cooking oil. This event was called Yucheng, "oil-syndrome" in Chinese. We followed the exposed persons and compared their cause-specific mortality with that of neighborhood referents 30 years after the accident.. We obtained age- and gender-matched referents from the 1979 neighborhoods of the exposed people. Cause-specific mortality was compared between exposed subjects (N=1803) and their neighborhood referents (N=5170) using standardized mortality ratios (SMR). Total person-years for the Yucheng subjects and neighborhood referents were 48,751 and 141,774, respectively.. The SMR for all causes (SMR=1.2, 95% CI: 1.1-1.3), diseases of the circulatory system (SMR=1.3, 95% CI: 1.0-1.6), and diseases of the musculoskeletal system and connective tissue (SMR=6.4, 95% CI: 2.8-12.7) were elevated in Yucheng subjects. Among Yucheng males, the SMRs for diseases of the digestive system (SMR=1.9, 95% CI: 1.2-2.8), malignant neoplasm of stomach (SMR=3.5, 95% CI: 1.5-7.0), and malignant neoplasm of lymphatic and hematopoietic tissue (SMR=3.0, 95% CI: 1.1-6.6) were increased. The SMR for total neoplasms was increased (SMR=1.3, 95% CI: 0.9-1.7).. We conclude that exposure to PCBs/PCDFs at levels that produced symptoms in many affects mortality patterns 3 decades after exposure.

Topics: Accidents; Adolescent; Adult; Benzofurans; Child; Child, Preschool; Female; Food Contamination; Humans; Infant; Male; Middle Aged; Poisoning; Polychlorinated Biphenyls; Taiwan; Young Adult

This study investigates the behavior of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) formation, dechlorination and destruction in PCP-contaminated sandy soil by low-temperature thermal treatment. Experimental tests were carried out in a nitrogen atmosphere in the temperature range of 200-400 °C with a treatment time of 30 min. 70% of PCP removal from the soil was achieved, resulting in 1436±230 ng/kg, the highest PCDD/F formation at 250 °C; however, the highest toxic concentration was measured around 4.20±0.62 ng TEQ/kg at 300 °C with 80% PCP removal from the soil. Further analysis has revealed that OCDD is the most dominant congener that is supposed to be formed from the pyrolysis of PCP, while OCDF is the second prevailing congener, possibly due to pyrolysis of 2,3,4,5-TeCP being a main byproduct of PCP pyrolysis. Detection of less chlorinated dioxins and furans over 300 °C indicates the dechlorination of highly chlorinated dioxins and furans, especially octachlorinated dibenzo-p-dioxin (OCDD) at 350 °C and 400 °C. Desorption from soil was supposed as a main mechanism for the distribution of PCDD/Fs in the gaseous phase, and not much difference in dioxins and furan levels was observed at 350 °C and 400 °C in the gaseous phase. Therefore, 350 °C is the most appropriate temperature to remove most PCP and PCDD/Fs from soil, as well as to meet PCDD/F emission standards (0.1 ng I-TEQ/Nm(3)).

Topics: Benzofurans; Gas Chromatography-Mass Spectrometry; Pentachlorophenol; Polychlorinated Dibenzodioxins; Silicon Dioxide; Soil Pollutants; Temperature

Combustion runs at 700 °C in a horizontal laboratory furnace were carried out on two different electric wires (PVC and halogen-free wire). Tests were performed in the presence and in the absence of the metal conductor of the wires. The analyses of the polycyclic aromatic hydrocarbons (PAHs), chlorobenzenes (CBzs), chlorophenols (CPhs), mono- to octa-chlorodibenzo-p-dioxin and dibenzofurans (PCDD/Fs), and dioxin-like PCBs are shown. Regarding semivolatile compounds, PAHs production decreases in the presence of metal, while a higher amount of chlorinated compounds are emitted. Respect to the PCDD/Fs, the PVC wire in the presence of metal presents the highest emission, with a much more emission of furans than dioxins. The maximum emission is with 2 or 3 chlorine atom PCDD/Fs. PCBs emission correlates with PCDD/F production and represents 3-4% of total toxicity, determined by using WHO2005 factors.

Topics: Air Pollutants; Benzofurans; Electric Wiring; Electronic Waste; Flame Retardants; Incineration; Metals; Polychlorinated Dibenzodioxins; Polycyclic Aromatic Hydrocarbons

Galectin-1 (gal-1), which binds β-galactoside groups on various cell surface receptors, is crucial to cell adhesion and migration, and is found to be elevated in several cancers. Previously, we reported on 6DBF7, a dibenzofuran (DBF)-based peptidomimetic of the gal-1 antagonist anginex. In the present study, we used a structure-based approach to optimize 6DBF7. Initial NMR studies showed that 6DBF7 binds to gal-1 on one side of the β-sandwich away from the lectin's carbohydrate binding site. Although an alanine scan of 6DBF7 showed that the two cationic groups (lysines) in the partial peptide are crucial to its angiostatic activity, it is the hydrophobic face of the amphipath that appears to interact directly with the surface of gal-1. Based on this structural information, we designed and tested additional DBF analogs. In particular, substitution of the C-terminal Asp for alanine and branched alkyl side chains (Val, Leu, Ile) for linear ones (Nle, Nva) rendered the greatest improvements in activity. Flow cytometry with gal-1(-/-) splenocytes showed that 6DBF7 and two of its more potent analogs (DB16 and DB21) can fully inhibit fluorescein isothiocyanate-gal-1 binding. Moreover, heteronuclear single-quantum coherence NMR titrations showed that the presence of DB16 decreases gal-1 affinity for lactose, indicating that the peptidomimetic targets gal-1 as a noncompetitive, allosteric inhibitor of glycan binding. Using tumor mouse models (B16F10 melanoma, LS174 lung, and MA148 ovarian), we found that DB21 inhibits tumor angiogenesis and tumor growth significantly better than 6DBF7, DB16, or anginex. DB21 is currently being developed further and holds promise for the management of human cancer in the clinic.

Topics: Alanine; Amino Acid Sequence; Angiogenesis Inhibitors; Animals; Benzofurans; Binding Sites; Cell Line; Cell Line, Tumor; Female; Galectin 1; Human Umbilical Vein Endothelial Cells; Humans; Lactose; Magnetic Resonance Spectroscopy; Male; Mice; Mice, Inbred C57BL; Mice, Nude; Molecular Sequence Data; Neovascularization, Pathologic; Peptidomimetics; Protein Binding; Structure-Activity Relationship

Polychlorinated biphenyl (PCB) and polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) concentrations were determined in composites of 18 different fish products and were prepared as raw, baked, boiled, and fried. ∑PCB concentrations were found to range from 0.12 ng·g(-1) whole weight (ww) in raw octopus to 33 ng·g(-1) ww in baked mackerel. Boiled monkfish was found to have the lowest ∑PCDD/F concentrations (0.41 pg·g(-1) ww), while maximum concentrations were observed in fried catfish (59 pg·g(-1) ww). PCB and PCDD/F concentrations in fish were generally reduced during cooking, although differences were small. The average PCB reduction in finfish was 7.9%, while an increase in PCB mass was observed in non-finfish (2.9%). PCDD/F losses, on average, were observed in both the finfish (3.6%) and non-finfish products (25%). Maximum ∑PCB, ∑PCDD/F, and TEQ(PCDD/F+DL-PCB) (toxic equivalency) intakes, based on 150 g serving size, were determined to be 3300 ng (mackerel), 6600 pg (catfish), and 270 pg (catfish), respectively. PCB and PCDD/F changes associated with cooking generally were small (<15%), although larger mean differences (∼40%) were observed in some fish products (e.g., catfish).

Topics: Animals; Benzofurans; Canada; Cooking; Environmental Pollutants; Fish Products; Fishes; Food Contamination; Hot Temperature; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Seafood

An intramolecular, organocatalyzed Michael addition has been developed to obtain biologically important 2,3-disubstituted cis-2,3-dihydrobenzofurans. By using mandelic acid salts of primary aminocatalysts, derived from cinchona alkaloids, the intramolecular cyclization reaction has been developed to proceed in high yield, with moderate to good diastereoselectivity, and up to 99% ee. Based on the absolute configuration of the formed 2,3-disubstituted-cis-2,3-dihydrobenzofurans and by considering the observed substrate scope restrictions, a mechanistic rationalization has been presented.

Topics: Benzofurans; Catalysis; Stereoisomerism

Topics: Benzofurans; Luminescent Agents; Polymers; Quantum Theory; Thermodynamics

Seventeen polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/PCDFs) of the highest priority as well as twelve dioxin-like polychlorinated biphenyls (dl-PCBs) were analyzed in the muscle tissues of the following freshwater fish species sampled from eleven Latvian freshwater lakes: perch (Perca flavescens), carp (Cyprinus carpio), eel (Anguilla rostrata), bream (Abramis brama), chub (Leuciscus cephalus), pike (Esox lucius), sheatfish (Silurus glanis) and roach (Rutilus). To analyze the selected persistent organic pollutants in fish matrices, an optimization of EPA-1613 and EPA-1668A clean-up procedures was carried out, followed by validation of the analytical procedure according to Commission Regulation (EC) No 1883/2006. The adopted analytical procedure was in compliance with requirements of the more recent Commission Regulation (EU) No 252/2012. Modifications of carbon column chromatography clean-up and separation steps were used for treatment of the fish samples. Other clean-up procedure stages were performed according to the methods EPA-1613 and EPA-1668A and involved gel permeation chromatography (GPC), as well as manual acidic silica and Florisil column chromatography for purification and fractionation of the samples. An isotope dilution method was used for the qualitative and quantitative determination of individual congeners. Analytes of interest were separated and detected using gas chromatography - high resolution mass spectrometry. The concentration of PCDD/PCDFs and dl-PCBs in freshwater fish and eel samples ranged from 0.05 to 8.0 pg WHO(1998)-PCDD/PCDF-PCB-TEQ g(-1) fresh weight. These levels are below the EU maximum permissible limits although calculation of the content of these compounds relative to the weight of fat shows contamination levels similar to those found in Baltic herring and sprats, that are known to be highly contaminated. A difference in congener pattern between the Baltic Sea fish and freshwater fish was detected with lower contribution of 2,3,4,7,8-PeCDF to the contamination of inland water fish.

Topics: Animals; Benzofurans; Environmental Monitoring; Fishes; Lakes; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Water Pollutants, Chemical; Water Pollution, Chemical

Sun Moon Lake (SML) is located at 23°52'N, 120°55'E near the center of Taiwan Island. In 2009, deposition of polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) in ambient air, water bodies and sediments were measured in SML in this study. The monthly atmospheric PCDD/F deposition ranged from 0.61 to 3.0 pg I-TEQm(-2)d(-1) in the vicinity area of SML. Average PCDD/F concentrations (0.008-0.012 pg I-TEQ L(-1)) in the surface water were uniform and sufficiently mixed at the center, outflow and south bay of SML. However, the PCDD/F content (2.42±0.5 ng I-TEQ kg(-1) d.w.) of surface sediments measured at the south bay of SML was significantly higher than the PCDD/F content at other sampling sites. To evaluate the anthropogenic pollution history in central Taiwan, PCDD/F concentrations were also analyzed at 1-2 cm intervals in three dated sediment cores collected at different locations of SML. The year dating by the sediment cores at different depths was estimated from the sedimentation rate (0.47±0.13-1.35±0.22 cm y(-1)) calculated by (210)Pb and (137)Cs analysis. Based on the results of isotope analysis of sediment cores collected from the center, outflow and south bay of SML, PCDD/F concentrations at different locations appeared to be quite similar. PCDD/F concentrations in sediment cores began to increase in 1964 and reached a peak (4.78 ng I-TEQ kg(-1) d.w.) in 1968. In addition, variation in PCDD/F content at different depth of the sediment cores appeared to correlate directly with the rate of organochlorine pesticides production in Taiwan.

Topics: Air Pollutants; Atmosphere; Benzofurans; Environmental Monitoring; Geologic Sediments; Lakes; Polychlorinated Dibenzodioxins; Taiwan; Water Pollutants, Chemical

We report on the content of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in 15 breast milk samples of nursing women living in the city of Taranto (Southern, Italy) or nearby. Breast milk samples were collected over the 2008-2009 period and analyzed by gas chromatography coupled with high-resolution mass spectrometry (GC-HRMS) upon accelerated solvent extraction (ASE) using acetone/n-hexane mixture 1:1 (v/v). The method was validated demonstrating good performing features. Profiles of PCDD/PCDF congeners in breast milk samples exhibited a prevalence of PCDFs compared to PCDDs. Toxic equivalents (TEQs in picogram per gram fat) of four breast milk were far above the legal limit for human consumption of 3.0 pg/g; their estimated daily and weekly dietary intake were almost 5-20 and 10-40 times higher, respectively, than the tolerable intake values established by the World Health Organization.

Topics: Adolescent; Adult; Benzofurans; Dioxins; Environmental Exposure; Female; Gas Chromatography-Mass Spectrometry; Humans; Italy; Milk, Human; Young Adult

Persistent organic pollutants (POPs) are of global concern due to their ubiquitous presence and toxicity. The occurence of polychlorinated dibenzo-p-dioxins (PCDDs), -dibenzofurans (PCDFs), co-planar biphenyls (PCBs), hexachlorocyclohexanes (HCH), dichlorodiphenyltrichloroethanes (DDT), and organochlorine pesticides (OCPs) in forest soil collected from Taurus mountains may have adverse effects on the environment and health. The aim of the study was to investigate the outcome and distribution of POPs in the environment and the possible grasshopper effect along an altitude transect from sea level up to nearly 2,000 m a.s.l at a spatial distance of about 60 km in the southeastern Turkish Mediterranean Sea.. The samples were collected at a height of 121, 408, 981, 1,225, 1,373, 1,639, and 1,881 m above sea level from Taurus Mountains, Turkey. The results were confirmed using high-resolution gas chromatography-high-resolution mass spectrometry.. The levels of the PCDD in forest soil from Taurus Mountains varied from nearly 4 to 12 pg g(-1) dry weight (dw). PCDF concentrations ranged from 2 to 7 pg g(-1) dw. Considerably high DDT levels detected in five stations indicated (3,223-24,564 pg g(-1)) its extensive local application or atmospheric transport. PCB levels were determined between 80 and 288 pg g(-1) dw. HCH concentrations ranged from 141 to 1,513 pg g(-1) dw. The other OCP was between 102 and 731 pg g(-1).. Although the use of POPs has been banned, our results show that they could still be found in Turkey. Their presence may be attributed to the degradation of pesticides which are newly banned and, as well as to the atmospheric migration and deposition. The lattitude of sampling sites, the chemical, and physical parameters of soil have observed no effect on the fate of POPs in the environment.

Topics: Benzofurans; DDT; Environmental Monitoring; Hazardous Substances; Hydrocarbons, Chlorinated; Mediterranean Sea; Pesticides; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Soil; Soil Pollutants; Turkey

The concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), as well as those of 18 polychlorinated biphenyls (PCBs), including 12-dioxin like (DL)-PCBs, were measured in foodstuffs randomly acquired in Catalonia (Spain) in November-December 2008. A total of 65 composite samples, belonging to various food groups were analyzed by HRGC/HRMS. The dietary intakes of PCDD/Fs and PCBs were subsequently estimated for four age groups of the population of Catalonia: children, teenagers, adults, and seniors, which were in turn divided according to sex. The highest dietary exposure to PCDD/Fs corresponded to fish and seafood (28.0%), dairy products (15.4%), and oils and fats (10.6%), while that of PCBs corresponded to fish and seafood (58.6%), and dairy products (8.9%). In contrast, the lowest contributions of PCDD/Fs and PCBs corresponded to vegetables, fruits and pulses. Concerning the sum of PCDD/Fs plus DL-PCBs, the current total intake expressed in pg WHO-TEQ/kg per day (0.60) showed a notable decreasing trend with respect to those found in previous surveys performed also in Catalonia in 2000 (3.51) and 2006 (1.12pg/kg per day). The current dietary intake of PCDDs plus DL-PCBs is similar or lower than that recently reported in studies performed in a number of regions and countries.

Topics: Adolescent; Adult; Aged; Benzofurans; Child; Diet; Environmental Exposure; Female; Food Analysis; Food Contamination; Humans; Male; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Risk Factors; Spain; Time Factors

The Stockholm Convention on Persistent Organic Pollutants includes in its aims the minimisation of unintentional releases of polychlorinated dibenzo-dioxins and dibenzofurans (PCDD/PCDF) and dioxin like PCB (dl-PCB) to the environment. Development and implementation of policies to achieve this aim require accurate national inventories of releases of PCDD/PCDF/dl-PCB. To support this objective, the Conference of Parties established a process to review and update the UNEP Standardized Toolkit for Identification and Quantification of Dioxin and Furan Releases. An assessment of all emission inventories was that for many countries open burning of biomass and waste was identified as the major source of PCDD/PCDF releases. However, the experimental data underpinning the release estimates used were limited in number and, consequently, confidence in the accuracy of the emissions predictions was low. There has been significant progress in measurement technology since the last edition of the Toolkit in 2005. In this paper we reassess published emission factors for release of PCDD/PCDF and dl-PCB to land and air. In total, four types of biomass and 111 emission factors were assessed. It was found that there are no systematic differences in emission factors apparent between biomass types or fire classes. The data set is best described by a lognormal distribution. The geometric mean emission factors (EFs) for releases of PCDD/PCDF to air for the four biomass classes used in the Toolkit (sugarcane, cereal crops, forest and savannah/grass) are 1.6μg TEQ (t fuel)(-1), 0.49μg TEQ (t fuel)(-1), 1.0μg TEQ (t fuel)(-1) and 0.4μg TEQ (t fuel)(-1), respectively. Corresponding EFs for release of PCDD/PCDF to land are 3.0ng TEQ (kg ash)(-1), 1.1ng TEQ (kg ash)(-1), 1.1ng TEQ (kg ash)(-1) and 0.67ng TEQ (kg ash)(-1). There are now also sufficient published data available to evaluate EFs for dl-PCB release to air for sugarcane, forest and grass/savannah; these are 0.03μg TEQ (t fuel)(-1), 0.09μg TEQ (t fuel)(-1) and 0.01μg TEQ (t fuel)(-1), respectively. The average EF for dl-PCB release to land is 0.19ng TEQ (kg ash)(-1). Application of these EFs to national emissions of PCDD/PCDF for global estimates from open burning will lower previous estimates of PCDD/PCDF releases to air and to land by 85% and 90%, respectively. For some countries, the ranking of their major sources will be changed and open burning of biomass will become less significant than previously concluded.

Topics: Air Pollutants; Benzofurans; Biomass; Incineration; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins

Pigs accidentally given feed contaminated by dioxin-like pollutants are a serious public health issue. We have examined whether pigs with limited exposure during early periods of fattening would be categorized as non-compliant with the EU limit at slaughtering when growth-dilution, excretion and metabolism effects are considered. Sixteen female and sixteen castrated male weaned pigs were divided into four groups (e.g. DG0, DG1, DG2 and DG3) in week 2 after birth. From weeks 3 to 13, groups DG1, DG2, and DG3 pigs were fed with a polychlorinated dibenzo-p-dioxin/dibenzofuran (PCDD/F) and polychlorinated biphenyl (PCB) mixture at dosages of 1, 10 and 100ng-toxic equivalent (TEQ) per kg dry mass feed in capsules, respectively. From weeks 13 to 23, the animals were nourished with clear feed. Control group DG0 was always fed with clear feed. Subcutaneous fat samples were collected at weeks 13, 18 and 23 by biopsies. The pollutant residues were analyzed by high resolution gas chromatography-high resolution mass spectrometry and quantified by a (13)C-isotope dilution method. The results showed the following: (1) when slaughtered at week 23, the TEQ for DG1 pigs (0.66±0.21pg/g fat) was under the EU limit of 1pg PCDD/F-TEQ/g fat; (2) PCDD/F congener-specific first-order elimination rates were linearly correlated with their toxicity equivalency factors (TEFs), and the rates were significantly dose-dependent for the more toxic congeners (TEF≥0.1). Therefore, the pigs' exposure above the EU limit during the early fattening stage did not necessarily lead to their categorization as non-compliant pork; and the residual TEQ for pork can be predicted from early exposure concentrations based on the models established here.

Topics: Adipose Tissue; Animal Feed; Animals; Benzofurans; Dioxins; European Union; Female; Food Contamination; Male; Meat; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Swine

Environmental pollutants, such as dioxins and furans, are extremely toxic and related with pulmonary disease development. Exposure of A549 human lung cells to dibenzofuran showed both time- and concentration-dependent decreases in cell proliferation and MTT reduction, but no alterations in cell viability. No differences were observed in the number of apoptotic nuclei, which can be due to the energetic failure caused by dibenzofuran-induced ATP depletion. Moreover, cells in culture exposed to the pollutant showed an increase in the conversion of LC3, a protein involved in the autophagic process. Incubation of A549 lung cells with dibenzofuran caused an increase in Lysotracker Red staining, indicating an increase in lysosomal vacuoles content. These results suggest that exposure to dibenzofuran affects lung mitochondrial phosphorylative function, causing an increase in the population of dysfunctional mitochondria and an impairment in the energetic status maintenance, therefore stimulating autophagy as a possible rescue mechanism in this cell line.

Topics: Adenine Nucleotides; Adenosine Triphosphate; Animals; Autophagy; Benzofurans; Blotting, Western; Cell Death; Cell Line; Cell Nucleus; Cell Proliferation; Cell Survival; Coloring Agents; Dose-Response Relationship, Drug; Energy Metabolism; Environmental Pollutants; Humans; L-Lactate Dehydrogenase; Lung; Lysosomes; Membrane Potential, Mitochondrial; Mice; Reactive Oxygen Species; Tetrazolium Salts; Thiazoles

Open burning for waste disposal is, in many countries, the dominant source of polychlorinated dibenzodioxins, dibenzofurans and biphenyls (PCDD/PCDF/PCB) release to the environment. To generate emission factors for open burning, experimental pile burns of about 100 kg of household waste were conducted with emissions sampling. From these experiments and others conducted by the same authors it is found that less compaction of waste or active mixing during the fire--"stirring"--promotes better combustion (as evidenced by lower CO/CO(2) ratio) and reduces emissions of PCDD/PCDF/PCB; an intuitive but previously undemonstrated result. These experiments also support previous results suggesting PCDD/PCDF/PCB generation in open burning - while still highly variable - tends to be greater in the later (smoldering) phases of burning when the CO/CO(2) ratio increases.

Topics: Air Pollutants; Benzofurans; Family Characteristics; Incineration; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Refuse Disposal

Sustainable management of contaminated sediments requires careful prioritization of available resources and focuses on efforts to optimize decisions that consider environmental, economic, and societal aspects simultaneously. This may be achieved by combining different analytical approaches such as risk analysis (RA), life cycle analysis (LCA), multicriteria decision analysis (MCDA), and economic valuation methods. We propose the use of stochastic MCDA based on outranking algorithms to implement integrative sustainability strategies for sediment management. In this paper we use the method to select the best sediment management alternatives for the dibenzo-p-dioxin and -furan (PCDD/F) contaminated Grenland fjord in Norway. In the analysis, the benefits of health risk reductions and socio-economic benefits from removing seafood health advisories are evaluated against the detriments of remedial costs and life cycle environmental impacts. A value-plural based weighing of criteria is compared to criteria weights mimicking traditional cost-effectiveness (CEA) and cost-benefit (CBA) analyses. Capping highly contaminated areas in the inner or outer fjord is identified as the most preferable remediation alternative under all criteria schemes and the results are confirmed by a probabilistic sensitivity analysis. The proposed methodology can serve as a flexible framework for future decision support and can be a step toward more sustainable decision making for contaminated sediment management. It may be applicable to the broader field of ecosystem restoration for trade-off analysis between ecosystem services and restoration costs.

Topics: Algorithms; Benzofurans; Cost-Benefit Analysis; Decision Support Techniques; Dioxins; Environment; Environmental Pollutants; Environmental Pollution; Geologic Sediments; Norway; Risk Factors; Seafood; Socioeconomic Factors; Stochastic Processes

The congener patterns of mono- to octa-chlorinated dibenzo-p-dioxins (PC(1-8)DD), dibenzofurans (PC(1-8)DF), naphthalenes (PC(1-8)N), mono- to deca-chlorinated biphenyls (PC(1-10)B), di- to hexa-chlorinated benzenes (PC(2-6)Bz) and mono- to penta-chlorinated phenols (PC(1-5)Ph) in flue gas samples collected simultaneously at 450°C, 300°C and 200°C in the post-combustion zone during waste incineration in a laboratory-scale reactor in a previous study, were in this study evaluated using principal component analysis (PCA). To our knowledge this is the most comprehensive chemical and multivariate analysis to date of the thermal formation of dioxins. The PCA indicated that different formation pathways occur in the temperature regions 450-300°C and 300-200°C, and reflected a chlorination effect of PCDF and PCDD between 450°C and 200°C which could not be discerned or was less pronounced for the other compound groups. Toxic equivalents (TEQs) of PCDDs, PCDFs and PCBs, as well as total TEQ values (TEQ(Total)) were also calculated, and correlations between changes in levels of specific congeners and the TEQs were explored in the PCA. Levels of four HxCDF congeners and 1,2,3,4,8-, 1,2,3,7,8-PeCDF and 2,3,4,7,8-PeCDF showed the strongest correlations with TEQ(Total) (R(2)≥0.9). In addition, levels of 1,2,4-TriCBz correlated strongly with TEQ(Total) (R(2)>0.7), supporting previous reports that it may be a potential indicator of the TEQ.

Topics: Benzofurans; Dioxins; Incineration; Naphthalenes; Pentachlorophenol; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins

Air, soils and sediments surrounding an abandoned pentachlorophenol (PCP) factory were sampled to determine the levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), unintentionally formed during PCP production. The mean concentration of PCDD/Fs in ambient air was one order of magnitude higher than that of the reference site. A trend of decreasing concentrations with increasing distance from the factory was observed, suggesting this site has a significant influence on the regional ambient air. As for soil samples collected within 3 km from the factory and sediment samples from the adjacent rivers, high levels of contamination were found with WHO-TEQ concentrations of 193 ± 211 pg/g and 667 ± 978 pg/g, respectively. The PCDD/F homologue profiles of all samples were consistent with those found in the technical product of PCP, with OCDD as the dominant congener. These results indicate PCDD/Fs in the historical contaminated site pose a long-term impact on surrounding environment.

Topics: Air Pollutants; Benzofurans; China; Environmental Monitoring; Environmental Pollution; Geologic Sediments; Polychlorinated Dibenzodioxins

High levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), mono- and non-ortho-polychlorinated biphenyls (PCBs), and polybrominated dibenzo-p-dioxins (PBDDs) are found in fish from coastal areas in the Baltic Sea, which may cause ecotoxicological effects. To increase our understanding of the persistency of the emerging pollutants polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs), fish feed was spiked with 21 PBDD/Fs, 17 PCDD/Fs, and 30 PCBs and fed to zebrafish (Danio rerio). Concentrations in fish and eggs were examined during a 6- or 12-week uptake period, and a 6-week elimination period. Steady-state was reached for 2-, 3-, 7-, and/or 8-substituted tri- and tetra-BDD/Fs; 2,3,7,8-tetra-BDD (2,3,7,8-TeBDD) was the most strongly retained. Steady-state was not reached for tetra- to hexa-CDDs. Non-2,3,7,8 congeners showed little or no retention. Most PCBs had high retention and did not reach steady state. Half-lives decreased in the order PCBs > PCDD/Fs > PBDD/Fs. Concentrations of 2,3,7,8-substituted penta- to octa-CDD/Fs decreased with their degree of chlorination, suggesting that the rate-limiting factor for uptake is low bioavailability. Maternal transfer was observed for all retained compounds, with most transfer factors <1, indicating that transfer rates are affected by the poor water solubility of the compounds. The limited retention of the major PBDD congeners found in Baltic Sea fish suggests that they are exposed to high or very high concentrations via either food or water.

Topics: Animals; Benzofurans; Diet; Dioxins; Environmental Exposure; Environmental Monitoring; Female; Oceans and Seas; Ovum; Polychlorinated Biphenyls; Water Pollutants, Chemical; Zebrafish

A new process involving copper-catalyzed aerobic C(sp(2))-H activation, followed by cycloetherification, has been developed. This reaction serves as a direct method for the preparation of multisubstituted dibenzofurans starting with o-arylphenols. The presence of a strong para-electron-withdrawing group (e.g., NO(2)) on the phenol is essential for the success of the reaction.

Topics: Benzofurans; Catalysis; Copper; Cyclization; Ethers; Molecular Structure; Oxidation-Reduction; Phenols

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are a group of compounds of major environmental concern. Once emitted into the atmosphere, PCDD/Fs undergo photochemical reactions and enter other environmental compartments via wet and dry deposition. In this study, atmospheric PCDD/F depositions were collected via an automated PCDD/F deposition sampler and traditional cylindrical vessels, respectively, in northern, central, and southern Taiwan from 2008 to 2010. The automated PCDD/F precipitation sampler used in this study can prevent both resuspension and photodegradation of the PCDD/Fs collected and also effectively separates the PCDD/F samples into dry and wet contributions. The results indicate that the average atmospheric PCDD/F concentrations collected by the high-volume sampling trains were 13.6 ± 10 (n = 10), 15.6 ± 5.2 (n = 7), and 10.9 ± 6.3 (n = 6) fg I-TEQ/m(3) in northern, central, and southern Taiwan, respectively. In addition, the results also indicate that the PCDD/F deposition flux collected with an automated PCDD/F sampler (1.84 ± 0.90-8.68 ± 5.1 pg I-TEQ/m(2)/day, n = 23) is significantly higher than that sampled with cylindrical vessels (1.11 ± 0.69-5.64 ± 5.2 pg I-TEQ/m(2)/day, n = 23). Based on the Mann-Whitney statistical analysis, the p value (0.037) of PCDD/F deposition flux between those two samplers measurement is lower than 0.05. The difference is attributed to the fact that part of the PCDD/F depositions collected by traditional cylindrical vessels is photodegraded and revolatilized. In addition, the wet deposition flux of PCDD/Fs (3.66 to 470 pg I-TEQ/m(2)/rainy day, n = 23) observed in Taiwan is significantly higher than the dry deposition flux (0.38 to 4.55 pg I-TEQ/m(2)/sunny day, n = 23). The results demonstrate that the wet deposition is the major PCDD/F removal mechanism in the atmosphere. Furthermore, the overall PCDD/Fs deposition velocity and scavenging (rainout) coefficient in Taiwan are calculated as 0.20 ± 0.07 cm/s and 6.5 ± 0.2 × 10(4), respectively.

Topics: Air; Atmosphere; Automation; Benzofurans; Chemical Precipitation; Environmental Monitoring; Polychlorinated Dibenzodioxins; Surface Properties; Taiwan; Water

Organic pollutants present in the pulp and paper mill sewage were extracted with dichloromethane/acetone (1:1v/v), and the extract was added to minimal salt medium to study the degrading and detoxifying potential of Pseudomonas sp. strain ISTDF1. GC-MS analysis performed after biodegradation showed removal of chlorinated compounds like dichloroacetic acid, heptadecyl ester (RT=28.99) and formation of simpler compounds like 4-isopropylbenzaldehyde (RT=7.52). Methyltetrazolium (MTT) assay for cytotoxicity, 7-ethoxyresorufin-O-deethylase (EROD) assay for dioxin-like behaviour and alkaline comet assay for genotoxicity were carried out in human hepato-carcinoma cell line HuH7 before and after bacterial treatment. The bacterium reduced toxicity as shown by a 5-fold increase in LC(50) value, 2110-fold reduction in benzo (α) pyrene equivalent value and an 8-fold reduction in Olive Tail Moment after 240h treatment. The EROD assay was found to be a useful method which indicated positive correlation with MTT and comet assay in post-biodegradation toxicity evaluation.

Topics: Benzofurans; Cell Line; Comet Assay; Gas Chromatography-Mass Spectrometry; Paper; Pseudomonas; Sewage; Textile Industry; Water Pollutants, Chemical

The biphenyl dioxygenase of Burkholderia xenovorans LB400 (BphAE(LB400)) catalyzes the dihydroxylation of biphenyl and of several polychlorinated biphenyls (PCBs) but it poorly oxidizes dibenzofuran. In this work we showed that BphAE(RR41), a variant which was previously found to metabolize dibenzofuran more efficiently than its parent BphAE(LB400), metabolized a broader range of PCBs than BphAE(LB400). Hence, BphAE(RR41) was able to metabolize 2,6,2',6'-, 3,4,3',5'- and 2,4,3',4'-tetrachlorobiphenyl that BphAE(LB400) is unable to metabolize. BphAE(RR41) was obtained by changing Thr335Phe336Asn338Ile341Leu409 of BphAE(LB400) to Ala335Met336Gln338Val341Phe409. Site-directed mutagenesis was used to create combinations of each substitution, in order to assess their individual contributions. Data show that the same Asn338Glu/Leu409Phe substitution that enhanced the ability to metabolize dibenzofuran resulted in a broadening of the PCB substrates range of the enzyme. The role of these substitutions on regiospecificities toward selected PCBs is also discussed.

Topics: Benzofurans; Biphenyl Compounds; Burkholderia; Catalysis; Dioxygenases; Escherichia coli; Mutagenesis, Site-Directed; Oxidation-Reduction; Polychlorinated Biphenyls; Recombinant Proteins

In the rosaceous subtribe Pyrinae (formerly subfamily Maloideae), pathogen attack leads to formation of biphenyls and dibenzofurans. Accumulation of these phytoalexins was studied in greenhouse-grown grafted shoots of Malus domestica cv. 'Holsteiner Cox' and Pyrus communis cv. 'Conference' after inoculation with the fire blight bacterium, Erwinia amylovora. No phytoalexins were found in leaves. However, both classes of defence compounds were detected in the transition zone of stems. The flanking stem segments above and below this zone, which were necrotic and healthy, respectively, were devoid of detectable phytoalexins. The transition zone of apple stems contained the biphenyls 3-hydroxy-5-methoxyaucuparin, aucuparin, noraucuparin and 2'-hydroxyaucuparin and the dibenzofurans eriobofuran and noreriobofuran. In pear, aucuparin, 2'-hydroxyaucuparin, noreriobofuran and in addition 3,4,5-trimethoxybiphenyl were detected. The total phytoalexin content in the transition zone of pear was 25 times lower than that in apple. Leaves and stems of mock-inoculated apple and pear shoots lacked phytoalexins. A number of biphenyls and dibenzofurans were tested for their in vitro antibacterial activity against some Erwinia amylovora strains. The most efficient compound was 3,5-dihydroxybiphenyl (MIC=115 μg/ml), the immediate product of biphenyl synthase which initiates phytoalexin biosynthesis.

Topics: Benzofurans; Erwinia amylovora; Malus; Microbial Sensitivity Tests; Phytoalexins; Plant Diseases; Plant Immunity; Plant Leaves; Plant Stems; Pyrus; Sesquiterpenes

Eggs laid by white-tailed sea eagles (Haliaeetus albicilla), one in 1941 and five eggs between 1996 and 2001, all from the same geographical region of the Baltic Sea, were screened for organohalogen substances. The 1941 egg contained hexachlorobenzene (HCB), but did not contain either of the pesticides hexachlorocyclohexane (HCH) or p,p'-DDT, nor any metabolites of the latter. In contrast, the more recent eggs (REs) contained all of these compounds. Of the seven polychlorinated biphenyls (PCBs) analyzed (CB28, -52, -101, -118, -138/-163, -153 and 180), only the more highly chlorinated congeners were detected in the 1941 sample, with CB153 followed by CB180 showing the highest concentrations. All eggs demonstrated the same congener pattern with respect to the more highly chlorinated PCBs, but concentrations were approximately 70-230 times higher in the REs. All of the polychlorinated-p-dioxin and dibenzofuran (PCDD/Fs) congeners analyzed were detected in the eggs, with the dominant congener being 2,3,4,7,8-PeCDF (1250pg/gl.w. in 1941 and 1540pg/gl.w. (GM) for the REs, respectively). None of the other congeners exceeded 400pg/gl.w., and the concentrations of 2,3,7,8-TCDD, 2,3,7,8-TCDF and 1,2,3,7,8-PeCDF were all lower in the REs. None of five congeners of polybrominated diphenyl ethers (PBDEs) found in the REs was detected in the egg from 1941. The three methoxylated brominated diphenyl ethers (MeO-BDEs) analyzed were found at similar levels and with a similar congener pattern in REs as in the egg from 1941. In conclusion, this study has shown the absence of DDE and PBDE and the presence of HCB and PCBs in a white-tailed sea eagle egg laid in 1941, and a strong increase of PCBs, DDE and PBDE in white-tailed sea eagle eggs from the same area in 1996-2001. The MeO-BDEs were found in similar concentrations in the analyzed eggs. The 1941 sample shows substantial concentrations of PCDD/Fs, noteworthy in the same magnitude as in the recent samples, illustrating the historical and recent exposure of these compounds.

Topics: Animals; Benzofurans; Eagles; Eggs; Environmental Pollutants; Halogenated Diphenyl Ethers; Hydrocarbons, Chlorinated; Hydrocarbons, Halogenated; Pesticides; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins

Mixed halogenated dibenzo-p-dioxins and dibenzofurans (PXDD/PXDFs, X=Br, Cl) are formed through combustion processes, and may be more toxic than their corresponding chlorinated and brominated analogues. With 4600 potential congeners, limited analytical standards, and complex environmental matrices, PXDD/PXDFs present a significant analytical challenge. Gas chromatography tandem mass spectrometry (GC-MS/MS) offers both selectivity and sensitivity through multiple reaction monitoring of unique transitions in a novel approach to PXDD/PXDF congener identification. Method validation was performed through analysis of soil samples obtained from a recycling plant fire. Of the PXDD/PXDFs examined, monobromo-dichlorodibenzofuran was the most prevalent, ranging in concentration from 8.6ngg(-1) to 180ngg(-1). Dibromo-dichlorodibenzo-p-dioxin, a compound of toxicological concern, ranged from 0.41ngg(-1) to 10ngg(-1). Concentrations of PXDD/PXDFs were between 6% and 10% that of the corresponding polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDFs), with the exception of dibromo-dichlorodibenzo-p-dioxin concentrations, which were 36% that of tetrachlorodibenzo-p-dioxins. Higher levels of polybrominated PXDD/PXDFs may indicate a significant bromine source was present during combustion.

Topics: Benzofurans; Dibenzofurans, Polychlorinated; Dioxins; Gas Chromatography-Mass Spectrometry; Halogenation; Reproducibility of Results; Soil Pollutants; Tandem Mass Spectrometry

The influence of gaseous ammonia and sulphur dioxide on the formation of 2378-substituted PCDD/F on a reference flyash from a municipal waste incinerator has been investigated using a laboratory scale fixed-bed reactor. The reference flyash samples (BCR-490) was reacted under a simulated flue gas stream at temperatures of 225 and 375°C for 96h. The experiments were carried out in two series: first with simulated flue gas alone, and then with injection of NH(3) or SO(2) gas into the flue gas just before the reactor inlet. It was found that the injection of gaseous ammonia into the flue gas could decrease the concentration of both PCDD and PCDF by 34-75% from the solid phase and by 21-40% from the gas phase. Converting the results to I-TEQ values, it could reduce the total I-TEQ values of PCDD and PCDF in the sum of the flyash and exhaust flue gas by 42-75% and 24-57% respectively. The application of SO(2) led to 99% and 93% reductions in the PCDD and PCDF average congener concentrations, respectively in the solid phase. In the gas phase, the total reductions were 89% and 76% for PCDD and PCDF, respectively. Moreover, addition of SO(2) reduced the total I-TEQ value of PCDD and PCDF in the flyash and exhaust flue gas together by 60-86% and 72-82% respectively. Sulphur dioxide was more effective than ammonia in suppressing PCDD/F formation in flyash under the conditions investigated.

Topics: Ammonia; Benzofurans; Coal Ash; Gases; Incineration; Polychlorinated Dibenzodioxins; Refuse Disposal; Sulfur Dioxide; Temperature

A molecular hybridization approach is an emerging structural modification tool to design new molecules with improved pharmacophoric properties. In this study, 1,2,3-triazole-based Mycobacterium tuberculosis inhibitors and synthetic and natural product-based tricyclic (carbazole, dibenzo[b,d]furan, and dibenzo[b,d]thiophene) antimycobacterial agents were integrated in one molecular platform to prepare various novel clubbed 1,2,3-triazole hybrids using click chemistry. Structure-activity correlations and in vitro activity against M. tuberculosis strain H37Rv of new analogues revealed the order: dibenzo[b,d]thiophene > dibenzo[b,d]furan > 9-methyl-9H-carbazole series. Two of the most potent M. tuberculosis inhibitors 13h and 13q with MIC = 0.78 μg/mL (∼1.9 μM) displayed a low cytotoxicity and high selectivity index (50-255) against four different human cancer cell lines. These results together provided the potential importance of molecular hybridization and the development of triazole clubbed dibenzo[b,d]thiophene-based lead candidates to treat mycobacterial infections.

Topics: Antitubercular Agents; Benzofurans; Carbazoles; Cell Line, Tumor; Click Chemistry; Cytostatic Agents; Drug Design; Humans; Mycobacterium tuberculosis; Thiophenes; Triazoles

Chlorinated pesticides can contain impurities of dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and their precursors, as a result of various manufacturing processes and conditions. As precursor formation of PCDD/Fs can also be mediated by ultraviolet light (UV), this study investigated whether PCDD/Fs are formed when currently used pesticides are exposed to natural sunlight. Formulations containing pentachloronitrobenzene (PCNB; n=2) and 2,4-dichlorophenoxyacetic acid (2,4-D; n=1) were exposed to sunlight in quartz tubes, and the concentration of 93 PCDD/F congeners were monitored over time. Considerable formation of PCDD/Fs was observed in both PCNB formulations (by up to 5600%, to a maximum concentration of 57000 μg ∑PCDD/F kg(-1)) as well as the 2,4-D formulation (by 3000%, to 140 μg ∑PCDD/F kg(-1)). TEQ also increased by up to 980%, to a maximum concentration of 28 μg kg(-1) in PCNB, but did not change in the 2,4-D formulation. Assuming similar yields as observed in the present study as a worst case scenario the use of PCNB in Australia may result in the formation of 155 g TEQ annum(-1), contributed primarily by OCDD formation. This warrants detailed evaluations on the contemporary release of PCDD/Fs to the environment after the use of pesticides. Changes in congener profiles (including the ratio of PCDDs to PCDFs (DF ratio)) suggest that pesticide sources of PCDD/Fs after sunlight exposure may not be recognized based on matching source fingerprints established from manufacturing impurities. These changes also provide preliminary insights into the possible formation routes and types of precursors involved.

Topics: Benzofurans; Dioxins; Nitrobenzenes; Pesticides; Photolysis; Sunlight

In a laboratory-scale combustion reactor, flue-gas samples were collected at two temperatures in the post-combustion zone, 700°C and 400°C, using two different water-cooled sampling probes. The probes were the cooled probe described in the European Standard method EN-1948:1, referred to as the original probe, and a modified probe that contained a salt/ice mixture to assist the cooling, referred to as the sub-zero probe. To determine the efficiency of the cooling probes, internal temperature measurements were recorded at 5cm intervals inside the probes. Flue-gas samples were analyzed for polychlorinated dibenzo-p-dioxin and dibenzofurans (PCDD/Fs). Samples collected at 700°C using the original cooling probe showed higher concentrations of PCDD/Fs compared to samples collected using the sub-zero probe. No significant differences were observed between samples collected at 400°C. The results indicated that artifact formation of PCDD/Fs readily occurs during flue-gas sampling at high temperatures if the cooling within the probe is insufficient, as found for the original probe at 700°C. It was also shown that this problem could be alleviated by using probes with an enhanced cooling capacity, such as the sub-zero probe. Although this may not affect samples collected for regulatory purposes in exit gases, it is of great importance for research conducted in the high-temperature region of the post-combustion zone.

Topics: Air Pollutants; Benzofurans; Hot Temperature; Incineration; Phase Transition; Polychlorinated Dibenzodioxins

Nonenzymatic oxidative degradation of aspalathin, a dihydrochalcone unique to green rooibos (Aspalathus linearis), resulted in formation of the characteristic red-brown color of processed rooibos tea. As recently reported, two colorless dimers were formed by oxidative coupling. Incubations of aspalathin showed further distinct signals. Isolation by multilayer countercurrent chromatography (MLCCC) followed by preparative high-performance liquid chromatography (HPLC) led to pure substances. Subsequent analysis by NMR and MS techniques identified a third colorless dimeric compound. In addition for the first time, two colored structures with dibenzofuran skeleton, (S)- and (R)-3-(7,9-dihydroxy-2,3-dioxo-6-β-d-glucopyranosyl-3,4-dihydrodibenzo[b,d]furan-4a(2H)-yl) propionic acid, and their corresponding mechanistic precursors were unequivocally established. Color-dilution analysis revealed these compounds as the key chromophores of the incubated aspalathin solutions, ultimately being degraded to unknown, more stable tannin-like structures. Their mechanistic importance to color formation was further underlined by detection of the dibenzofurans also in fermented rooibos tea after trapping with o-phenylenediamine as their corresponding quinoxaline derivatives.

Topics: Aspalathus; Benzofurans; Chalcones; Color; Dimerization; Fermentation; Food Handling; Oxidation-Reduction; Pigments, Biological; Plant Leaves; Plant Stems; Quinoxalines

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) in surface sediment samples from Taihu Lake--an important water supply of the Yangtze River Delta, China--were investigated in the present study. Concentrations of PCDD/Fs ranged from 0.91 to 4.8 pg TEQ g(-1) dw (mean: 2.9 pg TEQ g(-1) dw, TEQ: Toxic Equivalent), which were all higher than the threshold effect level established by interim sediment quality guidelines in Canada (0.85 pg TEQ g(-1) dw). The levels of PBDD/Fs ranged from 0.16 to 1.6 pg TEQ g(-1) dw (mean: 0.52 pg TEQ g(-1) dw) and accounted for 5-33% (mean: 14%) of the total PCDD/Fs and PBDD/Fs TEQ. Comparatively, the abundance of sedimentary PCDD/Fs in the three regions (Meiliang Bay, Gonghu Bay, and Xukou Bay) showed a decreasing trend from the inflow region to the outflow region, while no significant difference was observed among their 2,3,7,8-PBDD/Fs levels, which suggested that the sources of PCDD/Fs and PBDD/Fs differed in this area. Principal component analysis suggested that the historical production/usage of pentachlorophenol and sodium pentachlorophenate was the dominant source of PCDD/Fs in the sediment of these regions. Although the specific sources of PBDD/Fs in the sediment of Taihu Lake were unclear, it was suspected to be due to atmospheric deposition; however, an additional study is needed to confirm this.

Topics: Benzofurans; Bromine Compounds; China; Chlorine Compounds; Dioxins; Environmental Monitoring; Geologic Sediments; Lakes; Water Pollutants, Chemical; Water Pollution, Chemical

Levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) were determined in 23 blood samples of exposed workers from a transformer recycling plant in Dortmund, Germany. Compared to the most recent studies on German background levels of adults, elevated concentrations of up to 71.6 pg WHO(2005)-TEq/g(lipid base) were found for 8 participants, and for individual PCDF congeners for 15 participants.

Topics: Adult; Benzofurans; Chromatography, Gas; Cohort Studies; Electronics; Equipment Reuse; Germany; Humans; Male; Mass Spectrometry; Middle Aged; Occupational Exposure; Polychlorinated Dibenzodioxins; Solvents; Young Adult

Since 1996, a wide surveillance programme has been developed to get overall information on the impact of a municipal solid waste incinerator (MSWI) in Tarragona (Catalonia, Spain). The concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) have been periodically measured in soil and vegetation samples collected at locations in the incinerator surroundings. Furthermore, air PCDD/F levels have been also monitored by using active and passive sampling devices, generating a huge amount of information regarding the environmental status of the zone. In the last survey (2009-2010), mean PCDD/F levels in vegetation, soil and air were 0.06 ng I-TEQ kg(-1), 0.58 ng I-TEQ kg(-1) and 10.5 fg WHO-TEQ m(-3), respectively. Both soil and herbage showed a notable reduction in the PCDD/F concentrations in comparison with the baseline study, with this decrease only being significant for soils. In contrast, PCDD/F values in air remained similar during the whole assessment period. Human exposure to PCDD/Fs was evaluated under different scenarios, and the associated non-carcinogenic and carcinogenic risks were assessed. The hazard quotient was below unity in all cases, while cancer risks were under 10(-6), which is lower than the maximum recommended guidelines. The current results clearly show that the MSWI of Tarragona does not produce additional health risks for the population living nearby.

Topics: Air Pollutants; Benzofurans; Environmental Exposure; Environmental Monitoring; Gas Chromatography-Mass Spectrometry; Humans; Incineration; Plants; Polychlorinated Dibenzodioxins; Refuse Disposal; Risk Assessment; Seasons; Soil; Solid Waste; Spain

To understand the effect of leaf-surface pesticides on emissions of PCDD/F during biomass burns, nine combustion experiments simulating the open burning of biomass were conducted. Needles and branches of Pinus taeda (Loblolly pine) were sprayed with the pesticide 2,4-dichlorophenoxyacetic acid (2,4-D) at 1 and 10 times the manufacturer's recommended application concentration. The biomass was then dried overnight, burned in an open burn test facility, and emission samples were collected, analyzed, and compared against emission samples from burning untreated biomass. Blank tests and analysis of PCDD/F in the raw biomass were also performed. Emission results from burning a water-sprayed control show a ~20-fold increase in PCDD/F levels above that of the raw biomass alone, implicating combustive formation versus simple volatilization. Results from burns of pine branches sprayed with pesticide showed a statistically significant increase in the PCDD/F TEQ emissions when burning biomass at ten times the recommended pesticide concentration (from 0.22 to 1.14 ng TEQ/kg carbon burned (C(b)), both ND = 0). Similarly, a 150-fold increase in the total PCDD/F congener mass (tetra- to octa-chlorinated D/F) above that of the control was observed (from 52 to 7800 ng/kg C(b)), confirming combustive formation of PCDD/F from 2,4-D. More replicate testing is needed to evaluate effects at lower pesticide concentrations.

Topics: 2,4-Dichlorophenoxyacetic Acid; Air Pollutants; Benzofurans; Biomass; Herbicides; Incineration; Pinus taeda; Polychlorinated Dibenzodioxins

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), organotin and organolead compounds were measured in sewage sludge samples collected from 24 wastewater treatment plants from 18 cities of 13 provinces in China. Total international toxicity equivalent (I-TEQ) values were evaluated for PCDD/Fs. The total concentration of PCDD/Fs ranged from 104.0 to 1661 pg/g dry weight (d.w.) and 2.51-75.21 pg I-TEQ/g d.w., indicating that all I-TEQs were below Chinese legislation limit value regulated for land application. The concentrations ranged from 258 to 3886, 126 to 1129, and 84-2133 ng/g as Sn d.w., for tributyltin (TBT), dibutyltin (DBT), and diphenyltin (DPhT), respectively. On the other side, organolead concentrations ranged from 85 to 668 with an average of 279 ng/g as lead. High concentrations of organolead compounds in sewage sludge indicated that the environmental impact of organolead compounds remains in China.

Topics: Benzofurans; China; Environmental Monitoring; Organometallic Compounds; Polychlorinated Dibenzodioxins; Sewage; Waste Disposal, Fluid; Wastewater; Water Pollution, Chemical

In an effort to identify new anti-inflammatory and antibacterial agents with potential application in wound healing, five new dibenzofurans, 1,3,7,9-tetrahydroxy-2,8-dimethyl-4,6-di(2-methylbutanoyl)dibenzofuran (1), 1,3,7,9-tetrahydroxy-2,8-dimethyl-4-(2-methylbutanoyl)-6-(2-methylpropionyl)dibenzofuran (2), 1,3,7,9-tetrahydroxy-2,8-dimethyl-4,6-di(2-methylpropionyl)dibenzofuran (3), 1,3,7,9-tetrahydroxy-4,6-dimethyl-2-(2-methylbutanoyl)-8-(2-methylpropionyl)dibenzofuran (4), and 1,3,7,9-tetrahydroxy-4,6-dimethyl-2,8-di(2-methylpropionyl)dibenzofuran (5), were isolated from the leaves of Pilidiostigma glabrum together with one previously described dibenzofuran. Structure elucidation was achieved by way of spectroscopic measurements including 2D-NMR spectroscopy. Compounds with 2,8-acyl substitutions had potent antibacterial activity against several Gram-positive strains (MIC in the low micromolar range), while compounds with 4,6-acyl substitutions were less active. All compounds except 3 inhibited the synthesis of nitric oxide in RAW264 macrophages with IC(50) values in the low micromolar range. Compounds with 2,8-acyl substitutions also inhibited the synthesis of PGE(2) in 3T3 cells, whereas 4,6-acyl-substituted compounds were inactive. None of the compounds inhibited the synthesis of TNF-α in RAW264 cells. The compounds showed variable but modest antioxidant activity in the oxygen radical absorbance capacity assay. These findings highlight that much of the Australian flora remains unexplored and may yet yield many new compounds of interest. Initial clues are provided on structure/activity relationships for this class of bioactives, which may enable the design and synthesis of compounds with higher activity and/or selectivity.

Topics: Animals; Anti-Bacterial Agents; Anti-Inflammatory Agents; Australia; Benzofurans; Macrophages; Mice; Molecular Structure; Myrtaceae; Nitric Oxide; Nuclear Magnetic Resonance, Biomolecular; Plant Leaves; Structure-Activity Relationship; Tumor Necrosis Factor-alpha

Dioxins are a class of extremely toxic environmentally persistent pollutant, comprised of halogenated dibenzo-p-dioxins, dibenzofurans and biphenyls. Despite significant human exposure via multiple routes, very little is known about toxicity induced by dibenzofuran (DF). Current study shed lights on the potential toxicity mechanism of DF using human hepatoma cell line (HepG2). It was observed that the exposure to DF potentiate oxidative stress, apoptosis and necrosis at 10μM within 8h in HepG2 cells. Interestingly, when we pre-incubated the cells with α-NF (1nM) for 12h, an aromatic hydrocarbon receptor antagonist, the IC(50) of DF increased by 14 folds indicating the cytoprotective ability of α-NF from DF induced toxicity. Furthermore, three additional metabolites were observed while studying the metabolic profile of DF in HepG2 cells with and without pre-incubation with α-NF using chromatography-mass spectroscopy (GC-MS). Of these, two metabolites were characterized as dihydroxylated derivative of DF and third metabolite was characterized as quinone derivative of DF. By flow cytometry and confocal laser microscopy analysis we followed the ROS formation after DF (10μM) exposure for 3h. Significantly low ROS was generated in cells which were pre-incubated with α-NF than cells which were not pre-incubated with α-NF underlining the importance of metabolism in DF toxicity. The same pattern of protection was consistent while measuring mitochondrial membrane potential (MMP), i.e., less MMP dip was observed in 'with α-NF pre-incubated and DF (10μM) exposed cells' than 'without α-NF pre-incubated but DF exposed cells'. In cell cycle studies, it was confirmed that cell population of HepG2 at G1 stage progressively increased in number (∼74%) within 24h. Thus, DF and its metabolites induce significantly higher cytotoxicity after metabolism in HepG2 cells than its parent compound (DF) by ROS formation, MMP dip and impaired cell cycle.

Topics: Apoptosis; Benzoflavones; Benzofurans; Cell Cycle Checkpoints; Cell Survival; Flow Cytometry; Hep G2 Cells; Humans; Liver; Logistic Models; Membrane Potential, Mitochondrial; Microscopy, Confocal; Mitochondria, Liver; Oxidative Stress; Reactive Oxygen Species

Concentrations of polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) were determined in surface sediments from Lake Shihwa and from creeks that discharge into this artificial lake. The toxic equivalents (TEQs) in sediments ranged from 1.0 to 1770 pg/g dry weight, which were some of the highest values ever reported so far for coastal sediments on a global basis. The concentrations of PCDD/Fs and DL-PCBs decreased with increasing distance from the creeks to offshore regions of the lake. Based on a multivariate statistical analysis and congener profiles, it was found that high contamination by PCDD/Fs in creek sediments collected around Lake Shihwa was associated with releases from chlor-alkali processes. Significant correlations were found for total organic carbon content and the concentrations of highly chlorinated PCDD/F congeners. This is the first report to document chlor-alkali processes as a significant source of PCDD/F contamination in Korean coastal waters.

Topics: Benzofurans; Dioxins; Environmental Monitoring; Geologic Sediments; Lakes; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Republic of Korea; Water Pollutants, Chemical; Water Pollution, Chemical

Concentrations of polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDF), and dioxin-like non-ortho-PCBs were measured in white-tailed sea eagle (WTSE) eagle eggs collected along the Swedish coast of the Baltic Sea during the period 1992-2004. The eggs represent two different subpopulations with significantly different nestling brood sizes; the Baltic Proper (BP) with an approximately normal nestling brood size (1.62), and the south Bothnian Sea (sBS) with reduced nestling brood size (1.22) combined with a significantly higher rate of dead eggs. The aim was to investigate if this difference in reproductive outcome was linked to differences in exposure to dioxin-like compounds. Three eggs collected in Greenland in 2000 were included in the study to provide a reference sea eagle population outside of the Baltic Sea region. The concentrations of ∑PCDD, ∑PCDF and ∑non-ortho-PCB in the two subpopulations from the Baltic Sea (BS) region ranged from 0.41-4.1, 1.2-5.3 and 180-970 ng/g lipids, respectively, while in the Greenland population the ranges were 0.11-0.16, 0.22-0.33 and 57-83 ng/g lipid, respectively. 2,3,4,7,8-PCDF was the predominant congener in all areas and accounted for on average 31-49% of the total ∑PCDD/F concentrations. The total toxic equivalents (TEQ) in sBS WTSEs were higher (approximately 39 ng TEQ/g lipid) than reported in eggs for many other birds, and the major contributors to the TEQ in the Baltic Sea were the non-ortho-PCBs. A principal component analysis (PCA) showed a difference in congener pattern between the two Baltic regions that was statistically significant (Hotelling's T(2) test). We found no significant differences in the total TEQ between the two populations (sBS-BP) and thus no evidence was found linking the reproductive impairment in WTSE in sBS to the concentrations of PCDD/Fs or non-ortho-PCBs in the eggs.

Topics: Animals; Benzofurans; Chromatography, Gas; Dioxins; Eagles; Environmental Monitoring; Environmental Pollutants; Oceans and Seas; Ovum; Polychlorinated Biphenyls; Principal Component Analysis; Reproduction; Sweden

The concentrations of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (PCBs), and polychlorinated naphthalenes (PCNs) were measured in two sediment cores collected from Jiaozhou Bay. The concentrations of PCDD/Fs, dioxin-like PCBs, and PCNs in the cores were in the range of 2.8-26.3, 7.1-82.4 and 3.9-56.4 pg/g dw, respectively. The depth profiles of total concentrations PCDD/Fs and dioxin-like PCBs were similar in the sediment core J37 inside Jiaozhou Bay, but different from those in the sediment core J94 outside the bay, suggesting the different sources. In both cores Tri-CNs and Tetra-CNs were dominant, similar to the PCNs composition of some Halowax technical products. The maximal PCNs contamination occurred in the mid-1970s (outside the Bay) and early-1990s (inside the Bay). An increase of the indicator CN congeners characteristic for thermal source in the top layers of the sediment core inside the bay indicated that the contribution from the municipal solid waste incineration has been more important in recent years.

Topics: Benzofurans; China; Dioxins; Environmental Monitoring; Geologic Sediments; Incineration; Naphthalenes; Polychlorinated Biphenyls; Water Pollutants, Chemical

An efficient synthesis of 2- or 4-iododibenzofurans through CuI-mediated sequential iodination/cycloetherification of two aromatic C-H bonds in o-arylphenols has been developed. Both the preexisting electron-withdrawing groups (NO(2), CN, and CHO) and the newly introduced iodide are readily modified for a focused dibenzofuran library synthesis. Mechanistic studies and DFT calculations suggest that a Cu(III)-mediated rate-limiting C-H activation step is involved in cycloetherification.

Topics: Benzofurans; Copper; Cyclization; Ether; Halogenation; Iodides; Molecular Structure; Phenol

The concentrations of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) were determined in a number of foodstuffs purchased in various locations near a hazardous waste incinerator (HWI) in Tarragona County (Catalonia, Spain). The dietary intake of PCDD/Fs by the population of the area under potential influence of the HWI was subsequently estimated. The results were compared with previous surveys performed in the same area in 1998 (baseline), 2002 and 2006. In the present study, the highest WHO-TEQ corresponded to industrial bakery (0.183 ng/kg wet weight, ww), followed by fish (0.156 ng/kg ww), oils and fats (0.112 ng/kg fat weight), and seafood (0.065 ng/kg ww). In contrast, the lowest values were observed in pulses and tubers (0.003 ng/kg ww), and cereals and fruits (0.004 ng/kg ww). The dietary intake of PCDD/Fs by the general population was 33.1pg WHO-TEQ/day, having fish and seafood (11.6 pg WHO-TEQ), oils and fats (4.61pg WHO-TEQ), dairy products (3.79 pg WHO-TEQ), and industrial bakery (3.49 pg WHO-TEQ) as the groups showing the highest contribution to the total TEQ. The lowest daily contributions corresponded to pulses (0.08 pg WHO-TEQ) and tubers (0.25 pg WHO-TEQ). This intake was considerably lower than that found in the baseline study, 210.1 pgI-TEQ/day, and also notably lower than that found in the 2002 survey (59.6 pgI-TEQ/day), but slightly higher than the intake estimated in the 2006 survey, 27.8 pgWHO-TEQ/day. The results of this study show that any increase potentially found in the biological monitoring of the general population living in the area under evaluation should not be attributed to dietary exposure to PCDD/Fs.

Topics: Adolescent; Adult; Benzofurans; Child; Child, Preschool; Diet; Dioxins; Environmental Exposure; Environmental Pollutants; Environmental Pollution; Female; Food Contamination; Hazardous Waste; Humans; Incineration; Male; Middle Aged; Spain; Young Adult

In December 2009, ambient air was sampled with active high-volume air samplers at two sites: on the roof of the No. l building of Dalian Jiaotong University and on the roof of the building of Dalian Meteorological Observatory. The concentrations and the congeners between vapor phase and particulate phase of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the air were measured. Sample analysis results showed that the concentrations of PCDD/Fs in particulate phase was higher than that in gaseous phase. The ratio of PCDD to PCDF in gaseous phase and particulate phase was lower than 0.4 in all samples. The total I-TEQ value in gaseous phase and particulate phase was 5.5 and 453.8 fg/m(3) at Dalian Jiaotong University, 16.6 and 462.1 fg/m(3) at Dalian Meteorological Observatory, respectively. The I-TEQ value of Dalian atmosphere was 5.5-462.1 fg/m(3) which was lower than international standard, the atmospheric quality in Dalian is better.

Topics: Air Pollutants; Air Pollution; Benzofurans; China; Gases; Particulate Matter; Polychlorinated Dibenzodioxins; Seasons

The soils at a factory for manufacturing pentachlorophenol were heavily contaminated by polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). In order to verify the contributions of dry and wet deposition of PCDD/Fs from the ambient air, the concentration of PCDD/Fs in ambient air and soil were measured, the partition of particle- and gas-phases of atmospheric PCDD/Fs was calculated, and the annual fluxes of total dry and wet PCDD/F depositions were modeled. Average atmospheric PCDD/F concentration was 1.24 ng Nm(-3) (or 0.0397 ng I-TEQ Nm(-3)). Moreover, over 92.8% of total PCDD/Fs were in the particle phase, and the dominant species were high chlorinated congeners. The total PCDD/F fluxes of dry and wet deposition were 119.5 ng m(-2) year(-1) (1.34 ng I-TEQ m(-2) year(-1)) and 82.0 ng m(-2) year(-1) (1.07 ng I-TEQ m(-2) year(-1)), respectively. By scenario simulation, the total fluxes of dry and wet PCDD/F depositions were 87.1 and 68.6 ng I-TEQ, respectively. However, the estimated PCDD/F contents in the contaminated soil were 839.9 μ g I-TEQ. Hence, the contributions of total depositions of atmospheric PCDD/F were only 0.02%. The results indicated that the major sources of PCDD/F for the contaminated soil could be attributed to the pentachlorophenol manufacturing process.

Topics: Benzofurans; Environmental Monitoring; Industrial Waste; Pentachlorophenol; Polychlorinated Dibenzodioxins

An alkalotolerant Pseudomonas strain was enriched and isolated from effluent of the pulp and paper industry. This strain was able to degrade dibenzofuran and utilize it as a sole source of energy and carbon. The GC-MS based detection of various intermediary metabolites of biodegradation suggested the involvement of angular as well as lateral pathway of dibenzofuran biodegradation. The GC-MS based detection of various intermediary metabolites of biodegradation suggested the involvement of angular as well as lateral pathway of dibenzofuran biodegradation. This diverse dioxygenation property of the strain allowed it to utilize various recalcitrant chlorinated xenobiotics and PAHs compounds. This strain showed optimum utilization (~85%) of dibenzofuran (200 mg l⁻¹) within 36 h at pH 10 at 40 °C. The growth of the strain was supported by a wide range of environmental conditions such as temperature, pH, and concentration of dibenzofuran, suggesting that it can be used for in situ bioremediation of dioxin-like compound.

Topics: Benzofurans; Biodegradation, Environmental; Dioxins; Gas Chromatography-Mass Spectrometry; Hydrogen-Ion Concentration; Pseudomonas

This paper describes the first report of dioxins and furans (PCDDs/Fs) in sediment cores from Mexico. Sedimentation rates and vertical fluxes were estimated using (210)Pb dating. Two cores correspond to marine sediments and one to an endorheic lake. Concentrations of PCDDs/Fs found in the three sites are typical of non-impacted areas with low concentrations when compared to reference values. However the PCDDs/Fs sediment profiles show an increasing concentration trend in the upper core sections. This behavior is different from that found at many sites around the globe where diminishing concentrations have been reported. A strong predominance of OCDD was observed, and a comparison to typical composition profiles of industrial and other sources did not result in clear origin assignments for these measured compounds. We suggest that local sources may be responsible for the increase in concentration and, because these undetermined sources have not been curtailed, their importance is still growing.

Topics: Benzofurans; Geologic Sediments; History, 20th Century; History, 21st Century; Mexico; Polychlorinated Dibenzodioxins; Water Pollutants, Chemical

The reaction mechanisms of dibenzo-p-dioxin (DD) and 2,3,7,8-TCDD with OH radical have been studied using density functional theory calculations. Under the atmospheric conditions, ca 42% of DD+OH reaction proceeds as formation of DD-OH-β adduct, which will react with O(2) slowly; while the rest will proceed as formation of DD-OH-γ adduct, which will decompose to the substituted phenoxy radical P1 by the fused-ring C-O bond cleavage. For 2,3,7,8-TCDD+OH, the reaction will predominantly form the substituted phenoxy radical P2. The reaction mechanisms are drastically different from the peroxy mechanism for the atmospheric oxidations of benzene and dibenzofuran.

Topics: Air Pollutants; Atmosphere; Benzene; Benzofurans; Hydroxyl Radical; Kinetics; Models, Theoretical; Oxidation-Reduction; Polychlorinated Dibenzodioxins

The concentrations and removal efficiencies of various kinds of micropollutants were investigated and the relationships between the input sources of industrial wastewater and occurrence patterns of each micropollutant were identified at nine on-site industrial wastewater treatment plants (WWTPs). The distribution pattern of each compound varied according to the WWTP type and several micropollutants were significantly related with specific industries: chlorinated phenols (ClPhs) with paper and metal industries, polycyclic aromatic hydrocarbons (PAHs) with petrogenic- and pyrogenic-related industries, polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) with the paper industry, and chlorinated benzenes (ClBzs) with dye-related industries. The activated sludge (AS) process was very efficient in the removal of ClPhs and PAHs, and the filtration process in the removal of PCDD/Fs and 1,4-dioxane. Generally, the removal efficiencies of each micropollutant varied according to the WWTP type.

Topics: Benzene; Benzofurans; Dioxanes; Dioxins; Industrial Waste; Phenols; Polycyclic Aromatic Hydrocarbons; Waste Disposal, Fluid; Water Pollutants, Chemical

From 2008 to 2009, we evaluated the environmental impact of a cement plant (Montcada i Reixac, Catalonia, Spain) that is located close to densely populated areas. The potential health risks for the population living in the neighborhood were also assessed. The levels of various heavy metals and the concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were determined in soil, vegetation, and air samples collected at different directions and distances from the facility. Three 6-monthly consecutive campaigns were performed to establish temporal and seasonal trends. Multivariate statistical techniques, such as principal component analysis, were used. Human exposure to metals and PCDD/Fs, as well as the associated carcinogenic and noncarcinogenic risks, were also calculated. Environmental pollutant concentrations, especially those found in urban sites, were noted to be slightly higher than those recently reported around other cement plants in Catalonia. A seasonal pattern was observed, with higher values recorded during the colder sampling periods. Despite this, the carcinogenic and noncarcinogenic risks derived from human exposure to metals and PCDD/Fs were within the ranges considered acceptable by international regulatory organisms.

Topics: Air Pollutants; Benzofurans; Construction Materials; Environmental Exposure; Environmental Monitoring; Humans; Metals, Heavy; Plants; Polychlorinated Dibenzodioxins; Risk Assessment; Soil Pollutants; Spain

Polychlorinated biphenyls (PCBs), dibenzofurans (PCDFs), and dibenzo-dioxins (PCDDs) may affect the female reproductive system in humans. A mass poisoning occurred in Taiwan due to PCBs/PCDFs-contaminated cooking oil, and was called the Yucheng (oil-disease in Chinese). We aimed to determine whether Yucheng women were affected in their menstruation.. After the event, we followed the exposed individuals and an age-matched neighborhood reference group. Menstrual cycle characteristics and age at menarche were obtained by a telephone interview. We used multiple linear and logistic regression to examine the association between PCBs/PCDFs and menstrual cycle characteristics, after adjusting for confounding factors.. Totally 445 women responded satisfactorily and were included in the analyses of menstrual characteristics. Menstrual cycle irregularity and dysmenorrheal did not differ between Yucheng and referents. Yucheng women's menstrual cycles were 0.5 (95% CI: 0.0-0.5; p=0.03) days shorter than those of the referents. The Yucheng women with skin lesions caused by PCBs/PCDFs were more prominently affected, with the cycles 1.2 days shorter than the referents. Yucheng women exposed to PCBs/PCDFs at the premenacheal period had reduced cycle length (-0.7 day, 95% CI: -1.4 to 0.0; p=0.04) and longer days of menstrual flow (0.5 day, 95% CI: 0.0-1.0; p=0.04). Among those women who were exposed at an age of 5-9 years, menarche started slightly earlier with borderline significance.. Shorter menstrual cycle length and a longer duration of bleeding in each cycle were found among women previously exposed to PCBs/PCDFs. These effects were more obviously observed among those exposed at premenarcheal ages.

Topics: Adult; Benzofurans; Environmental Exposure; Environmental Pollutants; Female; Food Contamination; Humans; Interviews as Topic; Linear Models; Logistic Models; Menstrual Cycle; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Taiwan; Young Adult

The uptake of persistent organic pollutants (POPs) from soil by plants allows the development of phytoremediation protocols to rehabilitate contaminated areas. The use of diverse theoretical descriptors has been reported in the literature for developing quantitative structure-activity relationship (QSAR) models for predicting the bioconcentration factors (BCFs) of POPs in different plants. In this paper an evaluation is given on the molecular properties of POPs in terms of theoretical molecular descriptors that are relevant to the uptake and accumulation of these persistent pollutants from soil by two zucchini varieties. Statistically significant and predictive linear regression models have been developed for the BCF values of 20 polychlorinated dibenzo-p-dioxins/dibenzofurans and 14 polyhalogenated biphenyls in two zucchini varieties based on retrospective data. The relevant parameters have been selected from a set of 1660 DRAGON, 150 VolSurf, and 11 quantum chemical descriptors. The two most significant regression models, containing VolSurf, DRAGON GETAWAY, and quantum chemical descriptors, displayed the following statistical parameters: (eq 3) n = 27, R(2) = 0.940, q(2) = 0.922, SE = 0.155, F = 392.1; (eq 4) n = 27, R(2) = 0.921, q(2) = 0.898, SE = 0.161, F = 140.4. Predictive capabilities of the equations have been validated by using external validation sets. The QSAR models proposed might contribute to the development of viable soil remediation strategies.

Topics: Benzofurans; Cucurbita; Linear Models; Polychlorinated Dibenzodioxins; Quantitative Structure-Activity Relationship; Soil Pollutants

In the present work, air-conditioner filter dust samples collected from commercial office, secondary school, shopping mall, electronic factory and manufacturing plant in Hong Kong were collected for 7-ethoxyresorufin O-deethylase (EROD) assay using a hepatoma cell line (H4IIE) and chemical analysis of dioxins including polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and PCBs with dioxin-like structure. The result of EROD assay showed that bioassay derived TEQ of 2,3,7,8-TCDD (TEQ(bio)) of dust samples varied from 320 to 730 pg/g. Chemical analyses revealed that chemical derived TEQ of 2,3,7,8-TCDD (TEQ(cal)) of dust samples ranged from 134 to 531 pg/g. In addition, the TEQ(cal) of samples were significantly correlated with TEQ(bio) of samples (R=0.83, P<0.01). The average daily doses (ADDs) of dioxins via indoor dust with the estimated ADDs of dioxins via air and food were compared. The results showed that indoor dust is an important medium of exposure to dioxins.

Topics: Air Pollutants, Occupational; Air Pollution, Indoor; Animals; Benzofurans; Biological Assay; Cell Line, Tumor; Cytochrome P-450 CYP1A1; Dioxins; Dust; Environmental Monitoring; Hong Kong; Humans; Occupational Exposure; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Rats; Risk Assessment; Workplace

This study investigated the homogeneous gas-phase formation of polybrominated dibenzo-p-dioxin/dibenzofurans (PBDD/Fs) from 2-BP, 2,4-DBP, and 2,4,6-TBP as precursors. First, density functional theory (DFT) calculations were carried out for the formation mechanism. The geometries and frequencies of the stationary points were calculated at the MPWB1K/6-31+G(d,p) level, and the energetic parameters were further refined by the MPWB1K/6-311+G(3df,2p) method. Then, the formation mechanism of PBDD/Fs was compared and contrasted with the PCDD/F formation mechanism from 2-CP, 2,4-DCP, and 2,4,6-TCP as precursors. Finally, the rate constants of the crucial elementary reactions were evaluated by the canonical variational transition-state (CVT) theory with the small curvature tunneling (SCT) correction over a wide temperature range of 600-1200 K. Present results indicate that only BPs with bromine at the ortho position are capable of forming PBDDs. The study, together with works already published from our group, clearly shows an increased propensity for the dioxin formations from BPs over the analogous CPs. Multibromine substitutions suppress the PBDD/F formations.

Topics: Air Pollutants; Benzofurans; Bromine Compounds; Dioxins; Kinetics; Phenols

Presence, sources and behaviour of polybrominated diphenyl ethers (PBDEs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were evaluated in Spanish sewage sludge. A total of 120 samples were seasonally collected from October 2005 to September 2006 at 31 urban wastewater treatment plants (WWTPs). Concentrations of PBDEs (ranging between 57.5 and 2606 ng/g dry weight) were two to three orders of magnitude higher than those obtained for PCDDs (0.17-5.03 ng/g d.w.) and PCDFs (0.05-3.07 ng/g d.w.). All the samples presented International Toxicity Equivalents (I-TEQ) levels (ranging between 2.06 and 44.4 ng/kg d.w.) below the limit values proposed by European Union for land application. Congener patterns evaluation revealed that the use of Deca-BDE commercial mixture seems to be the major source of PBDEs in the sludge. Nevertheless, origin of PCDD/Fs should be related to atmospheric deposition, faeces and presence of PCDD/Fs precursors such as pentachlorophenol in the sludge. No correlations (p>0.05) were found between pollutant concentrations (PBDEs and PCDD/Fs) and wastewater treatment plant (WWTP) characteristics (capacity nor sludge rate). Lower levels of PBDEs and PCDFs were found in WWTPs using biological nitrogen and phosphorous elimination, suggesting that these compounds are susceptible of microbial elimination. According to our knowledge, this is the first work comparing together both PBDEs and PCDD/Fs sludge patterns.

Topics: Benzofurans; Dioxins; Gas Chromatography-Mass Spectrometry; Halogenated Diphenyl Ethers; Principal Component Analysis; Seasons; Sewage; Spain; Statistics, Nonparametric; Waste Disposal, Fluid

Reports on residue levels and accumulation profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in human adipose tissue are scarce in Korea. In this study, concentrations and accumulation features of PCDD/Fs and DL-PCBs were determined in the samples of adipose tissue collected from Korean women in 2007-2008. The total dioxin-like toxic equivalent (TEQ) concentrations (3.4-42 pg g(-1) lipid wt) in Korean adipose tissues were similar to those reported in European and other Asian countries. The relative contributions of individual compounds to total TEQs were as follows: non-ortho PCBs (mean: 45%) > PCDFs (28%) > PCDDs (24%) > mono-ortho PCBs (3%), a pattern similar to those reported for seafoods in Korea. The dominant PCDD/F congeners found in adipose tissues were OCDD and 2,3,4,7,8-PeCDF and dominant PCBs were 118, 156 and 105. No correlation was found between subject's age and concentrations of dioxin-like contaminants. Body mass index was not correlated with concentrations of PCDD/Fs and was negatively (p < 0.001) correlated with concentrations of DL-PCBs. The results of this study provide baseline information on PCDD/Fs and DL-PCBs in adipose tissues of the general population in Korea.

Topics: Adipose Tissue; Adult; Benzofurans; Body Mass Index; Female; Humans; Middle Aged; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins

The secondary formation of dibenzo-p-dioxin and dibenzofurans (PCDD/Fs) in the flue gas and ash from the municipal solid waste incinerator (MSWI) systems has attracted considerable public concern. The objective of our research was thus to examine reactions in fly ash from an MSWI operated with different precursors with similar chemical compositions, such as dibenzofurans (DFs), and metal chlorides, such as copper chloride (CuCl(2)). We observed that the concentrations of PCDD/Fs in CuCl(2) and in a mixture of CuCl(2) and DFs were 369.5 and 5307.8 ng/g, respectively, and thus significantly higher in the latter. Due to the catalytic effect of copper ions and the similar structure of dibenzofurans for PCDFs, the effect of the additive in forming PCDD/Fs were obvious. The concentrations of PCDD/Fs in CuCl(2) and copper oxide (CuO) were 369.5 and 97.05 ng/g, respectively. The results also show that the PCDD/Fs concentration when copper chloride was added was four times higher than when copper oxide was added. In addition, the level of activity of the chlorine atoms is greater than that of the oxygen atoms during the formation of PCDD/Fs. This study suggests that the use of metal-containing substances (such as Cu, Cl, Zn) or chlorination precursors (such as DF, chlorobenzene) should be avoided in the combustion process.

Topics: Air Pollution; Benzofurans; Carbon; Coal Ash; Copper; Dioxins; Incineration; Oxides; Particulate Matter; Refuse Disposal

A combination of multireference CASSCF/CASPT2 and time-dependent DFT (TD-B3P86) theoretical treatments was employed to test their predictions against recently proposed assignments of the vacuum-UV spectra of fluorene and its three heteroanalogues-dibenzofuran, carbazole, and dibenzothiophene-up to the ionization threshold. For the low-lying transitions, the theoretically based assignments are generally not problematic because of the well-resolved bands, although, even in this region, the two methods yield some opposing predictions. Further on toward the vacuum region, the assignments prove increasingly challenging because of predicted crowding of transitions, many of which exhibit significant intensity. Some of the transitions in this region and beyond-toward the ionization thresholds-are thus necessarily assigned only tentatively. Overall, the two methods are frequently found to complement each other well, and equivalent transitions usually appear as bracketed from the high- (CASPT2) and low- (TD-B3P86) energy sides.

Topics: Benzofurans; Carbazoles; Electrons; Fluorenes; Quantum Theory; Thiophenes; Time Factors

Logarithm values of octanol-water partition coefficients (logK(ow)) of polyfluorinated dibenzofurans (PFDFs) were calculated based on group contributions, and their thermodynamic properties in the ideal gas state at 298.15 K and 1.013 × 10(5) Pa were calculated using a combination of quantum mechanical computations performed with the Gaussian 03 program at the B3LYP/6-311G(*) level. The isodesmic reactions were designed to calculate standard enthalpy of formation (ΔH(f)(θ)) and standard free energy of formation (ΔG(f)(θ)) of PFDF congeners. By establishing relationships between these properties (including logK(ow), standard state entropy S(θ), ΔH(f)(θ),ΔG(f)(θ)) and the number and position of fluorine atom substituents (N(PFS)), it was found that the fluorine substitution pattern strongly influences all of these properties of the compounds. The relation curve of logK(ow) values varying with the fluorine substitution pattern presented a three-level sawtooth shape. Intramolecular repulsive forces exist between an oxygen-adjacent fluorine atom on phenyl ring and the oxygen of dibenzofuran, between ortho-substituted fluorine atoms on a phenyl ring, and between two adjacent fluorine atoms on different phenyl rings. Their repulsion energies were ascertained by comparing ΔG(f)(θ) values to be approximately 14 kJ mol(-1)-17 kJ mol(-1), 18 kJ mol(-1)-22 kJ mol(-1) and 7 kJ mol(-1)-9 kJ mol(-1), respectively. According to the relative magnitude of their ΔG(f)(θ), the relative stability order of PFDF congeners was theoretically proposed.

Topics: Benzofurans; Environmental Pollutants; Hydrophobic and Hydrophilic Interactions; Models, Molecular; Thermodynamics

Environmental pollutants, such as dioxins and furans, are extremely toxic and related with pulmonary diseases development. Impairment of mitochondrial function has been shown in pollutant-induced hepatic injury, but it has not been addressed in lungs, even though lung mitochondria are primary cellular targets for pollutants-induced toxicity. In isolated lung mitochondria, dibenzofuran significantly increased the lag phase preceding mitochondrial repolarization, suggesting a decrease in the efficiency of the mitochondrial phosphorylative system.

Topics: Adenosine Triphosphatases; Animals; Benzofurans; Cytochromes c; Lung; Membrane Potential, Mitochondrial; Membrane Potentials; Mitochondria; Oxygen Consumption; Permeability; Swine

A practical, Pd(0)/Pd(II)-catalyzed reaction was developed for phenol-directed C-H activation/C-O cyclization using air as an oxidant. The turnover-limiting step of the process was found to be C-O reductive elimination instead of C-H activation. This reaction can tolerate a variety of functional groups and is complementary to the previous methods for the synthesis of substituted dibenzofurans.

Topics: Benzofurans; Carbon; Catalysis; Cyclization; Hydrogen; Oxygen; Palladium; Phenol

Surface dust collected from printed circuit board recycling workshop floors, roads, a schoolyard, and an outdoor food market in Guiyu, China, a village intensely involved in e-waste processing, were investigated for levels of polybrominated diphenyl ethers (PBDEs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). PBDE concentrations in dust from workshop-floors (14,800 ± 5130 ng/g) and on adjacent roads to the workshops (24,900 ± 31,600 ng/g) were highest among the study sites whereas PCDD/F concentrations were highest at the schoolyard (1316 pg/g) and in a workshop (1264 pg/g). Analyses of <2 mm and <53 μm dust particle sizes did not show any significant differences in PBDE concentrations. The cytotoxicity was investigated using two bioassays: 7-ethoxyresorufin O-deethylase (EROD-TEQ) and MTT. EROD-TEQ values ranged from 260 to 432 pg/g, with the highest in dust collected from a street lined with workshops. Using the MTT assay, cytoxicity of dust from the plastic chips drying district in Guiyu was higher than dust from the other sites investigated. This study showed that the primitive recycling of e-waste introduced toxic pollutants into the environment which are potentially harmful to the health of e-waste workers and local residents, especially children, and warrants an urgent investigation into POPs related health impacts.

Topics: Analysis of Variance; Benzofurans; Biological Assay; China; Computers; Cytochrome P-450 CYP1A1; Dioxins; Dust; Environmental Pollutants; Halogenated Diphenyl Ethers; Refuse Disposal; Tetrazolium Salts; Thiazoles; Toxicity Tests

Concentrations of polybrominated dibenzo-p-dioxins, and -dibenzofurans (PBDDs/Fs) and polychlorinated dibenzo-p-dioxins, and -dibenzofurans (PCDDs/Fs), were determined in the pre- and post-air pollution control system (APCS) flue gas of a municipal waste combustor (MWC). Operational transients of the combustor were found to considerably increase levels of PBDDs/Fs and PCDDs/Fs compared to steady state operation, both for the raw and clean flue gas; ΣPBDDs/Fs increased from 72.7 to 700 pg dscm(-1) in the raw, pre-APCS gas and from 1.45 to 9.53 pg dscm(-1) in the post-APCS flue gas; ΣPCDDs/Fs increased from 240 to 960 ng dscm(-1) in the pre-APCS flue gas, and from 1.52 to 16.0 ng dscm(-1) in the post-APCS flue gas. The homologue profile of PBDDs/Fs and PCDDs/Fs in the raw flue gas (steady state and transients) was dominated by hexa- and octa-isomers, while the clean flue gas homologue profile was enriched with tetra- and penta-isomers. The efficiency of the APCS for PBDD/F and PCDD/F removal was estimated as 98.5% and 98.7%, respectively. The cumulative TEQ(PCDD/F+PBDD/F) from the stack was dominated by PCDD/F: the TEQ of PBDD/F contributed less than 0.1% to total cumulative toxic equivalency of MWC stack emissions.

Topics: Air Pollution; Benzofurans; Dioxins; Gases; Immunoassay; Incineration; Quality Control; Refuse Disposal

A new class of amidoalkyl dibenzofuranols and 1H-benzo[2,3]benzofuro[4,5-e][1,3]oxazin-3(2H)-ones was synthesized in very good yields through polyphosphoric acid supported on silica (PPA-SiO(2)) catalyzed one-pot three component condensation of 2-dibenzofuranol; aromatic aldehydes and acetamide or benzamide or urea under solvent free conditions. At 125°C the reaction led to the formation of amidoalkyl dibenzofuranols 5a-k where as at 160°C cyclization take place to give oxazin-3(2H)-one analogues 6a-e. Screening all the 16 compounds for in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv (MTB) resulted 1-((4-chlorophenyl)(2-hydroxydibenzo[b,d]furanyl)methyl)urea 5h; 1-((4-bromophenyl)(2-hydroxydibenzo[b,d]furanyl)methyl)urea 5i; 1-phenyl-1H-benzo[2,3]benzo furo[4,5-e][1,3]oxazin-3(2H)-one 6a (MIC 3.13μg/mL) and 1-(4-chlorophenyl)-1H-benzo[2,3]benzofuro[4,5-e][1,3]oxazin-3(2H)-one 6b; 1-(4-bromophenyl)-1H-benzo[2,3]benzofuro [4,5-e][1,3]oxazin-3(2H)-one 6c (MIC 1.56μg/mL) as most active antitubercular agents.

Topics: Antitubercular Agents; Benzofurans; Catalysis; Cyclization; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Oxazines; Phosphoric Acids; Polymers; Silicon Dioxide; Temperature; Urea

The present study assessed the temporal trend in serum concentrations of polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls (PCBs) among residents of a Russian town where levels of these chemicals are elevated due to prior industrial activity.. Two serum samples were collected from eight adult women (in 2000 and 2009), and analyzed with gas chromatography-high-resolution mass spectrometry.. The average total toxic equivalency (TEQ) decreased by 30% (from 36 to 25 pg/g lipid), and the average sum of PCB congeners decreased by 19% (from 291 to 211 ng/g lipid). Total TEQs decreased for seven of the eight women, and the sum of PCBs decreased for six of eight women. During this nine year period, larger decreases in serum TEQs and PCBs were found in women with greater increases in body mass index.. This study provides suggestive evidence that average serum concentrations of dioxins, furans, and PCBs are decreasing over time among residents of this town.

Topics: Adult; Benzofurans; Dioxins; Environmental Exposure; Environmental Pollutants; Female; Gas Chromatography-Mass Spectrometry; Humans; Longitudinal Studies; Polychlorinated Biphenyls; Russia; Young Adult

Tattooing has recently become increasingly popular. Using tiny needles, tattooists place the tattoo ink in the dermis along with numerous unknown ingredients. Most tattoos consist of black inks, which are predominantly composed of soot products (carbon black with polycyclic aromatic hydrocarbons).. Black tattoos cause skin problems, including allergic reactions, but the responsible substance frequently remains unknown.. We applied gas chromatograph-mass spectrometry analysis to search for hazardous compounds in 14 different commercially available black tattoo ink samples.. The analysis revealed that all inks contained the softener substance dibutyl phthalate (0.12-691.2 µg/g). Some of the inks contained hexachloro-1,3-butadiene (0.08-4.52 µg/g), metheneamine (0.08-21.64 µg/g), dibenzofuran (0.02-1.62 µg/g), benzophenone (0.26-556.66 µg/g), and 9-fluorenone (0.04-3.04 µg/g).. The sensitizing agent dibutyl phthalate acts directly on keratinocytes and can drive Th2 responses following skin exposure via induction of thymic stromal lymphopoietin gene expression. Hexachloro-1,3-butadiene is genotoxic in vitro and 9-fluorenone is cytotoxic, generating reactive oxygen species under light exposure. The substances found in the inks might be partially responsible for adverse skin reactions to tattoos.

Topics: Benzofurans; Benzophenones; Butadienes; Dibutyl Phthalate; Fluorenes; Gas Chromatography-Mass Spectrometry; Humans; Ink; Methenamine; Tattooing

Distribution, characteristics, and global inventory of dioxins (polychlorinated dibenzo-p-dioxins [PCDDs] and dibenzofurans [PCDFs] and dioxin like polychlorinated biphenyls) in kaolin clays collected from 10 countries were investigated. Dioxins were found in all kaolin clay samples analyzed, at total concentrations ranging from 1.2 pg/g (Brazil) to 520,000 pg/g (USA). Dioxin concentrations in kaolin clays from a few countries (e.g., Brazil and UK) were lower than those reported for background soils in Japan. Dioxin profiles in kaolin clays were characterized by the domination of the congener octachlorodibenzo-p-dioxin (OCDD), and the concentrations of other congeners decreased in the order of reduction in the levels of chlorination. Furthermore, specific distribution of congeners, with predominant proportions of 1,4,6,9-substituted PCDDs within each homologue group, was found in most clay samples. The ratios of concentrations of PCDD to PCDF and 1,2,3,7,8,9-HxCDD to 1,2,3,6,7,8-HxCDD indicated differences in the profiles found for anthropogenic sources (including pentachlorophenol) and kaolin clays. Concentrations of PCDD/Fs in kaolin clays, except for American ball clays, did not exceed the environmental criteria set by the Law Concerning Special Measures against Dioxins in Japan. Based on the average concentrations measured in our study, inventories of PCDD/Fs from the production/usage of ball clays on a global scale were estimated to be 650 kg/yr; the corresponding value on a TEQ basis is 2400 g-TEQ/yr. More than 480 kg of OCDD is estimated to be released annually from the production of kaolin clays worldwide, suggesting that kaolin clays can be a major contributor for additional source of dioxins, especially OCDD, in the environment.

Topics: Animals; Benzofurans; Dioxins; Environmental Monitoring; Humans; Kaolin; Polychlorinated Biphenyls; Soil Pollutants

In this study, rhizoremediation technology was applied to dioxins-spiked soil. A dibenzofuran-degrading bacterium Comamonas sp. strain KD7, reported in the previous paper, was used in combination with white clover (Trifolium repens L.). First, the effect of strain KD7 on clover seed germination and root elongation was examined in the presence of dioxins compounds. As a result, the white clover seeds inoculated with strain KD7 exhibited a higher germination efficiency and increased root elongation compared with uninoculated white clover. Next, the recovery efficiency of two extraction methods were considered for analyzing the dioxin concentration in soil samples, then, the potential of the plant-microbe combination was evaluated for the remediation of dioxins-spiked soil. After 12 week of growth, significant reductions in the soil were confirmed for most compounds. Our results demonstrated that clover can function as a carrier in order to increase the dioxin-degrading activity of strain KD7. The association of clover and strain KD7 is considered to be a potential tool in the remediation of dioxin-contaminated soil.

Topics: Benzofurans; Biodegradation, Environmental; Comamonas; Dibenzofurans, Polychlorinated; Dioxins; Germination; Plant Roots; Polychlorinated Dibenzodioxins; Seeds; Soil; Soil Pollutants; Trifolium

The atmospheric deposition of polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) was investigated at four locations in different suburban and urban functional districts of Guangzhou City. The annual deposition fluxes of total PBDD/Fs (eight 2,3,7,8-substituted tetra- to hexa-BDD/Fs) were in the range of 36-51 (mean 46) pg m(-2) day(-1), and the corresponding TEQ fluxes were estimated to range between 7.9 and 11.3 (mean 10.3) pg I-TEQ m(-2) day(-1), indicating a noticeable pollution level. The deposition fluxes of PBDD/Fs during the wet season were 2-4 times as high as those during the dry season. Both rainfall and temperature positively correlated with PBDD/F deposition fluxes. Ambient gas/particle partition coefficients (K(p)) were predicted with SPARC. It appears seasonal variations of PBDD/F deposition fluxes were influenced by meteorological parameters and the local usage of brominated flame retardants (BFRs). The congener profiles of PBDD/Fs at four locations were similar either spatially or temporally, indicating that the main PBDD/F emission sources were similar to one another. Seasonal variations and congener patterns of PBDD/Fs indicated the possible sources included electronic waste recycling, industrial waste incinerators and products containing BFRs.

Topics: Air Pollutants; Air Pollution; Atmosphere; Benzofurans; China; Dioxins; Environmental Monitoring; Seasons

Pyrolysis and combustion runs at 850°C in a horizontal laboratory furnace were carried out on different parts of a mobile phone (printed circuit board, mobile case and a mixture of both materials). The analyses of the carbon oxides, light hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), polychlorodibenzo-p-dioxin, polychlorodibenzofurans (PCDD/Fs), and dioxin-like PCBs are shown. Regarding semivolatile compounds, phenol, styrene, and its derivatives had the highest yields. In nearly all the runs the same PAHs were identified, naphthalene being the most common component obtained. Combustion of the printed circuit board produced the highest emission factor of PCDD/Fs, possibly due to the high copper content.

Topics: Benzofurans; Cell Phone; Dioxins; Environmental Pollutants; Incineration; Polychlorinated Biphenyls; Polycyclic Aromatic Hydrocarbons; Refuse Disposal; Spectrometry, X-Ray Emission; Spectroscopy, Fourier Transform Infrared; Volatile Organic Compounds; Waste Products

The artificial-turf granulates made from recycled rubber waste are of health concern due the possible exposure of users to dangerous substances present in the rubber, and especially to PAHs. In this work, we determined the contents of PAHs, metals, non-dioxin-like PCBs (NDL-PCBs), PCDDs and PCDFs in granulates, and PAH concentrations in air during the use of the field. The purposes were to identify some potential chemical risks and to roughly assess the risk associated with inhalation exposure to PAHs. Rubber granulates were collected from 13 Italian fields and analysed for 25 metals and nine PAHs. One further granulate was analysed for NDL-PCBs, PCDDs, PCDFs and 13 PAHs. Air samples were collected on filter at two fields, using respectively a high volume static sampler close to the athletes and personal samplers worn by the athletes, and at background locations outside the fields. In the absence of specific quality standards, we evaluated the measured contents with respect to the Italian standards for soils to be reclaimed as green areas. Zn concentrations (1 to 19 g/kg) and BaP concentrations (0.02 to 11 mg/kg) in granulates largely exceeded the pertinent standards, up to two orders of magnitude. No association between the origin of the recycled rubber and the contents of PAHs and metals was observed. The sums of NDL-PCBs and WHO-TE PCDDs+PCDFs were, respectively, 0.18 and 0.67×10(-5) mg/kg. The increased BaP concentrations in air, due to the use of the field, varied approximately from <0.01 to 0.4 ng/m(3), the latter referring to worst-case conditions as to the release of particle-bound PAHs. Based on the 0.4 ng/m(3) concentration, an excess lifetime cancer risk of 1×10(-6) was calculated for an intense 30-year activity.

Topics: Air Pollutants; Benzofurans; Dioxins; Gas Chromatography-Mass Spectrometry; Humans; Inhalation Exposure; Italy; Metals, Heavy; Polychlorinated Biphenyls; Polycyclic Aromatic Hydrocarbons; Risk Assessment; Rubber; Soccer; Sports Equipment

Two novel pyrazoline derivatives, named 2,8-bis(1,3-diphenyl-pyrazoline-5-yl)dibenzofuran (A) and 2,8-bis(1-(4-bromophenyl)-3-phenyl-pyrazoline-5-yl)dibenzofuran (B), were synthesized and characterized by elemental analysis, NMR, MS and thermogravimetric analysis. The absorption and emission spectra of them were determined by experimental methods in different polar solvents and were computed using the density functional theory (DFT) and the time-dependent density functional theory (TDDFT) at the same time. The calculated absorption and emission wavelengths are in good agreement with the experimental data. The fluorescence quantum yields and fluorescence lifetimes of them in different polar solvents were studied by means of steady state and time resolved fluorescence. The calculated reorganization energy for hole and electron indicates that the two compounds are in favor of hole transport than electron transport. The results show the two compounds present high fluorescence quantum yields and excellent thermal stability. It makes them of great interest as novel fluorescent probes and optoelectronic materials.

Topics: Benzofurans; Magnetic Resonance Spectroscopy; Mass Spectrometry; Models, Chemical; Models, Molecular; Pyrazoles; Quantum Theory; Thermogravimetry

The aim of this study was estimation of PCDD/PCDFs emissions from various sources in Iran. The results indicated total PCDD/PCDFs emissions in Iran in 2010, was 1,957 g TEQ. Of this amount, about 705.8, 0.5, 463.5, 144.1 and 643.2 g TEQ/year was released to air, water, land, products, and in residues, respectively. Open burning processes and metal production are the major contributors to be known environmental sources of PCDD/PCDFs that contribute to about 70% of total PCDD/PCDFs emissions in Iran. The results showed that total PCDD/PCDFs emissions in Iran per inhabitant were about 26.5 g TEQ/million that is high relatively.

Topics: Benzofurans; Dioxins; Environmental Monitoring; Environmental Pollutants; Incineration; Iran; Polychlorinated Dibenzodioxins

Polychlorinated biphenyls (PCBs), dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) binding with the aryl hydrocarbon receptor (AhR) have been correlated with many toxic responses. Hence, it is very necessary to study the interactions between these ligands and AhR for further understanding of the mechanism of toxicity. In this study, an integrated molecular docking and 3D-QSAR approach was employed to investigate the binding interactions between PCBs, PCDDs, PCDFs and AhR. From molecular docking, hydrogen-bonding and hydrophobic interactions were observed to be characteristic interactions between compounds and AhR. Based on the mechanism of interactions, an optimum 3D-QSAR model with good robustness (Q(CUM)(2)=0.907) and predictability (Q(EXT)(2)=0.863) was developed by partial least squares. Additionally, the developed QSAR model indicated that the molecular size, shape profiles, polarizability and electropological states of compounds were related to the binding affinities to AhR.

Topics: Benzofurans; Dioxins; Hydrogen Bonding; Hydrophobic and Hydrophilic Interactions; Models, Molecular; Polychlorinated Biphenyls; Quantitative Structure-Activity Relationship; Receptors, Aryl Hydrocarbon

Topics: Alkaloids; Benzofurans; Carbazoles; Lewis Acids; Molecular Structure; Triazenes

Tissue distribution provides important information regarding the pharmacokinetic behavior of pollutants and is invaluable when analyzing the risk posed to avian species by the exposure to such kind of pollutants. In this study, concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were determined in muscle, liver, spleen, kidney, stomach, gall bladder, skin, heart, pancreas, intestine and lung tissue extracts of cormorants collected from Dongting Lake, China. Tissue distribution results showed preferential accumulation of PCDD/Fs in both liver and skin. The total concentration of PCDD/Fs ranged from 421 to 5696 pg/g lipid weight. Octachlorinated dibenzo-p-dioxin (OCDD) was the predominant congener in all tissues and contributed between 31% and 82% to all 17 PCDD/Fs in different tissues. The liver/muscle ratios progressively increased with the degree of chlorination of PCDDs, except for OCDD. The relative toxic potential of PCDDs and PCDFs in tissues were calculated using the World Health Organization (WHO) Toxic Equivalency Factors (TEFs) for birds. The concentrations of WHO-toxic equivalent in different tissues ranged between 14.8 and 2021 pg/g lipid weight. These results indicated PCDD/Fs may have been bio-accumulated in cormorant via food-web. Furthermore, when compared with studies reported in the literatures, the PCDD/Fs levels in the cormorant collected from Dongting Lake were still relatively high.

Topics: Animals; Benzofurans; Birds; China; Gas Chromatography-Mass Spectrometry; Lakes; Polychlorinated Dibenzodioxins; Tissue Distribution; Water Pollutants, Chemical

The aim of this work has been to study the substrate specificity of two aromatic peroxygenases concerning polyaromatic compounds of different size and structure as well as to identify the key metabolites of their oxidation. Thus, we report here on new pathways and reactions for 2-methylnaphthalene, 1-methylnaphthalene, dibenzofuran, fluorene, phenanthrene, anthracene and pyrene catalyzed by peroxygenases from Agrocybe aegerita and Coprinellus radians (abbreviated as AaP and CrP). AaP hydroxylated the aromatic rings of all substrates tested at different positions, whereas CrP showed a limited capacity for aromatic ring-hydroxylation and did not hydroxylate phenanthrene but preferably oxygenated fluorene at the non-aromatic C(9)-carbon and methylnaphthalenes at the side chain. The results demonstrate for the first time the broad substrate specificity of fungal peroxygenases for polyaromatic compounds, and they are discussed in terms of their biocatalytic and environmental implications.

Topics: Agaricales; Benzofurans; Fungal Proteins; Mixed Function Oxygenases; Naphthalenes; Polycyclic Aromatic Hydrocarbons

Dichlorocarbene (CCl(2)), generated by laser flash photolysis of dichlorodiazirine, formed pi- and O-ylidic complexes with aromatic ethers such as anisole, 1,3-dimethoxybenzene, 1,3,5-trimethoxybenzene, dibenzofuran, and dibenzo-18-crown-6 and with the aromatic ester phenyl acetate. These complexes were visualized by UV-vis spectroscopy, and they retarded the addition of CCl(2) to tetramethylethylene by factors of 18-152. Computational studies based on density functional theory provided structures and energetics for the transient species and rationalized their absorption spectra. Complexes were not observed between CCl(2) and simple, nonaromatic ethers such as THF, dioxane, or 18-crown-6, nor did these ethers much affect the addition rate of CCl(2) to tetramethylethylene. Computations also suggested that pi-complexes of CCl(2) and, e.g., mesitylene and durene, were energetically reasonable transients. Although these species were not detected spectroscopically, the aromatic compounds did slow the addition of CCl(2) to tetramethylethylene by factors of 15 and 31, respectively.

Topics: Anisoles; Benzofurans; Computer Simulation; Crown Ethers; Ethers; Hydrocarbons, Chlorinated; Models, Chemical; Phloroglucinol; Photolysis; Solutions

Polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) were analyzed in both human adipose tissue and plasma from nine individuals, from the Swedish general population, using high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS). In addition, several other persistent organic pollutants (POPs) were determined in the same samples, including polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and perfluorinated chemicals (PFCs). Polybrominated dibenzofurans were detected in all of the human adipose tissue samples confirming their presence in the Swedish population. The highest concentration was found for 2,3,7,8-TeBDF, ranging from 0.27 to 2.4 pg g(-1) lipid, followed by 1,2,3,7,8-PeBDF, 0.23-0.89pgg(-1) lipid, 2,3,4,7,8-PeBDF, 0.44-0.54 pg g(-1) lipid, and 2,7/2,8-DiBDF, 0.19-0.30 pg g(-1) lipid. No PBDDs could be detected above the limit of detection (<0.02-<0.21 pg g(-1) lipid) in any of the samples. The levels of PCDD/Fs were in the range 1.79-31.5pg toxic equivalents (TEQ)g(-1) lipid, and PBDEs were found in the 1.16-7.46 ng g(-1) lipid range. The measured chlorinated dioxins indicate decreasing human concentrations in Sweden. The toxicity equivalents (TEQ) for PBDD/Fs (0.2-0.8 pg TEQg(-1) lipid) were found to contribute 1-15% of the total dioxin TEQ of the chlorinated dioxins and furans (5-18 pg TEQg(-1) lipid) depending on the individual. Also PBDEs concentrations are decreasing compared to 1997-2000, but most noteworthy a shift in BDE pattern where BDE#47 is surpassed by BDE#153. The levels of PFCs are in the same range as the highest levels of the traditional POPs (sum of 60 PCBs) based on volume. These findings illustrate the importance of continuous monitoring of brominated compounds in both human and the environment.

Topics: Adult; Aged; Benzofurans; Bromine; Dioxins; Female; Gas Chromatography-Mass Spectrometry; Halogenated Diphenyl Ethers; Humans; Male; Middle Aged; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Polymers

The development of new sampling devices or strategies to assess the concentration of persistent organic pollutants (POPs) in the environment has increased in the last two decades. In this study, a selective sampling device was used to evaluate the impact of potential local sources of polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/Fs) and dioxin-like polychlorinated biphenyl (dl-PCBs) emissions on the ambient air levels of such compounds in a town near an important industrial estate. Average concentrations of target compounds of up to 2.5 times for PCDD/Fs and 2 times for dl-PCBs were found to come from the industrial state confirming this area as the main responsible for the majority of such compounds reaching the town. This finding was supported by a PCDD/F and dl-PCB sample profile analysis and a principal component analysis (PCA), which established a direct link between the dioxin-like compounds found in the samples collected in the town and their source.

Topics: Air Pollutants; Benzofurans; Dioxins; Environmental Monitoring; Industrial Waste; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins

This work reports on the first known field study determining emission factors for polychlorinated and polybrominated dibenzodioxins/dibenzofurans (P[C/B]DDs/Fs) and polybrominated diphenyl ethers (PBDEs) from open burning of domestic waste. Two burning waste dump sites in Mexico were sampled using high-volume samplers mounted to a mobile sampling boom. Concurrent measurements of CO and CO(2) allowed determination of emission factors via the carbon balance method. PCDD/F emission factors averaged 823 ng toxic equivalency (TEQ)/kg C(burned) (N = 8, 68% relative standard deviation, RSD), a value at least five times higher than those from previous tests with domestic waste burned in barrels and approximately 2000 times higher than those from stacks of modern municipal waste combustors. These emission factors appear to be related to combustion quality, as conditions conducive to smoldering combustion, rather than flaming combustion, resulted in higher emission factors. Emissions of 40 PBDE congeners, likely originating from brominated flame retardants, averaged 724 mug/kg C(burned) (RSD = 96%) and had congener patterns similar to those of reported atmospheric sampling. Emissions of PBDDs/Fs were similar in magnitude to their chlorinated counterparts, averaging 470 ng TEQ/kg C(burned) (RSD = 105%), and may originate as reaction products of PBDE combustion or as thermally desorbed impurities from the PBDE flame retardant.

Topics: Air Pollutants; Benzofurans; Halogenated Diphenyl Ethers; Incineration; Mexico; Polybrominated Biphenyls; Polychlorinated Dibenzodioxins; Refuse Disposal

Concentrations of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in sediments from Bohai Sea and Yellow Sea coastal waters and lakes in Shandong Peninsula were determined. The total PCB concentrations of the measured 50 congeners (Sigma50PCBs) in the sediments ranged from 273.7 to 644.5 pg g(-1) dw (dry weight). The PCB congener profiles in the lacustrine sediments were different from those in the marine sediments. TriCBs and TetraCBs were the dominant homologues in marine sediments, whereas in the sediments from the Nansi Lakes, contributions of PCB homologues were similar. The total concentrations of 2,3,7,8-PCDD/Fs ranged from 6.2 to 27.4 pg g(-1) dw. The congener profiles of 2,3,7,8-substituted PCDD/Fs for the sediments were generally similar for both the lakes and the coastal sea areas in Shandong Peninsula. They were characterized by high OCDD, followed by 1,2,3,4,6,7,8-HpCDD and OCDF. The congener profiles of PCDD/Fs in the sediments were consistent with the profiles of main dominant PCDD/Fs in pentachlorophenol and sodium pentachlorophenate products in China. PCDD/F-TEQ ranged from 0.11 to 0.80 pg TEQg(-1) dw. The dioxin-like PCB-TEQ had concentrations ranging from 0.03 to 0.08 pg TEQ g(-1) dw, mainly from PCB126. PCBs and PCDD/Fs concentrations found in the sediments were from background to low polluted levels.

Topics: Benzofurans; China; Dioxins; Environmental Pollutants; Geologic Sediments; Oceans and Seas; Polychlorinated Biphenyls; Water Pollutants, Chemical

Because placental polychlorinated dibenzo-p-dioxins,dibenzofurans (PCDD/Fs) levels are associated with decreased free thyroxine (FT(4)) and thyroid stimulating hormone (TSH) in neonates, we assessed development by gender and maternal PCDD/Fs exposure at years 2 and 5 in 92 mother and newborn pairs. RIA quantified thyroid, sex, and growth hormones. Of 200 subjects followed up from November 2000, 136 and 149 were observed at year 2 and year 5,respectively. PCDD/Fs exposure levels were low (n = 35) or high (n = 35) in 70 subjects at year 2, low (n = 21) or high (n = 20) in 41 at year 5. Height, weight, BMI, and head circumference were significantly higher in males, chest girth significantly higher in females at year 2. Significantly, more girls had higher bone age (BA) and chronological age (CA) at both times. Height, weight, FT(4) x TSH, and transthyretin(TTR) at year 2; and height, triiodothyronine, and IGF-1 at year 5 differed significantly by PCDD/Fs level. In females, height, weight, CA,BA, and thyroid hormones differed significantly at year 2. In males, FT(4) x TSH at year 2 and IGF-1 at year 5 were significantly higher in the high PCDD/Fs group. In utero exposure to PCDD/Fs differentially affects growth and hormone levels in male and female preschool children.

Topics: Age Factors; Aging; Benzofurans; Body Height; Body Mass Index; Body Weight; Bone Development; Cephalometry; Child Development; Child, Preschool; Environmental Pollutants; Female; Follow-Up Studies; Head; Humans; Linear Models; Male; Polychlorinated Dibenzodioxins; Prealbumin; Pregnancy; Prenatal Exposure Delayed Effects; Sex Factors; Thorax; Thyroid Gland; Thyrotropin; Thyroxine; Time Factors

Limited information is available on the applicability of polychlorinated dibenzo-p-dioxin/furan (PCDD/F) toxicity assays to their brominated counterparts: polybrominated dibenzo-p-dioxins/furans (PBDDs/Fs). We estimated the toxicity of mixtures of chlorinated, brominated, and mixed bromochloro-dioxins and -furan (PBCDDs/Fs) laboratory standards using a chemically-activated luciferase gene expression cell bioassay (CALUX). The relative effects potency (REP) values obtained were comparable to the World Health Organization (WHO) toxic equivalency factors (TEFs) and in agreement with the concept of additive congener toxicity of mixtures of dioxins and furans. Enzyme immunoassay (EIA)-based toxic equivalents (TEQs), however, showed overestimation for PCDDs/Fs (0-4 orders of magnitudes higher) and underestimation for PBDDs/Fs (0-1 orders of magnitude lower) when compared to high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS)-based TEQ calculation (using WHO TEFs) in samples from an industrial source line. No correlation was found between the EIA and the HRGC/HRMS data, which could be attributed to differences in homologue-specific cross-reactivity responses, sample matrix type, and presence of other compounds competing for antibody binding in the immunoassay.

Topics: Benzofurans; Biological Assay; Chromatography, Gas; Dioxins; Environmental Pollutants; Enzyme-Linked Immunosorbent Assay; Hydrocarbons, Brominated; Hydrocarbons, Chlorinated; Industrial Waste; Mass Spectrometry; Statistics as Topic

Air monitoring of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (PCBs) was carried out in June 2008 and January 2009 to investigate the concentrations, profiles and estimating potential inhalation risks to the local residents around a steel plant area in northeast China. The air concentrations and WHO-TEQs of PCDD/Fs ranged 94-4944fgm(-3) (average 1352fgm(-3)) and 3-247fgm(-3) (average 81fgm(-3)), respectively. The WHO-TEQ concentrations of dioxin-like PCBs ranged 1-18fgm(-3) (average 5fgm(-3)), contributing to 3.6-26% of the total TEQ. Higher PCDD/F concentrations were observed in the winter, whereas higher dioxin-like PCB concentrations were found in the summer. The seasonal trend can be related to the significant correlation between the concentrations of dioxins and the reciprocal of temperature (positive for PCDD/Fs, P<0.01; negative for dioxin-like PCBs, P=0.05). A significant positive correlation (P<0.0001) was found between the concentration of total suspended particulate (TSP) and PCDD/F concentrations, but not for PCB congeners. Although the steel plant sites showed higher dioxin levels than the residential and background areas, the PCDD/F levels in the atmosphere of the steel plant area was at a relatively low level. The results from this study provides further aid in evaluating the impact of steel plants as PCDD/Fs emission sources to the ambient air in China.

Topics: Air Pollutants; Atmosphere; Benzofurans; China; Environmental Monitoring; Industrial Waste; Inhalation Exposure; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Risk Assessment; Seasons; Steel

The present study assesses effects of dioxins and related compounds (DRCs) including polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and dioxin-like polychlorinated biphenyls (DL-PCBs) on cytochrome P450 1A (CYP1A) expression level in liver of black-footed albatrosses (Phoebastria nigripes) collected from the North Pacific. Total 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-T(4)CDD) toxic equivalents (TEQs) derived from toxic equivalency factor for birds proposed by World Health Organization were in the range of 2100 to 10 000 pg/g lipid wt (120-570 pg/g wet wt). Simultaneously, microsomal alkoxyresorufin O-dealkylase (AROD) activities, including methoxy-, ethoxy-, pentoxy-, and benzyloxy-resorufin O-dealkylase activities were also measured in the same specimens. Total TEQs and TEQ (on wet wt basis) from some individual DRC congeners had significant positive correlations with AROD activities, suggesting induction of CYP1A by DRCs. Congeners like 2,3,7,8-T(4)CDD and most of the DL-PCBs that showed no significant positive correlations between the concentrations and AROD activities, exhibited significant negative correlations between AROD activities and the concentration ratio of the congener to a recalcitrant CB169, suggesting preferential metabolism of these congeners by induced CYP1A. As far as we know, this is the first direct evidence revealing that hepatic CYP1A level is elevated with the accumulation of DRCs in the wild black-footed albatross population. The present study gives more robust estimate of impacts of DRCs on CYP1A induction in this rare pelagic species than indexes like hazard quotient and TEQ-threshold comparison that have been so far carried out.

Topics: Animals; Benzofurans; Birds; Chlorine; Cytochrome P-450 CYP1A1; Dioxins; Environmental Pollutants; Liver; Microsomes, Liver; Risk Assessment; Water Pollutants, Chemical

In 2004, it is estimated that 1.18 kg I-TEQ of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) emitted from medical waste incinerators (MWIs) in China, accounting for 11.5% of the total PCDD/Fs emissions. So it is essential to assess the environmental impact of MWIs. A new MWI of China was started operation in May 2007, and implemented an advanced technology in the combustion and air pollution control system by the BAT/BEP guideline in August 2008. From 2007 to 2009, levels of PCDD/Fs were determined in soil collected in the vicinity of this MWI. The blank survey (2007) was conducted before the start-up operation of this plant. After the operation, soil samples were collected again at the same sampling sites as the blank survey. The average concentration of PCDD/Fs in soil increased from 1.13 pg I-TEQ g(-1) to 2.29 pg I-TEQ g(-1) after 1 year operation of the MWI (2007-2008), and a marked decrease (0.50 pg I-TEQ g(-1)) was observed during 2008-2009. In addition, the current level (2009) was still higher than the blank value (2007). The composited analysis of the experimental results indicated levels of PCDD/Fs were still comparative lower and a limited neighbourhood of the MWI was slightly affected by the emission from this incinerator, meanwhile other un-known PCDD/Fs sources and potential influenced factors could not be neglected in this investigated region.

Topics: Benzofurans; Carbon; China; Coal Ash; Environmental Monitoring; Incineration; Medical Waste; Medical Waste Disposal; Particulate Matter; Plants; Polychlorinated Dibenzodioxins; Principal Component Analysis; Soil; Soil Pollutants; Time Factors; Trees

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in sediment and fish of aqua farms close to a contaminated site of a pentachlorophenol production plant (CPDC-ASS) were investigated. The total PCDD/F I-TEQ level in sediment and fish ranged from 0.725 to 87.9 ng I-TEQ kg(-1)d.w.(-1) and 0.044 to 3.10 pg I-TEQ g(-1)w.w.(-1), respectively, meaning that the CPDC-ASS was a long-term exposure PCDD/F contaminated area. The four dominant congeners in sediment and fish were OCDD, OCDF, 1,2,3,4,6,7,8-HpCDF and 1,2,3,4,6,7,8-HpCDD. The correlated coefficient of total I-TEQ PCDD/F contents between fish and sediment was 0.82 (R(2)), indicating a positive correlation between exposure to PCDD/Fs in sediment and biota. In addition, the biota-to-sediment accumulation factors (BSAFs) values of low chlorinated PCDD/F congeners such as those of 2,3,7,8-TeCDD for Milkfish and Tilapia were 0.00739 and 0.00593, respectively, which were much higher than those of highly chlorinated congeners. For example, the BSAFs of OCDD for Milkfish and Tilapia were 0.000207 and 0.000277, respectively. A negative relationship of log K(ow) and log BSAF for PCDD/F congeners was found, and the highest value was observed at approximately K(ow)= 7.0-7.5. The results of this study provide valuable information for establishing the PCDD/F regulated standard for the sediment of fish ponds.

Topics: Animals; Aquaculture; Benzofurans; Dioxins; Environmental Monitoring; Geologic Sediments; Pentachlorophenol; Species Specificity; Taiwan; Tilapia

Chloracne, first described by Herxheimer in 1899, is a dermatosis consisting of more or less diffuse acneiform lesions distributed prevalently on the face and on body areas not usually affected by acne and caused by chronic or acute exposure to halogenated chemical compounds. Dioxin is the common name for dibenzo-p-dioxins and dibenzofurans, contaminants nearly ubiquitous in the environment and highly resistant to chemical and biological degradation. These compounds can survive for decades in the environment and accumulate in the human and animal food chains. Chloracne is characterized by the onset of numerous comedo-like lesions and yellowish cysts on the face, particularly on the cheeks, that can spread to the trunk and other body regions not usually affected by acne vulgaris, with diffuse grayish skin pigmentation and sometimes associated with hypertrichosis and areas of folliculitis. The lesions may occasionally be accompanied by skin or systemic manifestations. We report 9 cases of chloracne, 8 of them with rapid onset in patients residing in the same building, and 1 in a patient occupationally exposed to halogenated compounds. In our series, the doses of dioxin and polychlorinated biphenyls in the soil, water and plant material, and the serum titer of dioxin were within the normal range. This consideration raises the issue of the need to revise the serum threshold for dioxin poisoning and the environmental threshold. We wish also to underline the value of dermatopathology in the differential diagnosis of chloracne.

Topics: Aged; Aged, 80 and over; Benzofurans; Chloracne; Dioxins; Female; Humans; Male; Middle Aged; Triglycerides

This study was set out to investigate emissions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from both the stack (i.e., point source) and plant fugitives (i.e., area source) of an electric-arc furnace-dust treatment plant (EAFDTP) and their impact to the vicinity environments. The emission rate of the point source (2,360 ng I-TEQh(-1)) was determined directly by measuring PCDD/F concentrations of the stack flue gas. The emission rate of the area source (1,080 ng I-TEQ m(-2)h(-1)) was estimated by using the Industrial Sources Complex Short-Term (ISCST3) model based on concentrations measured at the downwind side of the plant. The mean emission factors of 785 and 893 ng I-TEQ ton(-1) ZnO were found for the point and area source, respectively. The above results suggest that the area source accounted for more than 50% of total PCDD/F emissions for the selected EAFDTP. The contribution of the point source to the atmospheric PCDD/F concentrations of the upwind site and downwind site of the EAFDTP were 0 and 0.27 fg I-TEQ Nm(-3), respectively. The contributions of the area source were 0.020 and 3.3 fg I-TEQ Nm(-3), respectively. The total contribution of the selected EAFDTP (including both the point and area sources) to the concentrations in both upwind and downwind side vicinities were all less than 10%. Finally, the impact of PCDD/F emissions from the selected EAFDTP to the vicinity atmospheric environments was discussed in the present study.

Topics: Air Pollutants; Benzofurans; Dioxins; Dust; Environmental Monitoring; Incineration

This work develops a comprehensive approach for quantitatively analyzing polychlorinated and polybrominated dibenzo-p-dioxins (PCDDs/PBDDs), dibenzofurans (PCDFs/PBDFs), biphenyls (PCBs/PBBs) and diphenyl ethers (PBDEs). This technique, based on multiple (silica, alumina, and active carbon) columns, can be applied to prepare samples for determining the five group compounds based on high-resolution gas chromatography/high-resolution mass spectrometry. The method was also validated by analyses of blank and spiked samples. In the sampled air, the mean PCDD/F, PCB, PBDD/F, PBDE, and PBB concentrations were 59.6 fg WHO-TEQ Nm(-3), 6.74 fg WHO-TEQ Nm(-3), 12.2 fg WHO-TEQ Nm(-3), 52100 fg Nm(-3), and 341 fg Nm(-3), respectively. The WHO-TEQ of dioxin-like PCB and PBDD/Fs counted for 8.9% and 16% of total TEQ (summed over PCDD/Fs, PBDD/Fs, and dioxin-like PCBs), respectively, suggesting that the atmospheric concentrations of dioxin and dioxin-like compounds should be regulated together because of the persistence and toxicity of PBDD/Fs and dioxin-like PCBs.

Topics: Atmosphere; Benzofurans; Biphenyl Compounds; Dioxins; Environmental Monitoring; Gas Chromatography-Mass Spectrometry; Halogenated Diphenyl Ethers; Incineration; Polychlorinated Dibenzodioxins

The results of an environmental program around the municipal solid waste incinerator (MSWI) of Mataró (Catalonia, Spain), which was designed to assess the potential impact of the facility on the close environment and the health of the population living in the vicinity, are here reported. Metals, polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) were analyzed in soil and air samples collected in/around the facility. In soils, Mn and Zn showed the highest metal concentrations (ranges: 136-648 mg kg(-1) and 29.6-97.8 mg kg(-1), respectively), while total concentrations of PCDD/Fs and PCBs were 0.14-0.46 ng WHO-TEQ kg(-1) and 167-3340 ng kg(-1), respectively. In air, the highest metal levels corresponded to Cu (range: 26.9-52.9 ng m(-3)) and Mn (range: 6.92-19.3 ng m(-3)), while those of PCDD/Fs and PCBs ranged 0.008-0.015 pg WHO-TEQ m(-3) and 9.20-42.1 pg m(-3), respectively. Carcinogenic and non-carcinogenic risks derived of exposure to metals, PCDD/Fs and PCBs did not exceed the threshold values. Complementarily analyzed with the results obtained in the concurrent biomonitoring study and the stack emissions, data indicate that the MSWI of Mataró does not mean significant human health risks derived of emissions of metals, PCDD/Fs and PCBs.

Topics: Air Pollutants; Benzofurans; Environmental Exposure; Environmental Monitoring; Environmental Pollutants; Humans; Incineration; Metals; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Risk Assessment; Soil Pollutants; Spain

Congeners are molecules based on the same carbon skeleton but different by the number of substituents and/or a substitution pattern. Various Persistent Organic Pollutants (POPs) exist in the environment as families of halogen substituted congeners and/or their hydroxyl and methoxy substituted derivatives. Numbers of possible congeners resulting from substitution of a parent POP molecule with only one type of chemical group are generally available. At the same time, numbers of mixed-substituent congeners have not been counted and presented yet, although there is an increasing interest in such as is the increasing number of research articles presenting results on already identified Cl-/Br-mixed type congeners and/or their HO-/CH(3)O-mixed metabolites. We have enumerated and counted possible mixed-substituent congeners of common POPs. This article presents the obtained numbers for congener families of benzene, naphthalene, biphenyl, diphenyl ether, dibenzo-p-dioxin, dibenzofuran, anthracene, pyrene and others and obtained by substitution of up to five chemical group types.

Topics: Anthracenes; Benzene; Benzofurans; Carbon; Dioxins; Environmental Monitoring; Environmental Pollutants; Molecular Structure; Naphthalenes; Organic Chemicals; Phenyl Ethers; Pyrenes

The occurrence and characteristics of 2,3,7,8-substituted polybrominated and polychlorinated dibenzo-p-dioxins and dibenzofurans (PBDD/F and PCDD/F) from various combustion and metallurgic industrial thermal processes were investigated. PBDD/F levels from metallurgic processes (TEQ) concentrations from 0.14 to 1.5 ng Nm(-3), mass concentrations from 0.56 to 5.8 ng Nm(-3)) were markedly higher than those from combustion processes (TEQ) concentrations from 0.010 to 0.054 ng Nm(-3), mass concentrations from 0.025 to 0.15 ng Nm(-3)). This indicated that metallurgic processes could be important sources of PBDD/F. Consequently, more attention should be paid to the metallurgical emission sources in addition to combustion of brominated flame retardants (BFRs) and related products. Specific isomeric patterns for PCDD/F from various industrial sources were highly consistent, while PBDD/F patterns were not. This revealed that PCDD/F might form through a common mechanism such as de novo synthesis mechanism, while PBDD/F might form by different mechanisms in thermal processes such as precursor mechanisms. Finally, an approach to identify the PBDD/F sources in ambient air by using the PBDD/F to PCDD/F ratio was developed.

Topics: Air Pollutants; Benzofurans; Dioxins; Gases; Industrial Waste; Metallurgy; Polychlorinated Dibenzodioxins

Here we show that combustion sources, including waste incinerators, metallurgical processes, power-heating systems and so on, are also important emitters of polybrominated diphenyl ethers (PBDEs) to the atmosphere. Geometric mean PBDE concentrations in the stack flue gases of the combustion sources ranged from 8.07 to 469 ng/Nm3. The sinter plants (24.7 mg/h), electric arc furnaces (EAFs) (11.3 mg/h) and power plants (50.8 mg/h) possessed the largest PBDE emission rates, which were several orders higher than those of the other reported sources. The occurrences of the PBDEs in the flue gases of the power plants and vehicles, as well as their PBDE concentrations statistically highly correlated with combustion-originated PCDD/Fs, revealing that PBDEs should be the products of combustion. The ranking of major PBDE emission sources in Taiwanese PBDE inventory for combustion sources was power plants (30.85 kg/year), vehicles (14.9 kg/year) and metallurgical processes (5.88 kg/year).

Topics: Air Pollutants; Air Pollution; Atmosphere; Benzofurans; Dioxins; Environmental Monitoring; Halogenated Diphenyl Ethers; Statistics as Topic

A congener profile of polychlorinated dibenzo-p-dioxin and dibenzofurans (PCDD/Fs) could provide valuable information for identifying possible sources of exposure to these compounds. The purpose of this study is to identify factors associated with PCDD/F congener profiles in the general population of Taiwan. Serum samples from 251 subjects of the general population in Taiwan were collected, and the levels of 17 2,3,7,8-chlorinated substituted PCDD/Fs were measured. The relationships between PCDD/F congener profiles and demographic parameters were evaluated using a multivariate analysis of variance method (MANOVA). Of the five demographic factors investigated, age was found to have the greatest impact on PCDD/F congener profiles. The PCDD/F congener pattern for the group I subjects (aged 18-29) was significantly different from those for the other three older age groups (p<0.001), and 12 congeners contributed to the effects (difference index: 71%). In addition, the group I subjects did not exhibit trends parallel to those of the other groups in the relationship between age and PCDD/F levels. Age was associated with PCDD/F levels and congener profiles in the general population of Taiwan and the young subjects (aged 18-29) was quite different from the other older subjects that could be influenced by the individual differences in pharmacokinetics and/or background exposure from dietary sources. We conclude that investigators must consider subjects' age and other underlying factors that could influence PCDD/F congener profiles in humans when identifying exposure sources.

Topics: Adolescent; Adult; Age Factors; Benzofurans; Environmental Exposure; Environmental Monitoring; Environmental Pollutants; Female; Humans; Male; Middle Aged; Polychlorinated Dibenzodioxins; Taiwan; Young Adult

We detail the development and characterization of a GC/QLT-Orbitrap hybrid mass spectrometer capable of high resolution (up to 100,000 at m/z 400) and sub-parts-per-million mass accuracy GC/MS. A high-duty cycle, innovative scan type, the nested scan, was implemented to synchronize the Orbitrap acquisition rate and the time scale of gas chromatography (up to 6.5 Hz at resolution 7500). We benchmark this instrument's key figures of merit, including resolution, mass accuracy, linear dynamic range, and spectral accuracy, and demonstrate its performance for two challenging applications: the determination of polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) in environmental samples and the profiling of primary metabolites in Arabidopsis thaliana extracts.

Topics: Arabidopsis; Benzofurans; Calibration; Gas Chromatography-Mass Spectrometry; Polychlorinated Dibenzodioxins

The hexaazamacrocycles [28](DBF)(2)N(6) {cyclo[bis(4,6-dimethyldibenzo[b,d]furaniminoethyleneiminoethylene]} and [32](DBF)(2)N(6) {cyclo[bis(4,6-dimethyldibenzo[b,d]furaniminopropyleneiminopropylene]} form stable dinuclear copper(ii) complexes suitable to behave as receptors for several anionic substrates. These two receptors were used to study the binding interactions with several substrates, such as imidazole (Him) and some carboxylates [benzoate (bz(-)), oxalate (ox(2-)), malonate (mal(2-)), phthalate (ph(2-)), isophthalate (iph(2-)), and terephthalate (tph(2-))] by spectrophotometric titrations and EPR spectroscopy in MeOH (or H(2)O):DMSO (1 : 1 v/v) solution. The largest association constant was found for ox(2-) with Cu(2)[32](DBF)(2)N(6)(4+), whereas for the aromatic dicarboxylate anions the binding constants follow the trend ph(2-) > iph(2-) > tph(2-), i.e. decrease with the increase of the distance of the two binding sites of the substrate. On the other hand, the large blue shift of 68 nm observed by addition of Him to Cu(2)[32](DBF)(2)N(6)(4+) points out for the formation of the bridged CuimCu cascade complex, indicating this receptor as a potential sensor for the detection and determination of imidazole in solution. The X-band EPR spectra of the Cu(2)[28](DBF)(2)N(6)(4+) and Cu(2)[32](DBF)(2)N(6)](4+) complexes and the cascade complexes with the substrates, performed in H(2)O:DMSO (1 : 1 v/v) at 5 to 15 K, showed that the CuCu distance is slightly larger than the one found in crystal state and that this distance increases when the substrate is accommodated between the two copper centres. The crystal structure of [Cu(2)[28](DBF)(2)N(6)(ph)(2)]·CH(3)OH was determined by X-ray diffraction and revealed the two copper centres bridged by two ph(2-) anions at a CuCu distance of 5.419(1) Å. Each copper centre is surrounded by three carboxylate oxygen atoms from two phthalate anions and three contiguous nitrogen atoms of the macrocycle in a pseudo octahedral coordination environment.

Topics: Anions; Benzofurans; Carboxylic Acids; Coordination Complexes; Copper; Crystallography, X-Ray; Electron Spin Resonance Spectroscopy; Imidazoles; Macrocyclic Compounds; Molecular Conformation; Spectrophotometry, Ultraviolet

In birds, activation of the aryl hydrocarbon receptor (AhR) by some polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) results in induction of cytochrome P4501A (CYP1A) expression. This response has been useful for predicting relative sensitivity of birds to dioxin-like compounds. To further investigate species-sensitivity to dioxins and dioxin-like compounds induction of cytochrome P450 1A4 and 1A5 (CYP1A4 and CYP1A5) mRNA and ethoxyresorufin O-deethylase (EROD) activity were quantified in liver of posthatch white leghorn chicken, common pheasant, and Japanese quail exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 2,3,4,7,8-pentachlorodibenzofuran (PeCDF), or 2,3,7,8-tetrachlorodibenzofuran (TCDF) via air cell injection. The rank-order of sensitivity of TCDD- and TCDF-exposed birds, based on CYP1A, was chicken>pheasant>quail. Based on CYP1A5 mRNA expression and EROD induction, the order of sensitivity of PeCDF-exposed birds was identical to that for TCDD and TCDF. However, based on CYP1A4 mRNA expression the rank-order was pheasant>chicken>quail. When comparing the potency of the three compounds in each species, based on CYP1A4 mRNA expression, TCDD was the most potent compound in chicken. However, PeCDF was equally potent to TCDD in quail and was more potent than TCDD in pheasant. These results suggest that quantitative real-time polymerase chain reaction (Q-PCR) analysis of CYP1A expression, particularly CYP1A4 mRNA expression, may be a more sensitive biomarker of exposure than analysis of EROD induction, especially in less responsive avian species. Based on these findings future risk assessments should consider the sensitivity of the species inhabiting a site and the congeners of concern that are present.

Topics: Animals; Base Sequence; Benzofurans; Chickens; Coturnix; DNA Primers; Enzyme Induction; Female; Hydrocarbons, Chlorinated; Polychlorinated Dibenzodioxins; RNA, Messenger; Species Specificity

Bioassay-guided fractionation of the methanolic extract of the roots of Rhaphiolepis indica var. tashiroi afforded four new dibenzofurans, 2-hydroxy-3,4,6-trimethoxydibenzofuran (1), 2-hydroxy-3,4,9-trimethoxydibenzofuran (2), 2-hydroxy-3,4,6,9-tetramethoxydibenzofuran (3), and 1,2-methylenedioxy-3,4,6-trimethoxydibenzofuran (4), two new biphenyls, 3-hydroxy-2',5-dimethoxybiphenyl (5) and 2',3-dihydroxy-5-methoxybiphenyl (6), and 3-hydroxy-5-methoxybiphenyl (7). Among the isolates, 3, 5, and 6 exhibited inhibitory effects on N-formyl-methionyl-leucyl-phenylalanine (fMLP)-induced superoxide production, with in vitro IC50 values < 8.36 μM.

Topics: Anti-Inflammatory Agents; Benzofurans; Biphenyl Compounds; Humans; Inhibitory Concentration 50; Molecular Structure; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Nuclear Magnetic Resonance, Biomolecular; Plant Roots; Rosaceae; Superoxides; Taiwan

The Rosaceous subtribe Pyrinae (formerly subfamily Maloideae) is well-known for its economically important fruit trees, such as apple and pear, and also includes Sorbus aucuparia. Elicitor-treated S. aucuparia cell cultures are used to study the biosynthesis of the Pyrinae-specific phytoalexins, biphenyls and dibenzofurans. Three biphenyls (aucuparin, noraucuparin, 2'-hydroxyaucuparin) and a dibenzofuran (eriobofuran) were isolated and structure elucidated using GC-MS and NMR. A second dibenzofuran of low abundance was tentatively assigned as noreriobofuran. Treatment of S. aucuparia cell cultures with yeast extract induced the formation of aucuparin as the major phytoalexin. In contrast, addition of preparations from the fire blight bacterium, Erwinia amylovora, and the scab-causing fungus, Venturia inaequalis, resulted in accumulation of eriobofuran as the major inducible constituent. Methyl jasmonate was a poor elicitor. The observations are suggestive of a biogenic relationship between biphenyls and dibenzofurans. Elicitor-treated S. aucuparia cell cultures provide an interesting in vitro system for studying biphenyl and dibenzofuran metabolism in the economically valuable Pyrinae.

Topics: Ascomycota; Benzofurans; Biphenyl Compounds; Cells, Cultured; Erwinia amylovora; Phytoalexins; Sesquiterpenes; Sorbus

Sampling and analysis of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are both time-consuming and expensive. In principle, real-time monitoring of chlorobenzene (CBz) as an indicator for PCDD/Fs could be useful to control and optimize incinerator operating conditions. To test this strategy, CBz was analyzed together with PCDD/Fs in flue gas samples collected from a hospital waste incinerator. Moreover, lab experiments were conducted to investigate the effect of temperature and oxygen on CBz formation from fly ash from the same incinerator. The experimental results demonstrate that chlorobenzene (in particular PeCBz) correlate well with PCDD/Fs, in line with previous research. The optimum temperature of CBz formation is in a range of 350 to 400 degrees C and CBz yield increases significantly with oxygen, in line with PCDD/Fs formation. This study is useful for confirming the de novo mechanism and defining correlations between CBz and PCDD/Fs.

Topics: Benzofurans; Chlorobenzenes; Oxygen; Polychlorinated Dibenzodioxins; Temperature

Emissions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from an industrial park operated as Taiwan's center of metallurgical industries were investigated. The characteristics of mean PCDD/F I-TEQ concentrations, congener profiles and emission factors of each source were studied over samples of stack flue gases of individual sources. Different characteristics of congener profiles and large variations of emission factors of secondary aluminum smelters (ALSs) were observed. The mean emission factors of electric arc furnaces were comparable to those for ALSs and much greater than those of municipal solid waste incinerators and sinter plants, but still less than that of clinical waste incinerators. Annual PCDD/F emission contribution of each source was estimated, raising critical concerns over the overall PCDD/F emissions from metallurgical processes. The metallurgical industries altogether contributed approximately 98.1% of the total annual emissions, while waste incinerators only 1.9%. The contributions by sinter plants and metallurgical industries to the total annual emissions of the Park were much higher than the corresponding national averages of Taiwan. The combined dioxin emissions from the entire metallurgical processes and their controls should be seriously envisaged by industrial parks devoted to metal productions.

Topics: Air Pollutants; Aluminum; Benzofurans; Dioxins; Environmental Monitoring; Incineration; Industrial Waste; Industry; Metallurgy; Metals; Models, Statistical; Taiwan

Since 2002, the chemical/petrochemical industrial zone of Tarragona County (Catalonia, Spain) is being annually monitored. As part of the environmental surveillance program, in this study the levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), polycyclic aromatic hydrocarbons (PAHs), and metals (As, Cd, Cr, Hg, Mn, Pb and V) were determined in soil and vegetation samples collected in 4 areas of Tarragona County (chemical, petrochemical, urban/residential, and unpolluted). Moreover, the airborne concentrations of the same micropollutants were determined in each area. In soil samples, significant higher levels of PCNs and higher concentrations of PCDD/Fs and PAHs were found in the urban zone. PCDD/F levels in vegetation samples significantly decreased from 2002. The concentrations of Cr in soil samples, as well as V levels in vegetation samples collected in the vicinity of an oil refinery were significantly higher than those found in the unpolluted zones. A significant and progressive increase in V concentrations was also noted. The current results clearly indicate that the petrochemical industry is still being an important focus of inorganic pollution for the surrounding environment. In air, the higher amount of the 7 carcinogenic PAHs suggests a relatively greater impact on the petrochemical and urban areas. The temporal trend of the global pollution was also studied an Integral Risk Index was applied.

Topics: Air; Benzofurans; Dioxins; Environmental Monitoring; Environmental Pollutants; Metals; Naphthalenes; Plants; Polychlorinated Biphenyls; Polycyclic Aromatic Hydrocarbons; Soil; Soil Pollutants; Spain; Time Factors

This study was intended to determine the background levels of PCDD/PCDFs and PCBs in the Taiwanese population and to investigate factors potentially related to PCDD/PCDF and PCB levels. The levels of seventeen PCDD/PCDFs in the 251 serum samples collected from the general population in Taiwan ranged from 4.92 to 26.7 pg WHO(1998)-TEQ/g lipid (median: 11.5) and those of the twelve dioxin-like PCBs ranged between 1.74 and 21.6 pg WHO(1998)-TEQ/g lipid (median: 6.14). Five factors, age, gender, region of residence, dietary status, and smoking status, showed statistically significant association with the TEQ level of PCDD/PCDFs. The TEQ level of PCBs was statistically associated with age only, but not with the other four factors. The trends observed between age and the levels of PCDD/PCDFs and PCBs were not parallel in young subjects (<30 years old) and old subjects (>30 years old). The levels of PCDD/PCDFs and PCBs increased by 0.16 and 0.03 WHO(1998)-TEQ/g lipid per year for subjects above the age of 30, but there was no evidence of any association between age and the levels for subjects below the age of 30 years. These factors should be considered when investigating relationships between background serum levels of persistent organic pollutants and parameters associated with exposure sources or health outcomes.

Topics: Adolescent; Adult; Age Factors; Benzofurans; Biphenyl Compounds; Blood Chemical Analysis; Dioxins; Female; Humans; Male; Middle Aged; Risk Factors; Taiwan; Young Adult

To determine the blood and urine concentrations of a number of metals and organic substances in workers at a hazardous waste incinerator (HWI) in Catalonia, Spain, 8 years after regular operations in the facility. To compare these concentrations with the baseline (1999) levels and with those obtained in previous (2000 and 2005) surveys.. The employees were divided into three groups according to their specific workplaces. Plasma analyses of hexachlorobenzene (HCB), polychlorinated biphenyls (PCBs 28, 52, 101, 138, 153 and 180) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), as well as urinary analyses of 2,4- and 2,5-dichlorophenol (DCP), 2,4,5- and 2,4,6-trichlorophenol (TCP), pentachlorophenol (PCP) and 1-hydroxypyrene (1-HP) were carried out. Blood concentrations of manganese and mercury, and urinary levels of nickel were also determined.. For organic compounds in plasma, the comparison of the current levels with those of previous surveys did not show any significant increase for any of the compounds analyzed. In contrast, plasma levels of PCBs 28, 52 and 101 were significantly lower than the respective baseline concentrations, while especially notable was the significant reduction in the levels of PCDD/Fs in plasma of plant workers, which decreased from 26.7 pg I-TEQ/g lipid in the baseline survey to the current 2.5 pg I-TEQ/g lipid.. According to the results of the present study, there are no evident signs of occupational exposure to a number of metals and organic substances in the workers of the HWI.

Topics: Benzene Derivatives; Benzofurans; Chlorophenols; Environmental Monitoring; Environmental Pollutants; Female; Gas Chromatography-Mass Spectrometry; Hazardous Waste; Heterocyclic Compounds, 1-Ring; Hexachlorobenzene; Humans; Incineration; Male; Metals, Heavy; Occupational Exposure; Pentachlorophenol; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Pyrenes; Spain

The crude recycling of electronic and electric waste (e-waste) is now creating a new set of environmental problems especially in developing countries such as China. The present study aimed to characterize the dioxin-like compounds in Taizhou area, one of the largest e-waste recycling centers in China, using both chemical analysis and in vitro bioassay. Agricultural soil samples were screened for aryl hydrocarbon receptor (AhR) activity with EROD bioassay in H4IIE cells, and the concentrations of the target AhR agonists including polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) were determined by instruments. The bioassay-derived TCDD equivalents (TEQ(bio)) and the chemical-calculated TCDD equivalents (TEQ(cal)) were then compared, and mass balance analysis was conducted to identify the contributors of the observed response. Raw soil extracts from all locations induced significant AhR activities, where the TEQ(bio) ranged from 5.3 to 210 pg/g dry weight soil (pg/g dw). The total concentrations of 17 PCDD/Fs, 36 PCBs and 16 PAHs varied from 210 to 850 pg/g dw, 11 to 100 ng/g dw, and 330 to 20,000 ng/g dw, respectively. Profile characterization of the target analytes revealed that there were similar sources originating from the crude dismantling of electric power equipments and the open burning of e-waste. There was a significant relationship between TEQ(cal) and TEQ(bio) (r=0.99, p<0.05). Based on the mass balance analysis, PCDD/Fs, PCBs and PAHs could account for the observed AhR responses in vitro elicited by soil extracts, though their respective contributions varied depending on sample location. In this study, the combination of chemical analysis and bioanalytical measurements proved valuable for screening, identifying and prioritizing the causative agents within complex environmental matrices.

Topics: Animals; Benzofurans; Cell Line; China; Conservation of Natural Resources; Dioxins; Industrial Waste; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Polycyclic Aromatic Hydrocarbons; Rats; Receptors, Aryl Hydrocarbon; Soil; Soil Pollutants

The distribution and concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dioxin-like PCBs, also called co-PCBs) in a typical area of eastern China were evaluated by analysis of 21 soil and 6 sediment samples. The range of WHO-TEQ values for the PCDD/Fs and dioxin-like PCBs in 17 soil samples representing the background investigation in the study area was 0.017-5.04 pg g(-1) (dry weight, dw), with a mean value 0.967(+/-1.361)pg g(-1) and medium value 0.348 pg g(-1), which indicates that the levels of PCDD/Fs and dioxin-like PCBs over the major part of this district were low. However, the WHO-TEQ values (6.52-16.7 pg g(-1) dw) for PCDD/Fs and dioxin-like PCBs in soil samples to the leeward of a known contaminated disassembly industrial park were much higher than that of the background investigation, and the levels of sediment samples downstream of this area were in the range 2.25-34.6 pg g(-1) (dw). The levels of WHO-TEQ in soil and sediment samples decreased with an increase in distance from the researched pollution source. The principal component analysis demonstrated that the PCDD/Fs and dioxin-like PCBs in major part of contaminated sediment and soil samples derived from the correlative matrix. Yet the different distribution patterns of them in part of sediment samples strongly indicate that other potential sources may be exist, further researches should be done to get more information about the sources and the distributions of the PCDD/Fs and PCBs.

Topics: Benzofurans; China; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Soil Pollutants

Since the "Toxic Egg Event" broke out in central Taiwan, the possible sources of the high content of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in eggs have been a serious concern. In this study, the PCDD/F contents in different media (feed, soil and ambient air) were measured. Evaluation of the impact from electric arc furnace dust treatment plant (abbreviated as EAFDT plant), which is site-specific to the "Toxic Egg Event", on the duck total-PCDD/F daily intake was conducted by both Industrial Source Complex Short Term model (ISCST) and dry and wet deposition models. After different scenario simulations, the worst case was at farm A and at 200 g feed and 5 g soil for duck intake, and the highest PCDD/F contributions from the feed, original soil and stack flue gas were 44.92, 47.81, and 6.58%, respectively. Considering different uncertainty factors, such as the flow rate variation of stack flue gas and errors from modelling and measurement, the PCDD/F contribution fraction from the stack flue gas of EAFDT plant may increase up to twice as that for the worst case (6.58%) and become 13.2%, which was still much lower than that from the total contribution fraction (86.8%) of both feed and original soil. Fly ashes contained purposely in duck feed by the farmers was a potential major source for the duck daily intake. While the impact from EAFDT plant has been proven very minor, the PCDD/F content in the feed and soil, which was contaminated by illegal fly ash landfills, requires more attention.

Topics: Animal Feed; Animals; Animals, Domestic; Benzofurans; Ducks; Eggs; Food Contamination; Models, Theoretical; Polychlorinated Dibenzodioxins; Soil Pollutants

Dibenzofuran (DF) is one of the dioxin carbon skeletal compounds used as a model to study the microbial degradation of dioxins. This study analyzed the transcriptional regulation of the DF dioxygenase genes dfdA1 to dfdA4 in the DF-utilizing actinomycetes Rhodococcus sp. strain YK2 and Terrabacter sp. strain YK3. An open reading frame designated dfdR was detected downstream of the dfdC genes. The C-terminal part of the DfdR amino acid sequence has high levels of similarity to several LuxR-type DNA binding helix-turn-helix domains, and a GAF domain sequence in the central part was detected by a domain search analysis. A derivative of YK2 with dfdR disrupted was not able to utilize DF and did not exhibit DF-dependent dfdA1 transcriptional induction ability, and these dysfunctions were compensated for by introduction of dfdR. Promoter analysis of dfdA1 in Rhodococcus strains indicated that activation of the dfdA1 promoter (P(dfdA1)) was dependent on dfdR and DF and not on a metabolite of the DF pathway. The cell extract of a Rhodococcus strain that heterologously expressed DfdR showed electrophoretic mobility shift (EMS) activity for the P(dfdA1) DNA fragment in a DF-dependent manner. In addition, P(dfdA1) activation and EMS activity were observed with hydrophobic aromatic compounds comprising two or more aromatic rings, suggesting that DfdR has broad effector molecule specificity for several hydrophobic aromatic compounds.

Topics: Actinomycetales; Amino Acid Sequence; Benzofurans; Conserved Sequence; Dioxygenases; DNA, Bacterial; Gene Expression Regulation, Bacterial; Hydrocarbons, Aromatic; Luciferases; Molecular Sequence Data; Multigene Family; Open Reading Frames; Promoter Regions, Genetic; Rhodococcus; Sequence Alignment; Sequence Homology, Amino Acid; Trans-Activators; Transcription, Genetic

Many species of lichen-forming fungi contain yellow or orange extracellular pigments belonging to the dibenzofurans (usnic acid), anthraquinones (e.g. parietin) or pulvinic acid group. These pigments are all equally efficient light screens, leading us to question the potential ecological and evolutionary significance of diversity in yellow and orange lichen substances. Here the hypothesis is tested that the different pigments differ in metal-binding characteristics, which suggest that they may contribute to adaptation to sites differing in pH and metal availability.. UV spectroscopy was used to study the dissociation and the pH dependence of the metal-binding behaviour of seven isolated lichen substances in methanol. Metals applied were selected macro- and micro-nutrients (Cu(2+), Fe(2+), Fe(3+), Mg(2+), Mn(2+) and Zn(2+)).. All the pigments studied are strong to moderate acids with pK(a1) values between 2.8 and 4.5. Metal complexation is common in the lichen substances studied. Complexation takes place under acidic conditions with usnic acid, but under alkaline conditions with parietin and most compounds of the pulvinic acid group. The pulvinic acid derivative rhizocarpic acid forms metal complexes both in the acidic and the alkaline range.. Metal complexation by lichen substances could be a prerequisite for lichen substance-mediated control of metal uptake. Assuming such an effect at pH values where the affinity of the metal for the lichen substance is intermediate would explain the strong preference of lichens with usnic or rhizocarpic acids to acidic substrata. Moreover, it would explain the preference of lichens with parietin and some lichens with compounds of the pulvinic acid group either for nutrient-rich substrata at low pH or for calcareous substrata.

Topics: Anthraquinones; Benzofurans; Carboxylic Acids; Copper; Hydrogen-Ion Concentration; Iron; Lactones; Lichens; Magnesium; Manganese; Metals; Spectrophotometry, Ultraviolet; Zinc

In this study we investigated occurrences and distribution patterns of dioxin-related compounds (DRCs) such as polybrominated dibenzo-p-dioxins/dibenzofurans (PBDD/Fs), polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs), monobromo-polychlorinated dibenzo-p-dioxins/dibenzofurans (MoBPCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in marine surface sediments collected from the coastal waters of Hong Kong and Korea. In most sampling sites, concentrations of PCDDs were the highest, followed by DL-PCBs, PCDFs, PBDFs, PBDDs, MoBPCDDs and MoBPCDFs in this order. Levels of PBDD/Fs were generally 1-2 orders of magnitude lower than chlorinated analogues. Levels of PCDDs are higher than PCDFs in Hong Kong while levels of PBDFs are higher than PBDDs in Korea (p<0.05). Report of PBDD/Fs and MoBPCDD/Fs in sediments from East Asian countries is novel and original. Environmental levels of PBDD/Fs are supposed to start increasing in accordance with rising production, use and disposal of brominated flame retardants (BFRs) and recycling processes of e-waste in Asian developing countries.

Topics: Benzofurans; Dibenzofurans, Polychlorinated; Dioxins; Environmental Monitoring; Food Contamination; Geologic Sediments; Hong Kong; Industrial Waste; Korea; Oceans and Seas; Polybrominated Biphenyls; Polychlorinated Biphenyls; Soil Pollutants

This study measured particle size distributions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in two workplace atmospheres of the sintering grate and rough roll shredder in a sintering plant, and to assess their workers' health-related exposures. We found that the PCDD/F concentration of the sintering grate (site A=14.47 pg m(-3)) was lower than that of the rough roll shredder (site B=17.20 pg m(-3)). Particle size distributions of PCDD/Fs were in the form of the unimodal with the mass median aerodynamic diameter (MMAD) of 4.74 microm and 5.23 microm, and geometric standard deviation (sigma(g)) of 3.15 and 2.15 for the site A and B, respectively. The above results suggest that the workplace of the site A had a less fraction of coarse particles than that of the site B. The estimated PCDD/F concentrations of the inhalable fraction (11.0 pg m(-3)) and thoracic fraction (8.89 pg m(-3)) of the site A were lower than those of the site B (12.4 and 9.39 pg m(-3), respectively). But to the contrary the estimated respirable fraction of the site A (5.05 pg m(-3)) was slightly higher than that of the site B (4.93 pg m(-3)). Our results clearly indicate the importance to conduct particle size segregating samplings for assessing human PCDD/F exposures.

Topics: Benzofurans; Environmental Monitoring; Humans; Metallurgy; Occupational Exposure; Particle Size; Polychlorinated Dibenzodioxins

In 2005, the partial substitution (20%) of fossil fuel by sewage sludge was tested in a Spanish cement plant. In order to establish the environmental impact for the surroundings, in 2006, the levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and heavy metals (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sn, Tl, V, and Zn) were monitored in soil and vegetation samples collected near the cement plant. The temporal trends in the pollutant levels were studied by comparing the concentrations with those obtained in a previous survey (2003) in the same sampling sites. Very slight changes of the PCDD/F concentrations in both monitors were registered in the period 2003-2006 (0.17-0.15 and 0.94-1.10 ng I-TEQ kg(-1) dw in herbage and soil, respectively). In turn, there was a notable heterogeneity in the evolution of metal levels, which varied according to each particular element. Anyhow, the current levels of organic and inorganic pollutants are in the low part of the range in comparison with other zones impacted by cement plants, as well as industrial and urban areas worldwide. The human health risks derived from the exposure to PCDD/Fs and metals were also assessed. Although the cancer risks due to PCDD/Fs slightly increased, a reduction of the total carcinogenic risks, including metals, was noted. In conclusion, there were not observed impact changes for the environmental and the local population as a consequence of using sewage sludge as secondary fuel.

Topics: Air Pollutants; Benzofurans; Environmental Exposure; Environmental Monitoring; Industrial Waste; Metals, Heavy; Poaceae; Polychlorinated Dibenzodioxins; Sewage; Soil Pollutants; Spain

The potential adverse effects on human health of hazardous waste incinerators (HWIs) are a subject of concern. The construction of the first and till now only HWI in Spain finished in 1999. In 2007, after approximately 9 years of regular operations in the facility, the concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) were determined by HRGC/HRMS in samples of adipose tissue of 15 autopsied subjects living in the area under potential impact of the HWI (Constantí, Tarragona County, Catalonia). These data were compared with the levels found in two previous surveys performed in 1998 (baseline) and 2002. The current mean PCDD/F concentration in adipose tissue was 14.6 pg WHO-TEQ/g of fat (range: 3.3-55.4 pg WHO-TEQ/g of fat). It means significant changes (a reduction of 64% and an increase of 47%) in the mean PCDD/F levels in comparison to those found in 1998 and 2002: 40.1 and 9.9 pg WHO-TEQ/g of fat, respectively. Women showed higher levels of PCDD/F than men (23.8 vs 11.2 pg WHO-TEQ/g of fat). The increase in the last 5 years would not be directly attributable to exposure to PCDD/F emitted by the HWI, as other biological monitors such as human plasma and milk decreased during the same period.

Topics: Adipose Tissue; Adult; Aged; Aged, 80 and over; Benzofurans; Environmental Exposure; Female; Gas Chromatography-Mass Spectrometry; Hazardous Waste; Humans; Incineration; Male; Middle Aged; Polychlorinated Dibenzodioxins; Spain

Concentrations and congener profile patterns of 2378-substituted PCDD/Fs and DLPCBs in offshore, nearshore and tributary sediments of Lakes Superior and Huron are reported, and spatial trends and source contributions assessed. PCDD/F concentrations ranged from 5 to 18,000 pg/g dw (Lake Superior) and 3 to 6100 pg/g dw (Lake Huron); DLPCBs ranged from 9 to 11,000 pg/g dw (Lake Superior) and 9 to 27,000 pg/g dw (Lake Huron). Our analysis indicated atmospheric deposition is a primary source to depositional areas of both lakes; however, greater PCDD/F and DLPCB concentrations were observed at several nearshore and tributary sites, and were attributed to corresponding land use in the watershed. Statistical analysis and pattern comparison suggested that industrial inputs mainly associated with wood treatment plants, pulp and paper mills, mining operations, and chlorine-based chemical manufacturing also contributed to contamination by PCDD/Fs and DLPCBs in certain nearshore and offshore areas of Lakes Superior and Huron.

Topics: Air Pollutants; Benzofurans; Canada; Environmental Monitoring; Fresh Water; Geologic Sediments; Pesticides; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Water Pollutants, Chemical

This article reports the computational and experimental results of the thermal decomposition of permethrin, a potential source of dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF). We have performed a quantum chemical analysis by applying density functional theory to obtain the decomposition pathways of permethrin and the formation mechanism of dibenzofuran. We have conducted the pyrolysis experiments in a tubular reactor and identified the pyrolysis products to demonstrate the agreement between the experimental measurements and quantum chemical calculations. The initiation of the decomposition of permethrin involves principally the aromatisation of permethrin into 3-phenoxyphenylacetic acid, 2-methylphenyl ester (J) and concomitant loss of 2HCl. This rearrangement is followed by the rupture of the O-CH2 linkage in J, with a rate constant derived from the quantum chemical results of 1 x 10(15) exp(-68 kcal/mol/RT)s(-1) for temperatures between 700 and 1300 K. This is confirmed by finding that the rate constant for unimolecular rearrangement of permethrin into J is 1.2 x 10(12) exp(-53 kcal/mol/RT)s(-1) over the same range of temperatures and exceeds the direct fission rate constant at all temperatures up to 850+/-120 degrees C as well as by the experimental detection of J prior to the detection of the initial products incorporating diphenyl ether, 1-methyl-3-phenoxybenzene, 3-phenoxybenzaldehyde and 1-chloromethyl-3-phenoxybenzene. As the temperature increases, we observe a rise in secondary products formed directly or indirectly (via phenol/phenoxy) including aromatics (naphthalene), biphenyls (biphenyl, 4-methyl-1,1'-biphenyl) and dibenzofuran (DF). In particular, we discover by means of quantum chemistry a direct route from 2-phenoxyphenoxy to naphthalene. We detect no polychlorinated dibenzo-p-dioxins and dibenzofurans. Unlike the case of oxidative pyrolysis [Tame, N.W., Dlugogorski, B.Z., Kennedy, E.M., 2007b. Formation of dioxins in fires of arsenic-free treated wood: Role of organic preservatives. Environ. Sci. Technol. 41, 6425-6432] where significant yields of both PCDD and PCDF were obtained, under non-oxidative conditions the thermal decomposition of permethrin does not form appreciable amounts of PCDD or PCDF and the presence of oxygen (and/or a sizable radical pool) appears necessary for the formation of dibenzo-p-dioxin itself or PCDD/F from phenol/phenoxy.

Topics: Benzofurans; Gas Chromatography-Mass Spectrometry; Hot Temperature; Oxidation-Reduction; Permethrin; Polychlorinated Dibenzodioxins; Quantum Theory; Thermodynamics

In a project to isolate and characterise anti-staphylococcal compounds from members of the genus Hypericum, a dibenzofuran and a pyranone were isolated from the dichloromethane and hexane extracts of Hypericum revolutum ssp. revolutum Vahl (Guttiferae) and Hypericum choisianum Wall. ex. N. Robson (Guttiferae), respectively. The structures of these compounds were elucidated by 1- and 2D-NMR spectroscopy and mass spectrometry as 3-hydroxy-1,4,7-trimethoxydibenzofuran (1) and 4-(3-O-3'')-3''-methylbutenyl-6-phenyl-pyran-2-one (2). The metabolites were evaluated against a panel of multidrug-resistant strains of Staphylococcus aureus. Compound 1 exhibited a minimum inhibitory concentration (MIC) of 256 microg/ml, whereas compound 2 was inactive at a concentration of 512 microg/ml.

Topics: Antifungal Agents; Benzofurans; Hypericum; Magnetic Resonance Spectroscopy; Microbial Sensitivity Tests; Molecular Structure; Pyrones; Staphylococcus aureus

Semi-domesticated reindeer and wild moose meat samples were analyzed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and polychlorinated biphenyls (PCBs). Both calves and adults were studied. Individual reindeer and moose meat samples and pooled reindeer calf meat samples were collected from the northern, the middle, and the southern reindeer herding regions in Finland. Samples represented the edible parts of carcasses. In individual samples of reindeer the fat based WHO-PCDD/F-PCB-TEQ concentration was on average 3.2pgg(-1) in calves and 2.3pgg(-1) in adults. In moose calves the fat based WHO-PCDD/F-PCB-TEQ concentration (1.9pgg(-1)) was lower than in reindeer calves. WHO-PCDD/F-PCB-TEQ concentration in the adult moose samples was equal as in the adult reindeer samples. The mean fat based WHO-PCDD/F-PCB-TEQ concentration was highest in reindeer calf samples from the middle region. These samples contained also the highest content of fat. Individual samples of reindeer contained on average more WHO-PCB-TEQ than WHO-PCDD/F-TEQ, while the opposite was true for moose samples, and also samples of adult reindeer from the southern area. The contributions of PCDD/Fs and PCBs to the total TEQ were similar in the reindeer calves' pooled samples which were collected from more western regions than individual samples.

Topics: Animals; Benzofurans; Deer; Environmental Pollutants; Female; Finland; Male; Meat; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins

We successfully optimized an analytical method using gel permeation chromatography followed by direct sample introduction comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry to quantify multiple groups of targeted persistent organic pollutants and halogenated natural products (HNPs) simultaneously in fish oil samples. This new method has a wider analytical scope than the traditional approach to use multiple methods to cover each class of compounds. Our analysis revealed that the relatively more volatile and lighter organic compounds, such as polychlorinated biphenyls (PCBs), organochlorine pesticides, and other smaller organohalogen compounds, were still present in two brands of "PCB-free" cod liver oils, albeit at much lower levels than in an untreated commercial sample. Moreover, the less volatile organic compounds, such as polybrominated diphenyl ethers and brominated HNPs, were detected at similar levels in all three cod liver oils. This suggests that the commercial molecular distillation treatment used for removal of organic/inorganic toxic contaminants is only effective for the lighter organic contaminants.

Topics: Benzofurans; Diet; Fish Oils; Food Contamination; Gas Chromatography-Mass Spectrometry; Halogenated Diphenyl Ethers; Humans; Hydrocarbons, Chlorinated; Hydrocarbons, Halogenated; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Quality Control

Nocardioides sp. DF412 degrades dibenzofuran (DF) to salicylate through the sequential actions of DF dioxygenase (dfdA), extradiol dioxygenase (dfdB), and hydrolase (dfdC). The involvement of a TetR-type regulator gene dfdS in the dfdB and dfdS gene expression was investigated. A reporter assay using a luciferase gene indicated repression of dfdB and dfdS promoter activities in the presence of the dfdS gene product, DfdS. Gel shift analysis indicated specific binding of DfdS to the dfdB promoter region. Both the presence of a DF-degradation intermediate, 2,2',3-trihydroxybiphenyl (2,2',3-THBP) or its analog, 2,3-dihydroxybiphenyl (2,3-DHBP), and mutation in the inverted repeat (IR) in the dfdB promoter, canceled repression by DfdS in vivo and the binding of DfdS to the dfdB promoter fragment in vitro. These results suggest derepression of DfdS in the presence of 2,2',3-THBP and 2,3-DHBP and the involvement of the IR in the repression by DfdS.

Topics: Base Sequence; Benzofurans; Electrophoretic Mobility Shift Assay; Genes, Bacterial; Molecular Sequence Data; Promoter Regions, Genetic; Propionibacteriaceae; Transcription, Genetic

Ambient air monitoring of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) was performed to investigate their concentrations, profiles, and sources near a municipal solid waste incinerator (MSWI) in Eastern China. The PCDD/F concentrations varied over a factor of 51.4 from 0.059 to 3.03 pg I-TEQ m(-3) (or over 41.4 from 3.96 to 164 pg m(-3)) and fell at the higher end of the range in recorded peer investigations around the world. Almost all ambient air samples show a unique TCDF-dominanthomologue pattern, characterized by decreasing concentrations with increasing levels of chlorination (except for OCDD). By contrast, the dominant congener in terms of concentration profiles shows temporal and spatial variations among the OCDD, OCDF, and 1,2,3,4,6,7,8-HpCDF. The results from a congener-specific factor analysis between ambient air and PCDD/F emission sources, as well as U.S. EPA Chemical Mass Balance (CMB8.2) and Industrial Source Complex Short Term Version 3 (ISCST3) modeling, suggest that the deterioration of air quality in the study area is primarily attributed to open burning of wastes (OB), followed by hot water boilers (HWBs), traffic, and the MSWI.

Topics: Air; Atmosphere; Benzofurans; China; Cities; Incineration; Polychlorinated Dibenzodioxins; Refuse Disposal; Seasons

The atmospheric concentrations of PCDDs and PCDFs were measured in four sites near the shores of the North American Great Lakes. The sites included an urban site (Chicago, Illinois) and three rural/remote sites (Eagle Harbor, Michigan; Sleeping Bear Dunes, Michigan; and Sturgeon Point, New York). Sampling occurred every 24 days between November 2004 and December 2007. The concentration of PCDD/Fs averaged 2.3 +/- 0.2 fg WHO TEQ/m3 at Eagle Harbor, 35 +/- 3 fg WHO TEO/ m3 at Chicago, 7.4 +/- 1.4 fg WHO TEO/m3 at Sleeping Bear Dunes, and 13 +/- 2 fg WHO TED/m3 at Sturgeon Point. The total concentration of the 17 toxic PCDD/F congeners showed a significant seasonal trend at all sites, except Chicago. The date of maximum concentration averaged Dec 6 +/- 35 days, which is consistent with residential heating being an important source of PCDD/Fs to the atmosphere. A significant positive relationship between the logarithm of the total concentration of the 17 toxic PCDD/F congeners and the logarithm of the number of people within a 25 km radius around the sampling site was found. We suggest that urban and industrial areas, which are heavily populated, act as sources of PCDDs and PCDFs to the atmosphere.

Topics: Air; Atmosphere; Benzofurans; Geography; Great Lakes Region; Humans; Polychlorinated Dibenzodioxins; Population Dynamics; Regression Analysis; Time Factors

In this experiment, three grasses, bermuda grass (Cynodon dactylon), bent grass (Agrostis palustris Huds.), lawn grass (Zoysia japonica), and a shallow-rooted legume, white clover (Trifolium repens L.) were planted into uncontaminated soil and dibenzofuran (DBF)-contaminated soil. The germination rates of all plants were investigated using contaminated soils to evaluate their sensitivities to DBF. During 2 months of growth, the root biomass and heterotrophic microbial numbers were measured in order to evaluate the potential of remediation. Furthermore, the number of DBF-degrading bacteria was counted to evaluate plants that enhance the microbial DBF degradation potential in contaminated soil. The DBF-removal performance of four plant species was also compared. Regardless of the contamination of DBF, white clover had not only the highest root biomass, but also the highest DBF-degrading bacterial numbers compared to those of the other three grasses. Moreover, white clover-planted contaminated soil exhibited the highest rate of DBF removal among all tested plants. These results suggest that microbial populations capable of degrading DBF were selectively increased by the addition of DBF in the rhizosphere, and also indicate that the presence of plants significantly enhances the reduction of DBF in soils. Based upon these results, white clover was selected for the further investigation of the phytoremediation of dioxin-contaminated soil.

Topics: Benzofurans; Biomass; Colony Count, Microbial; Environmental Restoration and Remediation; Germination; Plant Roots; Plants; Seeds; Soil Microbiology; Soil Pollutants; Species Specificity

The contamination of the Baltic Sea with polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) has resulted in restrictions on the marketing and consumption of Baltic Sea fish, making this a priority environmental issue in the European Union. To date there is no consensus on the relative importance of different sources of PCDD/Fs to the Baltic Sea, and hence no consensus on how to address this issue. In this work we synthesized the available information to create a PCDD/F budget for the Baltic Sea, focusing on the two largest basins, the Bothnian Sea and the Baltic Proper. The non-steady state multimedia fate and transport model POPCYCLING-Baltic was employed, using recent data for PCDD/F concentrations in air and sediment as boundary conditions. The PCDD/F concentrations in water predicted by the model were in good agreement with recent measurements. The budget demonstrated that atmospheric deposition was the dominant source of PCDD/Fs to the basins as a whole. This conclusion was supported by a statistical comparison of the PCDD/F congener patterns in surface sediments from accumulation bottoms with the patterns in ambient air, bulk atmospheric deposition, and a range of potential industrial sources. Prospective model simulations indicated that the PCDD/F concentrations in the water column will continue to decrease in the coming years due to the slow response of the Baltic Sea system to falling PCDD/F inputs in the last decades, but that the decrease would be more pronounced if ambient air concentrations were to drop further in the future, for instance as a result of reduced emissions. The study illustrates the usefulness of using monitoring data and multimedia models in an integrated fashion to address complex organic contaminant issues.

Topics: Benzofurans; Data Interpretation, Statistical; Environmental Monitoring; Forecasting; Models, Chemical; Oceans and Seas; Polychlorinated Dibenzodioxins; Seawater; Water Pollutants, Chemical

Aryl hydrocarbon receptor agonistic (Ah-agonistic) effects of 23 sediments from Wenyu River in Beijing, China were evaluated using the H4IIE cell bioassay. Five samples were selected for chemical analysis of most concerned Ah-agonists, i.e. polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). All raw sediment extracts induced significant Ah-agonistic effects, and the bioassay-derived 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalents of raw extracts (TEQ(raw)s) ranged from 8.5 to 336.0 pg/g dry weight (dw). Chemical analysis-derived TEQs (TEQ(chem)s) ranged from 20.5 to 64.8 pg/g dw. When raw extracts were purified by sulphuric acid silica gel column to derive acid stable fraction, the TCDD equivalents in this fraction (TEQ(stable)s) ranged from 2.7 to 63.8 pg/g dw. PCBs, PCDDs and PCDFs contributed about 51.4-72.1%, 1.2-7.3%, and 16.4-34.8% of TEQ(stable)s, respectively, and the sum was 69.1-108.6%. Therefore, about 65.0% of TEQ(raw)s could be attributed to acid labile fraction and only 3.3-9.6% to PAHs. These observations suggested that acid stable fraction and labile fraction contributed together to total Ah-agonistic effects in the sediments, and PCBs and PCDFs might be the two main components in acid stable Ah-agonists. The proposed approach using both H4IIE cell bioassay and chemical analysis could be used for characterization and prioritization of Ah-agonists in river sediments and helpful to the following progression of ecological remediation.

Topics: Animals; Benzofurans; Biological Assay; Biphenyl Compounds; Cell Line, Tumor; China; Environmental Pollutants; Geologic Sediments; Polychlorinated Dibenzodioxins; Polycyclic Aromatic Hydrocarbons; Receptors, Aryl Hydrocarbon; Rivers; Water Pollutants, Chemical

Usnic acid, a highly functionalized dibenzofuran, is a polyketide secondary metabolite produced by several species of lichens. Synthesis of usnic acid from commercially available starting material was accomplished in two steps. The synthesis involves the methylation of phloracetophenone followed by oxidation with horseradish peroxidase. This work will lay the foundation for further biosynthetic studies on usnic acid.

Topics: Anti-Infective Agents; Benzofurans; Chemistry, Organic; Horseradish Peroxidase; Lichens; Models, Chemical; Oxygen

The activity of Rieske non-heme iron oxygenases (aromatic hydrocarbon dioxygenases, AhDOs) is important for the bacterial degradation of aromatic pollutants such as polycyclic aromatic hydrocarbons and dioxins. During our analysis of the role of AhDOs in dioxin bioremediation, some enzymes derived from high G + C Gram-positive actinomycetes were difficult to produce in active form in the Escherichia coli protein expression system. In this study, we constructed a heterologous expression system for AhDOs in Rhodococcus species using a constitutive expression promoter, P(dfdB), and a shuttle vector, pRK401, and analyzed the ability of these enzymes to degrade dibenzofuran and deplete several chlorinated dioxins. Three active AhDOs expressed in Rhodococcus strains that were difficult to obtain by the E. coli system showed different regiospecificities for dibenzofuran bioconversion as well as different substrate depletion specificities for chlorinated dioxins. Moreover, AhDO derived from R. erythropolis TA421 showed relatively diverse depletion-substrate specificity for chlorinated dioxins.

Topics: Actinomycetales; Bacterial Proteins; Benzofurans; Biodegradation, Environmental; Cloning, Molecular; Dioxins; Dioxygenases; Environmental Pollutants; Promoter Regions, Genetic; Rhodococcus

A macrobicycle formed by a tetraoxadiaza macrocycle containing a dibenzofuran (DBF) spacer and an isophthalamide head unit, named DBF-bz, was used as receptor for anion recognition. The molecular structure of DBF-bz was established in solution by NMR and ESI-MS spectroscopies and in single crystal by X-ray diffraction analysis. The X-ray structure showed a water molecule encapsulated into the macrobicyclic cavity by four hydrogen bonds, two of them involving the two N-H amide binding sites and the oxygen of the water molecule (N-H...O hydrogen bonds) and the other two (O-H...N) involving the amine groups as hydrogen bonding acceptors. (1)H NMR temperature dependence studies demonstrated that the same structure exists in solution. The ability of this ditopic receptor to recognize alkali halide salts was evaluated by extraction studies followed by (1)H NMR and ESI-MS spectroscopies. The macrobicycle showed a capacity to extract halide salts from aqueous solutions into organic phases. The binding ability of this macrobicycle for halides was also quantitatively investigated using (1)H NMR titrations in CDCl(3) (and DMSO-d(6)) solution, and in acidic D(2)O solution. The largest binding association constant was found for the chloride anion and the completely protonated receptor. The results suggest that the diammonium-diamide unit of the receptor strongly bind the anionic substrate via multiple N-H...Cl(-) hydrogen bonds and electrostatic interactions. The binding trend follows the order Cl(-) > Br(-) > I(-) approximately F(-) established from the best fit between the size of the anion and the cavity size of the protonated macrobicycle. Molecular dynamics (MD) simulations of the DBF-bz in CHCl(3) solution allowed a detailed insight into the structural and binding properties of the receptor.

Topics: Anions; Benzofurans; Crown Ethers; Crystallography, X-Ray; Hydrogen Bonding; Macrocyclic Compounds; Molecular Structure

A new dibenzofuran, lucidafuran (1), was isolated from the stems of Pourthiaea lucida, together with eight known compounds. The structure of this new compound was determined through NMR and mass-spectrometric analyses. Among the isolated compounds, lucidafuran (1) and aucuparin (3) exhibited potent inhibitory activity against fMLP-induced superoxide (O(*-)(2)) production by human neutrophils with IC(50) values of 18.7+/-4.4 and 17.0+/-6.8 microM, resp.

Topics: Benzofurans; Free Radical Scavengers; Humans; Neutrophils; Plant Stems; Rosaceae; Superoxides

The impact of dibenzofuran (DF) and dibenzo-p-dioxin (DD) on the changes in bacterial community structure and the transition of catabolic genes were studied using forest soil. The bacterial community structure of soil suspensions amended with 1 microg/g of either DF or DD was analyzed by 16S rRNA and functional gene sequencing. To analyze the functional genes in the communities, we targeted a gene sequence that functions as the binding site of Rieske iron sulfur center common to ring-hydroxylating dioxygenases (RHDs) for monocyclic, bicyclic, and tricyclic aromatic compounds. The gene fragments were polymerase chain reaction-amplified from DNAs extracted from soil suspensions spiked with either DF or DD, cloned, and sequenced (70 clones). Bacterial community analysis based on 16S rRNA genes revealed that specific 16S rRNA gene sequences, in particular, phylotypes within alpha-Proteobacteria, increased in the soil suspension amended with DF or DD. RHD gene-based functional community analysis showed that, in addition to two groups of RHD genes that were also detected in unamended soil suspensions, another two groups of RHD genes, each of which is specific to DF- and DD-amended soil, respectively, emerged to a great extent. The DD-specific genotype is phylogenetically distant from any known RHDs. These results strongly suggest that soil microbial community potentially harbors a wide array of organisms having diverse RHDs including those previously unknown, and that they could quickly respond to an impact of contamination of hazardous chemicals by changing the microbial community and gene diversity.

Topics: Bacteria; Base Sequence; Benzofurans; Biodiversity; Dioxins; Dioxygenases; Electron Transport Complex III; Genes, Bacterial; Hydroxylation; Molecular Sequence Data; Phylogeny; RNA, Ribosomal, 16S; Soil; Soil Microbiology; Trees

Chlorinated toxic planar aromatic compounds were analyzed in the heavily industrialized Grenlandsfjords, which is a system of silled fjords in southern Norway. Surface water samples contained 7.4-160 ng/m3 polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs), 14-410 ng/m3 polychlorinated naphthalenes (PCNs), and 0.31-2.4 ng/m3 non-orthochlorinated biphenyls (non-orthoPCBs). The concentrations of PCDD/Fs were about 300 times higher than in the Baltic Sea. Highest level of the compounds wasfound near a magnesium production plant Hepta-CDFs and penta-CNs dominated in the inner-fjord waters, and tetra-CB 77 was the major non-orthoPCB congener. Sediment samples had PCDD/F concentration of 25-730 ng/g dw. Highest concentration was detected close to the magnesium plant. Octa-CDFdominated in the fjord sediments, especially near the magnesium plant indicating a discharge-specific contamination with this congener. The isomer composition of PCDD/Fs and of PCNs, was unchanged when comparing samples from different layers of a sediment core from the deep anoxic water. This concludes that essentially zero degradation had occurred during approximately 50 years in this environment.

Topics: Benzofurans; Dioxins; Fresh Water; Geologic Sediments; Industry; Naphthalenes; Norway; Polychlorinated Biphenyls; Water Pollutants, Chemical

The emission characteristics of PCDD/F from different waste incineration facilities in China, the correlations of different PCDD/F isomers with I-TEQ and the linear regression analysis of 23478-PeCDF with I-TEQ were reported in this article. Statistical analysis of the homologue patterns of PCDD/F in different incineration facilities will provide valuable information in environmental survey to find the contamination sources. PCDD/F congener patterns were almost constant among municipal and hazardous waste incineration facilities with only very small variations, but those patterns in medical waste incineration facilities were slightly different from medical and hazardous waste incineration facilities. It was found that the major contributors to the toxic PCDD/F concentrations were OCDD and 1234678-HpCDF contributing for 12.3%-23.0% and 15.0%-19.7% respectively. However, the largest contributor to I-TEQ was 23478-PeCDF and 33.1%-34.5% of I-TEQ was the presence of this congener. Correlation analysis showed that:23478-PeCDF posed the best the correlation relationship with I-TEQ, R2 0.93-0.99. The most toxic 2378-TCDD only posed weak correlation with I-TEQ, R2 0.29-0.49. The correlation coefficient between the most abundant OCDD and I-TEQ was only 0.03-0.12. However, another abundant congener 1234678-HpCDF posed better correlation with I-TEQ, R2 0.62-0.87. Linear regression analysis showed that even I-TEQ fell into the concentration range of 5-6 orders of magnitudes, the linear relationship between 23478-PeCDF and I-TEQ was still excellent. The slopes of that lines, in different waste incineration facilities, were in the range of 1.16-1.40 and R2 0.94-0.97.

Topics: Air Pollutants; Benzofurans; Carbon; Coal Ash; Environmental Monitoring; Incineration; Iron; Particulate Matter; Polychlorinated Dibenzodioxins; Refuse Disposal

The analysis of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) present in stack gas emissions and solid residues from incinerators will be mandatory in the foreseeable future. European standard EN-1948 is in the process of being updated through the addition of a new Part 4 related to the analysis of the 12 dl-PCBs. Therefore, either a comprehensive and reliable method capable of analyzing all of these 29 compounds (12 dl-PCBs and 17 2,3,7,8-PCDD/Fs) needs to be developed, or the existing PCDD/F analytical procedure must be adapted to include the dl-PCBs. This study has taken the latter approach of modifying PCDD/F methodology and in particular the fractionation step, by isolating dioxins and dl-PCBs into separate fractions ready for high resolution gas chromatography coupled to high resolution mass spectrometry (HRGC/HRMS) analysis. Results obtained from the analysis of Certified Reference Materials (CRM-490 and CRM-615) and fly ashes from the European Committee for Standardization (CEN) intercalibration study demonstrated that the proposed methodology is appropriate to determine the dl-PCBs in accordance with the impending European standard EN-1948. Uncertainty values obtained during the validation of the analytical methodology were 13% total I-TEQ (International Toxic Equivalent) for PCDD/Fs and 31% total WHO-TEQ (World Health Organization Toxic Equivalent) in the case of dl-PCBs. In addition, 'real' samples such as emissions and fly ashes were successfully analyzed following the proposed analytical method.

Topics: Air Pollutants; Benzofurans; Carbon; Coal Ash; European Union; Gas Chromatography-Mass Spectrometry; Particulate Matter; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Reproducibility of Results; Sensitivity and Specificity

To study the chemical constituents of Usnea longissima.. The compounds were isolated and purified by the methods of solvent extraction and chromatographic technique, and their structures were identified on the basis of the analyses of spectral data.. Two compounds were obtained and identified as 3, 6-diacetyl-2, 7, 9-trihydroxy-8, 9b-dimethyl-1 [9bH]-dibenzofuranone(1) and 1, 3, 8-trihydroxy4, 6-dimethyl-9, l0-anthracenedione(2), respectively.. Compounds 1 and 2 were new compounds and were named as longiusnine and longissimausnone, respectively.

Topics: Anthraquinones; Benzofurans; Magnetic Resonance Spectroscopy; Usnea

This study aims to develop estimation procedures for subcooled liquid vapor pressures of polycyclic aromatic hydrocarbons (PAHs), and of polychlorinated benzenes, biphenyls (PCBs), dibenzo-p-dioxines (PCDDs), and dibenzofurans (PCDFs) based on quantitative structure-property relationships (QSPRs) for the subcooled liquid vaporization enthalpy and entropy in terms of simple molecular structure descriptors and the system temperature. It turned out that subcooled liquid vaporization enthalpies and entropies for these compound classes can be estimated from the number of carbon atoms, the number of chlorine atoms, the number of PCB ortho-chlorine atoms and the system temperature. Subcooled liquid vapor pressures at 298 K calculated from the estimated vaporization enthalpies and entropies were equal to directly measured experimental values as well as to experimental values determined by gas chromatographic methods within, on average, 0.15 and 0.12-0.3 log units, respectively.

Topics: Algorithms; Benzofurans; Chlorobenzenes; Chromatography, Gas; Entropy; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Polycyclic Aromatic Hydrocarbons; Quantitative Structure-Activity Relationship; Regression Analysis; Temperature; Vapor Pressure

The isomer distribution patterns of mono- to hepta-chlorinated dibenzo-p-dioxins (PC1-7DD) and dibenzofurans (PC1-7DF) in postcombustion zone flue gas during incineration of an artificial municipal solid waste in a laboratory-scale fluidized-bed reactor were evaluated. Bidirectional orthogonal projections to latent structures (O2PLS) was used to correlate a set of physicochemical properties and chlorine substitution descriptors with the objective to identify parameters correlated with postcombustion zone PCDD and PCDF formation. The most influential variable for the distribution of PCDD congeners was chlorine substitution in positions 1 and 3 (Cl1+3), and overall the chlorine substitution descriptors exerted a larger impact on PCDDs than on PCDFs. For the PCDF, chlorination of the 9-position was the most influential X-variable. Distinct clustering was observed and was most pronounced for PCDFs, dividing mostof the homologues into two or three subgroups of congeners. These subgroups seemed to correspond to the probability of formation by chlorophenol condensation. The sterically crowded dibenzofuran bay-sites (1- and 9-positions) were found to negatively influence PCDF formation, with chlorination of the 9-position having the greatest impact. Since PCDD/F toxicity is related to the lateral positions, elucidating the factors governing chlorination may be of great importance for detoxification of incineration byproducts.

Topics: Benzofurans; Cities; Incineration; Isomerism; Models, Chemical; Multivariate Analysis; Polychlorinated Dibenzodioxins; Principal Component Analysis; Refuse Disposal; Reproducibility of Results

A biphenyl (BP)-utilizing bacterium, designated B6-2, was isolated from soil and identified as Pseudomonas putida. BP-grown B6-2 cells were capable of transforming dibenzofuran (DBF) via a lateral dioxygenation and meta-cleavage pathway. The ring cleavage product 2-hydroxy-4-(3'-oxo-3'H-benzofuran-2'-yliden)but-2-enoic acid (HOBB) was detected as a major metabolite. B6-2 growing cells could also cometabolically degrade DBF using BP as a primary substrate. A recombinant Escherichia coli strain DH10B (pUC118bphABC) expressing BP dioxygenase, BP-dihydrodiol dehydrogenase, and dihydroxybiphenyl dioxygenase was shown to be capable of transforming DBF to HOBB. Using purified HOBB that was produced by the recombinant as the substrate for B6-2, we newly identified a series of benzofuran derivatives as metabolites. The structures of these metabolites indicate that an unreported HOBB degradation pathway is employed by strain B6-2. In this pathway, HOBB is proposed to be transformed to 2-oxo-4-(3'-oxobenzofuran-2'-yl)butanoic acid and 2-hydroxy-4-(3'-oxobenzofuran-2'-yl)butanoic acid (D4) through two sequential double-bond hydrogenation steps. D4 is suggested to undergo reactions including decarboxylation and oxidation to produce 3-(3'-oxobenzofuran-2'-yl)propanoic acid (D6). 3-Hydroxy-3-(3'-oxobenzofuran-2'-yl)propanoic acid (D7) and 2-(3'-oxobenzofuran-2'-yl)acetic acid (D8) would represent metabolites involved in the processes of beta- and alpha-oxidation of D6, respectively. D7 and D8 are suggested to be transformed to their respective products 3-hydroxy-2,3-dihydrobenzofuran-2-carboxylic acid (D10) and 2-(3'-hydroxy-2',3'-dihydrobenzofuran-2'-yl)acetic acid. D10 is proposed to be transformed to salicylic acid (D14) via 2,3-dihydro-2,3-dihydroxybenzofuran, 2-oxo-2-(2'-hydroxyphenyl)acetic acid and 2-hydroxy-2-(2'-hydroxyphenyl)acetic acid. Further experimental results revealed that B6-2 was capable of growing with D14 as the sole carbon source. Because benzofuran derivatives may have biological, pharmacological, and toxic properties, the elucidation of this new pathway should be significant from both biotechnological and environmental views.

Topics: Benzofurans; Biodegradation, Environmental; Cloning, Molecular; Environmental Pollutants; Gene Expression Regulation, Bacterial; Genes, Bacterial; Molecular Structure; Pseudomonas putida

The gaseous photocatalytic degradation of dibenzofuran, dioxins-like substance, was investigated by using TiO2, Ce3+/TiOs and Fe3+/TiO2 as photocatalysts. The batch-type photocatalytic reaction experiments were conducted, and the effects of initial concentration of reactant, humidity, circulation flow rate and light intensity on the photocatalytic degradation of dibenzofuran were studied. And the models and methods for estimating photocatalytic reaction constants and Langmuir adsorption constants were proposed. Results showed that the photocatalytic activity of the TiO2 photocatalyst was obviously improved after doping with Fe3+ and Ce3+, and the photocatalytic activity of Fe3+/TiO2 was the best in three photocatalysts. The degradation rate of dibenzofuran increased with the increase of the initial concentration of gaseous dibenzofuran in the batch-type photocatalytic reaction system. The photocatalytic degradation of gaseous dibenzofuran was enhanced when proper quantities of water vapor existed. However, it would be inhibited if there was excessive water vapor. As the circulation flow rate and the light intensity increased, the photocatalytic degradation rate of gaseous dibenzofuran also increased. The photocatalytic reaction rate coefficients of dibenzofuran on the photocatalysts TiO2, Ce3+/TiO2 and Fe3+/TiO2 were 34.54 x 10(-5), 36.23 x 10(-5) and 37.95 x 10(-4) mg x (min x m2)(-1) respectively.

Topics: Air Pollutants; Benzofurans; Catalysis; Cerium; Ferric Compounds; Models, Theoretical; Photochemical Processes; Titanium

This study focuses on the atmospheric deposition of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) on the soils in the vicinity of two municipal solid waste incinerators (MSWIs), which were located in the Gangshan (GS) and the Renwu (RW) Townships of southern Taiwan. PCDD/Fs in the soils were sampled simultaneously with those in the ambient air and analyzed for 17 2,3,7,8-substituted PCDD/Fs. The results show that the mean contents of PCDD/Fs in the soils near MSWI-GS and MSWI-RW were 2.65 and 1.20 ng I-TEQ/kg dry weight, respectively. Annual wet deposition fluxes of total PCDD/Fs were 119 and 113 ng/m(2)-year in the ambient air near MSWI-GS and MSWI-RW, respectively. The results obtained in this study are much higher than those estimated for the Atlantic Ocean, where the average wet deposition was only 45 ng/m(2)-year. The annual dry deposition fluxes accounted for 58.2 and 66.7%, respectively, indicating that dry deposition was more dominant than wet deposition in the atmospheric deposition processes. The congener profiles of 17 2,3,7,8-substituted PCDD/Fs showed that OCDD dominates in the soils. The contributions of OCDD in the soils near MSWI-GS and MSWI-RW were 73.4 and 67.1%, respectively, while they were only 41.4 and 31.2% in the atmospheric deposition, respectively. These results imply that OCDD is more persistent in the environment than other congeners. The results of the present study strongly suggest that exposure to PCDD/Fs in these areas should be reduced.

Topics: Air Pollutants; Benzofurans; Dioxins; Environmental Exposure; Environmental Monitoring; Refuse Disposal; Soil; Taiwan

This study characterizes polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs), polycyclic aromatic hydrocarbons (PAHs), and heavy metal concentrations in stack flue gas, workplace air, fly ash, bottom ash, and ambient air of a secondary aluminum smelter. The total PAH concentration in workplace air was dominated by 2- and 3-ring PAHs, accounting for 86.2% of the gas phase in the total PAHs. The PCDD/F concentrations in workplace air are 1-7 fold higher than that in ambient air. The mass distribution ratio for total PCDD/Fs was soil > ash > workplace air > ambient air > flue gas. Aluminum and Zn had the highest concentrations. A positive correlation existed between PCDD/Fs and PAHs concentrations (r(2) = 0.920). The operation of secondary aluminum smelter affects the pollutant concentrations and surrounding air quality. Experimental results suggest that besides the terminal control technologies for stack flue gases, engineering control technologies in the workplace need further improvement.

Topics: Air Pollutants; Aluminum; Benzofurans; Carbon; Chromatography, Gas; Coal Ash; Dioxins; Environmental Monitoring; Metallurgy; Metals, Heavy; Particulate Matter; Polycyclic Aromatic Hydrocarbons; Taiwan

Since the mid-90s, an environmental surveillance program has been on-going to provide information on the levels of PCDD/Fs and various metals in soil and vegetation samples collected in the vicinity of a municipal solid waste incinerator (MSWI) in Tarragona (Catalonia, Spain). However, the presence of other potential sources of pollution in the zone, such as traffic, forest fires, local industries, etc., makes hard to determine the impact concerning the MSWI. Therefore, in 2007 a change in the monitoring program was implemented by collecting additional ambient air samples through active and passive sampling devices. Mean PCDD/F levels in herbage and soil were 0.10 ng I-TEQ/kg dry weight (range: 0.05-0.17 ng I-TEQ/kg dw) and 0.64 ng I-TEQ/kg dw (range: 0.13-2.41 ng I-TEQ/kg dw), respectively. A significant reduction of the PCDD/F concentration in both monitors was observed with respect to our previous surveys. Air mean concentrations of PCDD/Fs were 12.04 and 15.21 fg WHO-TEQ/m(3) in 2007 and 2008, respectively, meaning a non-significant increase of 26%. In addition, a generalized increase of environmental metal levels with respect to our baseline study was not observed. The current concentrations of PCDD/Fs and metals in the vicinity of the MSWI of Tarragona are relatively low in comparison with other areas under the influence of emissions from waste incinerators. This indicates that the environmental impact of the MSWI of Tarragona is not significant. Moreover, the modification of the surveillance program has proven to be successful.

Topics: Air Pollutants; Analysis of Variance; Benzofurans; Dioxins; Environmental Monitoring; Gas Chromatography-Mass Spectrometry; Incineration; Metals, Heavy; Spain; Statistics, Nonparametric

The Japanese Kanechlor technical PCB formulations such as KC-300, KC-400, KC-500, KC-600 and KC-1000 have been examined for possible contamination with by-side PCDD/Fs. 75 PCDDs and 135 PCDF have been determined using isotope dilution, separation and enrichment on silica gel impregnated with activated carbon, and final HRGC/HRMS measurement. MonoCDDs to OCDD were absent in KC-300, KC-600 and KC-1000. Tetra- and PentaCDDs occurred at > 1 ng/g in KC-400 and KC-500. The Kanechlors were contaminated with nearly all 135 PCDFsw. In parallel with an increasing degree of chlorination of a particular Kanechlor formulation examined increased also the content of more chlorinated PCDFs. In term of total dioxin-like toxicity and TEQ loads the KC-500 contained highly toxic PCDD/Fs at 270 ng TEQ/g and followed by KC-400 with 269 ng TEQ/g, KC-600 with 188 ng TEQ/g, KC-1000 with 164 ng TEQ/g and KC-300 with 79 ng TEQ/g. From 99.5 to 100% of PCDD/Fs toxicity found in the Kanechlors was from PCDFs.

Topics: Benzofurans; Chemical Industry; Dioxins; Gas Chromatography-Mass Spectrometry; Polychlorinated Biphenyls

A novel black carbon (BC) inclusive modeling tool is applied to estimate the distribution and long-term fate of dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the Norwegian Grenland Fjords. Three versions of the model were developed in which sediment-water partitioning was described using (i) an amorphous organic carbon (AOC) partitioning sorption model without BC sorption, (ii) a combined AOC and BC sorption model based on the Freundlich isotherm, and (iii) a combined BC-AOC model based on the Langmuir isotherm. The predictive ability of the three different models was evaluated for 17 PCDD/Fs by comparison of model predictions with observed organic carbon normalized sediment-water partition coefficients (K(TOC)) and with measured concentrations. All three versions of the model were able to predict concentrations that were in reasonable agreement with measured particulate concentrations (i.e., within a factor of 4 of median values). Estimated particulate concentrations were less sensitive to the model choice because the majority of the mass of these hydrophobic chemicals is associated with particulates regardless. However, for estimation of K(TOC) or dissolved water concentrations, both versions of the combined AOC and BC sorption models provided greatly improved estimates compared to the AOC-only model.

Topics: Benzofurans; Carbon; Dioxins; Environmental Monitoring; Models, Theoretical; Water Pollutants, Chemical

A new dibenzofuran named 1,2,4-trimethyl-7,8-dimethoxy-dibenzofuran (1), together with seven known compounds, euparin (2), 2,5-diacetyl-6-hydroxy-benzofuran (3), 2-acetyl-5,6-dimethoxy-benzofuran (4), gummosogenin (5), lupeol (6), stigmasterol (7) and (E)-2,5-dihydroxy-cinnamic acid (8), were isolated from the roots of Ligularia caloxantha, a Chinese medicinal plant. The structures of the compounds were elucidated by spectroscopic methods.

Topics: Asteraceae; Benzofurans; Drugs, Chinese Herbal; Molecular Structure; Plant Roots

With computational method of density functional theory (DFT), quantified model study of equilibrium partitioning properties of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) between lipid phase of organism (Poecilia reticulata) and water phase was carried out based on quantum chemical and further calculated parameters, namely frontier orbital energies, entropies, traceless quadrupole moments as well as molecular absolute hardness, electronegativities and electrophilicity indices, which all were derived from full geometry optimization of PCDD/Fs. Through multiple linear regression (MLR) analyses, quantitative structure-property relationship (QSPR) was successfully proposed in the form of multi-parameter quadratic function: lgK(hw) = 5.343 - 0.001(S - 125.480)(2) - 0.355(omega - 3.239)(2) + 0.006( Q = - 2.950)(2) - 22.728(eta - 2.365)(2). It was shown that the obtained QSPR had higher goodness of fitting and robustness, determination coefficient and cross-validated correlation coefficient being 0.943 and 0.908 respectively, and it was also provided with ideal interior and exterior predictive abilities so that it could be used for prediction of unknown lipid-water partitioning properties. By comparison, QSPR in this research was superior to that from previous SOFA (solubility parameter for fate analysis) method on the whole. Lipid-water partitioning properties (coefficients) of PCDD/Fs should be mainly related to molecular volume and aryl hydrocarbon molecular interactions determined by charge distribution. To a certain degree, they also might be influenced by potential biotransformation and molecular reactivity.

Topics: Benzofurans; Chemistry, Physical; Lipids; Models, Chemical; Polychlorinated Dibenzodioxins; Quantitative Structure-Activity Relationship; Water; Water Pollutants, Chemical

Dechlorination of spiked 1,2,3,4-tetrachlorodibenzo-p-dioxin (1,2,3,4-TeCDD) was investigated in sediment microcosms from three polychlorinated dibenzo-p-dioxin and dibenzofuran (CDD/F)-contaminated sites: River Kymijoki, Finland; Gulf Island Pond, Maine; and Lake Roosevelt, Washington. Dechlorination was stimulated by addition of electron donor and halogenated priming compounds, and bioaugmentation by a mixed culture containing Dehalococcoides ethenogenes strain 195. Amendment with 1,2,3,4-tetrachlorobenzene (1,2,3,4-TeCB) promoted rapid dechlorination of 1,2,3,4-TeCDD to 2-monochlorodibenzo-p-dioxin (2MCDD) in Gulf Island Pond and River Kymijoki sediments, however, only slow dechlorination to 1,4-dichlorodibenzo-p-dioxin was observed in Lake Roosevelt sediments. The dechlorination pathway in 1,2,3,4-TeCB-amended microcosms proceeded mainly via 1,3-dichlorodibenzo-p-dioxin, with less production of 2,3-dichlorodibenzo-p-dioxin in comparison with other treatments. Microbial community analyses indicated that Dehalococcoides-like bacteria were enriched with 1,2,3,4-TeCB. Quantitative real-time PCR analysis of Dehalococcoides-specific 16S rRNA genes and the D. ethenogenes strain 195 dehalogenase gene, tceA, showed at least an order of magnitude higher gene copy numbers in the bioaugmented than in the nonbioaugmented microcosms. An active-dechlorinating population is present in the River Kymijoki and biostimulation may enhance both native Dehalococcoides spp. and the bioaugmented D. ethenogenes strain 195.

Topics: Benzofurans; Chloroflexi; Ecosystem; Electrophoresis; Finland; Geologic Sediments; Maine; Molecular Sequence Data; Oxidoreductases; Polychlorinated Dibenzodioxins; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Soil Pollutants; Washington

A dibenzofuran (DF)-degrading bacterium, Nocardioides sp. DF412, was isolated and its genes responsible for the degradation of DF were cloned and characterized. The dfdA1A2A3A4 gene cluster coding for a ring hydroxylating dioxygenase was located on a plasmid, and the dfdBC gene cluster coding for a ring-cleavage dioxygenase and a following hydrolase respectively was located on the chromosome. Reverse transcription-PCR analysis revealed that the transcription of both gene clusters was induced in the presence of DF. These two gene clusters also conferred the activity of each enzyme to a host strain. These results strongly suggest that the clusters are responsible for the degradation of DF in strain DF412.

Topics: Actinomycetales; Bacterial Proteins; Benzofurans; Biodegradation, Environmental

Catechol has been identified as one of the most abundant organic products in tobacco smoke and a major molecular precursor for semiquinone type radicals in the combustion of biomass material. The high-temperature gas-phase pyrolysis of catechol under hydrogen-rich and hydrogen-lean conditions was studied using a fused-silica tubular flow reactor coupled to an in-line GC/MS analytical system. Thermal degradation of catechol over temperature range of 250-1000 degrees C with a reaction time of 2.0s yielded a variety products including phenol, benzene, dibenzofuran, dibenzo-p-dioxin, phenylethyne, styrene, indene, anthracene, naphthalene, and biphenylene. Ortho-benzoquinone which is typically associated with the presence of semiquinone radicals was not observed and is proposed to be the result of fast decomposition reactions that lead to a variety of other reaction products. This is in contrast to the decomposition of hydroquinone that produced para-benzoquinone as the major product. A detailed mechanism of the degradation pathway of catechol is proposed.

Topics: Benzofurans; Benzoquinones; Catechols; Dioxins; Gas Chromatography-Mass Spectrometry; Hot Temperature

An emplaced source of coal tar creosote within the sandy Borden research aquifer has documented the long-term (5140 days) natural attenuation for this complex mixture. Plumes of dissolved chemicals were produced by the essentially horizontal groundwater flowing at about 9 cm/day. Eleven chemicals have been extensively sampled seven times using a monitoring network of approximately 280, 14-point multilevel samplers. A model of source dissolution using Raoult's Law adequately predicted the dissolution of 9 of 11 compounds. Mass transformation has limited the extent of the plumes as groundwater has flowed more than 500 m, yet the plumes are no longer than 50 m. Phenol and xylenes have been removed and naphthalene has attenuated from its maximum extent on day 1357. Some compound plumes have reached an apparent steady state and the plumes of other compounds (dibenzofuran and phenanthrene) are expected to continue to expand due to an increasing mass flux and limited degradation potential. Biotransformation is the major process controlling natural attenuation at the site. The greatest organic mass lost is associated with the high solubility compounds. However, the majority of the mass loss for most compounds has occurred in the source zone. Oxygen is the main electron acceptor, yet the amount of organics lost cannot be accounted for by aerobic mineralization or partial mineralization alone. The complex evolution of these plumes has been well documented but understanding the controlling biotransformation processes is still elusive. This study has shown that anticipating bioattenuation patterns should only be considered at the broadest scale. Generally, the greatest mass loss is associated with those compounds that have a high solubility and low partitioning coefficients.

Topics: Benzofurans; Biotransformation; Coal Tar; Creosote; Electrons; Kinetics; Models, Chemical; Naphthalenes; Oxygen; Phenanthrenes; Phenol; Soil Pollutants; Solubility; Time Factors; Xylenes

Polychlorinated biphenyls (PCBs) and polychlorinated dibenzofurans (PCDFs) are ubiquitous pollutants found in the environment and human tissues. A cohort in Taiwan has undergone follow-up for 24 years after exposure to high levels of PCBs and PCDFs. The incidence of chloracne, hyperkeratosis, and abnormal nail was increased among exposed people. We conducted a study to identify the genes whose expressions were affected by such exposure. A cDNA microarray system consisting of 908 genes was used for pooled serum samples from non-smoking men exposed to PCBs and PCDFs (n=15) and their matched referents (n=15) in triplicate. After adjusting for background and housekeeping genes, genes with different expressions between the exposure and reference groups were determined by both regression and cluster analysis, and further confirmed by real-time RT-PCR. The tumor suppressor gene von Hippel-Lindau (VHL) was found to be down-regulated in the microarray analysis. VHL gene expression levels were also found to be positively associated with age, shown by real-time RT-PCR. Upon age adjustment, VHL gene expression was reduced in Yucheng ("oil disease") subjects as compared to referents. Among Yucheng people, those with abnormal nails had lower VHL expressions than those without abnormal nails. These findings provide new insights into the potential role of VHL in health conditions associated with PCB and PCDF exposures.

Topics: Adult; Aging; Benzofurans; Cohort Studies; DNA; Down-Regulation; Environmental Exposure; Environmental Pollutants; Follow-Up Studies; Gene Expression; Gene Expression Profiling; Humans; Keratosis; Lymphocytes; Male; Middle Aged; Nails, Malformed; Oligonucleotide Array Sequence Analysis; Polychlorinated Biphenyls; Reproducibility of Results; Reverse Transcriptase Polymerase Chain Reaction; Taiwan; Von Hippel-Lindau Tumor Suppressor Protein

This study is the first one using the Taguchi experimental design to identify the optimal operating condition for reducing polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/ Fs) formations during the iron ore sintering process. Four operating parameters, including the water content (Wc; range = 6.0-7.0 wt %), suction pressure (Ps; range = 1000-1400 mmH2O), bed height (Hb; range = 500-600 mm), and type of hearth layer (including sinter, hematite, and limonite), were selected for conducting experiments in a pilot scale sinter pot to simulate various sintering operating conditions of a real-scale sinter plant We found that the resultant optimal combination (Wc = 6.5 wt%, Hb = 500 mm, Ps = 1000 mmH2O, and hearth layer = hematite) could decrease the emission factor of total PCDD/Fs (total EF(PCDD/Fs)) up to 62.8% by reference to the current operating condition of the real-scale sinter plant (Wc = 6.5 wt %, Hb = 550 mm, Ps = 1200 mmH2O, and hearth layer = sinter). Through the ANOVA analysis, we found that Wc was the most significant parameter in determining total EF(PCDD/Fs (accounting for 74.7% of the total contribution of the four selected parameters). The resultant optimal combination could also enhance slightly in both sinter productivity and sinter strength (30.3 t/m2/day and 72.4%, respectively) by reference to those obtained from the reference operating condition (29.9 t/m (2)/day and 72.2%, respectively). The above results further ensure the applicability of the obtained optimal combination for the real-scale sinter production without interfering its sinter productivity and sinter strength.

Topics: Benzofurans; Incineration; Iron; Polychlorinated Dibenzodioxins; Research Design; Water

Catalytic destruction has been applied to control polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/Fs) emissions from different facilities. The cost of carbon-based catalysts is considerably lower than that of the metal oxide or zeolite-based catalysts used in the selective catalytic reduction (SCR) system. In this study, destruction and adsorption efficiencies of PCDD/Fs achieved with Cu/C and Fe/C catalysts from flue gas streams of a metal smelting plant (MSP) and a large-scale municipal waste incinerator (MWI), respectively, are evaluated via the pilot-scale catalytic reactor system (PCRS). The results indicate that Cu and Fe catalysts supported on carbon surface are capable of decomposing and adsorbing PCDD/ Fs from gas streams. In the testing sources of MSP and MWI, the PCDD/F removal efficiencies achieved with Cu/C catalyst at 250 degrees C reach 96%, however, the destruction efficiencies are negative (-1,390% and -112%, respectively) due to significant PCDD/F formation on catalyst promoted by copper. In addition, Fe/C catalyst is of higher removal and destruction efficiencies compared with Cu/C catalyst in both testing sources. The removal efficiencies of PCDD/Fs achieved with Fe/C catalyst are 97 and 94% for MSP and MWI, respectively, whereas the destruction efficiencies are both higher than 70%. Decrease of PCDD/F destruction efficiency and increase of adsorption efficiency with increasing chlorination of dioxin congeners is also observed in the test via three-layer Fe/C catalyst. Furthermore, the mass of 2,3,7,8-PCDD/Fs retained on catalyst decreases on the order of first to third layer of catalyst. Each gram Fe/C catalyst in first layer adsorbs 10.9, 6.91, and 3.04 ng 2,3,7,8-PCDD/Fs in 100 min testing duration as the operating temperature is controlled at 150, 200, and 250 degrees C, respectively.

Topics: Adsorption; Air Pollutants; Benzofurans; Carbon; Catalysis; Cities; Copper; Incineration; Iron; Metallurgy; Polychlorinated Dibenzodioxins; Temperature; Waste Management

A series of dibenzofurans were efficiently and conveniently synthesized via one-pot consecutive C(sp(2))-O bond formation reaction (SNAr) in the presence of anhydrous K(2)CO(3), followed by C(sp(2))-C(sp(2)) bond formation reaction (intramolecular palladium-catalyzed aryl-aryl coupling reaction) between aryl halides and ortho-bromophenols. The desired dibenzofurans were obtained in 32-99% isolated yields.

Topics: Benzofurans; Catalysis; Chromates; Chromatography, Thin Layer; Hydrocarbons, Halogenated; Indicators and Reagents; Magnetic Resonance Spectroscopy; Palladium; Phenols; Potassium Compounds; Spectrometry, Mass, Electrospray Ionization

Combustion experiments in a laboratory-scale fixed bed reactor were performed to determine the role of temperature and time in polychlorinated dibenzo-p-dioxin (PCDD) and polychlorinated dibenzofuran (PCDF) formation, allowing a global kinetic expression to be written for PCDD/F formation due to soot oxidation in fly ash deposits. Rate constants were calculated for the reactions of carbon degradation, PCDD/F formation, desorption, and degradation. For the first time, values for activation and thermodynamic parameters for the overall reactions have been calculated for PCDD/F formation, desorption, and destruction reactions. Good agreement was found between the calculated rate constants for carbon degradation and for PCDD/F formation, indicating that the two processes have a common rate-determining step. Moreover, PCDD/F formation was found to be still active after long reaction times (24 h). These results points out the importance of carbon deposits in the postcombustion stages that can account for emissions long after their formation (memory effects). The calculated formation rates were 7-15 times higher than those reported in the literature from fly ash-only experiments, indicating the importance of both soot and a continuous source of chlorine. A comparison between full-scale incinerator rates and model calculated rates indicates that our model based on carbon degradation kinetic can be a tool to estimate emissions.

Topics: Benzofurans; Carbon; Kinetics; Models, Chemical; Polychlorinated Dibenzodioxins; Temperature; Thermodynamics; Time Factors

The most direct route to the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in combustion and thermal processes is the gas-phase reaction of chemical precursors such as chlorinated phenols. Detailed insight into the mechanism and kinetics properties is a prerequisite for understanding the formation of PCDD/Fs. In this paper, we carried out molecular orbital theory calculations for the homogeneous gas-phase formation of PCDD/Fs from 2-chlorophenol (2-CP). The profiles of the potential energy surface were constructed, and the possible formation pathways are discussed. The single-point energy calculation was carried out at the MPWB1K/ 6-311+G(3f,2p) level. Several energetically favorable formation pathways were revealed for the first time. The rate constants of crucial elementary steps were deduced over a wide temperature range of 600 approximately 1200 K using canonical variational transition-state theory (CVT) with small curvature tunneling contribution (SCT). The rate-temperature formulas were fitted. The ratio of PCDD to PCDF formed shows strong dependency on the reaction temperature and chlorophenoxy radicals (CPRs) concentration.

Topics: Benzofurans; Chlorophenols; Dimerization; Kinetics; Polychlorinated Dibenzodioxins; Quantum Theory; Temperature

Results of an extensive 5 year study on a full-scale plant with the specific aim to investigate polychlorinated dibenzo-p-dioxin (PCDD) and polychlorinated dibenzo furan (PCDF) formation and release in a secondary aluminum casting plant are reported. PCDD and PCDF concentrations were evaluated for all the gaseous and solid streams (no liquid stream was present) as well as for the flue gas upstream and downstream of every single unit of the flue gas cleaning system. The study highlights PCDD and PCDF formation particularly in the narrow 320-360 degrees C range. To prevent formation reactions and/or minimize PCDD and PCDF concentration at the stack, effects of the fabric filter substitution, a quenching chamber and a postcombustor installation together with working conditions are investigated. The flue gas cleaning system results in PCDD and PCDF emission at stack of 0.1-0.2 ng I-TEQ/N m3 and in a mass flow of 250-550 nmol/h. The total PCDD and PCDF release into the environment is 0.06 g I-TEQ/yr and the corresponding emission factor, 0.35 microg I-TEQ/ton. It is shown that the global effects of the technological innovation on the reaction mechanisms are the prevention of PCDD/F formation by de novo synthesis and the minimization of their emission.

Topics: Aluminum; Benzofurans; Carbon; Filtration; Gases; Industry; Polychlorinated Dibenzodioxins; Temperature

Fly ash and ambient emissions of municipal solid waste incinerators contain polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polycyclic aromatic hydrocarbons (PAHs), other organic compounds, metals, and gases. Hazardous substances such as PCDD/Fs, mercury vapors and other silicates, and the components of bottom ash and fly ash elevate the oxidative damage. We compared oxidative damage in workers exposed to hazardous substances at a bottom ash recovery plant and 3 fly ash treatment plants in Taiwan by measuring their levels of plasma malondialdehyde (MDA) and urine 8-hydroxydeoxyguanosine (8-OH-dG). Significantly higher MDA levels were found in fly ash treatment plant workers (3.20 microM) than in bottom ash plant workers (0.58 microM). There was a significant association between MDA levels in workers and their working environment, especially in the fly ash treatment plants. Levels of 8-OH-dG varied more widely in bottom ash workers than in fly ash workers. The association between occupational exposure and 8-OH-dG levels may be affected by the life style of the workers. Because more dioxins and metals may leach from fly ash than from bottom ash, fly ash treatment plant workers should, as much as possible, avoid exposing themselves to fly ash.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Benzofurans; Biomarkers; Carbon; Coal Ash; Deoxyguanosine; Dioxins; Environment; Female; Fraxinus; Hazardous Waste; Humans; Incineration; Industrial Waste; Lipid Peroxidation; Male; Malondialdehyde; Metallurgy; Middle Aged; Occupational Exposure; Oxidative Stress; Particulate Matter; Polycyclic Aromatic Hydrocarbons; Taiwan; Workplace; Young Adult

The synthesis of salen ligands bearing two rigid dibenzofuran spacers functionalized with carboxylic acid and benzoic acid groups completes a series of "Hangman" ligands with the acid functionalities differentially extended across the molecular cleft. Stopped-flow studies show that a high-valent metal oxo intermediate is produced at Hangman platforms when H(2)O(2) is employed as a primary oxidant. The activity of this oxo species in promoting the disproportionation of hydrogen peroxide and olefin epoxidations is discussed in the context of the distance between the acid group and the metal center. The chemistry of the Hangman oxo complexes described here provides a roadmap for water-splitting chemistry.

Topics: Absorption; Benzofurans; Catalysis; Ethylenediamines; Kinetics; Ligands; Quantum Theory

According to our earlier study, molar-incisor-hypomineralisation (MIH) was associated with the exposure of a child via mother's milk to polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) in a group of Finnish children born in 1987. Since the levels of PCDD/Fs and PCBs in mother's milk/placenta have remarkably decreased, it was important to find out if an association still exists.. The study group was composed of 167 mothers and their children. Placental samples from the mothers were collected in maternity hospitals in Helsinki and Oulu in 1995--1999 and concentrations of the 17 most toxic PCDD/PCDF and 36 PCB congeners were measured. After 7-10 years the children were examined for MIH and the mothers were interviewed on the duration of breast-feeding.. MIH was found in 24 children (14.4%). The duration of breast-feeding ranged from 0 to 30 months (mean=7.2+/-4.7). WHOPCDD/FTEQ ranged from 2.5 to 39.1 pg/g fat (mean=13.7+/-6.8) and WHOPCBTEQ from 0.7 to 9.8 pg/g fat (mean=2.7+/-1.4). The mean sum of PCDD/Fs was 196+/-105 pg/g fat and that of PCBs was 57.2+/-28.1ng/g fat. The total exposure to PCDD/Fs, which was calculated from the placental concentration (used as a proxy for the milk concentration) and duration of breastfeeding, was not associated with the occurrence or severity of MIH. Neither was the total exposure to PCBs associated with the occurrence or severity of MIH.. At prevailing levels, exposure of a child via placenta/mother's milk to PCDD/Fs and PCBs is not associated with MIH.

Topics: Abnormalities, Drug-Induced; Benzofurans; Breast Feeding; Child; Dental Enamel; Dental Enamel Hypoplasia; Dioxins; Female; Humans; Incisor; Milk, Human; Molar; Placenta; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Pregnancy; Prenatal Exposure Delayed Effects; Teratogens; Time Factors; Tooth Demineralization

Environmental pollution arising from electronic waste (e-waste) disposal and recycling has received considerable attention in recent years. Treatment, at low temperatures, of e-wastes that contain polyvinylchloride and related polymers can release polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). Although several studies have reported trace metals and polybrominated diphenyl ethers (PBDEs) released from e-waste recycling operations, environmental contamination and human exposure to PCDD/Fs from e-waste recycling operations are less well understood. In this study, electronic shredder waste and dust from e-waste facilities, and leaves and surface soil collected in the vicinity of a large scale e-waste recycling facility in Taizhou, Eastern China, were analyzed for total PCDD/ Fs including 2,3,7,8-substituted congeners. We also determined PCDD/Fs in surface agricultural soils from several provinces in China for comparison with soils from e-waste facilities. Concentrations of total PCDD/Fs were high in all of the matrices analyzed and ranged from 30.9 to 11400 pg/g for shredder waste, 3460 to 9820 pg/g dry weight for leaves, 2560 to 148000 pg/g dry weight for workshop-floor dust, and 854 to 10200 pg/g dry weight for soils. We also analyzed surface soils from a chemical industrial complex (a coke-oven plant, a coal-fired power plant, and a chlor-alkali plant) in Shanghai. Concentrations of total PCDD/Fs in surface soil (44.5-531 pg/g dry wt) from the chemical industrial complex were lower than the concentrations found in soils from e-waste recycling plants, but higher than the concentrations found in agricultural soils. Agricultural soils from six cities in China contained low levels (3.44-33.8 pg/g dry wt) of total PCDD/Fs. Profiles of dioxin toxic equivalents (TEQs) of 2,3,7,8-PCDD/Fs in soils from e-waste facilities in Taizhou differed from the profiles found in agricultural soils. The estimated daily intakes of TEQs of PCDD/ Fs via soil/dust ingestion and dermal exposure (2.3 and 0.363 pg TEQ/kg bw/day for children and adults, respectively) were 2 orders of magnitude higher in people at e-waste recycling facilities than in people at the chemical industrial site (0.021 and 0.0053 pg TEQ/kg bw/day for children and adults, respectively), implying greater health risk for humans from dioxin exposures at e-waste recycling facilities. The calculated TEQ exposures for e-waste workers from dust and soil ingestion alone were 2-3 orders of magnitude grea

Topics: Adult; Benzofurans; Child; China; Conservation of Natural Resources; Dioxins; Electronics; Environmental Monitoring; Environmental Pollutants; Humans; Hydrocarbons, Chlorinated; Industrial Waste; Industry

To establish the methods of Polychlorinated Dibenzo-p-Dioxins and Dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) compounds determination by isotope dilution HRGC/HRMS simultaneously in human placenta tissue from mothers, and assess the human exposure risk to dioxins and PBDEs in study.. Concentrations of 17 PCDD/Fs and 12 dioxin-like PCBs as well as 7 PBDEs were measured in human placenta tissue samples by isotope dilution HRGC/HRMS. SigmaTEQ (PCDD + PCDFs + PCBs) concentration using WHO-TEF factor and PBDEs concentration was calculated respectively. Risk assessment of mother exposure to dioxins and PBDEs was evaluated.. Median of SigmaTEQ (PCDD + PCDFs + PCBs) concentration for six samples was 18.15 WHO-TEQ pg/g lipid, ranging from 5.14 - 67.01 WHO-TEQ pg/g lipid. Although the median of SigmaTEQ (PCDD + PCDFs + PCBs) was lower than that of human blood of EU and Japan, and close to that of Korea and Taiwan non-exposure as reported in the literatures, the highest SigmaTEQ (PCDD + PCDFs + PCBs) concentration of placenta sample exceeded the value of high dioxins exposure area subjects in Taiwan. The dominant contributor congener for WHO-TEQ were 2, 3, 4, 7, 8-PeCDF, 1, 2, 3, 7, 8-PeCDD, PCB126, totally accounted for 65 percent of SigmaWHO-TEQ. Median and average of PBDE concentration for six samples were 2.73 ng/g lipid and 7.17 ng/g lipid, respectively, ranging from 0.95 - 25.99 ng/g lipid. BDE47 was the dominant contributor congener for the total concentration, accounted for 35 percent.. The methods of PCDD/Fs, PCBs and PBDEs compounds determined by isotope dilution HRGC/HRMS simultaneously in human placenta tissue from mothers were established successfully, and the human exposure risk to PCDD/Fs, PCBs and PBDEs should be surveyed for the donor with the highest SigmaTEQ (PCDD + PCDFs + PCBs) and PBDEs concentration of placenta sample in the future.

Topics: Benzofurans; Female; Halogenated Diphenyl Ethers; Humans; Maternal Exposure; Placenta; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Pregnancy

Annual emissions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from open burning of crop residues in each province of China mainland between 1997 and 2004 were estimated to be ranged from 1.38x10(3) to 1.52x10(3) g I-TEQ/yr, with the average of 1.50+/-0.08x10(3) g I-TEQ/yr, which contributed to approximately 10% approximately 20% of the total emissions in China. The PCDD/F emissions mainly occurred in the largest crop-producing provinces, especially in those of higher economic levels. The major sources of PCDD/F emissions from open burning in China were found to be cereal residues (i.e. rice, wheat, and corn), which accounted about 70% of the total emissions. Moreover, the first-order one-variable grey differential equation model (GM (1,1) model) for annual emissions of PCDD/Fs was established based on grey system theory. The GM (1,1) model was proved to be robust to predict the annual PCDD/F emissions from crop residue field burning in forthcoming years.

Topics: Agriculture; Air Pollutants; Benzofurans; China; Dioxins; Environmental Monitoring; Incineration; Models, Theoretical; Oryza; Polychlorinated Biphenyls; Triticum; Zea mays

In order to understand the effect of different amounts of powder-activated carbon (PAC) injection and bio-solution (NOE-7F) addition on the removal efficiencies of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in a fly ash treatment plant with Waelz rotary kiln process, the PCDD/F concentrations in the stack flue gasses were measured and discussed. In the amount of 20, 40 and 50 kg/h PAC injection, the removal efficiencies of PCDD/Fs in the stack flue gas were 86, 96 and 97%, respectively. While adding more amounts of PAC did enhance the removal efficiencies, the reduction fractions of low chlorinated PCDD/F congeners were much higher than those of highly chlorinated PCDD/F congeners. Particularly, a lower amount of PAC injection (20 kg/h), not only cannot remove highly chlorinated PCDD/Fs, but also the carbon surface of the PAC can act as a precursor for the formation promotion of highly chlorinated PCDD/F congeners. The addition of NOE-7F in the raw materials had the dechlorination effect on the PCDD/F removal and mainly inhibited highly chlorinated PCDD/F formation. The combination of both PAC injection and NOE-7F addition has a high potential for practical application.

Topics: Bacteria; Benzofurans; Biodegradation, Environmental; Carbon; Chromatography, Gas; Coal Ash; Dust; Incineration; Industrial Waste; Particulate Matter; Polychlorinated Dibenzodioxins; Yeasts

Aimed to give a preliminary image of dioxin pollution in China, chemometric analysis was performed to determine background dioxin levels during the period 1994-2002 and potential emission sources. Using principal components analysis (PCA), the congener profiles of 71 sediment samples from rivers, lakes, and sea bays around China were compared with the congener profiles of various known or suspected industrial, residential, and municipal dioxin sources to determine whether the dioxin residues typically found in a broad range of potential environmental sources could explain the presence of these chemicals in China. It was found that the background dioxin levels of China were similar to those of lightly polluted samples from other countries during the period 1994-2002. Primary ferrous ore sintering and secondary lead and aluminum smelters were the major sources of dioxin emission in China. Chloranil and wastewater from chemical plants, sodium pentachlorophenate, and pulp bleaching were also important sources of dioxin emission. Open burning of e-waste as well as diesel-fueled and leaded gas-fueled vehicles were additional possible sources of dioxin. In contrast to other countries, in China, flue gases from incineration of municipal waste, hazardous waste, and medical waste might be minor sources of dioxin emission.

Topics: Air Pollutants; Air Pollution; Benzofurans; China; Environmental Monitoring; Geography; Polychlorinated Dibenzodioxins

A study was conducted on polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in surface soil in order to determine the concentration levels and possibly distinguishing between known and potential sources. The concentration levels are low (0.16-14 ng I-TEQ kg(-1)). The results show a clear pattern where the highest concentration levels were found in the oldest parts of the city. A number of sources were recognised in the soil samples through congener profiles, not all of them active, although similar congener profiles make it extremely difficult to distinguish between different sources. Estimations show that the municipal solid waste incinerator (MSWI) and domestic wood burning are the largest PCDD/F pollution sources within the area.

Topics: Benzofurans; Carcinogens, Environmental; Dust; Environmental Monitoring; Incineration; Norway; Polychlorinated Dibenzodioxins; Soil Pollutants; Urbanization; Volatilization; Wood

This study monitored particle size-dependent variations in atmospheric polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). Two gas/particle partitioning models, the subcooled liquid vapor pressure (P(L)(0)) and the octanol-air partition coefficient (K(OA)) model, were applied to each particle sizes. The regression coefficients of each fraction against the gas/particle partition coefficient (K(P)) were similar for separated particles within the same sample set but differed for particles collected during different periods. Gas/particle partitioning calculated from the integral of fractions was similar to that of size-segregated particles and previously measured bulk values. Despite the different behaviors and production mechanisms of atmospheric particles of different sizes, PCDD/F partitioning of each size range was controlled by meteorological conditions such as atmospheric temperature, O(3) and UV, which reflects no source related with certain particle size ranges but mixed urban sources within this city. Our observations emphasize that when assessing environmental and health effects, the movement of PCDD/Fs in air should be considered in conjunction with particle size in addition to the bulk aerosol.

Topics: Air; Air Movements; Air Pollutants, Occupational; Benzofurans; Environmental Monitoring; Gases; Models, Chemical; Ozone; Particle Size; Polychlorinated Dibenzodioxins; Seasons; Temperature; Ultraviolet Rays

Quasi-dynamic leaching characteristics of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from raw and solidified air pollution control (APC) residues were examined via a nine-time multiple leaching test. The effect of injected activated carbon in the APC residues on the PCDD/F leachability was also evaluated. When humic acid solution was used as a leachant, the leaching concentrations of PCDD/Fs fluctuated between the first and the fifth leaching, followed by a gradual increase and then suddenly reached maximum values at the leaching sequences around seventh and eighth. This significant enhancement in PCDD/F leachability was mainly due to an increase in the release of highly chlorinated PCDD/Fs. Leaching of PCDD/Fs with n-hexane was, in contrast, primarily caused by the partitioning of hydrophobic PCDD/Fs between the APC residue surface and the liquid phase of n-hexane. Consequently, the largest leaching concentrations for n-hexane tests achieved at the first leaching, followed by a decrease and reached plateaus. Solidification/stabilization (S/S) decreased the PCDD/F leachability up to the fifth leaching by the use of humic acid solution. However, S/S increased the PCDD/F leaching concentrations and rates with n-hexane. The activated carbon in APC residues significantly inhibited the release of PCDD/F with n-hexane. The inhibiting effect provided by activated carbon was, however, less significant by the use of humic acid solution.

Topics: Benzofurans; Carbon; Hexanes; Incineration; Polychlorinated Dibenzodioxins; Refuse Disposal; Soil Pollutants; Solubility; Waste Disposal, Fluid

Formation of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and chlorinated phenols on CuCl(2) from unsubstituted phenol and three monochlorophenols was studied in a flow reactor over a temperature range of 100-425 degrees C. Heated nitrogen gas streams containing 8.0% oxygen were used as carrier gas. The 0.00024mol of unsubstituted phenol and 0.00039mol of each monochlorophenol were passed through a 1g and 1cm SiO(2) particle containing 0.5% (Cu by mass) CuCl(2). Chlorination preferentially occurred on ortho-(2, 6) and para-(4) positions. Chlorination increased up to 200 degrees C, and thereafter decreased as temperature increased. Chlorination of phenols plays an important role in the formation of the more chlorinated PCDD/Fs. Chlorinated benzenes are formed possibly from both chlorination of benzene and chlorodehydroxylation of phenols. Chlorinated phenols with ortho chlorine formed PCDD products, and major PCDD products were produced via loss of one chlorine. For PCDF formation, at least one unchlorinated ortho carbon was required.

Topics: Benzene; Benzofurans; Catalysis; Copper; Dibenzofurans, Polychlorinated; Dioxins; Hot Temperature; Molecular Structure; Oxidation-Reduction; Phenols; Polychlorinated Dibenzodioxins

Polychlorinated dibenzo-p-dioxins and dibenzofurans in crude extracts of fly ash and flue gas from municipal waste incinerators were quantified using a comprehensive multidimensional gas chromatograph (GC x GC) coupled to a high-resolution time-of-flight mass spectrometer (HR-TOFMS). For identification and quantification, we developed our own program to prepare 3D chromatograms of selected mass numbers from the data of the GC x GC/HR-TOFMS. Isolation of all congeners with a TCDD toxic equivalency factor from the other isomers by only one injection was confirmed. The instrumental detection limit of TCDD on the GC x GC/HR-TOFMS was 0.9 pg by the relative calibration method. Quantification of these substances in the crude extracts was achieved by direct injection to the GC x GC/HR-TOFMS. The results agree with the values obtained using a generic gas chromatography/high-resolution mass spectrometry (GC/HRMS) system. It was confirmed that measurement by high-resolution TOFMS and GC x GC effectively reduces interference from other chemicals.

Topics: Benzofurans; Carbon; Coal Ash; Dioxins; Gas Chromatography-Mass Spectrometry; Particulate Matter

The concentration of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were determined in soils and different species of vegetation collected from the Dongting Lake region, China. Use of sodium pentachlorophenate (Na-PCP) was the main contamination source of PCDD/Fs for soil/sediment and vegetation in the Dongting Lake region. Reed (Phragmitas communis Trin), Polygonum orientale L., and Artemisia selengensis Turcz ex Bess were selected as model plants to explore the pathway of PCDD/Fs transfer from contaminated soil to vegetation. In the vegetation tissue samples, the total international toxic equivalency values ranged from 0.14 to 1.64 pg international toxic equivalency/g dry weight with a mean value of 0.67 pg international toxic equivalency/g dry weight. Polychlorinated dibenzo-p-dioxins and dibenzofurans congener distribution and bioaccumulation varied among vegetation species. Polychlorinated dibenzo-p-dioxins and dibenzofuran levels in the leaves were found to be higher than those in the root and stem, which were affected considerably by volatilization from contaminated soil. Volatilization from polluted soil and subsequent sorption to leaves may be a significant pathway for contamination of vegetation in Dongting Lake region.

Topics: Benzofurans; China; Dioxins; Environmental Monitoring; Pentachlorophenol; Plant Structures; Plants; Polychlorinated Dibenzodioxins; Soil Pollutants; Tissue Distribution; Volatilization

Two gas chromatography-mass spectrometry systems equipped with an ion-trap mass analyzer working in tandem mode (GC-MS-MS) were evaluated for the determination of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (PCBs) in food samples. The performance of the two ion-trap instruments, which dispose of an external ion source (ThermoFinnigan GCQ/Polaris) and internal ionization (Varian Saturn 2,200), have been compared in terms of linearity, repeatability, limit of detection and long-term precision. Both instruments provided similar run-to-run and day-to-day precisions, ranging from 2% to 8% and between 2% and 13%, and instrumental limits of detection between 0.09 and 0.36 pg injected for PCDD/Fs and from 0.03 to 0.09 pg injected for dioxin-like PCBs. Although both instruments seem to be suitable for food analysis, only the use of external ionization allowed to achieve reliable results for PCDD/F determination at concentrations close to the maximum residue levels established by the EU for foods. Internal ionization provides high limits of detection (from 10- to 30-fold higher) and worse precision (RSD, 14-43%). In contrast, for dioxin-like PCBs both instruments allowed to obtain excellent results with precisions lower than 15%.

Topics: Animals; Benzofurans; Chickens; Chromatography, Gas; Dioxins; Fish Oils; Food Analysis; Polychlorinated Biphenyls; Quality Control; Solutions; Tandem Mass Spectrometry

Protein tyrosine phosphatase 1B (PTP1B) is an enzyme that plays a critical role in down-regulating insulin signaling through dephosphorylation of the insulin receptor. Inhibitors of PTP1B showed increased insulin sensitivity and normalize plasma glucose level and thus are useful therapeutic agents for the treatment of diabetes. A series of functionalized 4,5-dihydronaphthofurans and dibenzofurans were synthesized, studied through molecular docking and evaluated for their PTP1B inhibitory activity.

Topics: Benzofurans; Binding Sites; Computer Simulation; Crystallography, X-Ray; Inhibitory Concentration 50; Kinetics; Models, Molecular; Molecular Conformation; Naphthalenes; Protein Tyrosine Phosphatases

Isomer-specific data were investigated in order to identify the sources of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in agricultural soils, including Fluvo-aquic and paddy soils, in the vicinity of a Chinese municipal solid waste incineration (MSWI) plant. Homologue and isomer profiles of PCDD/Fs in soils were compared with those of potential sources, including combustion sources, i.e., MSWI flue gas and fly ash; and the impurities in agrochemicals, such as the pentachlorophenol (PCP), sodium pentachlorophenate (PCP-Na) and 1,3,5-trichloro-2-(4-nitrophenoxy) benzene (CNP). The results showed that the PCDD/F isomer profiles of combustion sources and agricultural soils were very similar, especially for PCDFs, although their homologue profiles varied, indicating that all the isomers within each homologue behave identically in the air and soil. Moreover, factor analysis of the isomer compositions among 33 soil samples revealed that the contamination of PCDD/Fs in agricultural soils near the MSWI plant were primarily influenced by the combustion sources, followed by the PCP/PCP-Na and CNP sources. This implication is consistent with our previous findings based on chemometric analysis of homologue profiles of soil and flue gas samples, and identifies PCP/PCP-Na as an additional important source of PCDD/Fs in the local area. This makes the similarities and differences of isomer profiles between Fluvo-aquic and paddy soils more explainable. It is, therefore, advisable to use isomer-specific data for PCDD/F source identifications where possible.

Topics: Agriculture; Benzofurans; China; Incineration; Isomerism; Polychlorinated Dibenzodioxins; Soil Pollutants

Concentrations of 17 polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and 18 polychlorinated biphenyls (PCBs) were measured in 11 varieties of food groups collected from retail market of Shenzhen, Guangdong province, China from 2004 to 2006. PCDD/Fs and PCBs dietary intake from varies food for the local population was estimated in the study.. Concentrations of 17 polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and 12 dioxin-like polychlorinated biphenyls (PCBs) as well as 6 marker PCBs were measured in 11 varieties of food groups in total 110 food samples by isotope dilution HRGC/HRMS. PCDD/Fs and PCBs dietary intake for local population was estimated using total WHO-TEQ concentration and different food consumption amount of the local population.. The median WHO-TEQ concentrations of sum of PCDD/Fs and DL-PCBs varied from 0.0093 pg/g (parts per trillion) in vegetable to 9.89 pg/g in fish. Fish was followed by egg 2.46, chicken 1.73, beef 0.94, mutton 0.82, duck 0.39, pork 0.37, milk powder 0.25, vegetable oil 0.076, cereals 0.022 pg/g and vegetable. The monthly intake of PCDD/Fs and PCBs were 40.9 pg WHO-TEQ/kg b.w. for local population. Sum of fish, livestock, and poultry contributed 77% to the Estimated Monthly Intake (EMI) in local population.. Estimated dietary intake of PCDD/Fs and DL-PCBs for local population was below the provisional tolerable monthly intake(PTMI) set by Joint FAO/WHO Expert Committee on Food Additives (JECFA).

Topics: Benzofurans; China; Diet; Environmental Exposure; Food Contamination; Humans; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins

This study investigates the kinetic parameters of the formation of the chlorophenoxy radical from the 2-chlorophenol molecule, a key precursor to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCCD/F), in unimolecular and bimolecular reactions in the gas phase. The study develops the reaction potential energy surface for the unimolecular decomposition of 2-chlorophenol. The migration of the phenolic hydrogen to the ortho-C bearing the hydrogen atom produces 2-chlorocyclohexa-2,4-dienone through an activation barrier of 73.6 kcal/mol (0 K). This route holds more importance than the direct fission of Cl or the phenolic H. Reaction rate constants for the bimolecular reactions, 2-chlorophenol + X --> X-H + 2-chlorophenoxy (X = H, OH, Cl, O2) are calculated and compared with the available experimental kinetics for the analogous reactions of X with phenol. OH reaction with 2-chlorophenol produces 2-chlorophenoxy by direct abstraction rather than through addition and subsequent water elimination. The results of the present study will find applications in the construction of detailed kinetic models describing the formation of PCDD/F in the gas phase.

Topics: Benzofurans; Chlorine; Chlorophenols; Free Radicals; Gases; Hydrogen; Hydroxides; Kinetics; Oxygen; Phenols; Polychlorinated Dibenzodioxins; Quantum Theory

The concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDFs), and 18 polychlorinated biphenyls (PCBs) were determined in samples of foodstuffs widely consumed by the population of Catalonia, Spain. The dietary intake of PCDD/PCDFs and dioxin-like (DL)-PCBs was subsequently estimated for the population of this Spanish region. These results were compared with those of a previous survey performed during 2000. For PCDD/PCDFs, the highest WHO-TEQ values corresponded to oils and fats (0.223 ng/kg), followed by fish and seafood (0.131 ng/kg) and dairy products (0.057 ng/kg), while the lowest levels were found in fruits (0.003 ng/kg), as well as in vegetables and milk (0.009 ng/kg). For DL-PCBs the highest WHO-TEQ values corresponded to the groups of fish and seafood (0.761 ng/kg) followed by oils and fats (0.169 ng/kg), and dairy products (0.039 ng/kg), while the lowest values were observed in fruits (0.004 ng/kg), and vegetables (0.005 ng/kg) and tubers (0.006 ng/kg). The current dietary intakes of PCDD/PCDFs, DL-PCBs, and PCDD/PCDFs plus DL-PCBs were estimated to be 25.7, 52.4, and 78.1 pg WHO-TEQ/day vs. 95.4, 150.1, and 245.5 pg WHO-TEQ/day found in our previous survey. It means reductions of 73%, 65%, and 68%, for PCDD/PCDFs, DL-PCBs, and PCDD/PCDFs plus DL-PCBs, respectively. The current estimated intake for an adult male, 1.12 pg WHO-TEQ/kg body weight per day, is lower than most intakes recently reported in a number of countries over the world.

Topics: Adolescent; Adult; Age Factors; Aged; Air; Benzofurans; Child; Child, Preschool; Diet; Diet Surveys; Environmental Pollutants; Female; Food Analysis; Humans; Male; Mass Spectrometry; Middle Aged; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Spain

Although many researches focused on the polychlorinated dibenzo-p-dioxins/dibenzofuran (PCDD/F) emissions from stack, in the bottom ash and in the surrounding environment, researches focused on PCDD/F mass distributions in the whole incineration plant have seldom been addressed. This study determined PCDD/F emissions in the whole plant. A high-resolution gas chromatograph/high-resolution mass spectrometer was utilized for analyzing 17 PCDD/F species. Experimental results displayed that PCDD/Fs were formed during fly ash from super heater (SH), economizer (EC), semi-dryer absorber (SDA) and fabric filter (FF) was transferred to fly ash pit. Mass distribution ratios of PCDD/Fs in g I-TEQ (Toxicity Equivalency Quantity) per week from stack, SH, EC, SDA, FF, generation and bottom residue (BR) in start-up operations were 14.6%, 0.1%, 8.3%, 1.0%, 41.7%, 33.4% and 0.9%, respectively. Above results indicated that main PCDD/F source in the MSWI was from fly ash. However, the fly ash is easily controlled and PCDD/F emitted from stack flue gases will be difficult to be handled. Therefore, we should pay more attention on PCDD/F emission from flue gases especially from start-up procedure. Besides, fly ash should be controlled by sodium hypophosphite before being landfilled. MSWI did require further detoxification treatments for the solid residues and flue gases.

Topics: Air Pollutants, Occupational; Benzofurans; Carbon; Coal Ash; Environmental Monitoring; Environmental Pollutants; Incineration; Particulate Matter; Polychlorinated Dibenzodioxins; Refuse Disposal; Taiwan

Thermal treatment technology was used to remove polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from heavily contaminated soil. For a soil with an original PCDD/F content of 35,970ng International Toxic Equivalents (I-TEQ)/kg, >99.99% PCDD/F removal efficiency was obtained with a primary furnace at two different treatment temperatures (750 degrees C and 850 degrees C), while a secondary furnace at 1200 degrees C gave >98% decomposition efficiency. The total PCDD/F I-TEQ contents in treated soils at 750 degrees C and 850 degrees C were 1.56ngI-TEQ/kg and 2.15ngI-TEQ/kg, respectively, which were far below the soil pollution standard of Taiwan (1000ngI-TEQ/kg soil). Although air pollution control devices had significant effects on the removal of PCDD/Fs, the total I-TEQ concentrations in the upstream flue gas of PUF cartridge at 750 degrees C and 850 degrees C (2.61ngI-TEQ/Nm(3) and 2.38ngI-TEQ/Nm(3), respectively) were still higher than the stationary emission limit of the Taiwan EPA (0.5ngI-TEQ/Nm(3)). The above results also suggested that additional APCDs, such as activated carbon injection in front of the filter are needed to enhance PCDD/F removal efficiency.

Topics: Benzofurans; Environmental Restoration and Remediation; Hot Temperature; Polychlorinated Dibenzodioxins; Soil Pollutants; Temperature

Rhodococcus sp. strain HA01, isolated through its ability to utilize dibenzofuran (DBF) as the sole carbon and energy source, was also capable, albeit with low activity, of transforming dibenzo-p-dioxin (DD). This strain could also transform 3-chlorodibenzofuran (3CDBF), mainly by angular oxygenation at the ether bond-carrying carbon (the angular position) and an adjacent carbon atom, to 4-chlorosalicylate as the end product. Similarly, 2-chlorodibenzofuran (2CDBF) was transformed to 5-chlorosalicylate. However, lateral oxygenation at the 3,4-positions was also observed and yielded the novel product 2-chloro-3,4-dihydro-3,4-dihydroxydibenzofuran. Two gene clusters encoding enzymes for angular oxygenation (dfdA1A2A3A4 and dbfA1A2) were isolated, and expression of both was observed during growth on DBF. Heterologous expression revealed that both oxygenase systems catalyze angular oxygenation of DBF and DD but exhibited complementary substrate specificity with respect to CDBF transformation. While DfdA1A2A3A4 oxygenase, with high similarity to DfdA1A2A3A4 oxygenase from Terrabacter sp. strain YK3, transforms 3CDBF by angular dioxygenation at a rate of 29% +/- 4% that of DBF, 2CDBF was not transformed. In contrast, DbfA1A2 oxygenase, with high similarity to the DbfA1A2 oxygenase from Terrabacter sp. strain DBF63, exhibited complementary activity with angular oxygenase activity against 2CDBF but negligible activity against 3CDBF. Thus, Rhodococcus sp. strain HA01 constitutes the first described example of a bacterial strain where coexpression of two angular dioxygenases was observed. Such complementary activity allows for the efficient transformation of chlorinated DBFs.

Topics: Benzofurans; Dioxins; Dioxygenases; DNA, Bacterial; DNA, Ribosomal; Gene Expression Profiling; Magnetic Resonance Spectroscopy; Molecular Sequence Data; Multigene Family; Oxidation-Reduction; Phylogeny; Reverse Transcriptase Polymerase Chain Reaction; Rhodococcus; RNA, Ribosomal, 16S; Salicylates; Sequence Analysis, DNA; Sequence Homology, Amino Acid; Sequence Homology, Nucleic Acid; Substrate Specificity

In spring 2006, an Asian dust storm (ADS) that originated in the deserts of Mongolia and China eventually reached populated areas of East Asia, including Taiwan. The concentrations of total suspended particles (TSP), vapor/solid-phase dioxin-like compounds and metal content in atmospheric aerosols were monitored at two sampling sites in northern Taiwan during the ADS episode: one along the northern coast (Site A), and the other in Taipei city (Site B). The ADS swept across northern Taiwan from 13 March to 19 March, 2006. Data indicate that the atmospheric dibenzo-p-dioxin and dibenzofuran (PCDD/F, 32.2 to 52.5 fg-I-TEQ/m(3)) and polychlorinated biphenyl (PCB, 2.23 to 4.49 fg-TEQ(WHO)/m(3)) concentrations measured at the two sampling sites prior to the ADS episode were considerably lower than those measured in other Asian countries. However, measurements made at both sites on 13 and 18 March 2006 indicate that the atmospheric PCDD/F and PCB concentrations increased 2.5 and 3.2 times at Site A, and 2.1 and 1.9 times at Site B, respectively, during the ADS episode. The concentrations of aluminum (Al), potassium (K) and Titanium (Ti) in atmospheric aerosols were also found to increase about 2 to 5 times during this period. As no specific dioxin emission sources exist within nearly 20 km of Site A, the increase in PCDD/F and PCB concentrations observed there is likely to be related to the ADS from mainland China. Additionally, the amount of PCDD/Fs bound to suspended particles increased from 257-259 to 339-512 pg-I-TEQ/g-TSP during the ADS episode. The distribution of OCDD congener observed in Taipei city increased dramatically during the ADS episode, however, the distribution of PCB congener did not vary significantly.

Topics: Air Movements; Air Pollutants; Benzofurans; China; Cities; Disasters; Dust; Environmental Monitoring; Geography; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Risk Assessment; Taiwan; Time Factors

The effect of heavy metals on the degradation of dibenzofuran by Sphingomonas wittichii RW1 was determined in liquid cultures. The results showed that 10mg/L cadmium, mercury and copper not only affected the growth of RW1 with dibenzofuran but also the ability of resting cells to degrade this compound. Growth and degradation were strongly inhibited by mercury, even at 1mg/L, while the inhibitory effect of cadmium and copper at the same concentration or at 5mg/L were negligible. In contrast, arsenic and lead did not affect degradation or growth, even at very high concentrations of 100mg/L. Subsequent analyses additionally revealed that concentrations of arsenic and lead remained unchanged following incubation, while those of cadmium, mercury and copper decreased significantly.

Topics: Benzofurans; Biodegradation, Environmental; Cadmium; Copper; Mercury; Metals, Heavy; Solutions; Sphingomonas

Farmed fish can be exposed to persistent organic contaminants--such as polychlorinated biphenyls (PCBs), dibenzodioxins (PCDDs), and dibenzofurans (PCDFs)--via feed, this eventually resulting in accumulation levels of health concern. To study the correlation between feed contamination, chemical accumulation in fish muscle (fillet), and chemical depletion, an all-vegetal base (or blank) feed was prepared and fortified with a commercial PCB mixture (Aroclor 1254) and six PCDD and PCDF congeners (namely, 2,3,7,8-T(4)CDD, 2,3,7,8-T(4)CDF, 1,2,3,7,8-P(5)CDD, 1,2,3,7,8-P(5)CDF, O(8)CDD, and O(8)CDF) to reproduce realistic low, medium, and high contamination levels. After a 1-month exposure, trout (Oncorhynchus mykiss) were fed with the blank feed and sacrificed every 0.5 months over a 3-month period from exposure end; fillet specimens were sampled at each time. In all groups, the average fish weight increased linearly through the observation period. The chemical diminishing patterns observed were due to the combined effect of clearance and growth dilution: for 10 PCB and four PCDD and PCDF congeners, patterns were described with an empirical one-compartment (fish muscle) model. The canonical pseudo-first-order kinetic equation used was also modified into the form C=[C(0)exp(-k(C)t)] (m(W)t+1)(-1) to distinguish between the contributions to depletion from clearance, exp(-k(C)t), and growth dilution, (m(W)t+1)(-1). Most mean clearance half-life (HL(C)) estimates appear to be greater than 4 months, in a number of cases reaching magnitudes well over 10 months or even negative, thus clearly indicating a non-negligible contribution from a second compartment. Based on means and their 95% confidence intervals, the depletion HL(D) estimates of the 14 selected congeners seem to be comprised between 1.2-3.4 and 1.0-5.0 months, respectively: these values, accounting for both clearance and growth dilution, provide an indication of the relevance of a blank feed as a management option to reduce the overall PCB, PCDD, and PCDF content in farmed trout. Due to a lack of bioaccumulation, O(8)CDD and O(8)CDF yielded no results for evaluation, whereas for many PCB congeners results were insufficient for empirical modelling.

Topics: Animal Feed; Animals; Aquaculture; Benzofurans; Dioxins; Food Contamination; Half-Life; Oncorhynchus mykiss; Polychlorinated Biphenyls; Risk Management

Concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyl (PCBs) and polycyclic aromatic hydrocarbons (PAHs) have been determined using GC/HRMS in food (butter, seafood and meat) and feed samples (chicken, cattle and fish) purchased from Ismailia city, Egypt. PCDD/F concentrations in food samples ranged between 0.12 and 3.35 pg WHO TEQ/g wet w, while those in feed samples were between 0.08 and 0.2 pg WHO TEQ/g dry w. Levels of PCB TEQ ranged from 0.14 to 3.2 pg/g wet w in the food samples. The feed samples have an average of 0.35 pg PCB TEQ /g dry w. In this study, butter samples showed the highest contamination levels of PCDD/Fs and PCBs. The PCBs contribution to the total TEQ was on average 63% in seafood and on average 49% for meat and butter. The highest contamination levels of PCDD/Fs and PCBs were found in butter samples. The butter TEQ content is several times higher than that reported in all EU countries and exceeded the EU limits, while the PCDD/F levels in seafood and the feed samples is far below the current EU limit. Generally, congener profiles in the food samples reflect the non-industrialized nature of the city and suggest solid waste burning as a significant source of emission. Nevertheless, the profiles for butter suggest an impact from various sources. In the case of the sum of 16 PAH contamination levels in food samples were in the range of 11.7-154.3 ng/g wet w and feed samples had a range of 116-393 ng/g dry w. Benzo(a)pyrene (BaP) has been detected in the range of 0.05-3.29 ng/g wet w in the food samples; butter showed the highest contamination which exceeded the EU standard set for fats and oil. Fingerprints of PAHs suggested both petrogenic and pyrolytic sources of contamination.

Topics: Animal Feed; Animals; Benzofurans; Butter; Cattle; Chickens; Egypt; Environmental Monitoring; Food Contamination; Meat; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Polycyclic Aromatic Hydrocarbons; Seafood

The aim was to determine the body burden of dioxins and polychlorinated biphenyls (PCBs) and whether they are associated with variables influencing reproduction. Our subjects were healthy women (mean age of 29 [SD=4.5]) from central Taiwan. The congeners of dioxins and dioxin-like PCBs in placentas (n=119) were identified using gas chromatography/high resolution mass spectrometry. The median levels of polychlorinated dibenzo-p-dioxins/dibenzofurans and PCBs were 10.2 (geometric mean [GM]: 9.8, 95% confidence interval [95% CI]: 8.8-10.9) and 2.7 (GM: 2.7, 95% CI: 2.3-3.1) pg WHO-TEQ/g lipid, respectively. Total TEQ level in placentas was significantly correlated with mothers' arm circumference (r=0.22, p=0.043). Increased body fat percentage was associated with higher total TEQ level in placentas. After adjustment for maternal age, pre-pregnant body mass index (BMI), and parity, placental dioxin-TEQ level higher in women (age 19 years) with irregular menstrual cycle than in those (age <18 years) with regular menstrual cycle (p=0.032) and placental PCB-TEQ level was higher in women with menstrual cycles longer than 33 days versus less than 33 days (p=0.006). Thus, environmental exposure to dioxins and PCBs may be related to changes in current menstrual cycle characteristics.

Topics: Adipose Tissue; Adult; Age Factors; Analysis of Variance; Benzofurans; Body Burden; Confidence Intervals; Dioxins; Environmental Exposure; Environmental Pollutants; Female; Gas Chromatography-Mass Spectrometry; Humans; Menarche; Menstrual Cycle; Placenta; Polychlorinated Biphenyls; Pregnancy; Prenatal Exposure Delayed Effects; Surveys and Questionnaires; Taiwan

Paddy soils and sediments from the Yoneshirogawa, Omonogawa, and Koyoshigawa River Basins in Akita were analyzed for polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). The levels and compositions in those samples including soils from non-agricultural areas (non-agricultural soils) were investigated using isomer-specific analysis to determine characteristic sources. The PCDD/PCDF compositions in the samples were compared with respect to possible sources. The PCDD/PCDF concentrations in paddy soils were much higher than those in the non-agricultural soils and much higher than those found in other parts of Japan. Although PCDD/PCDFs were ubiquitous in sediments from river sources to mouths of the respective river basins, those concentrations were much lower than those from paddy soils and non-agricultural soils, and from other parts of Japan. Comparison of PCDD/PCDF homologues and isomer compositions for samples indicated that compositions of paddy soils and sediments, except for those from river sources, had similar characteristics to PCDD/PCDFs originating from impurities in herbicides, 2,4,6-trichlorophenyl 4-nitrophenyl ether (CNP) and pentachlorophenol (PCP), and that compositions of river-source sediments and non-agricultural soils resembled those of atmospheric depositions. Results of statistical analyses suggest that PCDD/PCDF contamination of paddy soils and sediments is attributable mainly to three sources: CNP, PCP, and atmospheric deposition. Results of this study also demonstrate that CNP and PCP are not only important contaminants of local areas of Japan, but that they exist throughout Akita, in northern Japan. We therefore conclude that PCDD/PCDF pollution caused by those compounds has a widespread influence on paddy soils and river sediments in Japan.

Topics: Benzofurans; Geologic Sediments; Isomerism; Japan; Polychlorinated Dibenzodioxins; Principal Component Analysis; Rivers; Soil Pollutants

Selective pressurized liquid extraction (PLE) of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) from various food and feed samples was performed with a selective PLE method previously developed for bulk PCBs. The method utilizes sulfuric acid impregnated silica inside the extraction cell to oxidize coextracted fat. Extractions were performed at 100 degrees C with n-heptane for 5 min in two cycles. Data obtained by selective PLE combined with gas chromatography/high-resolution mass spectrometry (GC-HRMS) were compared to concentrations derived from reference laboratories applying conventional sample preparation and GC-HRMS. Experiments performed on spiked vegetable oil, naturally contaminated crude fish oil and oil containing compound feed samples showed good results for these relatively simple matrices. The accuracy was generally +/-20% as compared to spiked levels or to values obtained by the reference laboratories. The precision, measured as the relative standard deviation (RSD) for 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalency values (TEQs), was below 10% in all cases. The method was also tested on naturally contaminated herring tissue, chicken tissue, pork tissue and sepiolitic clay, which all caused some trouble. It was observed that sufficient amounts of sodium sulfate should be used for dehydration of tissue samples and additionally, the cells should not be packed too dense in order to avoid suppressed extraction efficiency. Once this was attended to, satisfactory data could be obtained, except for sepiolithic clay. This study demonstrates that selective PLE can be applied with success to a number of food and feed matrices in analysis of PCDD/Fs and dl-PCBs. Since the fat removal step is on-line, the selective PLE method will reduce time and solvent consumption for sample preparation as compared to traditional clean-up.

Topics: Benzofurans; Dioxins; Food Analysis; Gas Chromatography-Mass Spectrometry; Meat Products; Plant Oils; Polychlorinated Biphenyls; Reproducibility of Results

Concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) and other organic micropollutants were determined in dated sediment/soil cores collected from the flood-plain of the river Elbe near Pevestorf (PT), approximately 125 km upstream of Hamburg, and Heuckenlock (HL) in southeast of Hamburg. Concentrations of PCDD/Fs peaked sharply at PT in the 1950s and at HL at the end of the 1940s. Cluster analyses provide evidence that the region of Bitterfeld-Wolfen (about 350-400 km upstream of Hamburg) could be the source of the PCDD/F contamination existing in the cores PT and HL since the 1940s. Obviously it is caused by sediments of the river Elbe of a similar composition. Whereas the PCDD/Fs, HCHs (hexacyclohexane isomers), DDX (DDT, DDD, DDE), and tetrachlorinated ethers in PT and HL presumably originated predominantly from the Bitterfeld-Wolfen region, organotin compounds in HL and dichlorinated haloethers in HL during the 1940s and 1950s can probably largely be attributed to emissions from the Hamburg region. Although they are separated by a large distance, in both sediment cores PT and HL concentrations and composition patterns of most organic micropollutants analyzed widely match. Inductively it can be concluded that similar contaminations will be found in many of the river bank soils between the Bitterfeld-Wolfen region and Hamburg. Excavation of top soils may uncover highly contaminated materials. Since the dated sediment cores show the variation in contaminants in the Elbe sediments over a defined time period, it is possible to make an approximate assessment of the actual degree of contamination to be expected in areas where in previous decades contaminated dredged sediments from the Elbe and from the Port of Hamburg have been deposited on land and used for building plots or for agricultural purposes.

Topics: Benzofurans; Chlorobenzenes; Geologic Sediments; Germany; Hydrocarbons, Chlorinated; Organotin Compounds; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Polycyclic Aromatic Hydrocarbons; Rivers; Soil Pollutants

Concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in dietary sources for humans have been declining over the previous two decades. These declines have been accompanied by decreases in concentrations of these compounds in humans, as evidenced by measurements in blood and milk. Because of the decreasing concentrations of PCDD/PCDFs in the environment and in humans, measuring PCDD/PCDF congeners in humans has become increasingly difficult, despite advances in analytic methods. An observational approach was recently described to address the quandary of non-detectable results in determining toxic equivalents. This approach, called the congener ratio approach, is specifically for cases where concentrations of 2,3,7,8-TCDD (TCDD) are below the limit of detection (LOD), and where concentrations of 1,2,3,7,8-pentachlorodibenzo-p-dioxin (PeCDD) are equal to or above the LOD. Development of this approach relied on evaluating data on measured concentrations of TCDD and PeCDD in human serum from the general population. The congener ratio approach for TCDD and PeCDD was based on the concentration of TCDD being approximately 40% that of PeCDD in serum from the general population. Additional analyses presented here reveal that when concentrations of both congeners are above the LOD, the data appear to generally support the congener ratio approach for TCDD and PeCDD, with the caveat that gender may affect the ratio. However, the TCDD/PeCDD relation is less clear when TCDD is less than the LOD; in this situation, the relation overpredicts levels of TCDD approximately 80% of the time for the 2001-2002 NHANES database. Using the congener ratio approach for other PCDD/PCDF congeners requires assessing the correlation and the frequency of detection for both TCDD and PeCDD.

Topics: Adolescent; Adult; Age Factors; Australia; Benzofurans; Environmental Exposure; Female; Humans; Isomerism; Male; Middle Aged; New Zealand; Nutrition Surveys; Polychlorinated Dibenzodioxins; Sensitivity and Specificity; Sex Factors; United States

The aim of this study was to measure, 6 years after regular operations, the concentrations of a number of organic substances in blood and urine of 19 workers employed at a hazardous waste incinerator (HWI) in Spain, and to establish the temporal variation with respect to baseline data and previously performed surveys. This facility was the first, and so far the only HWI in that country. The levels of hexachlorobenzene (HCB), polychlorinated biphenyls (PCB 28, 52, 101, 138, 153 and 180) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were analyzed in six composite plasma samples, while concentrations of di-, tri, and pentachlorophenols, as well those of 1-hydroxypyrene were measured in the urine of these workers. The current mean PCDD/F concentration, 10.4 ng I-TEQ/kg lipid, was significantly lower than that found in the baseline survey, 26.7 ng I-TEQ/kg lipid and similar to that found in the previous (2004) study (7.7 ng I-TEQ/kg lipid). PCDD/F levels in plasma were similar or even lower than those recently reported for various non-exposed populations. For the remaining analyzed substances in plasma and urine, there was not any significant increase in comparison with the levels found in the baseline survey. On the other hand, no marked differences between the concentrations of organic substances in plasma or urine were found according to the respective workplace (plant, laboratory and administration). The results of the present survey indicate that after 6 years of regular operation, the workers at the HWI are not occupationally exposed to PCDD/Fs and other organic substances in their workplaces.

Topics: Adult; Benzofurans; Female; Hazardous Waste; Hexachlorobenzene; Humans; Incineration; Male; Occupational Exposure; Polychlorinated Dibenzodioxins

The application of high resolution gas chromatography in combination with low resolution mass spectrometry with electron ionization and MS/MS detection (HRGC-MS/MS) is tested for its use in the analysis of PCDD/Fs in infant formulas. Development of the analytical method was based upon EPA directrices and international recommendations. Calibration linearity was tested and average relative response for any native and labelled compound over the five-point calibration range below 14% was found. The precision and accuracy of the proposed analytical procedure are also presented. Results obtained are in agreement with EPA criteria. The method is applied to the analysis of a number of initial and follow-on milk based infant formulas. In general, HRGC-MS/MS constitutes an interesting method for the analysis of dioxins in such matrices.

Topics: Benzofurans; Gas Chromatography-Mass Spectrometry; Infant Formula; Polychlorinated Dibenzodioxins; Reproducibility of Results; Tandem Mass Spectrometry

The applicability of 13 different GC columns (Agilent HP-5MS, Restek Rtx-5MS, Rtx-Dioxin2, Supelco Equity 5, SP-2331, Varian VF-5MS, CP-Sil 8 CB LowBleed/MS, J&W Scientific DB-5, DB-225, DB-XLB, DB-5MS, Phenomenex ZB-5MS, and ZB-5UMS) for US Environmental Protection Agency (EPA) methods 1613b, 8290 and European Standard Method EN 1948 for measurement of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) has been evaluated for the separation of all International Toxic Equivalent Factor (I-TEF) isomers (tetra- through octachlorinated at 2,3,7,8 positions) from closely eluting isomers using high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). The relative performance data are compared based on mass chromatograms using a "visualization approach", absolute retention times, 2,3,7,8-substituted, total dioxins and furans concentrations, as well as TEQ comparisons. None of the columns tested were able to separate all 17 I-TEFs from other co-eluted isomers. Our data indicate that all I-TEFs isomers can be fully differentiated from closely eluting isomers using either of two sets of non-polar and polar stationary phase combinations. One set consists of DB-5 (HP-5MS, Rtx-5MS, Equity-5) and DB-225 GC columns and another set would have a combination of DB-5MS (ZB-5MS, VF-5MS, CP-Sil 8 CB LowBleed/MS) with SP-2331. However, depending on the source of PCDDs/PCDFs a laboratory could choose a single GC column that separates the 2,3,7,8-substituted congeners that contribute most significantly to the overall TEQ. These data are the most comprehensive to date, provide a valuable addition to operational criteria for the standard EPA methods 1613b, 8290, European Standard Method EN 1948 and will allow researches to compare data generated according to the different compliance analytical procedures.

Topics: Benzofurans; Chromatography, Gas; Dioxins; Mass Spectrometry; Polychlorinated Dibenzodioxins

In this paper, the co-combustion behaviour of coal with wastes and biomass and the related toxic gaseous emissions were investigated. The objective of this work is to add on towards a cleaner co-combustion of lignite-waste-biomass blends by utilizing compounds that could inhibit the formation of toxic pollutants. A series of co-combustion tests was performed in a pilot scale incinerator, and the emissions of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were measured. The co-combustion behaviour of lignite with olive kernels, MDF and sawdust was studied and the ability of additives such as urea, almond shells and municipal sewage sludge to reduce the PCDD/F emissions was examined. All blends were proven good fuels and reproducible combustion conditions were achieved. The addition of inhibitors prior to combustion showed in some cases, relatively high PCDD/F emissions reduction. Among the inhibitors tested, urea seems to achieve a reduction of PCDD/F emissions for all fuel blends, while an unstable behaviour was observed for the others.

Topics: Air Pollutants; Air Pollution; Benzofurans; Biomass; Cities; Coal; Incineration; Polychlorinated Dibenzodioxins; Urea; Waste Management

We modified our prior age-dependent half-life model to characterize the range of child (ages 0-7) body burdens associated with dietary and environmental exposure to polychlorodibenzodioxins and furans (PCDD/Fs). Several exposure scenarios were evaluated. Infants were assumed to be either breast-fed or formula-fed from birth to 6 months of age. They then received intakes of PCDD/Fs through age 7 from foods based on weighted means estimates [JECFA, 2001. Joint FAO/WHO Committee on Food Additives. Fifty-seventh meeting, Rome, June 5-14 , 2001, pp. 24-40], and with or without exposures (ingestion and dermal) to urban residential soils at 1ppb TCDD toxic equivalents (TEQ). A one-compartment (adipose volume) toxicokinetic model for TCDD described by Kreuzer [Kreuzer, P.F., Csanady, Gy.A., et al., 1997. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and congeners in infants. A toxicokinetic model of human lifetime body burden by TCDD with special emphasis on its uptake by nutrition. Arch. Toxicol. 71, 383-400] was expanded to include the key non-TCDD congeners in human breast milk and adipose tissues, and two model parameter refinements were examined: (1) use of updated and more detailed age-correlated body fat mass data [CDC, 2000. Centers for Disease Control. CDC Growth Charts: United States. Advance Data from Vital and Health Statistics of the Centers for Disease Control and Prevention, National Center for Health Statistics, Number 314, December 2000]; (2) use of breast milk PCDD/F concentration data from sampling completed in 2000-2003 [Wittsiepe, J., Fürst, P., et al., 2004. PCDD/F and dioxin-like PCB in human blood and milk from German mothers. Organohalogen Compd. 66, 2865-2872]. The updated body fat mass data nearly halved the predicted peak body burden for breast-feeding and lowered the time-weighted average (TWA) body burdens from ages 0-7 by 30-40% for breast-fed and formula-fed infants. Combined use of the updated breast milk PCDD/F concentration and body fat mass data increased the contribution of breast-feeding but reduced TWA body burdens from diet and soil. We conclude that further refinements are needed, but reliance on these better data sets for body fat mass and breast milk PCDD/F concentration significantly improves the model's ability to accurately predict body burdens during early childhood.

Topics: Adipose Tissue; Age Factors; Benzofurans; Body Burden; Child; Child, Preschool; Environmental Exposure; Environmental Pollutants; Food Contamination; Half-Life; Humans; Infant; Milk, Human; Models, Biological; Polychlorinated Dibenzodioxins; Time Factors

Concentrations of 17 dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) and 12 dioxin-like polychlorinated biphenyls (dl-PCBs) were measured in total diet study samples of 14 food groups of animal origin from 11 locations in Taiwan, collected in 2003. Pork meat possessed the lowest background concentration level of 0.058 pg WHO-TEQ(PCDD/Fs+dl-PCBs)/g fresh weight. The dl-PCBs contribution were 31%, 59%, 36%, 46%, and 13% for meat and meat products, muscle meat of fish, milk and dairy products, fat and oil, and egg, respectively. The estimated monthly intake (EMI) was 44.7 and 39.5 pg WHO-TEQ(PCDD/Fs+dl-PCBs)/kg b.w./month for a male and female adult weighing 64.8 kg and 56.3 kg, respectively. Muscle meat of fish contributes 46% to the mean EMI. Factors affecting the EMI, in order of increasing importance are analytical method uncertainty, sample compositional difference, and food consumption data. In addition to the continuous efforts to identify and reduce the source of PCDD/Fs and dl-PCBs releases into the environment and the food-chain, the practice of a healthy dietary habit, i.e., eating foods of lower TEQ levels, was suggested to effectively reduce human exposure to PCDD/Fs and dl-PCBs.

Topics: Adult; Animals; Benzofurans; Dairy Products; Diet; Environmental Pollutants; Female; Fish Products; Food Contamination; Geography; Humans; Meat Products; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Taiwan; Time Factors

Decay kinetics resulting from the application of UV and UV/H(2)O(2) to the polycyclic aromatic hydrocarbons (PAHs) fluorene, dibenzofuran and dibenzothiophene was studied. Batch experiments were conducted with both low-pressure monochromatic (253.7nm) and medium pressure polychromatic (200-300nm) UV sources alone or in the presence of up to 25mg/L hydrogen peroxide, in a quasi-collimated beam apparatus. Degradation of all three PAHs, by both UV and UV/H(2)O(2), exhibited pseudo-first-order reaction kinetics and low quantum yields ranging from 1.4x10(-3) to 1.8x10(-2)mol/E using both UV lamps. Toxicity testing using a bioluminesence inhibition bioassay was correlated to the decay in concentration of the PAHs as analyzed analytically using HPLC. Results demonstrated that treatment efficacy of oxidative PAH degradation measured by following the decay of the target compound is best complemented by also evaluating the toxicity of the treated water due to byproduct formation concerns.

Topics: Aliivibrio fischeri; Benzofurans; Carcinogens; Chromatography, High Pressure Liquid; Fluorenes; Hydrogen Peroxide; Kinetics; Luminescent Measurements; Photolysis; Polycyclic Aromatic Hydrocarbons; Thiophenes; Ultraviolet Rays; Water Pollutants, Chemical

Blood samples of pregnant women aged between 19 and 42 years at the time they gave birth and milk samples from the same women following delivery were collected between September 2000 and January 2003 from 169 participants living in an industrialized area of Germany (Duisburg birth cohort study). All samples were analyzed for their content of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) as well as dioxin-like and indicator polychlorinated biphenyls (PCB). Levels of WHO-TEq were in the range of 4.34-97.3 pg/g(lipid base) (median: 26.37, arithmetic mean: 28.36) for blood, or 3.01-78.7 pg/g(lipid base) (median: 26.40, arithmetic mean: 27.27) for milk, respectively. The four congeners 12378-PeCDD, 23478-PeCDF, 33'44'5-PeCB (# 126) and 233'44'5-HxCB (# 156) contribute the main share to total WHO-TEq. The contribution of PCDD/F in relation to PCB to total WHO-TEq was 60:40% in blood and 52:48% in milk. Good correlations of the contaminant levels in lipid base between both matrices were found. The distribution between blood and milk depends on the molecular weight of the substances. Higher chlorinated PCDD/F- and PCB-congeners were found in 2-4-fold higher concentrations in blood in relation to milk and the concentrations of lower chlorinated PCB-congeners were up to 2-fold higher in milk in relation to blood. The body burden of PCDD/F and PCB increases with age and decreases over the total nursing period. Women who had lived outside highly industrialized countries showed lower concentrations of PCDD/F and PCB. In some cases, elevated levels of PCB were observed when the women had previously lived in Eastern Europe for a long time. In comparison with recent data, the decline in human PCDD/F and PCB levels observed during the nineties seems to have stopped. The individual exposures of the infants due to breastfeeding within the first 18 months were calculated to be from 4.4 to 318 ng WHO-TEq (median: 106, arithmetic mean: 118). The actual mean daily exposure of a breastfed infant can be estimated to 131 pg WHO-TEq/kg(body weight).

Topics: Adult; Benzofurans; Blood Chemical Analysis; Breast Feeding; Environmental Pollutants; Female; Germany; Housing; Humans; Industry; Infant; Milk, Human; Molecular Weight; Mothers; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Time Factors

Incremental lifetime health risks due to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) emitted from municipal waste incineration (MSWI) facilities were evaluated for resident population in the area of the plant. Risk assessment was performed through a multipathway combined probabilistic/deterministic approach for analyzing the effects of uncertainty and intrinsic variability of the main PCDD/F emission related parameters on final predicted values. Exposure through direct inhalation of contaminated air, soil ingestion, soil dermal contact and diet were considered, with the propagation of the variability of input parameters throughout the evaluation performed with Monte Carlo simulation techniques. The application to a case study representative of two different technological scenarios (modern facilities equipped with BAT - Best Available Technology - and older incinerators) in a location site typical of Northern Italy situation results in median values of the maximum individual excess risk on the order of 10(-9) and 10(-7) for most recent and older plant configurations, respectively. Corresponding ratios for the 90th and 10th percentile values are around 7 and 9. Individual risk estimates derived for the same scenarios from conventional deterministic approaches, where large conservative assumptions are normally adopted for compensating the lack of knowledge about uncertainty, are essentially comparable with maximum values resulting from the probabilistic approach, thus leading to situations with extreme and very low probabilities of occurrence. PCDD/F health risks from MSWI emissions might thus result largely overestimated if real emission characteristics are not properly considered in the assessment procedure. Sensitivity analysis for identifying the contribution of different input parameters on final predicted risk variance indicates, for the area considered in the simulation, a prevailing influence of PCDD/F stack concentration, with exposures arising from soil deposition phenomena substantially negligible: this latter result further points out the requirements for a very careful identification of base input data values for PCDD/F stack concentrations, at least for those situations where plants are located nearby urban areas.

Topics: Air Pollutants; Benzofurans; Cities; Environmental Exposure; Housing; Humans; Incineration; Italy; Monte Carlo Method; Polychlorinated Dibenzodioxins; Public Health; Risk Assessment

For the general population the intake of food of animal origin is the main route of human exposure to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F). Besides this the ingestion of contaminated soil might be an important exposure path for small children. For risk assessment the knowledge of the bioavailable fraction of soil bound contaminants is important. In a balance study with young Goettingen minipigs the oral bioavailability of PCDD/F from contaminated soil was estimated by determination of the retention of PCDD/F from soil in different organs and tissues. Relative bioavailability was estimated by comparing the retention from soil to the retention of PCDD/F in organs and tissues after oral administration of a PCDD/F mixture extracted from the same soil by solvent. The soil had a PCDD/F-contamination of 5.3 microg I-TEq/kg and originated from a former arable land that had been treated with sludge from the port of Hamburg some years ago. Two groups of each four animals were exposed daily for 28 days via their diet either to 0.5 g soil per kg body weight and day (2.63 ng I-TEq/(kg(bw).d)) or to a daily dose of 1.58 ng I-TEq/(kg(bw).d) given to the diet by solvent. Five unexposed animals were used as a control group. Liver, adipose tissue, muscle, brain and blood were analyzed for their PCDD/F content. Accumulation of PCDD/F from soil or solvent in comparison to control animals was only observed for congeners with 2378-chlorosubstitution and predominantly took place in the liver. Bioavailability of 2378-chlorosubstituted congeners was in the range of 0.64%-21.9% (mean: 10.1%) from soil and 2.8%-59.8% (mean: 31.5%) when administered by solvent. The soil matrix reduced the bioavailability by about 70%. Expressed as I-TEq only 13.8% of the PCDD/F contamination were bioavailable from soil. The relative bioavailability of 2378-chlorosubstituted congeners from soil in relation to administration by solvent was in the range of 2%-42.2% (mean: 28.4%). When not considering the bioavailability, the risk by oral uptake of PCDD/F contaminated soil might be overestimated.

Topics: Adipose Tissue; Administration, Oral; Age Factors; Animal Feed; Animals; Benzofurans; Biological Availability; Blood; Body Weight; Cities; Germany; Polychlorinated Dibenzodioxins; Risk Assessment; Soil Pollutants; Solvents; Swine; Swine, Miniature; Time Factors; Tissue Distribution

Minimum structures and harmonic vibrational frequencies of dibenzofuran (DF), 2,3,7,8-tetrachlorodibenzofuran (TCDF), and octachlorodibenzofuran (OCDF) were calculated using the multiconfigurational complete active space self-consistent field (CASSCF) and density functional theory (DFT) methods. The electronic transitions in these compounds were studied via the single-state multireference second-order perturbation theory (CASPT2) based on the CASSCF(14,13) references, as well as the time-dependent DFT (TD-B3P86) employing the cc-pVDZ (CASSCF/CASPT2) and 6-31G(d,p) (TD-B3P86) basis sets. The B3P86 geometry and harmonic vibrational frequencies of ground state DF agree very well with the experimental data, and the CASSCF/CASPT2 excitation energies and oscillator strengths are accurate enough to provide a reliable assignment of the absorption bands in the 200-300 nm region. The close agreements with experiment for the parent DF give the present theoretical approaches a valuable credit in predicting the properties of the environmentally toxic polychlorinated congeners, which is all the more important considering the difficulties and hazards in obtaining the experimental data.

Topics: Benzofurans; Dibenzofurans, Polychlorinated; Electrons; Mathematics; Models, Molecular; Molecular Conformation; Vibration

This study determined the concentrations of organochlorine contaminants in common seafood in two Chinese coastal cities (Guangzhou and Zhoushan), and assessed the health risk due to the daily consumption of contaminated seafood. Twenty-six pooled samples, belonging to five food categories (fish, bivalves, shrimp, crab, and cephalopods), were purchased from local markets in Guangzhou and Zhoushan in 2003 and 2004. These samples were analyzed for total polychlorinated biphenyls (PCBs), non- and mono-ortho-PCBs (coplanar PCBs), polychlorinated naphthalenes (PCNs), and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/DFs). The concentrations of total PCBs and coplanar PCBs in fish samples were higher in Guangzhou than in Zhoushan, while the levels of PCNs and PCDDs/DFs were comparable between the two cities. The total daily intake values of dioxin-like compounds were 1.05 and 0.86pg WHO-TEQ/kg body weight in Guangzhou and Zhoushan, respectively. Hazard ratios of non-cancer risk in the two cities were all less than unity.

Topics: Benzofurans; China; Environmental Pollutants; Food Contamination; Humans; Hydrocarbons, Aromatic; Naphthalenes; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Polycyclic Aromatic Hydrocarbons; Risk Assessment; Seafood

In this study, agriculture soil in Taiwan has been sampled and analyzed to determine the background level of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/DF) in the agricultural and nature preserve areas. Another objective is to investigate relationship between soil characteristics and air deposition in Taiwan. The results indicate that in nature preserve areas the topsoil shows an extraordinary profile of PCDD/DF compared to that in the air deposition. The PCDD/DF levels of the low-contaminated agricultural soils are compatible with those of the nature preserves soils. However, in the highly-contaminated agricultural soils, there is an abrupt jump in their concentrations, 10-100 times higher. The overall I-TEQ values of the background topsoils range from 0.101 to 15.2 ng I-TEQ/kg. Near industrial/urban areas in Taiwan the PCDD/DF are slightly higher compared to those in the low concentration group. Typically, the PCDD/DF background values found in this survey fall in the 90% confidence interval and can thus, be deemed the background levels in Taiwan. Ninety-five percent of these data are below the European and American soil standard of 10 ng I-TEQ/kg d.w. The PCDD/DF profile with one neighborhood soil sample was shown no significant difference.

Topics: Agriculture; Air; Benzofurans; Dioxins; Ecosystem; Industrial Waste; Polychlorinated Dibenzodioxins; Soil; Soil Pollutants; Taiwan; Urbanization

Recent efforts have been made to establish readily measurable surrogate compounds, such as chlorophenols, for polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), that would enable plant operations to limit formation. Despite the extensive studies conducted on PCDDs/Fs formation from chlorophenols, very few studies have been carried out in real combustion conditions with a realistic concentration of precursors and the presence of water. In the present study, low (10(-9) M), stable concentrations of chlorinated phenols that are representative of concentrations of such compounds in municipal waste incinerator (MWI) raw flue gas were used in experiments investigating the formation of PCDDs/Fs over fly ash. Different mixtures of the chlorophenols (CPs) studied (2-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, and 2,3,4,6-tetrachlorophenol) were passed through a bed of oxidized fly ash (carbon-free) and glass beads with and without the presence of water. The chlorophenol reactants used in this study were found to favor PCDD over PCDF formation. The presence of water was observed to considerably reduce the yields of all PCDD/F formed (< 0.3% phenol conversion). The PCDD homologue and isomer distributions were not affected by the presence of water, unlike the PCDF compounds. The major PCDD homologue groups formed were tetra- and penta-, both with or without water in the gas stream. The major PCDF homologue groups were mostly the lower chlorinated ones in the experiments performed in the presence or absence of water. These results contribute to the understanding of PCDD/Fs formation in realistic combustion conditions, including very low concentrations of precursors and the presence of water in the flue gas.

Topics: Benzofurans; Carbon; Chlorophenols; Cities; Coal Ash; Environmental Pollutants; Gases; Incineration; Particulate Matter; Polychlorinated Dibenzodioxins; Waste Products; Water

Waste printed circuit boards containing brominated flame retardants were pyrolyzed in a high-temperature melting system to observe the formation behaviors of polybrominated dibenzo-p-dioxins (PBDDs) and dibenzofurans (PBDFs). In this study, the results showed that the formation of PBDD/ Fs during pyrolysis can be destroyed under controlled primary combustion conditions. There were two significant factors that influenced the extent of PBDD/F formation. The first factor was temperature. The results showed that, both the total PBDD/F content in the bottom ash and the total PBDD/F emission factor from the flue gas decrease by approximately 50% with an increase of the pyrolysis temperature from 850 to 1200 degrees C. The second factor was the addition of CaO. The possible mechanism involves the reaction between CaO and HBr to form the solid-phase product CaBr2. Thus, the addition of CaO is effective in adsorbing HBr and results in the inhibition of PBDD/F synthesis by more than 90% and further prevents the acid gases (HCl and HBr) that corrode the equipment. In conclusion, due to the persistence and toxicity of PBDD/Fs, a combined regulation for controlling both PCDD/Fs and PBDD/Fs is of great importance for environmental protection issues.

Topics: Air Pollutants; Benzofurans; Bromides; Calcium Compounds; Environmental Monitoring; Hydrobromic Acid; Hydrochloric Acid; Incineration; Kinetics; Oxides; Polychlorinated Dibenzodioxins; Soil Pollutants; Temperature

A carbazole-utilizing bacterium was isolated by enrichment from petroleum-contaminated soil. The isolate, designated Sphingomonas sp. strain XLDN2-5, could utilize carbazole (CA) as the sole source of carbon, nitrogen, and energy. Washed cells of strain XLDN2-5 were shown to be capable of degrading dibenzofuran (DBF) and dibenzothiophene (DBT). Examination of metabolites suggested that XLDN2-5 degraded DBF to 2-hydroxy-6-(2-hydroxyphenyl)-6-oxo-2,4-hexadienic acid and subsequently to salicylic acid through the angular dioxygenation pathway. In contrast to DBF, strain XLDN2-5 could transform DBT through the ring cleavage and sulfoxidation pathways. Sphingomonas sp. strain XLDN2-5 could cometabolically degrade DBF and DBT in the growing system using CA as a substrate. After 40 h of incubation, 90% of DBT was transformed, and CA and DBF were completely removed. These results suggested that strain XLDN2-5 might be useful in the bioremediation of environments contaminated by these compounds.

Topics: Base Sequence; Benzofurans; Biodegradation, Environmental; Carbazoles; Chromatography, High Pressure Liquid; Environmental Pollutants; Mass Spectrometry; Molecular Sequence Data; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Spectrophotometry, Ultraviolet; Sphingomonas; Thiophenes

This paper describes a new shape-selective, pressurized liquid extraction (PLE) procedure for extracting polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and PCBs from food and feed samples with an integrated carbon fractionation step. Initially this was done using specially designed inserts for 34-mL cells, but subsequently, large solid cells (66 mL) were machined to increase the capacity and robustness of the system. Depending on the carbon load and extraction solvent strength, the non-ortho PCBs were recovered either with the bulk of the PCBs or with the PCDD/Fs. The former is preferable if PCDD/Fs are the targets. In most cases, however, data are required for all indicator PCBs, WHO-PCBs, and PCDD/Fs. Therefore, further efforts focused on developing, optimizing, and validating a cost- and time-efficient PLE procedure that can extract these targets, separate non-ortho PCBs and PCDD/Fs from the bulk of the PCBs, allow gravimetric fat determinations, and requires a minimum of postextraction cleanup. The performance of the resulting procedure was assessed in experiments with a fish tissue reference material. The trueness of the WHO-PCB-TEQ, PCDD/F-TEQ, and total-TEQ data were -8, -5, and -7%, respectively, and the corresponding CVs were 1.5, 0.5, and 1.3%; within the limits set by the European community for gas chromatography-high-resolution mass spectrometry methods for food and feed control.

Topics: Animals; Benzofurans; Carbon; Chromatography, Liquid; Equipment Design; Fish Oils; Fishes; Gas Chromatography-Mass Spectrometry; Particle Size; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Sensitivity and Specificity

This study attempts to relate the 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalent (TEQ) level with certain responses including the catalytic activities and expression of hepatic cytochrome P450 (CYP) 1A and CYP1B in wild population of Baikal seal (Pusa sibirica). We isolated full-length CYP1A1, 1A2, and 1B1 cDNAs, which encode proteins of 516, 512, and 543 amino acids, respectively. Immunochemical analysis demonstrated that a cross-reactive protein with polyclonal antibody against rat CYP1A1 or CYP1B1 was detected in the seal liver. Total TEQ levels showed significant positive correlations with expression levels of CYP1A1, 1A2, and 1B1 mRNAs, and further with both CYP1A- and CYP1B-like proteins, indicating chronic induction of these CYP isozymes by TEQs. The 50% effective concentration for CYP1A-like protein induction was estimated to be 65 pg TEQ/g wet weight. To evaluate the potential of congener-specific metabolism, profiles of negative correlations between the concentrations of eachcongener normalized to a relatively recalcitrant congener, PCB169, and CYP1A-like protein levels were also estimated. Significant negative correlations of 2,3,7,8-tetrachlorodibenzofuran and PCB77 to CYP1A-like protein expression may possibly be due to the preferential metabolism of these congeners. Anti-rat CYP1A1 and CYP1B1 antisera equivalently inhibited ethoxyresorufin O-deethylase (EROD) activity in the seal microsomes, suggesting that both CYPs are involved in EROD activity. Hepatic EROD revealed an increasing trend at lower TEQs, but a declining trend at higher levels, implying a catalytic inhibition of CYP1A and CYP1B. Furthermore, ratios of CYP1B1/CYP1A1 mRNA expression levels increased with TEQs, indicating the enhanced risk of carcinogenicity by preferential induction of CYP1B1 by TEQs in the liver.

Topics: Amino Acid Sequence; Animals; Antibodies, Blocking; Aryl Hydrocarbon Hydroxylases; Benzofurans; Biphenyl Compounds; Blotting, Western; Catalysis; Cloning, Molecular; Cytochrome P-450 CYP1A1; Cytochrome P-450 CYP1A2; Cytochrome P-450 CYP1B1; DNA, Complementary; Environmental Pollutants; Isoenzymes; Liver; Microsomes, Liver; Molecular Sequence Data; Phylogeny; Polychlorinated Dibenzodioxins; Reverse Transcriptase Polymerase Chain Reaction; RNA; Seals, Earless

Municipal solid waste incinerators (MSWIs) have been shown to be important sources of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). The emission of PCDD/Fs by MSWIs is a controversial subject in human health risk assessment. In this study the effect of a MSWI on a residential area was assessed before and after the installation of an additional treatment system for flue gas. This additional treatment system resulted in a dramatic decrease in PCDD/F concentrations in stack flue gas samples by 99.98%, while the concentrations in air decreased by approximately 50% (36,500 and 0.75 pg I-TEQ m(-3) for air in 1999; 3.5 and 0.38 pg I-TEQ m(-3) in 2002; 1.6 and 0.076 pg I-TEQ m(-3) in 2005 for stack gas and air, respectively). Considering the congener distributions of PCDD/Fs between stack flue gas and air samples, the study area seemed to have been contaminated by other urban sources as well as the MSWI. ISC3 model results support the conclusion that this incinerator became only a minor contributor to the study area after installation of the supplementary systems. This resulted from both proper MSWI operation using modern technology and additional sources of contaminants in this region. Finally, PCDD/F uptake by humans through inhalation of contaminated air was estimated. Assuming that inhalation exposure contributes 10% of total exposure, total exposure was lower than WHO guidelines. These results confirm that proper operation and maintenance of the incinerator led to a reduction in emissions and potential health impacts of PCDD/Fs.

Topics: Air Pollutants; Air Pollution; Benzofurans; Environmental Monitoring; Incineration; Polychlorinated Dibenzodioxins; Refuse Disposal

Polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were analysed in the muscle of various edible marine crustaceans (spider crab, edible crab, velvet swimming crab and Norway lobster) from the Brittany and Normandy coasts (France). The highest concentrations were measured in species collected from Antifer (Seine Bay). PCB and PBDE patterns in crustacean muscles were similar and independent of the geographical area with the predominance of the high chlorinated PCBs (CB153, 138, 118 and 180), and of a few PBDE congeners (BDE47, BDE99, BDE100 and BDE28). Oppositely, dioxin contamination differed with site. The major component in crustaceans from the Seine Bay was 2378-TCDF, whereas specimens from cleaner areas had higher relative concentrations of OCDD. Finally, the comparison of the spider crab contaminant profiles to those measured in mussel and sea bass highlighted two different trends: decapod crustaceans possess relatively strong capacity to metabolise PCBs and PBDEs; however these species might be used as bioindicators for dioxin pollution monitoring in the marine coastal environment.

Topics: Animals; Atlantic Ocean; Bass; Benzofurans; Biological Assay; Bivalvia; Decapoda; Environmental Monitoring; France; Polybrominated Biphenyls; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Seawater; Water Pollutants, Chemical

Measurements of the concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were made in ambient air, ash, and soil impacted by the open burning of wax apple and rice straw residues. Measurements showed that the mean PCDD/F concentration (0.458 pg I-TEQ/Nm3; international toxicity equivalence) in air at two wax apple orchards during open burning increased markedly, -8.1 times higher than that (0.057 pg I-TEQ/Nm3); before open burning. In addition, the mean PCDD/F concentration (0.409 pg I-TEQ/Nm3) in ambient air at a rice straw field was 4.6 times higher than that (0.089 pg I-TEQ/Nm3) before open burning. After burning the residues of wax apple stubble and rice straw, the contents of PCDD/F in ashes were 1.393 and 1.568 ng I-TEQ/kg-ash, respectively, and the contents of PCDD/F in soil were 2.258 and 2.890 ng I-TEQ/kg-soil, respectively. Therefore, the turnover of soil with the ash after open burning over years will result in the accumulation of PCDD/Fs in farm soils.

Topics: Air Pollutants; Benzofurans; China; Chromatography, Gas; Crops, Agricultural; Incineration; Mass Spectrometry; Oryza; Polychlorinated Dibenzodioxins; Soil Pollutants

Surface soils and combusted residue from a village located in southeast China, which has been intensely involved in the dismantling and "recycling" of computer parts (e-waste) for the past decade, were analyzed for polybrominated diphenyl ethers (PBDEs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). Total PBDE concentrations were highest in combusted residue of plastic chips and cables collected from a residential area (33,000-97,400 ng/g, dry wt), in soils from an acid leaching site (2720-4250 ng/g, dry wt), and a printer roller dump site (593-2890 ng/g, dry wt). BDE-209 was the most dominant congener (35-82%) among the study sites indicating the prevalence of commercial Deca-BDE, however signature congeners from commercial Penta- and Octa-BDE were also found. PCDD/F concentrations were also highest in soil from the acid leaching site (12,500-89,800 pg/g, 203-1100 pg WHO-TEQ/g, dry wt) and in combusted residue (13,500-25,300 pg/g, 84.3-174 pg WHO-TEQ/g, dry wt) and were comparable to PCDD/F levels of some open dumping sites in Asian developing countries. Of the e-waste activities, acid leaching and open burning emitted the highest concentrations of PBDEs and PCDD/Fs. This study is among the very few studies dealing with the important issue of pollution generated from crude e-waste recycling. Our results showthatthe crude processing of e-waste has become one of the major contributors of PBDEs and PCDD/Fs to the terrestrial environment.

Topics: Benzofurans; China; Conservation of Natural Resources; Dioxins; Environmental Pollution; Incineration; Polybrominated Biphenyls; Polychlorinated Biphenyls; Soil; Soil Pollutants

Fly ash from municipal solid waste incineration may catalytically enhance the formation and degradation of chlorinated aromatic compounds. The activities of three Deacon catalysts in this process were investigated in a statistically designed experiment. Chlorides of copper, chromium, and nickel were added to fly ash samples and the resulting samples heated at 300 degrees C for 2 h in an air atmosphere. The addition of copper increases the formation of all chlorinated aromatic compounds except the low chlorinated congeners of polychlorinated dibenzo-p-dioxins and dibenzofurans. The addition of chromium decreased the formation of most chlorinated aromatic compounds except the highest chlorinated species, where it was without effect. The addition of nickel did not show any significant effect. The outcome of the experiment can be interpreted as two competing processes: the chlorination of aromatic rings and the oxidation of carbon-carbon and carbon-oxygen bonds. The delicate balance between chlorination and oxidation could probably be further exploited to minimize both the emissions and the net production of chlorinated aromatic compounds from combustion.

Topics: Analysis of Variance; Benzofurans; Carbon; Catalysis; Chromium; Coal Ash; Confidence Intervals; Copper; Dioxins; Hydrocarbons, Chlorinated; Particulate Matter; Regression Analysis

Fish from Dutch markets were analysed for concentrations of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) and compared with the new European maximum residue levels (MRLs), set in 2006. In a first study on 11 different fish and shellfish from various locations, concentrations of PCDD/Fs were nearly all below the MRL for PCDD/Fs [4 pg toxic equivalents (TEQ) per gram wet weight (ww)] and nearly all below 8 pg total TEQ/g ww, the new MRL for the sum of PCDD/Fs and DL-PCBs. Some samples exceeded the total TEQ MRL, such as anchovy, tuna and sea bass. Furthermore, 20 (out of 39) wild eel samples exceeded the specific MRL for eel (12 pg total TEQ/g ww), as the study revealed PCDD/F TEQ levels of 0.2-7.9 pg TEQ/g ww and total TEQ values of 0.9 to 52 pg/g ww. TEQ levels in farmed and imported eel were lower and complied with the MRLs. Smoking eel, a popular tradition in the Netherlands, only had marginal effects on PCDD/F and DL-PCB concentrations. Owing to volatilization, concentrations of lower-chlorinated PCBs were reduced to below the limit of quantification after smoking. DL-PCBs contributed 61-97% to the total TEQ in all eel samples. This also holds for other fish and shellfish (except shrimps): DL-PCB contributed (on average) from 53 (herring) to 83% (tuna) to the total TEQ. Principal-component analysis revealed distinctive congener profiles for PCDD/Fs and non-ortho PCBs for mussels, pikeperch, herring and various Mediterranean fish. The application of new TCDD toxic equivalency factors (TEFs) set by the World Health Organization in 2006 (to replace the 1997 TEFs) resulted in lower TEQ values, mainly owing to a decreased mono-ortho PCB contribution. This decrease is most pronounced for eel, owing to the relative high mono-ortho PCB concentrations in eel. Consequently, a larger number of samples would comply with the MRLs when the new TEFs are applied. The DR CALUX(R) assay may be used for screening total TEQ levels in eel, in combination with gas chromatography-high resolution mass spectrometry confirmation of suspected samples. An almost 1:1 correlation was found when the 1997 TEFs were applied, but, surprisingly, a 1.4-fold overestimation occurred with application of the 2006 TEFs.

Topics: Animals; Benzofurans; Biological Assay; Biphenyl Compounds; Dioxins; Fishes; Food Analysis; Hydrocarbons, Chlorinated; Netherlands; Shellfish; Smoking; Time Factors; World Health Organization

A novel oxidative cyclization of quinone-arenols 5 leading to products 6 with a dibenzofuran-1,4-dione structure, which forms the core of several natural products, has been developed and applied to the synthesis of violet-quinone (4).

Topics: Benzofurans; Cyclization; Molecular Structure; Oxidation-Reduction; Quinones

A density functional theory (DFT) study was carried out to investigate possible reactions of dibenzofuran (DF) and dibenzo-p-dioxin (DD) in a reducing environment. Reaction energies, barrier heights, and molecular parameters for reactants, intermediates, products, and transition states have been generated for a wide range of possible reactions. It was found that C-O beta-scission in DF incurs a very large energy barrier (107 kcal/mol at 0 K), which is just 3 kcal/mol less than the direct H fission from C-H in DF to form dibenzofuranyl radicals. It was found that DF allows direct H addition to C1-C4 and C6-C9 as well as addition of two H atoms from a hydrogen molecule at sites 1 and 9 of DF. A bimolecular reaction of DF with H or H2 is found to have a significantly lower barrier than unimolecular decomposition through C-O beta-scission. An explanation for the predominance of polychlorinated dibenzofurans (PCDF) over polychlorinated dibenzo-p-dioxins (PCDD) in municipal waste pyrolysis is presented in the view of the facile conversion of DD into DF through ipso-addition at the four C sites of the two C-O-C central bonds in DD.

Topics: Air Pollutants; Algorithms; Benzofurans; Carbon; Cities; Dioxins; Free Radicals; Hydrogen; Incineration; Models, Theoretical; Molecular Structure; Refuse Disposal; Thermodynamics

The aim of this study was to examine the relationship between placental polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/F) and polychlorinated biphenyls (PCBs) toxic equivalent (TEQ) levels and the consumption of various food types in pregnant women from central Taiwan. Placental PCDD/Fs and PCB congener TEQ levels were evaluated in 109 pregnant women and dietary information was obtained by questionnaire. TEQ levels of PCDD/Fs and PCBs were positively associated with age and annual family incomes (p < 0.05). PCDD/F TEQs were significantly associated with freshwater fish and dairy product consumption after adjustment for age and body mass index (BMI) (p < 0.05). For PCB TEQs, significant associations were detected for saltwater fish consumption (p < 0.05). In summary, positive correlations were found between freshwater fish and dairy product intake and PCDD/F levels, and a marginal correlation between saltwater fish intake and the body burden of PCBs in pregnant women from central Taiwan. Risk assessment of PCDD/Fs and PCB in fishery products is warranted in a future study to quantify the benefits of fish consumption during the perinatal period.

Topics: Adult; Benzofurans; Diet; Dioxins; Environmental Exposure; Environmental Pollutants; Female; Food Contamination; Humans; Placenta; Polychlorinated Biphenyls; Pregnancy; Taiwan

Polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) were detected in sediments from Suzhou Creek with mean concentrations of 478.1, 245.1, and 4727.6 pg/g dw, respectively. WHO-TEQ concentrations of PCDD/Fs in sediments ranged from 2.90 to 13.96 pg/g dw, while TEQ concentrations of PCBs varied from 0.27 to 1.41 pg/g dw. OCDD or HpCDD were the dominant congeners but PeCDF or HpCDD was the major contributor to PCDD/Fs-TEQ in all the sites. For dioxinlike biphenyls, PCB 118 was the major congener while PCB-TEQ was attributable to PCB 126 in all the samples.

Topics: Animals; Benzofurans; China; Dioxins; Geography; Geologic Sediments; Polychlorinated Biphenyls; Rivers; Water Pollutants, Chemical

Alkalophilic bacterial consortium developed by continuous enrichment in the chemostat in presence of 4-chlorosalicylic acid as sole source of carbon and energy contained six bacterial strains, Micrococcus luteus (csa101), Deinococcus radiothilus (csa102), csa103 (Burkholderia gladioli), Alloiococcus otilis (csa104), Micrococcus diversus (csa105), Micrococcus luteus (csa106), identified by the Biolog test method. The strains were tested for utilization of organic compounds in which one of the strains (csa101) had higher potency to utilize dibenzofuran (DF) as sole carbon and energy source identified as Serratia marcescens on the basis of 16S rDNA. The degradation of DF by bacterial strain proceeded through an oxidative route as indicated by 2,2'3-trihydroxybiphenyl, 2-hydroxy-6-(2-hydroxyphenyl)-6-oxo-2,4-hexadienoic acid, salicylic acid, and catechol, which was identified by gas chromatography-mass spectrometry.

Topics: Bacterial Proteins; Benzofurans; Biodegradation, Environmental; Electrophoresis, Polyacrylamide Gel; Enzymes; Gas Chromatography-Mass Spectrometry; Molecular Structure; Phylogeny; RNA, Ribosomal, 16S; Serratia marcescens

Topics: Animals; Benzofurans; Dioxins; Geologic Sediments; Rivers; Ships; Texas

A multimedia mass balance model (MMM), POPsME, was evaluated for its performance to assess the fate and transport of 2,3,7,8-substituted PCDD/Fs in Seoul and a neighboring area (150 km x 150 km) in Korea. As part of the evaluation, the effects of the grid size with the homogeneous mixing assumption were estimated on the sign and magnitude of the prediction bias. The prediction compared with the monitoring data generally within 1 order of magnitude. In the presence of a concentration gradient within individual cells of 30 km x 30 km,the prediction bias for air and soil tended to increase with the distance from the sources. It was observed that the ratio of the predicted to the measured values could vary more than 4 times with the location of the monitoring site. Use of the large grid size in POPsME (and perhaps other MMMs) resulted in overpredictions for a major portion of the model domain at the cost of underprediction for limited areas nearthe sources. Beyond the source areas, a substantial contribution of the total prediction bias originated from the congeners with a large atmospheric loss rate and small TEF value. On a TEQ basis, therefore, the magnitude of the overpredictions could be significantly reduced as compared to that of the underprediction for the source areas.

Topics: Air; Benzofurans; Environmental Exposure; Environmental Monitoring; Geography; Geologic Sediments; Models, Theoretical; Multimedia; Polychlorinated Dibenzodioxins; Risk Assessment; Soil; Water

Polychlorinated dibenzo-p-dioxins and dibenzofurans (dioxins) are persistent contaminants that bioaccumulate and pose serious risks to humans. The primary objective of this study was to determine the history and mechanisms of dioxin accumulation in sediments of the Houston Ship Channel (HSC) using analytical data on natural and anthropogenic radionuclides (7Be, 137Cs, and 210Pb) and dioxins. Results showed that present-day sedimentary dioxin accumulation rates are orders of magnitude higher than atmospheric inputs to the HSC. Most stations showed dioxin peaks in the near surface, indicating continuing inputs despite federal regulations. Stations with high dioxin inventories reflect accentuated accumulation in the HSC as one moves west toward Houston, at the confluence of the HSC and the San Jacinto River and upstream in the San Jacinto River. These results indicate that a significant quantity of dioxins continues to be released into the environment here or that sedimentary storage and release of previously supplied dioxins is significant, or both. The results support the interpretation that the HSC is influenced by episodic sediment resuspension, erosion and lateral transport processes driven by tides, wind, shipping, and dredging, which can cause intermittently high accumulations of dioxins, and underscores the need for additional research on the roles of sedimentary processes in organic contaminant bioavailability.

Topics: Benzofurans; Carbon; Chronology as Topic; Dioxins; Geography; Geologic Sediments; Particle Size; Radioisotopes; Rivers; Ships; Texas; Transportation

Topics: Adult; Air Pollutants; Benzofurans; China; Conservation of Natural Resources; Electronics; Humans; Inhalation Exposure; Polychlorinated Dibenzodioxins; Refuse Disposal; Risk Assessment

The presence of chlorinated and brominated compounds in electronic waste (EW) results in the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) during the EW dismantling process. In this study, we investigated the dioxins present in ambient air around the EW dismantling area Guiyu in Guangdong, China. Atmospheric PCDD/F (tetra to octa) abundances and toxic equivalent (TEQ) values were 64.9-2365 pg/m3 and 0.909-48.9 pg of W-TEQ/m3, respectively; these are the highest documented values of these compounds found in ambient air in the world. PBDD/Fs (eight 2,3,7,8-substituted congeners) were also found at high pollution levels (concentrations of 8.124-61 pg/m3 and 1.6-2104 pg of I-TEQ/m3). Profiles of the 2,3,7,8-PCDD/F homologues in the air of Guiyu differed from typical urban air patterns reported in the literature, and the concentration of homologues increased with the chlorination degree of 2,3,7,8-PCDD/Fs except for OCDF. The severe dioxin pollution present in Guiyu substantially influences the adjacent area of Chendian, where atmospheric PCDD/F and 2,3,7,8-PBDD/F levels are higher than those of common urban areas in the world. Our tentative inhalation risk assessment showed that residents in Guiyu are at a high risk of exposure to dioxins. The total PCDD/F intake doses far exceed the WHO 1998 tolerable daily intake limit of 1-4 pg of W-TEQ kg(-1) day(-1).

Topics: Air Pollution; Atmosphere; Benzofurans; China; Electronics; Gases; Humans; Inhalation Exposure; Polychlorinated Dibenzodioxins; Refuse Disposal; Regression Analysis; Risk Assessment; Seasons

This paper reports on the applicability of gas chromatography coupled to ion-trap tandem mass spectrometry (GC/ITMS/MS) for the analysis of polychlorinated dibenzo- p-dioxins (PCDDs), dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (dl-PCBs) in food. MS/MS parameters were selected to achieve the high sensitivity and selectivity required for food analysis. Good precision (RSD=5-18% for PCDD/Fs and 6-14% for dl-PCBs) and low limits of detection for PCDD/Fs (0.1-0.93 pg/g of fat) and dl-PCBs (0.1-0.89 pg/g of fat) were obtained. A comparative study of the congener-specific determination using both GC/ITMS/MS and GC-high resolution mass spectrometry (GC/HRMS) was performed by analyzing several matrices such as milk, fish oil, chicken, pork, fish, eggs, and a chicken compound feed, at low pg/g levels. The results using GC/ITMS/MS were in good agreement with those obtained by GC/HRMS. Consequently, GC/ITMS/MS is proposed for the analysis of PCDD/Fs and dl-PCBs in food and feed samples.

Topics: Benzofurans; Dioxins; Food Analysis; Gas Chromatography-Mass Spectrometry; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Sensitivity and Specificity; Tandem Mass Spectrometry

With DFT method of quantum chemistry, the electronic structures of all polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were fully optimized at the level of B3LYP/6-311G**, and the corresponding quantum parameters, viz. the mean polarizability(alpha), entropy(S) as well as the tensor components of polarizability and quadrupole moment (alpha(xx), alpha(yy), alpha(zz) and Q(xx), Q(yy), Q(zz)) and so on were used to the study on quantitative structure-property relationship (QSPR) of water solubility. And three QSPRs were successfully proposed on the basis of the internally consistent experimental values. The determination coefficients are 0.977, 0.968 and 0.961 respectively and the cross-validated correlation coefficients are 0.968, 0.959 and 0.946 respectively. It is indicated that water solubility of PCDD/Fs should mainly be related to the molecular volume, but much less influenced by the molecular interactions. And the differences of predicted values of QSPRs for the whole dioxins are probably related to the limited available experimental values and the characteristics of introduced variables. In comparison with the newly developed QSPR, the performance of QSPRs in this study is improved, which may attribute to both the precise calculations of electronic properties of PCDD/Fs by B3LYP/6-311G** and the introduction of tensor components of quadrupole moment into models.

Topics: Benzofurans; Models, Chemical; Polychlorinated Dibenzodioxins; Quantitative Structure-Activity Relationship; Solubility; Water Pollutants, Chemical

This study investigated concentrations, contents and congener profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the workplaces of a sintering plant. Air samples were collected from the charging zone, the sintering zones of the sintering grate and the rough roll shredder, and the control room. The charging zone was found to have a higher total suspended particulate (TSP) but lower PCDD/F concentrations (=4969 microg nm(-3) and 7.61 pg nm(-3), respectively) than the sintering zone (=1422-1448 microg nm(-3) and 19.16-23.17 pg nm(-3), respectively). The TSP and PCDD/F concentrations were lowest in the control room (=98 microg nm(-3) and 1.75 pg nm(-3), respectively). However, the above concentrations were within the range of a typical urban-industrial area. Quite similar PCDD/F contents were found in particles in the sintering zones and control room (=11.72-14.30 and 15.85 ng g(-1), respectively) suggesting that the sintering zone and the control room are very similar. In both charging and sintering zones, 2,3,4,7,8-PeCDF contributed 40-60% to the total I-TEQ in both the gas phase and particle phase. However, in control room, both congeners 2,3,4,7,8-PeCDF and 2,3,7,8-TCDD were the main contributors; the later contributed 30% of the total I-TEQ in gas phase. In control room, the contribution of 2,3,7,8-TCDD to the total PCDD/F concentration in the gas phase greatly exceeded that in particle phase (=5.5% and 0.8%, respectively). Therefore, solutions must be sought to avoid the transfer of not only the particle-phase but also the gas-phase PCDD/Fs from the sintering zone to the control room in the future.

Topics: Air Pollutants; Atmosphere; Benzofurans; Dioxins; Environmental Monitoring; Extraction and Processing Industry; Workplace

The concentrations and composition profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans, polychlorinated biphenyls, polybrominated diphenyl ethers and polychlorinated naphthalenes were determined in herring individuals collected from the commercial catches of the Bothnian Sea, northern Baltic. The median age of herring was 5.0 years and in the muscle the median toxic equivalent concentration of PCDD/Fs was 5.6 WHO(PCDD/F)-TEQ pg/g fresh weight (fw) and that of PCBs 2.7 WHO(PCB)-TEQ pg/g fw. The median sum concentration of PBDEs was 1.4 ng/g fw and that of PCNs 0.1 ng/g fw. Differences in age-dependent accumulation between the organohalogen groups and individual congeners were major. In the Bothnian Sea the content of organohalogen compounds in herring is obviously elevated due to the availability and large proportion of Mysis crustaceans in their diet. More intensive fishing could reduce the concentrations of organohalogens, including the abundant, accumulative and toxic 2,3,4,7,8-PeCDF congener in the Baltic herring catch.

Topics: Age Factors; Animals; Benzofurans; Body Size; Environmental Monitoring; Female; Fishes; Hydrocarbons, Halogenated; Male; Naphthalenes; Oceans and Seas; Phenyl Ethers; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Water Pollutants, Chemical

Spore-forming bacterial strains capable of utilizing dibenzofuran (DF) as a sole source of carbon and energy were isolated. Characteristics of the isolates justified their classification into the genus Paenibacillus, and their closest relative was P. naphthalenovorans. Degenerate primers for aromatic hydrocarbon dioxygenase alpha subunit (AhDOa) genes and genomic DNA of the strain YK5 were used for gene isolation. The nucleotide sequences of clones of the PCR products revealed that the strain YK5 carries at least five different AhDOa genes. Northern hybridization analysis showed that one of the AhDOa genes was transcribed under DF-containing culture conditions. A gene cluster encoding the AhDOa was isolated. The genes predicted to encode extradiol dioxygenase (dbfB) and hydrolase (dbfC) were found to be an upstream of genes encoding the alpha and beta subunit of the AhDO (dbfA1 and dbfA2, respectively); the latter two gene products showed 60 and 53% identity to the amino acid sequences of DbfA1 and DbfA2 of Terrabacter sp. DBF63, respectively. Two Paenibacillus validus JCM 9077 strains transformed with the dbf gene clusters acquired the ability to convert DF to 2,2',3-trihydroxybiphenyl (THBP) and salicylic acid (SAL). These results suggest that the enzymes encoded by the gene cluster isolated in this study are involved in DF metabolism in YK5.

Topics: Base Composition; Benzofurans; Cloning, Molecular; Dioxygenases; Gram-Positive Bacteria; Hydrocarbons, Aromatic; Hydrolases; Molecular Sequence Data; Multigene Family; Oxygenases; Sequence Analysis, DNA; Spores, Bacterial

This study was designed to evaluate soil and air (gas and particle) transfer of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) to vegetation in residential and industrial areas. In a first part, soil-vegetation transfer was assessed. The levels of PCDD/Fs in 120 soil and 120 herbage samples collected from 1996 to 2002 in an industrial area of Montcada (Barcelona, Spain), near a municipal solid waste incinerator (MSWI), were determined. Some additional individual samples were also evaluated. It was concluded that high soil concentrations, which are not at steady state with the air layer above it, show a tendency for PCDD/Fs to escape via volatilization. In a second part of the study, air-vegetation transfer was examined. PCDD/F concentrations from 24 herbage samples were used, while PCDD/F concentrations were also measured in seven high-volume air samples and seven passive air-vapor samples. Scavenging coefficients (m3 air "sampled"/g grass d.m.) ranged from 1.9 to 11.3 m3/g. A good trend with K(OA) was observed for PCDDs (R=0.82), while it was lower for PCDFs (R=0.55). The current results corroborate that PCDD/F concentrations in vegetation are associated with atmospheric deposition. For the highest substituted PCDD/F congeners, the air-particle uptake from plants is the principal pathway. In regions impacted by combustion emission sources, PCDD/F gas-particle partitioning is influenced by a higher concentration of particles in the air. Particles and associated particle-bound PCDD/Fs would sorb to leaf surfaces, and are subject to removal via wash off. However, in areas where emissions to air are not very notable, vapor absorption would be the principal source of vegetation pollution. The results of this investigation can have a potential interest in risk assessment studies and environmental fate models.

Topics: Benzofurans; Carcinogens, Environmental; Dioxins; Environmental Monitoring; Environmental Pollution; Incineration; Models, Theoretical; Plant Leaves; Plants; Polychlorinated Dibenzodioxins; Rain; Refuse Disposal; Soil Pollutants; Spain; Volatilization

The purpose of this study was to assess the environmental impact of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the vicinity of a new hazardous waste incinerator (HWI) 4 years after regular operation of the facility. A double approach was carried out. The PCDD/F congener profiles corresponding to environmental samples, soil and herbage, collected before the HWI (baseline) and 4 years after starting regular operations, as well as PCDD/F profiles of air emission samples, were compared. The potential health risks (carcinogenic and noncarcinogenic) due to PCDD/F exposure were assessed for adults and children living in the neighborhood of the facility. Human exposure to PCDD/Fs was mainly due to dietary food intake. Comparisons between the PCDD/F congener profiles corresponding to the baseline and current surveys, as well as data concerning the human health risk assessment, indicate that the HWI in question does not cause additional risks to the environment orto the population living in the vicinity of the facility.

Topics: Benzofurans; Dioxins; Environmental Exposure; Environmental Monitoring; Hazardous Waste; Humans; Incineration; Refuse Disposal; Risk Assessment

The levels and homologue profile of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from stack gas of three typical fluidized bed incinerators co-firing municipal solid waste (MSW) with Chinese coal were measured. The PCDD/Fs emission was in the range of 0.0054-0.1961 ng I-TEQ/N m(3). Comparison of PCDD/Fs detection results by HRGC/HRMS and HRGC/LRMS suggested that it was feasible to detect fly ash with high PCDD/Fs concentration by HRGC/LRMS. Several factors on PCDD/Fs emission were discussed. The primary reason for the lower PCDD/Fs emission was the inhibition mechanism of relatively high sulfur in feeding coal on PCDD/Fs formation. The emission results also showed that there was no directly correlation between PCDD/Fs levels and CO, O(2) and HCl concentration in flue gas. It was estimated that about 0.1034 g I-TEQ was annually emitted to atmosphere from the tested three MSW incinerators (total daily treatment capacity is 800 tonnes MSW).

Topics: Benzofurans; China; Cities; Coal; Dioxins; Fires; Porphyrins; Power Plants; Soil Pollutants; Water Pollutants

The purpose of this study was to determine if elevated ambient exposure to incinerator generated polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) may affect birth outcomes of exposed infants born in Taipei metropolitan areas, Taiwan. The relationships between exposure to elevated PCDD/Fs concentration and various birth outcomes including birth weight, gestational age, and proportion of females were cross-sectionally assessed in 1991 (one year before the incinerator started to operate) and 1997 (five years later), respectively. We used the US EPA Industrial Source Complex Model-Sort Term modeling technique to determine the ambient PCDD/Fs concentrations in the study areas, in which 40 districts with annual averaged PCDD/Fs exposure of > or = 0.03 pg TEQ/m3 were considered as the exposed areas and another 40 districts with an estimated concentration of zero were randomly selected as reference areas. Information on birth outcomes was retrieved from the Taiwan's Birth Registry. A total of 6697 and 6282 neonates were included in the analysis for 1991 and 1997, respectively. After controlling for potential confounders, the results showed that the odds ratios (ORs) of low birth weight (< 2500 g) for higher exposures were 0.94 (> 0.05 pg TEQ/m3) and 091 (0.03-0.05 pg TEQ/m3) in 1991 and were 1.07 (> 0.05 pg TEQ/m3) and 1.06 (0.03-0.05 pg TEQ/m3) in 1997. The corresponding ORs were 1.05/0.86 (1991) and 1.12/1.22 (1997) for preterm (< 37 completed weeks of gestation), as well as 0.95/1.00 (1991) and 0.95/0.90 (1997) for female births. The above ORs were all close to unity and were statistically insignificant. When birth weight was analyzed as a continuous variable, the difference in mean birth weight between exposed group (> 0.03 pg TEQ/m3) and reference group decreased from 3.02 g in 1991 to -5.87 g in 1997. Analysis of continuous data also showed that the mean difference in gestational age between exposed and reference areas decreased from 0.05 weeks in 1991 to -0.09 week (p<0.05) in 1997. This study tends to conclude that the incinerator generated dioxin poses little effects on birth weight and female birth, but might pose small effects on gestational age. If the observed adverse effects turn out to be real, the measures now taken for improvement of abatement of waste gases seem to be a wise thing to do.

Topics: Air Pollutants; Animals; Benzofurans; Birth Weight; Female; Humans; Incineration; Infant, Newborn; Live Birth; Male; Maternal Exposure; Polychlorinated Dibenzodioxins; Retrospective Studies; Taiwan

The distribution of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) was examined according to particle size in marine sediments, with a particular focus on fine particulates. Samples from different coastal sites were fractionated into five size groups (<2, 2-5, 5-10, 10-20, and 20-63 microm diameter) by gravitational split-flow thin fractionation. Despite the different size profiles and PCDD/F contents of the sediments at each site, PCDD/F levels in fractionations tended to increase as the particle size decreased; the PCDD/F levels in the finest particles were up to 16 times higher than in the coarsest particles, which was associated with their organic carbon contents. Log normalization showed high levels of PCDD/Fs in the fine silt particles (2-10 microm), which are consumable by aquatic biota. Because of the different toxicity and bioavailability of PCDD/Fs in different sediment particle sizes, it is important to study particle actions to understand their effects on the aquatic ecosystem.

Topics: Benzofurans; Chemical Fractionation; Environmental Monitoring; Geologic Sediments; Industrial Waste; Korea; Particle Size; Polychlorinated Dibenzodioxins; Water Pollutants, Chemical

The aim of this study was to evaluate possible factors affecting serum polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) levels of people living near municipal waste incinerators (MWIs). We selected 19 MWIs in Taiwan and collected 1708 serum samples from residents 18-65 years old who had lived within 5 km of one of the selected MWIs for at least 5 years. The samples were analyzed using a standardized study protocol to assure comparability of the concentrations from 17 PCDD/F congeners. The results suggested that a vegetarian regimen was a protective factor to avoid serum PCDD/F accumulation in the subjects. In addition, the current data seemed to support the hypothesis that serum PCDD/F levels of residents living near MWIs are related to they consumed the locally grown or cultivated vegetable and animal foods, such as poultry products near the MWIs. Our results can be used to create guidelines for preventing excessive PCDD/F accumulation from eating animal and vegetable foods grown near MWIs.

Topics: Adolescent; Adult; Aged; Benzofurans; Diet, Vegetarian; Environmental Exposure; Female; Food Analysis; Guidelines as Topic; Humans; Incineration; Industrial Waste; Longitudinal Studies; Male; Middle Aged; Polychlorinated Dibenzodioxins; Taiwan

The homogeneous, gas-phase oxidative thermal degradation of a 50:50 mixture of 2-bromophenol and 2-chlorophenol was studied in a 1 cm i.d., fused silica flow reactor at a concentration of 88 ppm, with a reaction time of 2.0 s, over a temperature range of 300 to 1000 degrees C. Observed products in order of decreasing yield included the following: dibenzo-p-dioxin (DD), 4-bromo-6-chlorodibenzofuran (4-B,6-CDF), phenol, 4,6-dibromodibenzofuran (4,6-DBDF), 2,6-dibromophenol, 4,6-dichlorodibenzofuran (4,6-DCDF), 2-bromo-4-chlorophenol, 2,4-dibromophenol, 2-chloro-4-bromophenol, 4-monobromodibenzofuran (4-MBDF), 4-monochlorodibenzofuran (4-MCDF), dibenzofuran (DF), 1-monobromodibenzo-p-dioxin (1-MBDD), 1-monochlorodibenzo-p-dioxin (1-MCDD), 2,4,6-tribromophenol, naphthalene, chloronaphthalene, bromonaphthalene, chlorobenzene, bromobenzene, and benzene. The results are compared and contrasted with previous results reported for the oxidations of pure 2-chlorophenol and 2-bromophenol as well as results for the pyrolysis of the mixture of 2-chlorophenol and 2-bromophenol. 4,6-DBDF and 4,6-DCDF were observed in higher yields than under pyrolytic conditions but considerably less than the yields observed for the individual oxidation of 2-chlorophenol and 2-bromophenol. The effect on chlorine and bromine on the concentration of hydroxyl radical is shown to control the dioxin-to-furan ratio.

Topics: Benzofurans; Chlorophenols; Dioxins; Environment; Gases; Hydroxyl Radical; Models, Chemical; Naphthalenes; Oxygen; Phenols; Polychlorinated Dibenzodioxins; Temperature

Rhodococcus opacus strain SAO101 was shown to degrade on various polycyclic aromatic hydrocarbons such as naphthalene, dibenzofuran (DF), and dibenzo-p-dioxin (DD). One of the unique traits of the strain SAO101 is its ability to oxidize DF compounds by lateral dioxygenation. To clone the lateral dioxygenase gene involved in compound degradation in strain SAO101, we identified a cosmid clone that oxidizes aromatic compounds by using SAO101 genomic DNA. Sequencing analysis revealed that isolated cosmid clone contained ring-hydroxylating dioxygenase genes (narAaAb) with homologies to indene dioxygenase genes of Rhodococcus strain I24 and naphthalene dioxygenase genes of Rhodococcus strain NCIMB12038. The NarAaAb-expressing Rhodococcus cells exhibited broad substrate specificity for bicyclic aromatic compounds and had high ability to degrade dibenzofuran and naphthalene. Metabolite analysis revealed that dihydrodiol compounds were detected as metabolites from dibenzofuran by the NarAaAb-expressing Rhodococcus strain, indicating that dibenzofuran was converted by lateral dioxygenase activity of NarA dioxygenase. Based on reverse transcriptase-polymerase chain reaction analysis, it was found that the narAaAb genes were cotranscribed and that their expression was induced in the presence of aromatic hydrocarbon compounds. It is likely that these genes are involved in the degradation pathways of a wide range of aromatic hydrocarbons by this strain. Strain SAO101 harbors three huge linear plasmids, pWK301 (1,100 kbp), pWK302 (1,000 kbp), and pWK303 (700 kbp), and the nar genes were found to be located on the pWK301 plasmid.

Topics: Benzofurans; Cosmids; Dioxygenases; DNA; Gene Library; Hydrocarbons; Hydrogen-Ion Concentration; Metabolic Networks and Pathways; Models, Chemical; Oxygen; Plasmids; Rhodococcus; Substrate Specificity

The dibenzofuran (DF)-degrading bacterium, Janibacter terrae strain XJ-1, was isolated from sediment from East Lake in Wuhan, China. This strain grows aerobically on DF as the sole source of carbon and energy; it has a doubling time of 12 hours at 30 degrees C; and it almost completely degraded 100 mg/L(-1) DF in 5 days, producing 2,2',3-trihydroxybiphenyl, salicylic acid, gentisic acid, and other metabolites. The dbdA (DF dioxygenase) gene cluster in the strain is almost identical to that on a large plasmid in Terrabacter sp. YK3. Unlike Janibacter sp. strain YY-1, XJ-1 accumulates gentisic acid rather than catechol as a final product of DF degradation.

Topics: Actinomycetales; Benzofurans; Biodegradation, Environmental; Dioxygenases; Gas Chromatography-Mass Spectrometry; Gentisates; Models, Chemical; Molecular Sequence Data; Molecular Structure; Phylogeny; RNA, Ribosomal, 16S; Salicylic Acid; Sequence Analysis, DNA; Substrate Specificity

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the surrounding environment (outdoor) and workplace air of two municipal solid waste incinerators (MSWIs, T and M) were characterized and compared. T and M represented two typical municipal solid waste incinerators in the north of Taiwan, which have different processes for controlling the PCDD/F emissions. The results of this study are summarized as follows. (1) The total PCDD/F and the total PCDD/F WHO-TEQ concentrations in the workplace air were 5-13 and 5-15 times higher than those in the outdoor air, respectively. Obviously, it is worthwhile to explore more on health risk assessment for exposure of PCDD/Fs emitted from MSWIs, particularly in the workplace air. (2) Mean total PCDD/F I-TEQ concentrations in the outdoor air ranged between 0.0216 and 0.155 pg I-TEQ/Nm(3) and averaged 0.0783 pg I-TEQ/Nm(3) (0.0828 pg WHO-TEQ/Nm(3)) during two seasons for two MSWIs, which were 6.5-fold higher than that of a remote site (0.0119 pg I-TEQ/Nm(3) or 0.0132 pg WHO-TEQ/Nm(3)) in Taiwan. However, the above outdoor air concentration levels in the MSWIs were still much lower than the air quality limitation of PCDD/Fs (0.6 pg I-TEQ/Nm(3)) in Japan []. (3) PCDFs were the primary toxicity distributors for PCDD/Fs in the outdoor air, since the ratios of PCDDs/PCDFs (I-TEQ) at all sampling sites ranged from 0.180 to 0.492 and were less than unity. (4) The OCDD, OCDF, 1,2,3,4,6,7,8-HpCDD and 1,2,3,4,6,7,8-HpCDF were the four dominant species in both workplace and outdoor air near MSWIs. (5) By spraying water on and wetting both the fly and bottom ashes, the mean total PCDD/F I-TEQ concentration in the workplace air was reduced 86.9% in the T MSWI. The above results indicate an appropriate improving action did inhibit the fugitive emission of PCDD/Fs and reduce the health risk of workers during work handling ashes in MSWIs.

Topics: Air Pollutants; Benzofurans; Chlorine; Dioxins; Environmental Monitoring; Incineration; Seasons

A substantial formation of PBDF congeners was observed during photolytic decomposition of decaBDE in toluene. The decaBDE degradation was monitored by chemical and toxicological analysis and in all, twenty-seven mono- to hexasubstituted polybrominated dibenzofurans (PBDFs) were detected in toluene solutions of decabromodiphenyl ether (decaBDE) after irradiation with UV-A, UV-AB and UV-ABC. The concentration levels of PBDFs formed after 16 h of UV exposure increased with wider spectra and were determined to be 3.5, 4.2 and 14 microg/ml after UV-A, UV-AB and UV-ABC irradiation, respectively. In accordance, bioassay derived TEQs (bio-TEQs), determined with the DR-CALUX assay, increased with a similar pattern. The PBDFs formed after the three UV exposures accounted for 0.31%, 0.35% and 1.2% of the initial amount of decaBDE (molar basis). The PBDF congener patterns were consistent in all three UV experiments which imply that no alterations were induced in the PBDF formation or degradation processes due to differences in UV irradiation. However, these processes tended to increase with wider spectra and increasing radiation energy most likely due to the strong absorbance of for example decaBDE at shorter wavelengths. After total decaBDE decomposition the PBDF formation increased significantly in the UV-ABC experiment. The tetra to hexasubstituted BDFs constituted the majority of detected compounds in all experiments. In all samples, the estimated chemical TEQ indicate that the bio-TEQs observed are largely explained by the presence of non-2,3,7,8-substituted PBDFs with relatively low toxicological potencies.

Topics: Benzofurans; Biological Assay; Environmental Exposure; Flame Retardants; Phenyl Ethers; Photolysis; Polybrominated Biphenyls; Time Factors; Toluene; Ultraviolet Rays

The objective of this study was to determine the concentrations and compositions of polybrominated biphenyls (PBBs), polybrominated dibenzo-p-dioxins (PBDDs), and polybrominated dibenzofurans (PBDFs) as contaminants in the commercial polybrominated diphenyl ether (PBDE) mixtures DE-71, DE-79, and DE-83 and to ascertain the lot-to-lot variations in the proportions of these contaminants. Commercial PBDE mixtures tested in the present study contained both PBBs and PBDFs, as impurities, at concentrations in the range of several tens to several thousands of nanograms per gram. Concentrations of total PBDFs were greater than those of total PBBs in DE-79 and DE-83 mixtures. PBDDs were not detected at levels above the limit of detection. Profiles of PBB and PBDF congeners varied with the degree of bromination of the commercial PBDE mixtures (i.e., more highly brominated mixtures of PBDEs contained heavily brominated homologues of PBBs and PBDFs). On the basis of the production/ usage of commercial PBDE mixtures in 2001, potential global annual emissions of PBBs and PBDFs were calculated to be 40 and 2300 kg, respectively. Results of our study suggestthat PBDFs can also be formed during the production of commercial PBDE mixtures, in addition to their formation during pyrolysis of brominated flame retardants.

Topics: Benzofurans; Dioxins; Ethers; Polybrominated Biphenyls; Reference Standards; Sensitivity and Specificity

The gene cassette encoding enzymes responsible for degrading carbazole to anthranilic acid was introduced into a dibenzothiophene degrader. The resultant strain, Rhodococcus erythropolis XPDN, could simultaneously transform the model pollutants dibenzothiophene, carbazole, and dibenzofuran to nontoxic metabolites and may have an application potential for bioremediation.

Topics: Benzofurans; Biodegradation, Environmental; Carbazoles; Environmental Pollutants; Genetic Engineering; Nitrogen; Oxygen; Recombination, Genetic; Rhodococcus; Sulfur; Thiophenes

The reaction of dibenzofuran 1, lithium pieces (2.2 equiv), and TMEDA (2.2 equiv) in dry ether under reflux led to a solution of the corresponding C,O-dilithiated intermediate 2 which, upon treatment with different ketones or aldehydes (0.8 equiv) at -78 degrees C, afforded, after hydrolysis and dehydration, 6,6-substituted-6H-dibenzo[b,d]pyrans 3 in good yields. The reaction undergoes reductive ring opening and cyclization, and the intermediate diol 4e was isolated.

Topics: Benzofurans; Lithium; Organometallic Compounds; Pyrans

Topics: Animals; Benzofurans; Bivalvia; China; Chromatography, Gas; Dioxins; Environmental Monitoring; Fresh Water; Pesticide Residues; Water Pollutants, Chemical

The emissions from simulated sugarcane (Saccharum officinarum) field burns were sampled and analyzed for polychlorinated dibenzodioxins and dibenzofurans (PCDDs and PCDFs). Sugarcane leaves from Hawaii and Florida were burned in a manner simulating the natural physical dimensions and biomass density found during the practice of preharvest field burning. Eight composite burn tests consisting of 3-33 kg of biomass were conducted, some with replicate samplers. Emission factor calculations using sampled concentration and measured mass loss compared well to rigorous carbon balance methods commonly used in field sampling. The two sources of sugarcane had distinctive emission levels, as did tests on separate seasonal gatherings of the Florida sugarcane. The average emission factor for two tests of Hawaii sugarcane was 253 ng toxic equivalents (TEQ)/kg of carbon burned (ng TEQ/kg(Cb)) (rsd = 16%) and for two gatherings of Florida sugarcane was 25 ng TEQ/kg(Cb) (N = 4, rsd = 50%) and 5 ng TEQ/kg(Cb) (N = 2, rsd = 91%). The Hawaii sugarcane, as well as most of the Florida sugarcane, had emission values which were well above the value of 5 ng TEQ/kg(Cb) commonly attributed to biomass combustion. Application of this emission factor range to the amount of U.S. sugarcane fields burned suggests that this practice may be a relatively minor source of PCDDs and PCDFs in the U.S. national inventory, but the limited sample size and range of results make this conclusion tenuous.

Topics: Air Pollutants; Benzofurans; Environmental Monitoring; Incineration; Polychlorinated Dibenzodioxins; Refuse Disposal; Saccharum

An approach based on hypothesis testing for the management of persistent inorganic and organic toxic chemicals (PTS/POPs) detected in clams and mussels from the Venice lagoon is presented. The chemicals of interest for this evaluation were the polychlorinated biphenyls (PCBs), dibenzodioxins (PCDDs), and dibenzofurans (PCDFs), hexachlorobenzene (HCB), and the heavy metals cadmium (Cd), mercury (Hg), and lead (Pb). Two statistically different populations of data for PCDDs+PCDFs (TEQs), HCB, Cd, and Pb, associated with biota samples collected respectively in the lagoon central district and in the southern and northern districts were identified. The central district is under the impact of the Porto Marghera industrial settlement and the city of Venice, whereas the southern and northern districts are subject to a general impact. Of the aforementioned chemicals, those with more discriminating power were found to be HCB and PCDDs+PCDFs.

Topics: Algorithms; Animals; Benzofurans; Biodiversity; Bivalvia; Cadmium; Dioxins; Environmental Monitoring; Hexachlorobenzene; Humans; Italy; Lead; Mercury; Polychlorinated Biphenyls; Shellfish; Water Pollutants

Total PCDDs concentration ranged from 6.8 to 41 pg g d.w. and for PCDFs from 3.9 to 19 pg/g d.w. with total toxic equivalency within a range 0.023-5.9 pg TEQ/g d.w. A somewhat elevated concentrations of PCDDs and PCDFs were found in the samples collected from the south of Poland in the vicinity of highly industrialized regions known for former extensive mining industry of hard coal and metallurgy, as well as for regions with high rates of urbanization in central Poland and in the vicinity of the western border of the country. Nevertheless, if consider homologue specific pattern of PCDDs and PCDFs no major differences were noted between spatially scattered sampling sites. In all samples highly chlorinated PCDDs/DFs dominated (12345678-OcCDD, 1234678-HpCDD, 12346789-OcCDF, 1234789-HpCDF, 1234678-HpCDF were found in all investigated soils). Their similar pattern can suggest that formation of these chemicals occur in similar conditions. Energy production and fossil fuel co-fired power boilers, chemical industry, metallurgical industry are probably the main sources in industrial regions, however heating of houses by small stoves and hard coal with added household wastes, and former use of agrochemical formulations consisting byimpurities of PCDD/F may also play important role at rural sites. The particularly elevated concentrations of OcCDF in some samples might be connected to the former production and use of highly chlorinated polychlorinated biphenyl formulation--Chlorofen.

Topics: Benzofurans; Dioxins; Environmental Monitoring; Food Contamination; Gas Chromatography-Mass Spectrometry; Poland; Polychlorinated Dibenzodioxins; Soil; Soil Pollutants

Organochlorine compounds (OCs) including polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p-p'-DDE), heavy metals (Pb, Cd, Zn, Cu), and arsenic were measured in house sparrows (Passer domesticus) and common ground doves (Columbina passerina) from Baja California Sur, México. Concentrations of PCDD/Fs were low, with 21 pg/g for house sparrows, and 7.7 pg/g for common ground doves. Non-ortho-PCB concentrations in house sparrow and common ground doves were 58 and 254 pg/g, respectively, and are within the highest concentrations reported in species that are in the low levels of food webs. The major differences in organochlorine levels between species were found for ortho-PCBs and DDTs. ortho-PCB levels were higher in the seedeater species, whereas DDT levels were higher in the omnivorous species. Heavy metal levels were far below those associated with negative effects.

Topics: Animals; Arsenic; Benzofurans; Birds; Cadmium; Copper; DDT; Dichlorodiphenyl Dichloroethylene; Environmental Pollutants; Hydrocarbons, Chlorinated; Insecticides; Lead; Metals, Heavy; Mexico; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Songbirds; Zinc

A concise synthesis of the complete tricyclic dibenzofuran-1,4-dione aromatic core of popolohuanone E has been demonstrated by mild base treatment of a biquinone intermediate, thus establishing a biomimetic route to this family of heterocyclic ring systems and the total synthesis of popolohuanone E.

Topics: Benzofurans; Molecular Mimicry; Polycyclic Compounds

We examined the metabolism of dibenzofuran (DF) and dibenzo-p-dioxin (DD) by the biphenyl dioxygenase (BPDO) of Comamonas testosteroni B-356 and compared it with that of Burkholderia xenovorans LB400. Data showed that both enzymes oxygenated DF at a low rate, but Escherichia coli cells expressing LB400 BPDO degraded DF at higher rate (30 nmol in 18 h) compared with cells expressing B-356 BPDO (2 nmol in 18 h). Furthermore, both BPDOs produced dihydro-dihydroxy-dibenzofuran as a major metabolite, which resulted from the lateral oxygenation of DF. 2,2',3-Trihydroxybiphenyl (resulting from angular oxygenation of DF) was a minor metabolite produced by both enzymes. Deuterated DF was used to demonstrate the production of 2,2',3-dihydroxybiphenyl through angular oxygenation of DF. When tested for their ability to oxygenate DD, both enzymes produced as sole metabolite, 2,2',3-trihydroxybiphenyl ether at about the same rate, indicating similar catalytic properties toward this substrate. Altogether, although LB400 and B-356 BPDOs oxygenate a different range of chlorobiphenyls, their metabolite profiles toward DF and DD are similar. This suggests that co-planarity influences the regiospecificity of BPDO toward DF and DD to a higher extent than the presence of an ortho substituent on the molecule.

Topics: Benzofurans; Biodegradation, Environmental; Biphenyl Compounds; Burkholderia; Comamonas testosteroni; Dioxins; Dioxygenases; Escherichia coli; Polychlorinated Biphenyls

Biphenyl-degrading bacteria are able to metabolize dibenzofuran via lateral dioxygenation and meta-cleavage of the dihydroxylated dibenzofuran produced. This degradation was considered to be incomplete because accumulation of a yellow-orange ring-cleavage product was observed. In this study, we want to characterize the 1,2-dihydroxydibenzofuran cleaving enzyme which is involved in dibenzofuran degradation in the bacterium Ralstonia sp. SBUG 290.. In this strain, complete degradation of dibenzofuran was observed after cultivation on biphenyl. The enzyme shows a wide substrate utilization spectrum, including 1,2-dihydroxydibenzofuran, 2,3-dihydroxybiphenyl, 1,2-dihydroxynaphthalene, 3- and 4-methylcatechol and catechol. MALDI-TOF analysis of the protein revealed a strong homology to the bphC gene products. We therefore cloned a 3.2 kb DNA fragment containing the bphC gene of Ralstonia sp. SBUG 290. The deduced amino acid sequence of bphC is identical to that of the corresponding gene in Pseudomonas sp. KKS102. The bphC gene was expressed in Escherichia coli and the meta-fission activity was detected using either 2,3-dihydroxybiphenyl or 1,2-dihydroxydibenzofuran as substrate.. These results demonstrate that complete degradation of dibenzofuran by biphenyl degraders can occur after initial oxidation steps catalysed by gene products encoded by the bph-operon. The ring fission of 1,2-dihydroxydibenzofuran is catalysed by BphC. Differences found in the metabolism of the ring fission product of dibenzofuran among biphenyl degrading bacteria are assumed to be caused by different substrate specificities of BphD.. This study shows for the first time that the gene products of the bph-operon are involved in the mineralization of dibenzofuran in biphenyl degrading bacteria.

Topics: Amino Acid Sequence; Benzofurans; Biodegradation, Environmental; Conserved Sequence; Dioxygenases; Escherichia coli; Gene Expression; Genes, Bacterial; Molecular Sequence Data; Peptide Mapping; Ralstonia; Sequence Alignment; Soil Microbiology

[reaction: see text] Tributyltin hydride mediated addition of 3-iodosalicylaldehyde to benzene in the presence of catalytic benzeneselenol affords (1,4-cyclohexadien-3-yl)salicylaldehyde. Homologation of the aldehyde group is followed by cycloetherification with dimethyl dioxirane to give a 4,6-disubstituted tetrahydrodibenzofuran. Adjustment of oxidation states and introduction of a second chain by Wittig olefination affords the beta-sheet initiator, ethyl 4-(2-tert-butoxycarbonylaminoethyl)-6-dibenzofuranpropanoate.

Topics: Alkylation; Benzene; Benzofurans; Cyclization; Free Radicals; Molecular Conformation; Oxidation-Reduction

In response to aggressive attempts to control dioxin emissions over the last 35 years, human exposures to dioxins from the environment have declined significantly. The primary source of human exposure to dioxins at present is food. The sources of dioxins in food are not well understood and are probably varied. Data on the levels of dioxins measured in various foods for samples collected from 2000 to 2002 have recently been released by the US Food and Drug Administration as part of its Total Diet Study. Data on samples collected in 1999, and released in 2002, are also available. Based on those data and on the US Department of Agriculture's most recent food consumption survey (1994-1996 & 1998 Continuing Survey of Food Intakes by Individuals), estimates of dioxin intake for the total US population and for three age groups of children were obtained. Results show that the most recent mean dietary exposures for all groups are below 2 pg TEQ/kg BW/day, the tolerable daily intake established for dioxins by the World Health Organization. Between 1999 and 2002 mean dioxin intakes from food appear to have decreased, but when estimates are adjusted based on a standardized limit of detection and evaluating only those {congenerxfood} combinations common to all 4 years, no trend is apparent. When dioxin concentrations below the limit of detection are represented by one-half the limit, approximately 5% of the intake estimates for 2-year-olds and 1% of the intake estimates for 6-year-olds exceed the tolerable daily intake by about 10%, although such upper-percentile estimates should not be equated with excess risk. When non-detectable dioxin values are set to zero (i.e., when only dioxin values actually measured are used), only 1% of intake estimates exceed the tolerable daily intake for 2-year-olds. As expected, about 50% of daily dietary dioxin intake by the total US population is attributable to meat and dairy products, based on the same food group classifications used by the National Academy of Sciences' Committee on the Implications of Dioxin in the Food Supply. This information may be useful for targeting future risk management activities.

Topics: Adolescent; Benzofurans; Body Burden; Child; Child, Preschool; Diet Surveys; Dioxins; Female; Food Analysis; Food Contamination; Humans; Male; Polychlorinated Biphenyls; Reproducibility of Results; Risk Assessment; Risk Management; Sensitivity and Specificity; United States; United States Department of Agriculture; United States Food and Drug Administration

Seven strains of dibenzofuran (DF)-degrading bacteria isolated from dioxin-polluted environments were characterized. These isolates were able to grow with dibenzofuran as the sole carbon and energy source. During the growth with dibenzofuran, they produced a soluble yellow metabolite that exhibited a unique pH-dependent shift of absorption maxima. Dibenzo-p-dioxin and biphenyl were also degraded with pigment production. The isolates were strictly aerobic and chemoorganotrophic and had gram-positive, nonmotile, rod-shaped cells. Chemotaxonomic analyses showed that cells contained L,L-diaminopimeric acid in the peptidoglycan, branched-chain fatty acids as major fatty acids, and menaquinone MK-8(H4) as the sole respiratory quinone. The G + C content of the DNA of the isolates ranged from 72.0 to 72.4 mol%. The 16S rRNA gene sequences of the isolates were very similar to each other (> or = 99.8%). The phylogenetic analysis showed that the isolates formed a cluster with species of the genus Nocardioides with Nocardioides simplex and Nocardioides nitrophenolicus as their nearest neighbors. DNA-DNA hybridization studies showed that the isolates showed a hybridization level of less than 55% to any tested species of the genus Nocardioides. Based on these data, Nocardioides aromaticivorans sp. nov. is proposed for the new DF-degrading isolates. The type strain is strain H-1 (IAM 14992, JCM 11674, DSM 15131).

Topics: Actinomycetales; Bacterial Typing Techniques; Benzofurans; Dioxins; DNA, Bacterial; DNA, Ribosomal; Genes, rRNA; Geologic Sediments; Molecular Sequence Data; Nucleic Acid Hybridization; Phenotype; Phylogeny; Rivers; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Water Pollutants, Chemical

Fifteen sediment samples were analysed in order to determine their content of polybrominated diphenylethers (PBDEs), polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and biphenyls (PCBs). Samples were collected from several hot spots on the Spanish coast, such as the harbours of Almeria and Tarragona, and the mouths of the Besos and Llobregat rivers in Barcelona. A generic analytical procedure based on Soxhlet extraction followed by an automated cleanup system and gas chromatography-ion trap-mass spectrometry was employed for determining the toxic congeners of PCDDs and PCDFs, as well as dioxin-like PCBs. As regards PBDE determinations, a rapid method based on the use of selective pressurized liquid extraction followed by gas chromatography-negative ion chemical ionization-mass spectrometry was applied. Total toxicity equivalent (WHO-TEQ) values were calculated using the toxicity equivalent factors proposed by WHO for dioxin-like PCBs, PCDDs and PCDFs. WHO-TEQ values ranged from 0.3 to 75 pg/g dry weight (dw), with PCB contribution on the toxicity of the samples between 1 and 84%. Total PBDE levels ranged from 2.7 to 134 ng/g dw, with BDE-209 contribution on the total PBDE contamination between 50 and 99%.

Topics: Benzofurans; Chromatography, Gas; Environmental Monitoring; Environmental Pollutants; Fresh Water; Geologic Sediments; Polybrominated Biphenyls; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Spain

Transthyretin (TTR) amyloidogenesis requires rate-limiting tetramer dissociation and partial monomer denaturation to produce a misassembly competent species. This process has been followed by turbidity to identify transthyretin amyloidogenesis inhibitors including dibenzofuran-4,6-dicarboxylic acid (1). An X-ray cocrystal structure of TTR.1(2) reveals that it only utilizes the outer portion of the two thyroxine binding pockets to bind to and inhibit TTR amyloidogenesis. Herein, structure-based design was employed to append aryl substituents at C1 of the dibenzofuran ring to complement the unused inner portion of the thyroxine binding pockets. Twenty-eight amyloidogenesis inhibitors of increased potency and dramatically increased plasma TTR binding selectivity resulted. These function by imposing kinetic stabilization on the native tetrameric structure of TTR, creating a barrier that is insurmountable under physiological conditions. Since kinetic stabilization of the TTR native state by interallelic trans suppression is known to ameliorate disease, there is reason to be optimistic that the dibenzofuran-based inhibitors will do the same. Preventing the onset of amyloidogenesis is the most conservative strategy to intervene clinically, as it remains unclear which of the TTR misassembly intermediates results in toxicity. The exceptional binding selectivity enables these inhibitors to occupy the thyroxine binding site(s) in a complex biological fluid such as blood plasma, required for inhibition of amyloidogenesis in humans. It is now established that the dibenzofuran-based amyloidogenesis inhibitors have high selectivity, affinity, and efficacy and are thus excellent candidates for further pharmacologic evaluation.

Topics: Amyloid; Benzofurans; Dicarboxylic Acids; Kinetics; Models, Molecular; Prealbumin; Structure-Activity Relationship; Substrate Specificity

Polybrominated diphenyl ethers (PBDEs) have been widely used as flame retardants in plastics and textile coatings, and these compounds have been recognized as ubiquitous environmental contaminants. Furthermore, it is considered a serious problem that polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/DFs), having toxicities similar to those of chlorinated dioxins, are generated by the manufacture of brominated flame retardants (BFRs) such as PBDEs, and formed by the combustion of substances containing BFRs. Several congeners of PBDD/DFs and PBDEs have been detected in the adipose tissue of the Japanese. Although food is suspected as an exposure source, little information is available regarding the levels of these brominated compounds in food, as compared with information regarding dioxin or polychlorinated biphenyls. It is necessary to investigate the levels of these brominated organic compounds in various foods and to estimate their influence in the case of human exposure. We developed an efficient method of analyzing PBDEs and PBDD/DFs contents in food samples using accelerated solvent extraction and determined the concentrations in several marine products such as raw fish, processed foods, and seaweed purchased in Japan. A recovery test (n = 5) using the method and involving dried fish showed acceptable recoveries of 57.7-78.5% (RSD 5.4-15.9%) for PBDEs and 50.0-56.4% (RSD 1.5-7.9%) for PBDD/DFs. In the analysis of marine product samples, several congeners of PBDEs were detected in raw fish, processed fish, and seaweed; the highest concentration of sigmaPBDEs was detected in yellowtail (1161 pg/g whole basis), followed by mackerel (553.5 pg/g whole basis). The most dominant congener present in these marine samples was 2,2',4,4'-tetraBDE (#47).

Topics: Animals; Benzofurans; Dioxins; Ethers; Fishes; Polybrominated Biphenyls; Seafood; Seaweed; Shellfish

Postnatal exposure to dioxins in breastfed infants occurs mainly during breast-feeding. The exposure to a substantial amount of endocrine disruptors in the early days of life may cause long-term health effects. Test subjects were healthy and primiparous mothers with a mean age of 28 (S.D. = 3.8) in 2001. The PCDD/F congeners were analyzed in the breast milk using gas chromatograph/high resolution mass spectrometry. The mean level of PCDD/Fs was 7.4 pg-WHO-TEQ/g lipid, which is significantly lower than the level found in individuals from other countries. The total PCDD WHO-TEQ levels in breast milk had a significant positive association with maternal age and a slightly negative association with perinatal BMI (body mass index of the period before and after the delivery). The estimated daily intake of 10.5 pg-WHO-TEQ/kg/day from individual breast milk was predicted for a breastfed infant at 6 months of age with proper assumption of 8 kg body weight, 854 milk per day of consumption, 95% of dioxin absorption rate, and linear decline of dioxin during lactation. Based on the lower WHO-TEQ levels in the breast milk, breast-feeding should still be encouraged and continued in Taiwan.

Topics: Adult; Asia; Benzofurans; Breast Feeding; Dioxins; Environmental Exposure; Europe; Female; Food Contamination; Health Surveys; Humans; Infant; Infant Formula; Maximum Allowable Concentration; Milk, Human; Parity; Taiwan; World Health Organization

Low molecular weight peptidomimetics with simple amphiphilic sequences can help to elucidate the structures of cross beta-sheet assemblies, such as amyloid fibrils. The peptidomimetics described herein comprise a dibenzofuran template, two peptide strands made up of alternating hydrophilic and hydrophobic residues, and carboxyl termini, each of which can be varied to probe the structural requirements for beta-sheet self-assembly processes. The dibenzofuran template positions the strands approximately 10 A apart, allowing corresponding hydrophobic side chains in the strands to pack into a collapsed U-shaped structure. This conformation is stabilized by hydrophobic interactions, not intramolecular hydrogen bonds. Intermolecular stacking of the collapsed peptidomimetics, enabled by intermolecular hydrogen bonding and hydrophobic interactions, affords 25-27 A wide protofilaments having a cross beta-sheet structure. Association of protofilaments, mediated by the dibenzofuran substructures and driven by the hydrophobic effect, affords 50-60 A wide filaments. These widths can be controlled by changing the length of the peptide strands. Further assembly of the filaments into fibrils or ribbons can be controlled by modification of the template, C-terminus, and buffer ion composition.

Topics: Amides; Benzofurans; Biomimetic Materials; Hydrophobic and Hydrophilic Interactions; Models, Molecular; Peptides; Protein Structure, Secondary; Proteins

Polychlorinated biphenyls (PCBs), dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and hexaclorobenzene (HCB) were determined in three sediment cores of the Venice Lagoon: I1, from the San Giuliano Canal that is likely the main source of pollutants for the study area; E, representing the lagoon sediment of the zone of Campalto; and M3, typical of a salt marsh environment and mostly subject to atmospheric inputs. Maximum concentrations were found in core I1: 25-1858 ngI-TE kg(-1) (PCDD/Fs), 1.7-13 microg kg(-1) (HCB), and 107-717 microg kg(-1) (PCBs) are surficial and peak values, respectively. The lagoon sediment (E), is much less contaminated: 24-47 ngI-TE kg(-1) for PCDD/Fs, 2.3-3.6 microg kg(-1) for HCB, and 56-203 microg kg(-1) for PCBs, whereas M3 shows the lowest values: 1.6-6.0 ngI-TE kg(-1) for PCDD/Fs, 0.3-0.6 microg kg(-1) for HCB, and 7.1-39 microg kg(-1) for PCBs. In any case, the recent trend is toward a decrease of pollutant concentration. The chronology of cores E and M3 is based on both 210Pb and 137Cs activity-depth profiles. The maximum concentrations of PCDD/Fs, HCB, and PCBs correspond to the years 1949, 1980, and 1968, respectively. The homologue profiles of PCDD/Fs confirm that I1 has been subject to an industrial source while the other sites also recorded significant contributions, changing over time, of octachlorinated dioxin from combustion. A comparison of the pollutant inventories, all normalised to 210Pb inventories, suggests that the atmospheric contribution to the contamination of the area of Campalto is low: the upper limits range from 6% (PCDD/Fs) to 17% (HCB).

Topics: Benzofurans; Chronology as Topic; Cities; Environmental Monitoring; Environmental Pollutants; Geologic Sediments; Hexachlorocyclohexane; Italy; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Seawater

The dietary intake of arsenic (As), cadmium (Cd), mercury (Hg), lead (Pb), hexachlorobenzene (HCB), polychlorinated naphthalenes (PCNs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated diphenyl ethers (PCDEs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) by elite sportsmen and sportswomen of Catalonia, Spain, was assessed. In 2000, food samples were randomly acquired in various cities of Catalonia. Analysis of the above pollutants were determined according to the appropriate analytical techniques (ICP-MS, HRGC/HRMS, HPLC). In general terms, elite sportsmen and sportswomen showed a higher intake of Cd, Hg, Pb, HCB, PCNs, PCDD/Fs and PAHs than the general population, while it was lower for PCDEs (both sexes), and PCBs and PBDEs (women). According to the FAO/WHO provisional tolerable weekly intake (PTWI) for metals, the WHO tolerable daily intake (TDI) for HCB, and the US EPA's reference dose (RfD) for PAHs, the dietary intakes of environmental pollutants should not mean a potential toxic hazard. However, the WHO-TDI for PCDD/Fs and "dioxin-like" PCBs is exceeded in sportsmen. The current results indicate that the consumption of those food groups showing the highest contribution to the intake of these pollutants should be diminished. In relation to this, the reduction of the consumption of dairy products and cereals would be important.

Topics: Arsenic; Benzofurans; Chromatography, High Pressure Liquid; Diet; Diet Surveys; Environmental Pollutants; Female; Food Analysis; Food Contamination; Humans; Male; Mass Spectrometry; Mental Recall; Metals, Heavy; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Risk Assessment; Risk Factors; Spain; Spectrophotometry; Sports

1,2a-Disubstituted 1,2,2a,8b-tetrahydro-3H-benzo[b]cyclobuta[d]pyran-3-ones bearing an electron-withdrawing group at the 2a-position were treated with two equivalents of dimethylsulfoxonium methylide to give r-1,t-4a,t-9b-1,3-disubstituted 1,2,4a,9b-tetrahydrodibenzofuran-4-ols stereoconvergently regardless of the stereochemistry of the 1-position on the benzocyclobutapyran ring. This methodology was applied to the second-generation synthesis of (+/-)-linderol A, a melanin biosynthesis inhibitory natural product.

Topics: Benzofurans; Magnetic Resonance Spectroscopy; Models, Molecular; Pyrans; Spectrometry, Mass, Electrospray Ionization

Although the metabolism of dibenzofuran by the biphenyl catabolic enzymes had been inferred in previous reports, the metabolic pattern has never been determined unambiguously. In this work, we describe the evolved biphenyl dioxygenase (BPDO) RR41 that exhibits a higher turnover rate of metabolism toward dibenzofuran and chlorodibenzofurans than the parental Burkholderia xenovorans LB400 BPDO. We used RR41 BPDO to identify unambiguously the metabolites produced from the oxygenation of dibenzofuran by LB400 BPDO, and we evaluated their further metabolism by the biphenyl catabolic pathway enzymes of strain LB400. RR41 BPDO was obtained by saturation mutagenesis of targeted amino acid residues. I335F336N338I341L409 of LB400 BphA were replaced by A335M336Q338V341F409 in RR41 BphA. Data confirm the critical role played by these amino acid residues for substrate specificity and regiospecificity.

Topics: Amino Acids; Benzofurans; Biotransformation; Biphenyl Compounds; Burkholderia; Catalysis; Cells, Cultured; Dibenzofurans, Polychlorinated; Dioxygenases; Escherichia coli; Mass Spectrometry; Mutagenesis; Oxidation-Reduction; Substrate Specificity

The role of phenol precursors in polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) formation in municipal waste incinerators is assessed on the basis of homologue and isomer patterns. Homologue and isomer patterns of PCDD and PCDF congeners formed from phenols both in the gas phase and via particle-mediated reactions were studied in an isothermal flow reactor. A mixture of unsubsitituted phenol and 19 chlorinated phenols in relative concentrations found in a municipal waste incinerator (MWI) stack gas was used for this study. PCDD and PCDF homologue and isomer patterns obtained from the phenol experiments were compared with those observed in MWI data. From the phenol experiments, gas-phase formation at 600-700 degrees C favors PCDF formation whereas particle-mediated formation at 400 degrees C favors PCDD formation. Unsubstituted phenol, which was present in high concentration, played a significant role in the formation of PCDD/F congeners under both sets of experimental conditions. PCDD/F distributions in MWI flue gas and fly ash samples were differentfrom those observed in the phenol experiments, suggesting that direct phenol condensation was not the primary route of PCDD/F formation at the incinerators. Gas-phase phenol condensation is a source of dibenzofuran, with subsequent particle-mediated chlorination resulting in PCDF formation. In the case of PCDD formation, phenol condensation may be responsible for the formation of certain highly chlorinated congeners. In this paper we demonstrate the use of homologue and isomer patterns for PCDD/F formation mechanism attribution in municipal waste incinerators.

Topics: Benzofurans; Chromatography, Gas; Incineration; Phenols; Polychlorinated Dibenzodioxins; Refuse Disposal; Temperature; Waste Products

Bleaching earth (dried, powdered, bentonite-montmorillonite clay) is commonly used as a processing aid in edible oil refinement. Used bleaching earth may be incorporated into animal feed indirectly, for example because it is included into seed meal, or directly (e.g., as a binding agent). Control must be demonstrated to ensure that the levels of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in feed ingredients do not infringe European Community regulations. The low legislative action level assigned is analytically challenging and may be at or below the limits of quantification achievable by many laboratories. A statistical comparison (following the IUPAC/ISO/AOAC protocol) was made of analyses of PCDDs and PCDFs in selected bleaching earth samples by laboratories from Europe and the USA to assess the comparability of data. Of 19 sets of results submitted by laboratories for replicate samples, 11 demonstrated acceptable agreement.

Topics: Aluminum Silicates; Animal Feed; Animals; Bentonite; Benzofurans; Clay; Dietary Fats, Unsaturated; Europe; Polychlorinated Dibenzodioxins; Reproducibility of Results; Soil Pollutants; United States

This study presents concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and dioxin-like coplanar PCBs (Co-PCBs) in the liver and breast muscle of jungle crows (JCs; Corvus macrorhynchos) collected from Tokyo, Japan. 2,3,7,8-Tetrachlorodibenzo-p-dioxin toxic equivalents (TEQs) derived by WHO bird-TEF were in the range of 23 to 280 pg/g (lipid) in the liver, which are lower or comparable to the lowest-observed-effect-level of CYP induction in chicken, and 5.6-78 pg/g (lipid) in the pectoral muscle. Cytochrome P450 (CYP) 1A-, 2B-, 2C-, and 3A-like proteins were detected using anti-rat CYP polyclonal antibodies in hepatic microsomal fractions. Significant (p < 0.05) positive correlations between hepatic TEQs and CYP1A or CYP3A-like protein expression levels were noticed, implying induction of these CYP isozymes by TEQs. On the other hand, there was no significant positive correlation between muscle TEQ and any one of analyzed CYP isozyme expression levels. CYP1A- and CYP3A-like protein expression levels represented better correlations with pentoxy- and benzyloxyresorufin-O-dealkylase activities rather than methoxy- and ethoxyresorufin-O-dealkylase activities, indicating unique catalytic functions of these CYPs in JCs. Furthermore, we succeeded in isolating CYP1A5 cDNA from the liver of JC, having an open reading frame of 531 amino acid residues with a predicted molecular mass of 60.3 kDa. JC CYP1A5 mRNA expression measured by real-time RT-PCR had a significant positive correlation with hepatic TEQs, suggesting induction of CYP1A5 at the transcriptional level. Ratios of several Co-PCB congeners to CB-169 in the liver of JCs revealed significant negative correlations with CYP1A protein or CYP1A5 mRNA expression levels, implying metabolism of these congeners by the induced CYP1A. The liver/breast muscle concentration (L/M) ratios of PCDDs/DFs and CB-169 increased with an increase in hepatic CYP1A protein or CYP1A5 mRNA expression levels, suggesting congener-specific hepatic sequestrations by the induced CYP1A. The present study provides insights into the propensity of CYP1A induction to the exposure of dioxin-like chemicals, and unique metabolic and sequestration capacities of CYP1A in JC.

Topics: Amino Acid Sequence; Animals; Aryl Hydrocarbon Hydroxylases; Base Sequence; Benzofurans; Crows; Dioxins; Enzyme Induction; Gene Expression; Liver; Male; Microsomes, Liver; Molecular Sequence Data; Muscle, Skeletal; Oxidoreductases; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Transcription, Genetic

Subcooled liquid vapor pressures (P(L)) are of great importance for assessing the persistent behavior of organic pollutants. As P(L) cannot be determined by direct experiments, it is of interest to develop and evaluate various predictive methods. In the current study, gas chromatography retention index (GC-RI) and quantitative structure-property relationship (QSPR) methods were used to develop predictive models for P(L) of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). The model development was based on P(L) values converted from consistent experimental solid vapor pressures (P(S)). The P(L) values predicted by the two methods are highly consistent with each other, and in-between sets of values predicted by others. Since the QSPR method can be regarded as independent of experiments, and can be used to interpret intermolecular interactions that govern the magnitude of P(L), it may be superior to the GC-RI method.

Topics: Benzofurans; Chemical Phenomena; Chemistry, Physical; Chromatography, Gas; Mathematics; Polychlorinated Dibenzodioxins; Pressure; Quantitative Structure-Activity Relationship; Thermodynamics; Volatilization

Strain YA was newly isolated from an enrichment culture of river sediment and was identified as Janibacter sp. It was able to utilize dibenzofuran as the sole source of carbon and energy. Strain YA degraded > 90% of 1-chloro-dibenzo-p-dioxin (1-CDD) and > 80% of 2-chloro-dibenzo-p-dioxin in 18 hours with each initial concentration at 40 mg/L. A novel metabolite, 2-chloro-2',6-dihydroxydiphenylether, was observed in 1-CDD degradation. From the metabolites detected by gas chromatography-mass spectrometry, strain YA was supposed to have at least two types of oxidation pathways in 1-CDD degradation.

Topics: Actinomycetales; Benzofurans; Biodegradation, Environmental; Dioxins; DNA, Bacterial; DNA, Ribosomal; Gas Chromatography-Mass Spectrometry; Geologic Sediments; Molecular Sequence Data; Molecular Structure; Rivers; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Water Microbiology

QSPR models for water solubility (S), n-octanol/water partition coefficient (K(OW)), and Henry's law constant (H) for polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzo-p-furans (PCDFs) and phthalates have been established based on two different sets of parameters. Those parameters were topology based characteristic root index (CRI) and three semi-empirical molecular descriptors, namely--energies of the highest occupied and the lowest unoccupied molecular orbital (E(HOMO) and E(LUMO)), and dipole moment (mu). The best fit equation found by "forward multiple linear regression" showed that the topology based CRI was the most important parameter for the modelling of solubility and n-octanol/water partition coefficient. For n-octanol/water partition coefficient a two-parameter equation including the CRI and E(HOMO) with a correlation coefficient of r = 0.992 was obtained whereas a three-parameter equation for solubility and Henry's law constant including the CRI, E(LUMO) and mu with a correlation coefficient of r = 0.986 and r = 0.933 was obtained, respectively. E(HOMO) and mu didn't appear in the same model because of the collinearity. The results of modified jackknife tests indicated that the three models were statistically robust. Mean deviation of calculated values from experimental data amounted to 0.27, 0.17, and 0.28 log units for the three properties mentioned. The developed models have been used to predict the S, K(OW) and H of compounds not included in the training sets.

Topics: 1-Octanol; Benzofurans; Chemistry, Physical; Esters; Linear Models; Phthalic Acids; Polychlorinated Dibenzodioxins; Quantitative Structure-Activity Relationship; Regression Analysis; Solubility

Activated carbon injection (ACI) is commonly used to control PCDD/F (polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans) emissions from stationary sources. In this study, the characteristics of PCDD/Fs emitted from one municipal waste incinerator (MWI) and two industrial waste incinerators (IWI-1 and IWI-2) that apply activated carbon systems for controlling the emissions are investigated via intensive stack sampling. MWI and IWI-1 are equipped with ACI and bag filters (BF) while IWI-2 is equipped with a fixed activated carbon bed (FCB). Results indicate that most PCDD/Fs in flue gas downstream of ACI+BF exist in vapor phase (over 90%) while most PCDD/ Fs exist in solid phase (over 60%) downstream of FCB. For MWI and IWI-1, the removal efficiencies of vapor and solid-phase PCDD/Fs are 98.5-99.6% and 99.8-99.9%, respectively. In addition,the removal efficiencies of vapor- and solid-phase PCDD/Fs are 84.5% and -13.4% in IWI-2, respectively. The results also indicate that the partition of vapor/solid-phase PCDD/F is affected by the type of the air pollutant control devices (APCDs) applied upstream and the particulate matter concentration in flue gas. On the basis of the sampling results of waste incinerators, this study preliminarily establishes the equations for predicting vapor/solid-phase PCDD/F partition in flue gases downstream of various APCDs including cyclone (CY), electrostatic precipitator (EP), FCB, ACI+BF, and selective catalytic reduction system (SCR).

Topics: Air Pollutants; Air Pollution; Benzofurans; Carbon; Dioxins; Gas Chromatography-Mass Spectrometry; Incineration; Phase Transition; Refuse Disposal

To assess emissions of dioxins (chlorinated dibenzodioxins and dibenzofurans) and PCB from uncontrolled domestic combustion of waste ("backyard burning"), test combustions in barrels and open fires were monitored. The waste fuels used were garden waste, paper, paper and plastic packaging, refuse-derived fuel (RDF), PVC, and electronic scrap. Combustions including PVC and electronic scrap emitted several orders of magnitude more dioxins than the other waste fuels. Emissions from the other fuels had considerable variations, but the levels were difficult to relate to waste composition. Emission factors of PCDD/F and PCB from the backyard burning ranged from 2.2 to 13 000 ng (WHO-TEQ)/kg. The levels found in ash usually were less than 5% of the total. For assessment of total emissions of dioxins and PCB from backyard burning of low and moderately contaminated wastes, an emission factor range of 4-72 ng (WHO-TEQ)/kg is suggested. These figures implythat combusting waste in the backyard could contribute substantially to total emissions, even if the amounts of fuel involved are equivalent to just a few tenths of a percent of the amounts combusted in municipal waste incinerators.

Topics: Air Pollutants; Benzofurans; Environmental Monitoring; Incineration; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Refuse Disposal; Soil Pollutants; Sweden

Combustion experiments performed in the presence of hydrogen chloride (HCl) in a laboratory-scale fluidized-bed reactor were carried out to elucidate the role of chlorine in the formation of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs; together: PCDD/Fs) in various sections of a municipal waste incinerator. We first demonstrated that the homologue profile and the pattern of the congener proportions of PCDD/Fs for a model waste containing poly(vinyl chloride) (PVC) combusted in the absence of HCl were similar to those for a PVC-free waste combusted in the presence of HCl. This showed no difference between PVC in the waste and injected HCl in the role as a chlorine source in PCDD/F formation during incineration. Next, to investigate PCDD/F formation in each section of the incinerator, we carried out combustion experiments with the PVC-free waste, injecting HCl at different locations of the incinerator. The amounts of PCDDs and PCDFs formed were significantly reduced when HCI was not supplied to the main combustion section. The presence of HCI in the main combustion section was essential for the formation of PCDD/Fs, even in the downstream sections. This finding indicates that compounds that were able to form PCDD/Fs in the downstream sections were mainly formed in the main combustion section in the presence of HCl.

Topics: Air Pollutants; Benzofurans; Chlorine; Hydrochloric Acid; Incineration; Polychlorinated Dibenzodioxins; Polyvinyl Chloride; Waste Management

The dibenzofuran (DF)-utilizing bacterium strain YY-1 was newly isolated from soil. The isolate was identified as Janibacter sp. with respect to its 16S rDNA sequence and fatty acid profiles, as well as various physiological characteristics. In addition to DF, strain YY-1 could grow on fluorene and dibenzothiophene as sole sources of carbon and energy. It was also able to cometabolize a variety of polycyclic aromatic hydrocarbons including dibenzo- p-dioxin, phenanthrene, and anthracene. The major metabolites formed from DF, biphenyl, dibenzothiophene, and naphthalene were identified by using gas chromatography-mass spectrometry as 2,3,2'-trihydroxybiphenyl, biphenyl-dihydrodiol, dibenzothiophene 5-oxide, and coumarin, respectively. These results indicate that strain YY-1 can catalyze angular dioxygenation, lateral dioxygenation, and sulfoxidation.

Topics: Actinomycetales; Benzofurans; Fluorenes; Phylogeny; Polycyclic Aromatic Hydrocarbons; Thiophenes

Adipose tissue samples from 158 cattle raised locally at experiment stations across the USA were analysed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F). While 80% of the samples had PCDD/F concentrations that fell within the range of a previous US survey of beef animals (not detected -4.1 ppt toxic equivalency), several animals had exceptionally high concentrations (8-54 ppt toxic equivalency). The investigations of three facilities where highly contaminated animals were raised found pentachlorophenol-treated wood at each site. The congener pattern in the animals' tissues and the lack of elevated PCDD/F levels in other environmental samples, i.e. hay and soil, indicated that the treated wood was the source of contamination. A congener pattern similar to that of pentachlorophenol-exposed animals was seen for the means and medians of the entire data, i.e. OCDD, HpCDD and 1,2,3,6,7,8-HxCDD dominated, the PCDD concentrations equalled or exceeded the furan concentrations, and the concentration of 1,2,3,6,7,8-HxCDD was six times that of the other HxCDD isomers. This suggested that pentachlorophenol-treated wood contributed measurably to many of the animals in this survey. The largest contributors to the median toxic equivalencies were 1,2,3,7,8-PeCDD (40%) and 1,2,3,6,7,8-HxCDD (16%). No clear geographical trends emerged from the data.

Topics: Adipose Tissue; Animal Husbandry; Animals; Benzofurans; Cattle; Dioxins; Environmental Pollutants; Female; Food Contamination; Male; Meat; Pentachlorophenol; United States; Wood

We characterized legacy and new contaminants in the highly endangered Vancouver Island (British Columbia, Canada) marmot and found generally low blood and fat concentrations of a complex mixture of pesticides, polychlorinated biphenyls (PCBs), -dibenzo-p-dioxins (PCDDs), -dibenzofurans (PCDFs), polybrominated biphenyls (PBBs), polybrominated diphenyl ethers (PBDEs), and polychlorinated naphthalenes (PCNs) in their tissues. The dominance of the more volatile alpha-hexachlorocyclohexane (HCH) and hexachlorobenzene (HCB) pesticides and the lesser chlorinated PCB congeners suggests that atmospheric processes largely explain the contamination of this high-altitude herbivore.

Topics: Adipose Tissue; Animals; Atmosphere; Benzofurans; British Columbia; Carbon Isotopes; Dioxins; Environmental Monitoring; Environmental Pollutants; Gas Chromatography-Mass Spectrometry; Marmota; Pesticides; Polybrominated Biphenyls; Polychlorinated Biphenyls

The concentrations and profiles of dibenzo-p-dioxins, dibenzofurans, polychlorinated biphenyls and polynuclear aromatic compounds in various environmental matrices are presented in this study. The examined environmental matrices are total suspended particles, fly ash and soil collected in NW Greece, an area characterized by intensive coal burning for electrical power generation. Moreover, the occurrence of organic micropollutants in soot after an accidental fire was examined and the possible impact on the outdoor environment was evaluated. Results were statistically treated to obtain information on representative PCDD/F profiles in each matrix and to compare these profiles with the compositional patterns of possible sources from literature. Coal combustion, fly ash and vehicle exhausts appeared to be the most possible sources in local atmosphere.

Topics: Benzofurans; Carbon; Coal; Dioxins; Environmental Pollutants; Gas Chromatography-Mass Spectrometry; Greece; Polychlorinated Biphenyls; Polycyclic Aromatic Hydrocarbons; Principal Component Analysis; Soil; Vehicle Emissions

To develop an enzyme-linked immunosorbent assay (ELISA) for monitoring the toxicity due to polychlorinated dibenzo-p-dioxins and dibenzofurans contaminated in human breast milk, we have generated novel monoclonal antibodies using some haptenic derivatives linked to bovine serum albumin via the C-1 or C-2 position on the dioxin skeleton. BALB/c or A/J mice were repeatedly immunized with the immunogen, and spleen cells were fused with P3/NS1/1-Ag4-1 myeloma cells. After five fusion experiments, a hybridoma clone was established that secretes an antibody D9-36 group specifically recognizing the major toxic congeners, 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD), 1,2,3,7,8-pentachlorodibenzo-p-dioxin, and 2,3,4,7,8-pentachlorodibenzofran. An ELISA is developed on the basis of the competitive and labeled-antigen format. The toxic congeners extracted from butter or milk specimens by a novel extraction cartridge and a peroxidase-labeled dioxin analogue were sequentially reacted with a fixed amount of D9-36 in the presence of Triton X-100. The bound fraction was captured on a microtiter plate, immobilizing a second antibody, and the enzyme activity was colorimetrically determined. This ELISA afforded a practical sensitivity (measurable range, 1-100 pg/assay; detection limit, 1.0 pg/assay as 2,3,7,8-TCDD equivalent). The assay values for milk and butter samples were in reasonable accordance with the sum of the toxicity-equivalent quantity of each congener, which had been determined by a high-resolution gas chromatography/high-resolution mass spectrometry method.

Topics: Animals; Antibodies, Monoclonal; Benzofurans; Cattle; Dioxins; Environmental Pollutants; Enzyme-Linked Immunosorbent Assay; Humans; Mice; Milk, Human; Polychlorinated Dibenzodioxins

A model for predicting the distribution of dibenzofuran and polychlorinated dibenzofuran (PCDF) congeners from a distribution of phenols was developed. The model is based on a simplified chemical mechanism. Relative rate constants and reaction order with respect to phenol precursors were derived from experimental results using single phenols and equal molar mixtures of up to four phenols. For validation, experiments were performed at three temperatures using a distribution of phenol and 19 chlorinated phenols as measured in municipal waste incinerator exhaust gas. Comparison of experimental measurements and model predictions for PCDF isomer distributions and homologue pattern shows agreement within measurement uncertainty. The R-squared correlation coefficient exceeds 0.9 for all PCDF isomer distributions and the distribution of PCDF homologues. These results demonstrate that the distribution of dibenzofuran and the 135 PCDF congeners from gas-phase condensation of phenol and chlorinated phenols can be predicted from measurement of the distribution of phenol and the 19 chlorinated phenol congeners.

Topics: Air Pollutants; Benzofurans; Dibenzofurans, Polychlorinated; Incineration; Kinetics; Models, Chemical; Phenols; Temperature

Data on occurrence of dioxins (polychlorinated dibenzo-p-dioxins [PCDDs] and dibenzofurans [PCDFs]), dioxin-like PCBs (polychlorinated non-ortho and mono-ortho biphenyls) and non-dioxin-like PCBs (as represented by the so-called indicator-PCBs: congeners 28, 52, 101, 118, 138, 153 and 180) in food products consumed in The Netherlands that were collected in measurement programs carried out during 1998 and 1999, and combined with food consumption data to assess the dietary intake of these persistent food contaminants. The estimated median life-long-averaged intake of the sum of dioxins and dioxin-like PCBs in the population is 1.2 pg WHO-TEQ (toxic equivalents) per kg body weight (bw) per day, while the estimated median life-long-averaged intake of indicator-PCBs is 5.6 ng per kg bw per day. The contribution of different food groups to the total intake of both dioxins + dioxin-like PCBs and non-dioxin-like PCBs is fairly uniformly distributed over the foods consumed: meat products (23% and 27%, respectively), dairy products (27% and 17%, respectively), fish (16% and 26%, respectively), eggs (4% and 5%, respectively), vegetable products (13% and 7%, respectively), and industrial oils and fats (17% and 18%, respectively). Compared with earlier intake estimations the present estimation shows a continued reduction in the intake of dioxins as well as PCBs. This reduction is related to the decrease in the concentration of these substances in the majority of foodstuffs. Nevertheless, a small part of the population still has a rather high life-long averaged intake: 8% of the population is exposed to intake levels above the tolerable weekly intake for dioxins and dioxin-like PCBs of 14 pg WHO-TEQ per kg bw per week, as recently derived by the Scientific Committee on Food of the European Commission. For the non-dioxin-like PCBs an internationally accepted maximum intake level is still lacking. However, to provide risk managers with a health-based guideline to prevent health effects of exposure to non-dioxin-like PCBs, the (international) derivation of a tolerable daily intake is recommended. Monitoring the dietary intake of PCBs is just as important as monitoring the intake of dioxins and dioxin-like PCBs, and attempts to decrease the exposure to both compound classes need continuous attention.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Benzofurans; Body Burden; Child; Child, Preschool; Dioxins; Environmental Exposure; Female; Food Analysis; Humans; Infant; Male; Middle Aged; Netherlands; Polychlorinated Biphenyls

This study determined PCDD/F and PCB levels in human milk, examined factors associated with levels of contamination, and assessed the infant body burden from breast-feeding. The congeners of PCDD/Fs, dioxin-like PCBs, and indicator PCBs were analyzed by HRGC/HRMS for 36 human milk samples from healthy women, aged 20-35 years, from December 2000 to November 2001 in central Taiwan. Mean levels of WHO-TEQs in human milk were 10.5 (95% CI=8.8-12.2) and 14.5 (95% CI=12.5-16.5) pg-TEQ/g lipid for those <29 and > or =29 years old, respectively. PCB 138 concentration significantly predicted total WHO-TEQs with r2=0.84 (p <0.001). Milk level of dioxin-TEQ was 9.63 pg-TEQ/g lipid (95% CI=7.0-13.2) in those with a yearly income $29,000 compared to 6.3 pg-TEQ/g lipid (95% CI=5.2-7.6) for those whose yearly income was $18,000 per year. Women who reported being Buddhist (64.3 ng/glipid) had significantly higher indicator PCB concentrations than did those who reported being Taoist (35.3 ng/g lipid). The monthly dioxin intake of exclusively breastfed infants decreased with increasing duration of lactation. The cumulative dose of exclusively breastfed infants (76.5 ng TEQ, 95% CI=69.7-83.3) was significantly greater compared to that of formula-fed infants (CI=16.4-17.0) at one year and to that of infants at birth (3.90 ng TEQ, 95% CI=3.6-4.2). Our findings suggest that breast-feeding should be strongly encouraged for infants in Taiwan.

Topics: Adult; Age Factors; Benzofurans; Biphenyl Compounds; Body Burden; Breast Feeding; Diet; Dioxins; Education; Environmental Pollutants; Female; Humans; Income; Infant; Infant Food; Infant, Newborn; Milk, Human; Polychlorinated Biphenyls; Religion; Socioeconomic Factors

Adult Atlantic salmon (Salmo salar) were fed on four diets containing polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) for 30 weeks. Lipid-normalized concentrations showed that all congeners were equally partitioned between whole-fish and fillet samples. Skinned fillet accumulated approximately 30% of the total PCDD/F and PCB content in fish. Accumulation efficiencies in whole fish were 43% for 2,3,7,8-chlorinated dibenzo-p-dioxins and dibenzofurans, 83% for dioxin-like PCBs, and 78% for other PCB congeners. Among PCDD/Fs, tetra- and pentachlorinated congeners were preferentially accumulated in salmon, whereas hepta- and octachlorinated dibenzo-p-dioxins were excreted in the feces. Substitution patterns that were associated with a preferential accumulation of PCBs in salmon included non-ortho substitution and tetrachlorination. Accumulation efficiencies and lipid-normalized biomagnification factors (BMFs) were not influenced by the PCDD/F and PCB concentrations of the diets. Biomagnification (BMF > 1) of tetra- and pentachlorinated dibenzo-p-dioxins and dibenzofurans and of all the PCBs was observed. Differences in the behavior of PCDD/F and PCB congeners resulted in a selective enrichment of the most toxic congeners in salmon.

Topics: Animals; Atlantic Ocean; Benzofurans; Dibenzofurans, Polychlorinated; Diet; Environmental Pollutants; Humans; Lipids; Multivariate Analysis; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Salmo salar; Water Pollutants, Chemical

The ability of the imperfect soil fungus Paecilomyces lilacinus to transform the environmental pollutant dibenzofuran was investigated. Transformation of dibenzofuran and related derivatives lead to 14 products, which were identified by UV spectroscopy, mass spectrometry, and proton nuclear magnetic resonance spectroscopy. Biotransformation was initiated by two separate hydroxylation steps, leading to the accumulation of 4-monohydroxylated and 4-dihydroxylateddibenzofurans. Hydroxylation at both aromatic rings produced 2,7-dihydroxydibenzofuran, 3,7-dihydroxydibenzofuran, and 2,8-dihydroxydibenzofuran. Further oxidation yields ring cleavage of dibenzofuran, which has not been described before for filamentous fungi. The ring fission products were identified as benzo[ b]furo[3,2-d]-2-pyrone-6-carboxylic acid and [2-(1-carboxy-methylidene)-benzofuran-3-ylidene]-hydroxy-acetic acid and its derivatives hydroxylated at carbon 7 and 8 at the non-cleaved ring. Other metabolites were riboside-conjugates of 2-hydroxydibenzofuran and 3-hydroxydibenzofuran. The results showed that P. lilacinus transforms the hydrophobic compound dibenzofuran by phase I/phase II reactions to produce hydroxylated products and excretable sugar conjugates.

Topics: Benzofurans; Biotransformation; Hydroxylation; Oxidation-Reduction; Paecilomyces; Soil Microbiology

Sediment, pore water and water samples from the Hyeongsan River, Korea were analyzed for several classes of halogenated aromatic hydrocarbons (HAHs) and their dioxin-like activities were evaluated using the in vitro H4IIE-luc bioassay. Polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) were detected in sediments from all six sampling locations with mean concentrations of 2.8 x 10(2) pg/g, 190 pg/g, and 61.4 ng/g, dw, respectively. Polycyclic aromatic hydrocarbons (PAHs) were predominated by 4-6 ring compounds with concentrations in the range of 5.30-7680 ng/g, dw. Chemical profiles of target analytes in sediment and water samples revealed that there was a gradient of concentrations along the river from upstream to downstream, which suggested that the primary source was a wastewater reservoir adjacent to a sewage treatment plant (STP). TEQs derived by summing the product of concentrations of individual congeners by their respective relative potencies (REPs or TEFs) ranged from 4.3 x 10(-1) to 1.1 x 10(3) pg/g, dw. Raw Soxhlet extracts from all six sampling locations induced significant dioxin-like responses in the H4IIE-luc bioassay. TCDD-EQs derived from H4IIE bioassay ranged from 7 x 10(-3) to 1.5 x 10(3) pg/g, dw, which were significantly correlated with TEQs (r2 = 0.994, p < 0.05). Among the three Florisil fractions tested, PCDD/Fs in fraction (F2) induced the greatest magnitude of response (range: 24-83%-TCDD-max.) in the H4IIE-luc assay. Comparison of the TEQ and TCDD-EQ suggested little non-additive interaction between fractions and AhR-active and inactive compounds. Concentrations of individual congeners as well as TEQs and TCDD-EQs suggest inputs from the industrial center waste stream in the Hyeongsan River.

Topics: Benzofurans; Carbon; Environmental Pollutants; Environmental Pollution; Geologic Sediments; Korea; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Polycyclic Aromatic Hydrocarbons; Rivers; Sewage; Soil Pollutants

Three different extraction methods were evaluated: Soxhlet extraction, accelerated solvent extractor extraction and alkali digestion with high-resolution gas chromatography/high-resolution mass spectrometry, for the analysis of edible freshwater fish and frogs. The recovery efficiencies for the different extraction methods were also compared. Using these extraction methods, the concentrations and spatial distributions of these compounds in freshwater fish and frogs (n = 99), collected from 31 locations on four major river systems (Han, Nakdong, Kum and Youngsan) and two wetlands in South Korea, were examined. The concentrations of total polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in all the freshwater fish and frog samples were analysed. The toxic equivalency (TEQ) concentration of PCDD/Fs in fish ranged from 0 (n.d.) to 1.309 pg I-TEQ g(-1) wet weight. Detailed concentrations for different types of fish were as follows (pg I-TEQ g(-1) wet weight): 0 (n.d.)-1.309 for crucian (mean 0.331, n = 28), 0.004-0.743 for carp (0.244, n = 10), 0.004-0.592 for dace (0.198, n = 8), 0.187-0.400 for cornet fish (0.287, n = 3), 0.164-0.410 for Korean piscivorous chub (0.303, n = 6), 0.105-0.516 for bass (0.310, n = 2), 0.451-0.812 for mullet (0.631, n = 2), 0.082 for long-nosed barbell, 0.100 for common Korean bitterling and 0.995 for dark chub. The total TEQ concentration ranged from 0 (n.d.) to 1.258 pg I-TEQ g(-1) wet weight for the two kinds of frogs (n = 36) investigated: 0 (n.d.)-1.258 pg I-TEQ g(-1) (mean 0.346, n = 29) for the bullfrog and from 0 (n.d.)-0.474 pg I-TEQ g(-1) (0.185, n = 7) for the mountain frog.

Topics: Animals; Bass; Benzofurans; Carps; Dioxins; Fishes; Food Contamination; Fresh Water; Gas Chromatography-Mass Spectrometry; Goldfish; Korea; Rana catesbeiana; Ranidae

Three dibenzofuran (DF)-degrading strains were newly isolated from roots of white clover ( Trifolium repens L.) and poplar trees grown in DF-contaminated soil samples. These strains, designated KD2, KD7, and PD1, were characterized as Comamonas sp. on the basis of their 16S rDNA sequences and physiological characteristics. The metabolites produced when strain KD7 was incubated with DF were identified by gas chromatography-mass spectrometry (GC-MS) analysis. Interestingly, strain KD7 was found to have two pathways for DF degradation, beginning with angular dioxygenation at carbons 4 and 4a, and lateral dioxygenation at carbons 1 and 2, respectively. Furthermore, strains KD2 and KD7 not only achieved efficient root colonization in clover but also promoted clover growth. They are the first reported Comamonas sp. strains capable of utilizing DF as a sole carbon source. This provides additional information on the diversity of DF-degrading bacteria.

Topics: Benzofurans; Biodegradation, Environmental; Comamonas; Molecular Sequence Data; Phenotype; Plant Roots; Populus; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Soil Microbiology; Soil Pollutants; Trifolium

Thirteen dibenzofuran (DF)-utilizing bacteria carrying the DF terminal dioxygenase genes homologous to those of Terrabacter sp. strain DBF63 (dbfA1A2) were newly isolated from activated sludge samples. The amplified ribosomal DNA restriction analysis and the hybridization analyses showed that these strains were grouped into five genetically different types of bacteria. The sequence analyses of the 16S rRNA genes and the dbfA1A2 homologues from these five selected isolates revealed that the isolates belonged to the genus Rhodococcus, Terrabacter or Janibacter and that they shared 99-100% conserved dbfA1A2 homologues. We investigated the genetic organizations flanking the dbfA1A2 homologues and showed that the minimal conserved DNA region present in all five selected isolates consisted of an approximately 9.0-kb region and that their outer regions became abruptly non-homologous. Among them, Rhodococcus sp. strain DFA3 possessed not only the 9.0-kb region but also the 6.2-kb region containing dbfA1A2 homologues. Sequencing of their border regions suggested that some genetic rearrangement might have occurred with insertion sequence-like elements. Also, within their conserved regions, some insertions or deletions were observed.

Topics: Actinobacteria; Actinomycetales; Benzofurans; Biodegradation, Environmental; Blotting, Southern; Dioxygenases; DNA, Ribosomal; Molecular Sequence Data; Physical Chromosome Mapping; Restriction Mapping; Rhodococcus; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Sewage

Ash from the secondary combustor/boiler of a rotary kiln burning hazardous chemical waste was tested in the laboratory for its potential to form polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F). The ash contained only a small quantity of "native" PCDD/F, i.e., formed on the ash in the facility. However, it produced a considerable amount of these compounds when heated in 10% O(2)/N(2) under "de novo" conditions, i.e., with residual carbon (present on the ash as result of incomplete combustion) as the only organic material. The ash yielded PCDD/F for up to 90 min; gave PCDD/F yields proportional to the amount of ash used in the reaction bed; and displayed an optimum temperature range for formation (397-548 degrees C) higher than seen for most municipal solid waste (MSW) fly ashes. The role of copper and iron as catalytic material on the ash is discussed.

Topics: Benzofurans; Catalysis; Copper; Environmental Pollutants; Hazardous Waste; Iron; Polychlorinated Dibenzodioxins; Refuse Disposal; Temperature

The dioxin-degrading strain Pseudomonas veronii PH-03 was isolated from contaminated soil by selective enrichment techniques. Strain PH-03 grew on dibenzo-p-dioxin and dibenzofuran as a sole carbon source. Further, 1-chlorodibenzo-p-dioxin, 2-chlorodibenzo-p-dioxin and other dioxin metabolites, salicylic acid, and catechol were also metabolized well. Resting cells of strain PH-03 transformed dibenzo-p-dioxin, dibenzofuran, 2,2',3-trihydroxybiphenyl, and some chlorodioxins to their corresponding metabolic intermediates such as catechol, salicylic acid, 2-hydroxy-(2-hydroxyphenoxy)-6-oxo-2,4-hexadienoic acid, and chlorocatechols. The formation of these metabolites was confirmed by comparison of gas chromatography-mass spectrometry (GC-MS) data with those of authentic compounds. Although we did observe the production of 3,4,5,6-tetrachlorocatechol (3,4,5,6-TECC) from 1,2,3,4-tetrachlorodibenzo-p-dioxin (1,2,3,4-TCDD) with resting cell suspensions of PH-03, growth of strain PH-03 in the presence of 1,2,3,4-TCDD was poor. This result suggests that strain PH-03 is unable to utilize 3,4,5,6-TECC, even at very low concentration (0.01 mM) due to its toxicity. In cell-free extracts of DF-grown cells, 2,2',3-trihydroxybiphenyl dioxygenase, 2-hydroxy-6-oxo-6-phenyl-2,4-hexadienoic acid hydrolase, and catechol-2,3-dioxygense activities were detected. Moreover, the activities of meta-pyrocatechase and 2,2',3-trihydroxybiphenyl dioxygenase from the crude cell-free extracts were inhibited by 3-chlorocatechol. However, no inhibition was observed in intact cells when 3-chlorocatechol was formed as intermediate.

Topics: Benzofurans; Biodegradation, Environmental; Biotransformation; Catechols; Dioxins; Kinetics; Oxygen Consumption; Pseudomonas

An extended study of seven fused silica capillary gas chromatographic (GC) columns has been conducted with regard to separation of international toxic equivalent factor (I-TEF) isomers (tetra- through octa-chlorinated at 2,3,7,8 positions) of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/PCDFs) from closely co-eluted other isomers using high-resolution gas chromatography-high-resolution mass spectrometry (HRGC-HRMS). The data are explicated in mass chromatograms of Series 5 GC columns from a variety of manufacturers (Varian CP-Sil 8 CB LowBleed/MS, Phenomenex ZB-5UMS, Agilent HP-5MS, Restek Rtx-5MS, Supelco Equity-5, J&W Scientific DB-5 and DB-5MS), according to relative retention times, and 2,3,7,8-substituted isomer concentrations for each of the columns tested. Results showed differences between 5% phenyl methyl silicone and 5% silphenylene (Si-arylene) silicone polymer type GC stationary phases in separation of 2,3,7,8-substituted PCDDs/PCDFs from closely co-eluted isomers. The separation differences for Si-arylene type columns resulted in lower toxic equivalence (TEQ) values compared to the siloxane-based columns. Because of differences in product nomenclature and manufacturing practices by various manufacturers, incorrect assumptions and comparisons may be made regarding the interchangeability of these columns for PCCD/PCDF separations. The data presented are the most comprehensive to date and provide a valuable addition to operational criteria for the standard US Environmental Protection Agency methods 1613b and 8290.

Topics: Benzofurans; Chromatography, Gas; Dioxins; Mass Spectrometry; Sensitivity and Specificity

Multivariate models are reported that can predict the relative toxicity of compounds with severe environmental impact, namely polychloro dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). Multiple linear regression analysis (MLR) and partial least square projections of latent variables (PLS) show the usefulness of graph-theoretical descriptors, mainly topological charge indices (TCIs), in these series. The general trends of the group are correctly reproduced and better results are presented than have previously been published. In general, the more toxic compounds exhibit more symmetric molecular structures.

Topics: Animals; Benzofurans; Carcinoma, Hepatocellular; Cytochrome P-450 CYP1A1; Dioxins; Disease Models, Animal; Drug Design; Environmental Pollutants; Least-Squares Analysis; Linear Models; Models, Chemical; Models, Statistical; Models, Theoretical; Multivariate Analysis; Neoplasms, Experimental; Polychlorinated Dibenzodioxins; Quantitative Structure-Activity Relationship; Rats; Reproducibility of Results; Soil Pollutants

Congener-specific analyses of seventeen 2,3,7,8-substituted PCDD/Fs, three non-ortho and 8 mono-ortho dioxin-like polychlorinated biphenyls (PCBs) were performed on 258 Spanish foodstuff samples, mainly of animal origin, for 2000--03. Daily dietary intakes of PCDD/Fs and PCBs, expressed as toxic equivalents (WHO-TEQs), were estimated by combining food consumption data from the Spanish National Institute Statistics survey and concentration levels measured in individual samples, using upper bound determination values (not detectable = limit of detection). The calculated dietary intake of PCDD/Fs for a person weighing 70 kg was 1.35+/-0.11pg WHO-TEQs kg(-1) bw day(-1), and 3.22+/-0.75 pg WHO-TEQs kg(-1) bw day(-1) if dioxin-like PCBs (non- and mono-ortho PCBs) were included, showing the importance of their inclusion in monitoring studies. Both values were within the range of tolerable daily intake (TDI) proposed by the WHO (1-4pg WHO-TEQs kg(-1) bw day(-1)). The current levels are lower than earlier intakes estimates conducted in Spain. Meat and meat products accounted for more than 35% of the intake, followed by milk and milk products (29%), vegetables oils (19%), fish and seafood (11%) and eggs (4%). Dioxin-like PCBs are an important component in the total WHO-TEQs in foodstuffs. This is particularly true for the fish food group, where the total WHO-TEQs is dominated by dioxin-like PCBs (up to 80% of WHO-TEQs in some cases).

Topics: Benzofurans; Diet; Diet Surveys; Dioxins; Food Analysis; Food Contamination; Humans; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Spain

The principle and application in the environmental analysis of Solid Phase Extraction (SPE) combined with Room Temperature Phosphorescence (RTP) analysis were reviewed. The principle, device, separation modes, operation procedures and application of SPE were commented. The merits and shortages in the operation procedure and quantitative analysis of classic RTP were also summarized. The potential application in the trace sample analysis and the advantage of coupling technique of SPE and RTP were indicated. The sensitivity and selectivity of the coupling technique could be greatly increased because of the strong enrichment ability of the SPE materials and the high selectivity of RTP. So far the technique has been successfully used in the analysis of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and polychlorinated dibenzofurans (PClDBFs) in the environmental samples according to their phosphorescence emission after preconcentration on the Whatman 1PS filter paper and C18 or C8 SPE membranes.

Topics: Adsorption; Benzofurans; Luminescent Measurements; Polychlorinated Biphenyls; Polycyclic Aromatic Hydrocarbons; Sensitivity and Specificity; Solid Phase Extraction; Temperature

Porphyrin architectures bearing a hydrogen-bonding scaffold have been synthesized. The H-bond pendant allows proton-coupled electron transfer (PCET) to be utilized as a vehicle for effecting catalytic O-O bond activation chemistry. Suzuki cross-coupling reactions provide a modular synthetic strategy for the attachment of porphyrins to a rigid xanthene or dibenzofuran pillar bearing the H-bond pendant. The resulting HPX (hanging porphyrin xanthene) and HPD (hanging porphyrin dibenzofuran) systems permit both the orientation and acid-base properties of the hanging H-bonding group to be controlled. Comparative reactivity studies for the catalase-like disproportionation of hydrogen peroxide and the epoxidation of olefins by the HPX and HPD platforms with acid and ester hanging groups reveal that the introduction of a proton-transfer network, properly oriented to a redox-active platform, can orchestrate catalytic O-O bond activation. For the catalase and epoxidation reaction types, a marked reactivity enhancement is observed for the xanthene-bridged platform appended with a pendant carboxylic acid group, establishing that this approach can yield superior catalysts to analogues that do not control both proton and electron inventories.

Topics: Benzofurans; Catalase; Cytochrome P-450 Enzyme System; Epoxy Compounds; Hydrogen Bonding; Oxidation-Reduction; Peroxidases; Porphyrins; Protons; Xanthenes

Pseudomonas sp. strain C3211 was isolated from a temperate climate soil contaminated with creosote. This strain was able to degrade carbazole, dibenzothiophene and dibenzofuran at 10 degrees C with acetone as a co-substrate. When dibenzothiophene was degraded by strain C3211, an orange compound, which absorbed at 472 nm, accumulated in the medium. Degradation of dibenzofuran was followed by accumulation of a yellowish compound, absorbing at 462 nm. The temperature optimum of strain C3211 for degradation of dibenzothiophene and dibenzofuran was at 20 to 21 degrees C, while the maximum temperature for degradation was at 27 degrees C. Both compounds were degraded at 4 degrees C. Degradation at 10 degrees C was faster than degradation at 25 degrees C. This indicates that strain C3211 is adapted to life at low temperatures.

Topics: Benzofurans; Biodegradation, Environmental; Carbazoles; Carcinogens; Molecular Structure; Pseudomonas; Temperature; Thiophenes; Time Factors

Dibenzofuran (DF) is formed from phenol and benzene in combustion gas exhaust streams prior to particle collection equipment. Subsequent chlorination at lower temperatures on particle surfaces is a potential source of chlorinated dibenzofuran (CDF). Gas streams containing 8% O(2) and approximately 0.1% DF vapor were passed through particle beds containing copper (II) chloride (0.5% Cu, mass) at temperatures ranging from 200 to 400 degrees C to investigate the potential for CDF formation during particle collection. Experiment duration was sufficient to provide an excess amount of DF (DF/Cu=3). The efficiency of DF chlorination by CuCl(2) and the distribution of CDF products were measured, with effects of temperature, gas velocity, and experiment duration assessed. Results of a more limited investigation of dibenzo-p-dioxin (DD) chlorination by CuCl(2) to form chlorinated DD (CDD) products are also presented. The efficiency of DF/DD chlorination by CuCl(2) was high, both in terms of CuCl(2) utilization and DF/DD conversion. Total yields of Cl on CDF/CDD products of up to 0.5 mole Cl per mole CuCl(2) were observed between 200 and 300 degrees C; this suggests that nearly 100% CuCl(2) was utilized, assuming a conversion of two moles of CuCl(2) to CuCl per mole Cl added to DD/DF. In a short duration experiment (DF/Cu=0.3), nearly 100% DF adsorption and conversion to CDF was achieved. The degree of CDF chlorination was strongly dependent on gas velocity. At high gas velocity, corresponding to a gas-particle contact time of 0.3 s, mono-CDF (MCDF) yield was largest, with yields decreasing with increasing CDF chlorination. At low gas velocity, corresponding to a gas-particle contact time of 5 s, octa-CDF yield was largest. DF/DD chlorination was strongly favored at lateral sites, with the predominant CDF/CDD isomers within each homologue group those containing Cl substituents at only the 2,3,7,8 positions. At the higher temperatures and lower gas velocities studied, however, broader isomer distributions, particularly of the less CDD/CDF products, were observed, likely due to preferential destruction of the 2,3,7,8 congeners.

Topics: Air Movements; Benzene; Benzofurans; Copper; Dioxins; Incineration; Phenol; Refuse Disposal; Temperature

The Suzuki cross-coupling methodology provides a facile synthetic approach for the modular preparation of meso-tetraaryl cofacial bisporphyrins anchored by xanthene and dibenzofuran. This synthetic method furnishes cofacial bisporphyrin templates with enhanced steric and electronic protection from mu-oxo formation and oxidative degradation. The ability of these platforms to support multielectron oxidation chemistry mediated by proton-coupled electron transfer (PCET) is demonstrated by their reactivity for the catalytic disproportionation of hydrogen peroxide to oxygen and water.

Topics: Benzofurans; Catalysis; Hydrogen Peroxide; Indicators and Reagents; Magnetic Resonance Spectroscopy; Metalloporphyrins; Molecular Structure; Oxidation-Reduction; Water; Xanthenes

The chemical-activated luciferase expression (CALUX) assay is a reporter gene assay that detects dioxin-like compounds based on their ability to activate the aryl hydrocarbon receptor (AhR) and thus expression of the reporter gene. In this paper, the CALUX assay was examined for its application in the screening of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dioxin-like PCBs) in retail fish. The sample extracts were cleaned up on a sulfuric acid-silica gel column followed by an activated carbon column, and the AhR activity of the separated PCDD/F and dioxin-like PCB fractions was determined using the assay. The quantitative limit for 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) was 0.98 pg ml(-1) (0.19 pg assay(-1) in the standard curve, corresponding to 0.16 pg g(-1) of CALUX-based toxic equivalency (2,3,7,8-TCDD equivalents) in the tested sample. Recovery tests in which dioxins were added to fish samples resulted in acceptable recoveries (77-117%). The CALUX assay performed well in the analysis of dioxins in fish samples and a comparative study revealed a strong correlation between the CALUX assay and high-resolution gas chromatography-high-resolution mass spectrometry analysis for the determination of PCDD/Fs (r = 0.89) and dioxin-like PCBs (r = 0.91) in retail fish (n = 22). These data revealed that the CALUX assay would be a useful screening method for PCDD/Fs and dioxin-like PCBs in retail fish.

Topics: Animals; Benzofurans; Biological Assay; Carcinogens, Environmental; Fishes; Food Contamination; Gene Expression; Genes, Reporter; Luciferases; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins

Bioremediation is a low-cost treatment alternative for the cleanup of polychlorinated-dioxin-contaminated soils and fly ash when pollution spread is wide-ranging. An interesting fungus, Ceriporia sp. MZ-340, with a high ability to degrade dioxin, was isolated from white rotten wood of a broadleaf tree from Kyushu Island in Japan. We have attempted to use the fungus for bioremediation of polychlorinated-dioxin-contaminated soil on site. However, we have to consider that this trial has the potential problem of introducing a biohazard to a natural ecosystem if this organism is naturalized. We have therefore developed a monitoring system for the introduced fungus as a part of the examination and evaluation of bioremediation in our laboratory. We have also developed a PCR-based assay to reliably detect the fungus at the bioremediation site. DNA isolated from the site was amplified by PCR using a specific primer derived from internal transcribed spacer region (ITS: ITS1, 5.8S rDNA and ITS2) sequences of Ceriporia sp. MZ-340. We successfully monitored Ceriporia sp. MZ-340 down to 100 fg/ micro l DNA and down to 2 mg/g mycelium. We also successfully monitored the fungus specifically at the bioremediation site. The polychlorinated dibenzo- p-dioxin and polychlorinated dibenzofuran content was observed to decrease in response to treatment with the fungus. The species-specific PCR technique developed in the present work is useful in evaluating the possibility of on-site bioremediation using the fungus Ceriporia sp. MZ-340.

Topics: Air Pollutants; Benzofurans; Biodegradation, Environmental; Carbon; Coal Ash; Dioxins; DNA, Fungal; DNA, Ribosomal Spacer; Particulate Matter; Polymerase Chain Reaction; Polyporales; Sensitivity and Specificity

Marine bacterial strains (BP-PH, CAR-SF, and DBF-MAK) were isolated using biphenyl, carbazole (CAR), or dibenzofuran (DF) respectively as substrates for growth. Their 16S ribosomal DNA sequences showed that the species closest to strain BP-PH, strain CAR-SF, and strain DBF-MAK are Alteromonas macleodii (96.3% identity), Neptunomonas naphthovorans (93.1% identity), and Cycloclasticus pugetii (97.3% identity), respectively. The metabolites produced suggested that strain CAR-SF degrades CAR via dioxygenation in the angular position and by the meta-cleavage pathway, and that strain DBF-MAK degrades DF via both lateral and angular dioxygenation. Polychlorinated biphenyl (KC-300) and 2,3-dichlorodibenzo-p-dioxin were partially degraded by strain BP-PH and strain DBF-MAK, while 2,7-dichlorodibenzo-p-dioxin and 2,4,8-trichlorodibenzofuran remained virtually unchanged.

Topics: Bacteria; Benzofurans; Biodegradation, Environmental; Biphenyl Compounds; Carbazoles; Culture Media; Dioxins; Molecular Sequence Data; Phylogeny; Polychlorinated Dibenzodioxins; Seawater; Water Microbiology

The widespread use of brominated flame-retarded products in the last two decades has resulted in an increasing presence of bromine in thermal processes such as waste combustion and accidental fires. Brominated and brominated-chlorinated dibenzodioxins and dibenzofurans (PBDDs/PBDFs, PXDDs/PXDFs) are micropollutants of concern arising from such processes. The present review aims to evaluate the relevance of these compound classes in actual thermal processes. Four categories of thermal processes are discussed in this respect according to their potential for PBDD/PBDF and PXDD/PXDF generation: thermal stress, pyrolysis/gasification, insufficient combustion conditions and controlled combustion conditions. Under thermal stress situations, as they may occur in production or recycling processes, PBDDs/PBDFs precursors like polybrominated diphenylethers (PBDE) can have a relevant potential for PBDD/PBDF formation via a simple elimination. Under insufficient combustion conditions as they are present in, e.g. accidental fires and uncontrolled burning as well as gasification/pyrolysis processes, considerable amounts of PBDDs/PBDFs can be formed from BFRs, preferably via the precursor pathway. In contrast, under controlled combustion conditions, BFRs and PBDDs/PBDFs can be destroyed with high efficiency. The relevance of de novo synthesis of PXDDs/PXDFs is discussed for this condition. Providing a basis for the understanding of PXDD/PXDF formation in actual thermal processes, the present paper also summarises the formation pathways of brominated and brominated-chlorinated PXDDs/PXDFs from brominated flame retardants (BFRs) investigated during laboratory thermolysis experiments. Relevant mechanistic steps for PBDD/PBDF formation from brominated precursors are discussed including elimination reactions, condensation steps and debromination/hydrogenation reactions. In addition, chlorination/bromination and halogen exchange reactions are briefly discussed with respect for their relevance on the final distribution of PBDDs/PBDFs, mixed chlorinated PXDDs/PXDFs and PCDDs/PCDFs resulting from thermal processes.

Topics: Benzofurans; Chemical Phenomena; Chemistry, Physical; Chlorine; Dioxins; Flame Retardants; Hydrocarbons, Brominated; Models, Chemical; Thermodynamics

Levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were determined in twenty-one ambient air samples, eight soil samples and two stack gas samples, collected near or in a municipal solid waste incinerator (MSWI) in Hsinchu, Taiwan. A systematic decrease of PCDD/Fs in the ambient air from the northeastern area was observed. PCDD/Fs levels measured in the ambient air range from 0.058 to 0.127 pg-TEQ/m3. Higher PCDD/Fs levels in the ambient air were found during winter. In addition, PCDD/Fs levels measured in the soil range from 0.524 to 5.02 pg-TEQ/g d.m. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) did not provide sufficient evidence that the environmental PCDD/Fs contamination was caused by emissions from the Hsinchu MSWI. An unknown PCDD/Fs source was proposed using congener profile analysis and supported by both PCA and HCA.

Topics: Air Pollutants; Benzofurans; Cluster Analysis; Environmental Monitoring; Incineration; Polychlorinated Dibenzodioxins; Seasons; Soil Pollutants; Taiwan; Time Factors

Polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) were extracted by accelerated solvent extraction from animal feed samples and analysed by high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). In all of the feed samples analysed, the concentrations of PCDD/Fs and PCBs were below the existing tolerance limit of 5 pg I-TEQ g(-1) and 200 ng g(-1) fat, respectively. The mean concentrations of the total PCDDs, total PCDFs and total PCBs were 1.73-11.50 pg g(-1), 0.23-11.91 pg g(-1) and 60.00-234.40 pg g(-1) feed, respectively. Investigation of the correlations among the concentrations of PCDDs, PCDFs and PCBs showed that samples containing increased amounts of PCDFs also contained higher concentrations of PCDDs, with an average ratio of PCDF:PCDD of about 1.23:1 (r(2)=0.72, p<0.05). The correlation between the concentrations of PCDD/Fs and PCBs was positive but not significant.

Topics: Animal Feed; Animals; Benzofurans; Biphenyl Compounds; Cattle; Dioxins; Food Contamination; Fungicides, Industrial; Gas Chromatography-Mass Spectrometry; Korea; Poultry; Swine

Technical polychlorinated byphenyl (PCB) preparations--Delors 103, 104, 105, and 106--produced in the former Czechoslovakia were analyzed for their chlorobiphenyl (CB), chloronaphthalene (PCN) and chlorinated dibenzofuran (PCDF) composition and content using high resolution gas chromatography-mass spectrometry techniques. The congener patterns of Delors 103, 104, 105, and 106 resembled Aroclors 1242, 1248, 1254, and 1260. Delors contained PCNs and PCDFs, as impurities, at microgram per gram concentrations. Concentrations of PCNs and PCDFs in Delors were greater than those found in the corresponding Aroclors. The potential for the emissions of PCNs and PCDFs from Delor was estimated to be 3680 and 860 kg, respectively. Non- and mono-ortho PCBs were the major contributors to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalents in Delor mixtures.

Topics: Benzofurans; Czech Republic; Environmental Pollutants; Gas Chromatography-Mass Spectrometry; Isomerism; Naphthalenes; Polychlorinated Biphenyls

Based on structure-activity relationships of the angiostatic beta-sheet-forming peptide anginex, we have designed a mimetic, 6DBF7, which inhibits angiogenesis and tumor growth in mice. 6DBF7 is composed of a beta-sheet-inducing dibenzofuran (DBF)-turn mimetic and two short key amino acid sequences from anginex. This novel antiangiogenic molecule is more effective in vivo than parent anginex. In a mouse xenograft model for ovarian carcinoma, 6DBF7 is observed to reduce tumor growth by up to 80%. It is suggested that the activity is based on antiangiogenesis, because in vitro tube formation is inhibited, and because treatment of tumor-bearing mice led to a significant reduction in microvessel density within the tumor. This partial peptide mimetic is the first endothelial cell-specific molecule designed as a substitute for an angiostatic inhibitory peptide.

Topics: Alanine; Amino Acid Sequence; Angiogenesis Inhibitors; Animals; Antineoplastic Agents; Benzofurans; Cell Division; Cell Line, Tumor; Cells, Cultured; Endothelium, Vascular; Female; Humans; Immunohistochemistry; In Situ Nick-End Labeling; Magnetic Resonance Spectroscopy; Mice; Mice, Nude; Models, Molecular; Molecular Sequence Data; Neoplasm Transplantation; Ovarian Neoplasms; Peptides; Protein Structure, Secondary; Proteins; Sequence Homology, Amino Acid; Structure-Activity Relationship; Time Factors; Umbilical Veins

In the present study, a dialytic method that uses a DNA aqueous solution to remove and enrich dioxins from polluted water was proposed. Circular dichroism (CD) and fluorescent spectra indicated that dibenzo-p-dioxin (DD), dibenzofuran (DF) and biphenyl (BP), which are dioxin derivatives, form complexes with DNA. Their experimental dialytic sorption coefficients were measured by quantifying the concentrations of DD, DF, and BP in aqueous solutions before and after dialysis of the DNA solution, and the values were 2.1x10(5), 1.3x10(5), and 1.5x10(7), respectively. As a simulated water treatment model, DNA solution was dialyzed in an aqueous mixture of DD, DF, and BP for 96h, the HPLC studies showed that the dioxin derivatives have been concentrated in the DNA solution about 200 times. The dialyzed DNA solution was reusable by an extraction with hexane.

Topics: Benzofurans; Biphenyl Compounds; Circular Dichroism; Dialysis; Dioxins; DNA; Metals; Molecular Structure; Solutions; Spectrometry, Fluorescence

A clean-up method for polybrominated dibenzo-p-dioxins (PBDDs), dibenzofurans (PBDFs) and diphenyl ethers (PBDEs) was modified using combinations of multi-layered silica gel, Florisil and active carbon columns. By using active carbon column chromatography in the final procedure, PBDEs were well separated from PBDD/Fs in an elution test with reference standards. We report the application of this method to sediment samples taken from industrialized areas in Japan. These sediments contained PBDEs ranging in concentration from 13 to 2394 pg/g, dry wt. PBDEs did not interfere with the quantification of PBDD/Fs. In addition, PBDEs found in the PBDD/F fraction did not interfere with the identification of PBDFs using the HRGC/HRMS separation method. Some 2,3,7,8-tetra- to hexabrominated dioxins and furans were also detected in the sediment samples.

Topics: Benzofurans; Carbon; Carbon Isotopes; Chromatography; Dioxins; Environmental Pollution; Geologic Sediments; Phenyl Ethers; Polybrominated Biphenyls; Reference Standards

Agent Orange, a phenoxyherbicide contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), was used by American military forces during the United States-Vietnam war between 1962 and 1971 primarily as a defoliant to destroy forests where enemy troops might find cover. Agent Orange was used mainly in Vietnam, but also to a lesser extent in Laos and Cambodia. In Laos, there have been no prior studies of TCDD contamination from Agent Orange, despite known defoliation and documented records of Agent Orange spraying. This article presents findings of TCDD in human blood and milk from two geographic areas in Laos: Vientiane, a nonsprayed area, and Sepone, an Agent Orange-sprayed area. German and Canadian laboratories used high-resolution gas chromatography-mass spectrometry to measure 7 dioxin, 10 dibenzofuran, and 4 non-ortho or coplanar polychlorinated biphenyls in Laotian blood and milk samples. Most subjects tested in this Laos Ministry of Health Study showed low dioxin and dibenzofuran levels, consistent with what would be expected in a primarily rural nonindustrial country. These findings are consistent with relatively low dioxin and dibenzofuran levels recently found in food from these same areas. The chemically and toxicologically related non-ortho PCBs were measured but were found at low levels compared to specimens from other countries, presumably because of less industrialization and industrial pollution in Laos.

Topics: 2,4-Dichlorophenoxyacetic Acid; 2,4,5-Trichlorophenoxyacetic Acid; Adult; Agent Orange; Benzofurans; Defoliants, Chemical; Dioxins; Environmental Exposure; Environmental Pollutants; Female; Food Contamination; Humans; Laos; Milk, Human; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Rural Population; Warfare

Ten Gram-positive strains that degraded dibenzofuran belonged to one homogeneous cluster with common biochemical and chemotaxonomic properties. The strains included the previously described strains [Terrabacter sp.] DPO 360 and DPO 1361 and were isolated from different locations in central Europe. They all shared menaquinone MK-8(H(4)) and meso-diaminopimelic acid in the cell wall and showed the same cellular fatty acid, polar lipid and RiboPrint patterns. Chemotaxonomic properties, as well as DNA G+C content (72.8 mol%), were consistent with those described for the genus Janibacter. Analysis of 16S rDNA sequences suggested a close relationship to Janibacter terrae and Janibacter brevis. DNA-DNA hybridization of two dibenzofuran-degrading strains (DPO 360 and DPO 1361) and the type strains of J. terrae and J. brevis revealed that these strains belong to the same species. An emended description of the species J. terrae is given. J. brevis is a later heterotypic synonym of J. terrae.

Topics: Actinomycetales; Base Composition; Benzofurans; DNA, Bacterial; Fatty Acids; Geography; Germany; Molecular Sequence Data; Phylogeny

During the Vietnam War, a phenoxy-herbicide mixture called Agent Orange, which was contaminated with 2,3,7,8-tetrachlorodibenzodioxin, or TCDD, was used primarily for destruction of forest and other foliage in order to prevent enemy troop movement and protect American and allied troops and military bases in the south of Vietnam. Smaller areas of Laos and Cambodia were also sprayed with Agent Orange between 1962 and 1971 from fixed-wing aircraft. In 2001, 28 food samples consisting of meat, fish, and dairy products were collected in sprayed and nonsprayed areas of Laos and analyzed for dioxins, dioxinlike dibenzofurans, and selected polychlorinated biphenyl (PCB) congeners by high-resolution gas chromatography/high-resolution mass spectrometry at laboratories in Germany and Canada. Low levels of dioxin and other dioxinlike substances were found in Laotian food, similar to levels present in recent exported Vietnamese food to United States. Vietnam is geographically adjacent to Laos. Total dioxin toxic equivalent (TEQ) levels were similar in samples from sprayed and non-sprayed areas, ranging from 0.009 to 0.851 pg/g or parts per trillion (ppt) in sprayed Sepone, and from 0.022 to 0.537 pg/g or ppt wet weight in non sprayed Vientiane. However, the Laotian fish samples from the Agent Orange-sprayed area had, on average, a higher proportion of total TEQ from TCDD (31.7% vs. 9.4%) compared to the nonsprayed area. Some other food items, duck eggs and pork liver from Sepone, also had severalfold higher TCDD levels than similar food samples from Vientiane, 0.029 vs. 0.011 pg/g and 0.070 vs. 0.004 pg/g wet weight, respectively. There were no substantial differences in levels of dibenzofuran and PCB congeners. In general, elevated TCDD levels were not found in Laotian food samples. It is possible that dioxin-contaminated areas, or "hot spots," exist in Laos as they do in Vietnam, although they have not yet been identified.

Topics: 2,4-Dichlorophenoxyacetic Acid; 2,4,5-Trichlorophenoxyacetic Acid; Agent Orange; Animals; Benzofurans; Dairy Products; Defoliants, Chemical; Dioxins; Environmental Monitoring; Environmental Pollutants; Fishes; Food Contamination; Laos; Meat; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Vietnam; Warfare

We determined the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (Co-PCBs) in three types of fast foods [(1) seventeen hamburgers and two hot dogs, (2) six portions of fried potatoes and (3) three chicken products] obtained from fast food shops or convenience stores in Japan. All samples tested showed low toxic equivalent quantity (TEQ) levels of dioxins in the range of 0.001-0.083 pg-TEQ/g wet weight (0.006-0.053 pg-TEQ/g for hamburgers and hot dogs, 0.001-0.083 pg-TEQ/g for fried potatoes and 0.053-0.065 pg-TEQ/g for chicken products). The congener profile in hamburgers and hot dogs suggested that the total TEQ was mainly determined by Co-PCBs, especially by 3,3',4,4',5-PeCB (#126), which accounted for 44% of the total TEQ value. Findings for animal foods such as beef and cheese were consistent with this result. For fried potatoes, PCDD/Fs accounted for 94% of the total TEQ value, and 2,3,4,7,8-PeCDF accounted for 32% of PCDD/Fs. Dioxins in the chicken products consisted of 3,3',4,4',5-PeCB (#126) and 1,2,3,7,8-PeCDD, which accounted for 23% and 21% of the total TEQ, respectively. If an adult (50 kg weight) eats 150 g of hamburger, 100 g of potatoes and 150 g of chicken, the daily intake is estimated to be 0.299 pg-TEQ/kg b.w./day using the average values (0.022, 0.028 and 0.059 pg-TEQ/g, respectively) obtained in this study. This value corresponds to 7.5% of the tolerable daily intake (TDI) for PCDD/Fs and Co-PCBs in Japan.

Topics: Adult; Animals; Benzofurans; Cattle; Chickens; Food Contamination; Humans; Japan; Meat; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Restaurants; Solanum tuberosum

The objective was to perform a dioxin body burden estimate based on a probabilistic intake assessment of PCDDs, PCDFs and dioxin-like PCBs because of the so-called 1999 'Belgian dioxin incident'. Monte Carlo simulation techniques were used to combine detailed 7-day food intake data on the individual level from a sample of 14-18-year-old adolescents with 'background' and 'incident-related' food contamination data. In background conditions, 3% of the adolescents had an intake <1 pg TEQ kg(-1) bw day(-1), while 85% had <4 pg TEQ kg(-1) bw day(-1). Milk and other dairy products were the basic source of dioxin-like contaminants, while fish constituted the main source at the higher percentiles of intake. During the dioxin incident, the estimated median dioxin intake showed a moderate increase. At the 99th percentile, the highest intake level, and the 95% upper bound uncertainty level, peak body burden-23.73 ng TEQ kg(-1) bw-remained below body burdens that in the experimental animal or in man are accompanied by a population-based observable increase in the incidence of adverse effects. The 1999 Belgian dioxin incident most likely did not affect public health in Belgium in a measurable way, although exceptions remain possible on the individual level.

Topics: Adolescent; Animals; Benzofurans; Body Burden; Dairy Products; Diet Surveys; Dioxins; Female; Fishes; Food Contamination; Humans; Male; Meat; Monte Carlo Method; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins

While polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDF) and the corresponding polybrominated congeners must be considered as animal teratogens and carcinogens, little information is available on corresponding polyfluorinated compounds (PFDD/PFDF). Kinetic studies on a few fluorinated dibenzo-p-dioxins and dibenzofurans revealed a rapid elimination, suggesting a much lower toxicity than the corresponding polychlorinated and polybrominated congeners. In order to obtain further clues on the possible toxicity, the kinetics and organ distribution (in liver, thymus and adipose tissue) of a PFDD/PFDF-mixture were studied in Wistar rats after intravenous application. The congeners investigated included four of the 2,3,7,8-substituted, and four of the not-2,3,7,8-substituted dibenzo-p-dioxins, as well as two dibenzofurans. The main result of our studies is the finding that the concentration in the thymus of several of the 2,3,7,8-substituted PFDD/PFDF greatly exceeded that in hepatic tissue. An organotropy quite different from that of the other polyhalogenated congeners must be expected, immunosuppressive effects presumably being the predominant ones. Overall, the elimination half-life of all the PFDD/PFDF studied is considerably shorter than that of the corresponding polychlorinated or polybrominated congeners, in the rat, suggesting a much lower toxicity in this species. No information is available for other species, e.g. nonhuman primates or humans.

Topics: Animals; Benzofurans; Dioxins; Female; Half-Life; Injections, Intravenous; Liver; Rats; Rats, Wistar; Thymus Gland; Tissue Distribution

A fast automated extraction and clean-up procedure for low-level analysis of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (cPCBs) in biological fluids is presented. Online extraction of prepared fluids is carried out using disposable octadecyl bonded (C(18)) solid-phase extraction columns. Extracts are then cleaned up through disposable multi-layer silica (acidic, basic and neutral) and dispersed PX-21 carbon columns. This new methodology is compared with classical Soxhlet extraction and manual solid-phase extraction in terms of repeatability, reproducibility, accuracy and recovery rates for reference and certified materials. Robustness is evaluated on different matrices, such as cow's milk, breast milk and human serum. As a consequence of the reduced number of reusable glassware used, as well as lowering of solvent consumption, recorded blank levels are decreased in favor of limits of detection (LODs). Total analysis time and cost are further reduced using simultaneous sample preparation units and the sample throughput is increased compared to classical methods. As a result, this new approach appears to be suitable for the fast sample preparation often required for such fluids in case of emergency foodstuffs analysis or during large epidemiological studies.

Topics: Animals; Automation; Benzofurans; Dioxins; Humans; Milk; Quality Control; Reference Standards; Reproducibility of Results; Sensitivity and Specificity

The genes responsible for angular dioxygenation of dibenzofuran in actinomycetes were cloned by using a degenerate set of PCR primers designed by using conserved sequences of the dioxygenase alpha subunit genes. One sequence of alpha subunit genes was commonly amplified from four dibenzofuran-utilizing actinomycetes: Terrabacter sp. strains YK1 and YK3, Rhodococcus sp. strain YK2, and Microbacterium sp. strain YK18. A 5.2-kb PstI fragment encoding the alpha and beta subunits of the terminal dioxygenase, ferredoxin, and ferredoxin reductase (designated dfdA1 to dfdA4, respectively) was cloned from the large circular plasmid pYK3 isolated from Terrabacter sp. strain YK3. We confirmed that transcription of the dfdA1 gene was induced by dibenzofuran in Terrabacter sp. strain YK3. Southern blot hybridization analysis revealed that this type of dioxygenase gene is distributed among diverse dibenzofuran-utilizing actinomycetes. However, genes homologous to dfdA1 were not detected in dibenzofuran utilization-deficient mutants of Terrabacter, Rhodococcus, and Microbacterium species. When the dfdA1 to dfdA4 genes were introduced into a non-dibenzofuran-degrading mutant of Rhodococcus sp. strain YK2, strain YK2-RD2, which had spontaneously lost the gene homologous to dfdA1, the ability to degrade dibenzofuran was restored. Analysis of the breakdown products indicated that DfdA has angular dioxygenase activity. This dfdA transformant degraded several aromatic compounds, indicating that the novel angular dioxygenase possesses broad substrate specificity.

Topics: Actinomycetales; Benzofurans; Biodegradation, Environmental; Cloning, Molecular; Escherichia coli; Ferredoxin-NADP Reductase; Ferredoxins; Molecular Sequence Data; Multigene Family; Oxygenases; Phylogeny; Plasmids; Sequence Analysis, DNA; Substrate Specificity

Concentrations of 2378-substituted polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (DFs) and non- and mono-ortho-substituted polychlorinated biphenyls (dioxin-like PCBs) were measured in livers of polar bears from the Alaskan Arctic and in eggs of Adelie penguin and south polar skua and weddell seal liver, fish and krill from Antarctica. This is one of the first reports to document the concentrations of PCDDs/DFs in polar bear livers from Alaska, and in penguin and skua eggs from Antarctica. Concentrations of total PCDD/DFs in livers of polar bears ranged from 8 to 66 (mean: 26) pg/g, on a lipid weight basis. Concentrations of total PCDD/DFs in Antarctic samples were in the increasing order on a lipid weight basis; weddell seal liver (8.9 pg/g) < fish (11-17 pg/g) < krill (27 pg/g) > penguin eggs (30 ng/g) > seal liver (57 ng/g) > fishes (6.2 ng/g) > krill (0.9 ng/g). Concentrations of 2378-tetrachlorodibenzo-p-dioxin equivalents (TEQs) calculated based on the WHO TEFs were higher in the eggs of polar skua (mean: 344: range: 220-650 pg/g, lipid wt.) from Antarctica than in polar bear livers from Alaska (mean: 120; range: 69-192 pg/g). In general, concentrations of PCDFs were greater than those of PCDDs in polar organisms. 23478-PeCDF is one of the dominant congener found in several samples. Concentrations of TEQs in polar bear livers and skua eggs were close to those that may cause adverse health effects. Dioxin-like PCBs, particularly, non-ortho coplanar PCBs were the major contributors to TEQ concentrations in penguin and skua eggs whereas mono-ortho PCBs accounted for a major portion of TEQs in polar bear livers.

Topics: Animals; Antarctic Regions; Arctic Regions; Benzofurans; Birds; Environmental Pollutants; Fishes; Hydrocarbons, Chlorinated; Liver; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Raptors; Ursidae

Reverse transcription-PCR of the dbfA1A2, dbfBC, and pht genes, encoding oxygenase component of multicomponent dioxygenase, meta cleavage enzyme and hydrolase, and phthalate-degrading enzymes, respectively, revealed their role in the aromatic compound degradation by Terrabacter sp. strain DBF63. The specific expression in strain DBF63 cells grown on dibenzofuran (the model compound of dioxin; DF) and/or fluorene (FN) indicated that the DbfA1A2 and DbfBC catalyze the conversion of DF to salicylate, and that the DbfA1A2 and Pht enzymes are involved in FN degradation. Pulsed-field gel electrophoresis analyses revealed that the dbfA1A2 cistron and pht operon were located on the two linear plasmids, pDBF1 (160 kb) and pDBF2 (190 kb), while dbfBC genes were located on the chromosome. Because the pht operon is located immediately upstream of the dbfA1A2 cistron, the dioxin-catabolic genes were dispersed on the genome of strain DBF63, while FN-catabolic genes were gathered on the plasmids.

Topics: Actinomycetales; Bacterial Proteins; Benzofurans; Biodegradation, Environmental; Carcinogens; Dioxins; Fluorenes; Genes, Bacterial; Molecular Structure; Open Reading Frames; Oxygenases; Phthalic Acids; Soil Microbiology

A model of the absorption and desorption of persistent lipophilic organic pollutants in the human gastrointestinal tract was formulated. The influence of the dietary intake of chemical, the chemical concentration in human tissue, the physical-chemical properties of the chemical, and the sorption properties of the feces on the predicted net mass transfer of chemical was explored and shown to be consistent with experimental observations. The model was parametrized and tested using a data set of approximately 800 measurements of net absorption/excretion of polychlorinated biphenyls, dibenzo-p-dioxins, and dibenzofurans that were obtained in experiments with 14 human volunteers. Overall good agreement was obtained between the predicted and measured values. The largest discrepancies were observed in cases of net excretion because the model was not able to account for the considerable individual and temporal variability in the sorption properties of the feces. In a sample model application, good agreement was found between concentrations of octachlorodibenzo-p-dioxin in blood measured in different age groups of the background population and values predicted by the model.

Topics: Absorption; Benzofurans; Diet; Digestive System; Dioxins; Environmental Pollutants; Feces; Humans; Models, Theoretical; Polychlorinated Biphenyls

Sixteen actinomycetes capable of utilizing dibenzofuran as a sole source of carbon and energy were isolated, including Rhodococcus, Microbacterium, and Terrabacter genera. Heretofore, no dibenzofuran-utilizing strain belonging to the genus Microbacterium has been reported. Five extradiol dioxygenase genes (dfdB, and edil to 4) of the strain Rhodococcus sp. YK2 were cloned and analyzed. The nucleotide sequence of dfdB gene was almost identical to the bphC1 gene of Terrabacter sp. DPO360, which was involved in dibenzofuran metabolism in this strain. Southern and Northern hybridization analyses using these extradiol dioxygenase genes as probes suggest that the dfdB gene in YK2 was conserved in diverse dibenzofuran-utilizing actinomycetes; also, the dfdB gene was the only expressed gene among five extradiol dioxygenase genes in the medium containing DF as a sole carbon source. These results suggest that the dfdB gene is important for dibenzofuran metabolism not only in the strain YK2, but also in diverse dibenzofuran-degrading actinomycetes.

Topics: Actinobacteria; Benzofurans; Blotting, Northern; Blotting, Southern; Chromatography, High Pressure Liquid; Cloning, Molecular; Culture Media; Dioxygenases; Escherichia coli; Genes, Bacterial; Oxygenases; Rhodococcus; Transcription, Genetic

Dioxins and dioxin-like PCBs are given toxic equivalency factors (TEFs) in order to calculate the combined toxic equivalence (TEQ) of these contaminants in a sample of food. This study calculates the probability of an average consumer exceeding the recommended tolerable daily intake of 1-4 pg WHO-TEQ kg(-1) bw day(-1) as the amount of salmon in the diet is increased. Probabilistic risk analysis is used to account for the known uncertainties in this calculation. When the TEF uncertainty was excluded with no salmon consumption, the background dietary intake ranged from 1.36 to 1.78 pg TEQ kg(-1) bw day(-1). A weekly consumption of three standard salmon portions resulted in a 36% chance of exceeding the upper limit of the TDI. Inclusion of the TEF uncertainty increased the background dietary intake range from 2.1 to 4.4 pg TEQ kg(-1) bw day(-1), and the weekly consumption of one salmon portion resulted in a 79% chance of the average consumer exceeding the upper TDI. The most important factors contributing to the uncertainty in these results were, in order of magnitude, the TEF for PCB 126 and the sampling uncertainty (sample size) followed by the measurement uncertainty of PCB 126. We recommend that it is more important to increase sample size and produce more precise estimates in the TEF than to improve analytical accuracy.

Topics: Animals; Benzofurans; Diet; Dioxins; Food Contamination; Humans; Maximum Allowable Concentration; Meat; Monte Carlo Method; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Risk Assessment; Salmon

Hydroxylation of dibenzo- p-dioxin (DD), dibenzofuran (DF), biphenyl (BP) and diphenyl ether (DPE) by the white-rot fungus Phlebia lindtneri GB-1027 was studied. DD and DF were rapidly degraded in a culture of P. lindtneri. The initial oxidation products were identified by gas chromatography-mass spectrometry. P. lindtneri oxidized DD to 2-hydroxy-DD, and DF to 2- and 3-hydroxy-DF. BP and DPE were also oxidized to p-hydroxy-BP and p-hydroxy-DPE, respectively. The oxidation catalyzed by P. lindtneri with each substrate was position-specific, because the hydroxyl group was introduced to the molecular edge of every substrate. Significant inhibition of the degradation of DD and DF was observed in incubation with the cytochrome P-450 monooxygenase inhibitors 1-aminobenzotriazole and piperonyl butoxide. These experiments with cytochrome P-450 inhibitors, and formation of the mono-hydroxyl metabolites suggest that P. lindtneri initially oxidizes DD, DF, BP, and DPE by a cytochrome P-450 monooxygenase and that it directly introduces a hydroxyl group to each of these substrates.

Topics: Basidiomycota; Benzofurans; Biodegradation, Environmental; Biphenyl Compounds; Cytochrome P-450 Enzyme System; Dioxins; Hydroxylation; Kinetics; Mass Spectrometry; Oxidation-Reduction; Oxygenases; Phenyl Ethers

The biotransformation of biphenyl, dibenzofuran, and diphenyl ether by 24 strains belonging to 18 species of the genus Trichosporon was investigated to assess the taxonomic relevance of this property at species and genus level. With the exceptions of T. brassicae and T. porosum CBS 2040, all other strains were able to transform the parent compounds to monohydroxylated intermediates. A second hydroxylation on the same aromatic ring was carried out by fewer strains and depended on the substrate. It appears that this step is the rate-limiting one in the biotransformation of the biarylic compounds tested. Ring fission of dihydroxylated derivatives of biphenyl was observed within 12 species. The aromatic ring system of dihydroxylated dibenzofuran was cleaved by strains of 5 species, while strains of 13 species were able to cleave the aromatic ring system of dihydroxylated diphenyl ether. Only 4 strains out of 18 species were able to cleave the aromatic ring system of all three parent compounds. These most active yeasts belong to the species T. coremiiforme, T. montevideense, T. mucoides, and T. sporotrichoides. In addition, strains of the species Cryptococcus curvatus and Cryptococcus humicola, closely related to the genus Trichosporon, were tested in parallel.

Topics: Benzofurans; Biodegradation, Environmental; Biphenyl Compounds; DNA, Fungal; DNA, Ribosomal; Mycological Typing Techniques; Phenyl Ethers; Phylogeny; RNA, Ribosomal; Trichosporon

The actions of a white-rot fungus on two chlorinated aromatic compounds, known to be persistent environmental contaminants, were studied. Two models, both-ring chlorinated dioxin, 2,7-dichlorodibenzo-p-dioxin (2,7-diCDD) and 2,8-dichlorodibenzofuran (2,8-diCDF), were metabolized by the white-rot fungus Phlebia lindtneri. 2,7-DiCDD disappeared linearly in the culture of P. lindtneri; over a 20-day incubation period, with only 45% remaining in the culture. One of the metabolites produced by P. lindtneri from a 5-day incubated culture with 2,7-diCDD or 2,8-diCDF was identified by gas chromatography-mass spectrometry. P. lindtneri was shown to metabolize 2,7-diCDD and 2,8-diCDF to hydroxy-diCDD and hydroxy-diCDF, respectively.

Topics: Basidiomycota; Benzofurans; Biodegradation, Environmental; Chromatography, Gas; Dioxins; Environmental Pollutants; Hydroxylation; Mass Spectrometry; Oxidation-Reduction; Polychlorinated Dibenzodioxins

This is the first known study of dioxins, dibenzofurans, and polychlorinated biphenyls (PCBs) in commercial American bottled baby foods purchased in the United States. Dioxins, persistent chlorinated organics, are inadvertent by-products of chemical synthesis or combustion and are toxic to humans and other animals. Almost all dioxins enter the body through food consumption, specifically from food products containing animal fat. Major-brand bottled baby food containing meat was purchased at U.S. supermarkets and 12 pooled samples were analyzed for dioxins using high-resolution gas chromatography with high-resolution mass spectrometry. Low levels of dioxins were found in these products. The range was from 28 to 226 parts per quadrillion (ppq) dioxin toxic equivalents (TEQ). This is reported on a whole or wet weight (as eaten) basis. As a comparison, findings of dioxins in U.S. supermarket meat ranged from 28 to 540 ppq. Although dioxin levels are generally lower in these baby foods than in meat or poultry, the presence of dioxins in commercial baby food containing meat is cause for concern.

Topics: Benzofurans; Dioxins; Environmental Pollutants; Food Contamination; Humans; Infant; Infant Food; Infant, Newborn; Polychlorinated Biphenyls; Reference Values; United States

Two typical cleanup methods, sulfuric acid treatment and multi-layer silica gel column chromatography, for the determination of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dioxin-like PCBs) in seventeen food samples were examined and compared. Vegetables, fruits, cereals, fish, meat and dairy foods were extracted by conventional methods (shaking with acetone/n-hexane or with n-hexane after alkaline treatment). The extracts were cleaned up by sulfuric acid treatment or multi-layer silica gel column chromatography, followed by several column chromatographic steps. Of the samples treated, the vegetable, fruit and cereal samples could be directly applied to the multi-layer silica gel column after extraction. However, the samples containing fats and oils such as fish, meat and dairy foods needed to be treated several times with concentrated sulfuric acid before multi-layer column chromatography, because these samples plugged the column with oily residues. Both cleanup methods gave similar values of isomeric concentrations and showed similar efficiency of purification, and the recoveries ranged from 40 to 120%. These results are considered to provide useful data for the efficient analysis of dioxins in foods which have wide-ranging compositions.

Topics: Benzofurans; Chromatography, Gel; Dairy Products; Edible Grain; Fish Products; Food Analysis; Fruit; Meat; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Silica Gel; Silicon Dioxide; Sulfuric Acids; Vegetables

Wood and other environmental samples were collected from sites that produced beef with higher than average residues of dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF). Analyses of these samples for PCDD/Fs and pentachlorophenol (PCP) indicated that the high beef residues were associated with PCP-treated wood in the animal facilities. Concentrations of PCDD/Fs in wood as toxic equivalents ranged from 10 to 320,000 pg/g. These concentrations were closely related to the concentrations of PCP, indicating that analysis for PCP provides an economical method to identify wood with high concentrations of PCDD/Fs. Further evidence for the PCP-treated wood as the source of the beef residues is provided by the similarity of the congener profiles in beef from the sites and those profiles predicted from the profiles in wood.

Topics: Animals; Benzofurans; Cattle; Dioxins; Environmental Exposure; Food Contamination; Housing, Animal; Meat; Pest Control; Polychlorinated Dibenzodioxins; Soil Pollutants; Wood

Since the thermal management of municipal solid waste (MSW) is considered to be one of the major sources of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), the purpose of this study was to show the results of a dioxin abatement program performed in the municipal waste incineration (MWI) plant of Tarragona (NE Spain). Previously, stack gas emission levels of PCDDs/PCDFs around 3.26 ng I-TEQ/Nm3 were determined when the gas-cleaning system consisted only of an electrostatic precipitator (ESP). Decreased levels, below 0.1 ng I-TEQ/ Nm3, were observed when a new air pollution control system was installed. This new system was improved by the injection of activated carbon, which helped to lower the levels of PCDDs/PCDFs to around 0.01 ng I-TEQ/Nm3. Considering the absence of a particular impact on herbages, soils, and ambient air around the plant, as reported in previous works, and the hypothesis that a modern installation could become a sink for dioxins instead of a source, a dioxin mass balance was evaluated. The study compared in a large-scale MWI plant the levels of PCDDs/PCDFs of all input and output contributors (MSW, ambient air, stack gas emission, fly ash, and slag) forming part of the inventory collected in various monitoring campaigns. The findings revealed a remarkable homogeneity in output values (between 1.19 and 2.62 ng I-TEQ/yr) in contrast to the large variability observed in input values. In the first sampling campaign, the dioxin content in MSW was around 64.15 ng I-TEQ/kg, and a negative balance of 7.68 g I-TEQ/yr was calculated. However, in the latest campaign, levels were about 2.36 ng I-TEQ/kg MSW, resulting in a positive balance of 2.28 g I-TEQ/yr.

Topics: Air Pollutants; Air Pollution; Benzofurans; Dioxins; Environmental Monitoring; Incineration; Polychlorinated Dibenzodioxins; Refuse Disposal; Soil Pollutants

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/DFs) were measured in sediments collected from Masan Bay, Korea. Almost all tetra- through octachlorinated PCDDs/DFs were identified, including the 17 2,3,7,8-substituted PCDDs/DFs. Total concentrations of PCDDs/DFs in sediments ranged from 102 to 6,493 pg/g dry weight. Concentrations of 2,3,7,8-tetrachlorinated dibenzo-p-dioxin (TeCDD) equivalents (TEQs) in sediments estimated based on I-TEFs were in the range of 1 to 76 pg/g dry weight. Total concentrations of PCDDs/DFs in Masan Bay sediments were comparable to those reported for the Rhine and Humber Rivers on the North Sea, the Housatonic River in the United States, and some rivers and lakes in Japan and the United Kingdom. A spatial gradient of total concentrations of PCDDs/DFs decreased toward the open sea. Two of the 11 sampling sites near the coastal zone contained relatively great concentrations, suggesting the presence of point sources. The homologue composition of PCDFs in sediments from two highly contaminated locations in Masan Bay was correlated with that of commercial polychlorinated biphenyl (PCB) preparations, such as Kanechlors 300, 400, or 500. The wide range of PCDD isomers and greater concentrations of PCDDs than of PCDFs at certain locations suggest that, in addition to technical PCB preparations such as Kanechlors, other sources, like solid waste incineration, uncontrolled trash burning, and pentachlorophenol, have contributed to the contamination.

Topics: Benzofurans; Environmental Monitoring; Geologic Sediments; Incineration; Korea; Polychlorinated Dibenzodioxins; Refuse Disposal; Soil Pollutants

Two groups of male Wistar rats were treated 16 times (every 3rd day) subcutaneously with a defined mixture of polychlorinated dibenzo-p-dioxins (PCDDs) or of polychlorinated dibenzofurans (PCDFs). These mixtures contained no measurable amount of 2,3,7,8-TCDD. Each single dose was calculated to contain either 57 ng I-TEq (international 2,3,7,8-T4CDD toxicity equivalencies)/kg body weight of the PCDD mixture or 39 ng I-TEq/kg body weight of the PCDF mixture. Both mixtures contained a large excess of non-2,3,7,8-substituted congeners. The activities of ethoxyresorufin O-deethylase (EROD) in liver microsomes were correlated with the corresponding concentrations of PCDDs or PCDFs in hepatic tissue. Data were compared with results obtained after single injections of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-T4CDD). As expected, a complex kinetic situation resulted, because of the different tissue distributions and elimination half-lives of the various congeners: (1) 2,3,7,8-substituted PCDDs: the time course of the concentrations in liver and adipose tissue was similar for all congeners, the levels increased during the treatment period and decreased after treatment. Tissue concentrations of all 2,3,7,8-substituted PCDDs were considerably higher in liver than in adipose tissue. The liver/adipose tissue concentration ratios increased with the degree of chlorination. The ratio of 1,2,3,7,8-P5CDD was much lower than those of all other 2,3,7,8-substituted congeners. (2) 2,3,7,8-substituted PCDFs: 1,2,3,7,8-P5CDF was rapidly eliminated from liver and adipose tissue while 2,3,4,7,8-P5CDF largely persisted after the treatment period in both tissues. 2,3,7,8-T4CDF was eliminated even more rapidly than 1,2,3,7,8-P5CDF and could not be detected after treatment in both tissues. Time courses of the concentrations of 2,3,4,7,8-P5CDF, H6CDFs, H7CDFs and OCDF in liver and adipose tissue were similar: the levels of all congeners increased during the treatment period but no clear-cut decrease was observed within 34 days after the last treatment. Tissue concentrations of all 2,3,7,8-substituted PCDFs were higher in liver than in adipose tissue. The liver/adipose tissue concentration ratios increased with the degree of chlorination. The ratios of 2,3,7,8-T4CDF and 1,2,3,7,8-P5CDF were much lower than those of all other 2,3,7,8-substituted congeners. (3) non-2,3,7,8-substituted PCDDs and PCDFs: a number of non-2,3,7,8-substituted PCDD and PCDF congeners were found in both tissue

Topics: Adipose Tissue; Animals; Benzofurans; Cytochrome P-450 CYP1A1; Dose-Response Relationship, Drug; Drug Combinations; Enzyme Induction; Liver; Male; Polychlorinated Dibenzodioxins; Rats; Rats, Wistar

The performance of the supercritical fluid extraction (SFE) technique to obtain a new and more appropriate model support for PCDD/F formation studies was investigated. To characterize fly ash and model supports and relate their chemical-physical properties, surface area and pore size were determined. To evaluate the influence on reactivity of the different model supports with respect to raw fly ash, a kinetic study of the thermal behavior of dibenzofuran (DF) was performed. Rate constants as well as the activation and thermodynamic parameters for the different systems were also compared. The model support obtained from SFE was very similar to raw fly ash from the structural, physical-chemical, and kinetic points of view.

Topics: Benzofurans; Incineration; Kinetics; Models, Theoretical; Polychlorinated Dibenzodioxins; Porosity; Refuse Disposal; Soil Pollutants; Temperature

Bacterial samples were collected from three marine beaches in coastal Newfoundland, Canada, and enriched by growth on 1-methylnaphthalene. The most prominent bacterial cell type for each consortium was isolated in a serial dilutions test, and a substrate utilization profile was obtained for each using the Biolog MicroStation System. Each bacterial community was tested for its ability to co-metabolize sulfur heterocycles (benzothiophene: BT, 3-methylbenzothiophene: 3-MBT, and dibenzothiphene: DBT), a nitrogen heterocycle (carbazole: CARB), and an oxygen heterocycle (dibenzofuran: DBF). Co-metabolism of the starting material was determined using gas chromatography-mass spectroscopy (GC-MS), and formation of products was investigated by GC-MS and Fourier transform infrared (FTIR) spectroscopy. Bacterial growth was monitored turbidimetrically to determine the dry weight (microgram) of cells/ml. The 2-ringed heterocycles were co-metabolized faster and to a greater extent than the 3-ringed compounds. Co-metabolism of BT was not statistically different from that for 3-MBT and, likewise, a comparison of the 3-ringed heterocycles showed no significant differences in degradation rates. Statistical examination showed that no one culture demonstrated a significantly greater ability to co-metabolize the heterocycles studied. This study represents the first comprehensive investigation of the ability of local bacteria to co-metabolize a range of aromatic compounds and provides a preliminary understanding of their fate in sediments should contamination by these compounds occur.

Topics: Aerobiosis; Benzofurans; Biodegradation, Environmental; Carbazoles; Ecosystem; Gas Chromatography-Mass Spectrometry; Gram-Negative Bacteria; Heterocyclic Compounds; Newfoundland and Labrador; Nitrogen; Oxygen; Seawater; Spectroscopy, Fourier Transform Infrared; Sulfur; Thiophenes

We measured plasma concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and polychlorinated biphenyls (PCBs) in fishermen from the Finnish Baltic Sea area and fishermen fishing in inland lakes. The concentrations clearly correlated with the frequency of fish meals and consumption of Baltic fatty fish. The body burden of PCDD/Fs reached the median level of 170 pg/g toxic equivalents (I-TEq) in fat for Baltic Sea fishermen, with the maximum being 420 pg/g. Results for 2,3,7,8-tetrachlorodibenzo-p-dioxin (range = 4.9-110 pg/g fat) showed that lifetime exposure in a population consuming much Baltic fatty fish can reach the levels of exposures seen in Seveso, Italy, in 1976. After we summed the PCB-TEqs, the total median exposure of Baltic Sea fishermen increased to 290 pg/g TEq in fat, and the highest concentration was 880 pg/g. There was a noted individual variation in fishermen's PCDD/F congener patterns, and it was possible to associate this variation with congener patterns of PCDD/Fs in the fish species that the fisherman reported they had consumed. Linear regression models for ln WHO(PCDD/F)-TEq, ln WHO(PCB)-TEq, and ln total WHO-TEq, from the World Health Organization, explained 48%, 60%, and 53% of the variability, respectively. Age was the only significant predictor of ln WHO(PCDD/F)-TEq, whereas age, amount of fish eaten, and place of residence were significant predictors of ln WHO(PCB)-TEq, and ln total WHO-TEq.

Topics: Adult; Age Factors; Aged; Animals; Benzofurans; Body Burden; Diet; Environmental Exposure; Environmental Pollutants; Finland; Fisheries; Fishes; Humans; Male; Middle Aged; Occupational Exposure; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Risk Factors; Soil Pollutants

Exhaust gases from the combustion of poly(vinyl chloride) (PVC), polyethylene (PE), polystyrene (PS), poly(ethylene terephthalate) (PET), and theirvarious mixtureswere analyzed for PCDDs, PCDFs, and coplanar PCBs by gas chromatography/mass spectrometry (GC/MS) in order to investigate the role of PVC in these chlorinated compounds. Total amounts of dioxins (PCDDs + PCDFs) found in the samples were 11.7 ng/g PE alone, 1.17 ng/g from PS alone, 25.3 ng/g from PET alone, 448 ng/g from PE with PVC, 140 ng/g from PS with PVC, 126 ng/g from PET with PVC, 824 ng/g from PVC alone under low-CO level, and 8,920 ng/g from PVC alone under high-CO level. CO level in high-CO level condition was 880 ppm which was 20 times greater than that in low-CO level condition. Formation of coplanar PCBs ranged from 0.095 ng/g (PE alone) to 77 ng/g (PVC alone under high-CO level). There is a clear correlation between dioxin formation and chloride content. PCDFs composed 80% (PET + PVC)--98% (PET alone) of the total dioxins formed in the exhaust gases. The results indicate that PVC contributes significantly to the formation of PCDDs, PCDFs, and coplanar PCBs from mixtures of plastics upon combustion.

Topics: Benzofurans; Environmental Pollutants; Gases; Incineration; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Polyvinyl Chloride; Refuse Disposal; Soil Pollutants

Two bacterial strains capable of utilizing dibenzofuran (DF) as a sole carbon source were isolated from soil samples of reclaimed land. The strains designated HL1 and HL7 were identified as Klebsiella sp. and Sphingomonas sp., respectively, on the basis of biochemical characteristics and the sequences of the 16S ribosomal DNA. Sphingomonas sp. strain HL7 degraded non-, mono- and also dichlorinated DF and dibenzo-p-dioxin (DD). Klebsiella sp. strain HL1 was able to degrade non- and monochlorinated DFs and DDs, but not dichlorinated ones. The metabolites formed from DF by strains HL1 and HL7 were similar to those by dioxin-degrading bacteria Sphingomonas sp. strain RW1 except for salicylic acid and catechol. Strain HL7 had a gene homologous to that encoding the dioxin dioxygenase alpha-subunit (dxnA1) gene of Sphingomonas sp. strain RW1. However, Southern hybridization analysis showed that the size of an EcoRV-digested genomic fragment involving the dioxin dioxygenase gene of strain HL7 was smaller than that of strain RW1, and that strain HL1 did not have the homologous gene. Strains HL1 and HL7 provided useful information regarding the dioxygenase genes.

Topics: Benzofurans; Dibenzofurans, Polychlorinated; Dioxins; Klebsiella; Oxygenases; Phylogeny; Soil Microbiology; Sphingomonas

Yeast communities from heavily polluted sediments that received the discharge from oil refineries and other industries were studied. Yeast species were isolated from these sediments and their ability to degrade dibenzofuran were determined. Twenty-four different yeast strains were isolated and cultured on aromatic medium; two Candida krusei strains. Candida tenuis, Candida tropicalis, two Pichia anomala strains, Pichia haplophila, two Rhodotorula glutinis strains, Rhodotorula mucilaginosa, two Trichosporon pullulans strains and Yarrowia lipolytica were able to hydroxylate dibenzofuran. Three metabolites were identified by HPLC analysis: 3-hydroxydibenzofuran was in all the cases the most abundant isomer, and while 4-hydroxydibenzofuran was also common, 2-hydroxydibenzofuran was detected in very small quantities and with few species. In the R. glutinis and Y. lipolytica cultures a ring cleavage product was also found. While in the R. gluttinis assays the hydroxydibenzofuran was detected earlier, at 2 days' incubation time, in the other yeast experiments they were observed at the 4-5th incubation days with the maximum amounts at the 7th day. Our results confirmed the ability of autochthonous yeast species to hydroxylate dibenzofuran and to cleave the rings, and it is the first report for C. krusei, C. tenuis, P. anomala, P. haplophila and R. mucilaginosa. The ecological relevance of this study is based on the fact that dibenzofuran is a xenobiotic not easily transformed, so the catabolic activities observed in authochonous yeasts contribute to broadening the biodegradable substrate spectrum.

Topics: Benzofurans; Biodegradation, Environmental; Geologic Sediments; Hydroxylation; Yeasts

Three strains of " Agrobacterium sanguineum", an aerobic marine bacterial species described previously, were re-characterized from phylogenetic and taxonomic viewpoints. 16S rDNA sequence comparisons showed that the " A. sanguineum" strains belong to the alpha-4 subgroup of alpha-Proteobacteria, with members of the genera Erythromicrobium and Porphyrobacter as their closest relatives. DNA-DNA hybridization studies indicated that the " A. sanguineum" strains were distinguishable from any previously known species of these genera. Bacteriochlorophyll a, monosaccharide-type glycosphingolipids, 2-OH fatty acids of C14:0, C15:0, C16:0, and C16:1, and ubiquinone-10 were detected in the " A. sanguineum" strains. The G+C of the DNA was 63.8-64.0 mol%. Two of the " A. sanguineum" strains, IAM 12620 (=ATCC 25659) and ATCC 25661, were able to grow with biphenyl and dibenzofuran as sole carbon source in the presence of 0.05% yeast extract. The medium in these cultures turned yellowish-orange at the exponential phase of growth due to the release of soluble chromogenic metabolites. The remaining " A. sanguineum" strain, ATCC 25660, and all test strains of Erythromicrobium and Porphyrobacter neither grew nor produced yellow-orange pigment with biphenyl or dibenzofuran. In PCR experiments, bphA1 gene, coding for the large subunit protein of biphenyl dioxygenase, was detected in " A. sanguineum" IAM 12620 and ATCC 25661. Based on these results, we propose classifying " A. sanguineum" IAM 12620 and ATCC 25661 as a new species of the genus Porphyrobacter with the name Porphyrobacter sanguineus sp. nov.

Topics: Bacteria, Aerobic; Bacteriochlorophylls; Benzofurans; Biphenyl Compounds; Fatty Acids; Photosynthesis; Phylogeny; Proteobacteria; RNA, Ribosomal, 16S; Species Specificity

Thirty-five strains of soil bacteria were grown with biphenyl (BP) and tested for their capacity to cooxidize dibenzofuran (DBF). During metabolism of DBF, the culture medium of 17 strains changed from colorless to orange, indicating a meta-cleavage pathway of DBF degradation. The ring cleavage product of these isolates was shown to be 2-hydroxy-4-(3'-oxo-3' H-benzofuran-2'-yliden)but-2-enoic acid (HOBB). The strain SBUG 271, studied in detail and identified as Rhodococcus erythropolis, degraded DBF via 1,2-dihydroxydibenzofuran. The ensuing meta-cleavage yielded HOBB and salicylic acid. In addition, the four monohydroxylated monomers of DBF and two metabolites, which were not further characterized, were detected. Thus, our results demonstrate that the metabolic mechanism involves lateral dioxygenation of DBF followed by meta-cleavage and occurs in Gram-negative as well as in Gram-positive BP-degrading bacteria.

Topics: Benzofurans; Biodegradation, Environmental; Biphenyl Compounds; Gram-Negative Bacteria; Gram-Positive Bacteria; Hydroxylation; Oxidation-Reduction; Sewage; Soil Microbiology

Topics: Benzofurans; Models, Theoretical; Polychlorinated Dibenzodioxins; Structure-Activity Relationship; Volatilization

Bioaccumulation of PCDD/F in the foodweb was investigated in the Ya-Er Lake area, which was heavily polluted by PCDD/F. The high concentrations of PCDD/F in sediment can be transferred and bioaccumulated by aquatic organisms and humans through various pathways. Benthonic invertebrate animals and aquatic plants with a lot of fibers in the root can accumulate PCDD/F from sediment and water. Snail (Bellamya aeruginosa), shrimp (Macrobranchium sp.) and freshwater mussel (Acuticosta chinensis (Lea)) took up PCDD/F from the water and maintained the emission patterns, whereas fish tended to selectively accumulate 2,3,7,8-substituted isomers. The tissues of fish-eating bird and duck (Anas platyrhynchos) were very highly contaminated by PCDD/F due to ingestion of fish and other aquatic organisms from sediment. The residual concentration in breast milk depended on the original concentration of PCDD/F in the food. A resident in Ya-Er Lake area showed a daily intake of PCDD/F of about 9.14 pg TEQ/kg body weight/day. This is higher than the tolerable daily intake (TDI) for PCDD/F (1 pg TEQ/kg body weight/day), which was recommended by the World Health Organization (WHO).

Topics: Animals; Benzofurans; Biotransformation; Birds; Bivalvia; China; Decapoda; Ducks; Female; Fishes; Fresh Water; Geologic Sediments; Humans; Milk, Human; Polychlorinated Dibenzodioxins; Snails; Water Pollutants, Chemical

By the use of the partial least squares (PLS) method and 13 fundamental quantum chemical descriptors computed by PM3 Hamiltonian, a OSPR model was developed for first order rate constants of photodegradation of 10 PCDD/Fs dissolved in cuticular wax from laurel cherry (Prunus laurocerasus) leaves and exposed to sunlight. The QSPR showed that photodegradation rates increase with the degree of chlorination of the homologues. PCDD/Fs with large values of Q(Cl) (the largest positive atomic charge on a chlorine atom in a molecule), Q(O)- (the most negative atomic charge on the oxygen atoms in a molecule), and mu (dipole moment) tend to photodegrade fastest. PCDD/Fs with large values of E(lumo) (the energy of the lowest unoccupied molecular orbital), E(homo) (the energy of the highest occupied molecular orbital), and E(lumo) - E(homo) tend to have the lowest photodegradation rates.

Topics: Benzofurans; Light; Models, Theoretical; Plants; Polychlorinated Dibenzodioxins; Soil Pollutants; Structure-Activity Relationship

Biphenyl dioxygenase (Bph Dox) is responsible for the initial dioxygenation of biphenyl. The large subunit (BphA1) of Bph Dox plays a crucial role in determination of substrate specificity of biphenyl-related compounds including polychlorinated biphenyls (PCBs). Functional evolution of Bph Dox of Pseudomonas pseudoalcaligenes KF707 was accomplished by random priming recombination of the bphA1 gene, involving two rounds of in vitro recombination and mutation followed by selection for increased activity in vivo. Evolved Bph Dox acquired novel and multifunctional degradation capabilities not only for PCBs but also for dibenzofuran, dibenzo-p-dioxin, dibenzothiophene, and fluorene, the compounds scarcely attacked by the original KF707 Bph Dox. The modes of oxygenation were angular and lateral dioxygenation for dibenzofuran and dibenzo-p-dioxin, sulfoxidation for dibenzothiophene, and mono-oxygenation for fluorene. These enzymes also exhibited enhanced degradation abilities for PCB congeners, retaining 2,3-dioxygenase activity and gaining 3,4-dioxygenase activity, depending on the chlorine substitution of PCB congeners. Further mutation analysis revealed that the amino acid at position 376 in BphA1 is significantly involved in the acquisition of multifunctional oxygenase activities and mode of oxygenation.

Topics: Base Sequence; Benzofurans; Cloning, Molecular; Dioxins; DNA Primers; Fluorenes; Gas Chromatography-Mass Spectrometry; Mutagenesis, Site-Directed; Oxygenases; Polychlorinated Biphenyls; Pseudomonas; Recombination, Genetic; Thiophenes

A gram-positive bacterium Terrabacter sp. strain DBF63 is able to degrade dibenzofuran (DF) via initial dioxygenation by a novel angular dioxygenase. The dbfA1 and dbfA2 genes, which encode the large and small subunits of the dibenzofuran 4,4a-dioxygenase (DFDO), respectively, were isolated by a polymerase chain reaction-based method. DbfA1 and DbfA2 showed moderate homology to the large and small subunits of other ring-hydroxylating dioxygenases (less than 40%), respectively, and some motifs such as the Fe(II) binding site and the [2Fe-2S] cluster ligands were conserved in DbfA1. DFDO activity was confirmed in Escherichia coli cells containing the cloned dbfA1 and dbfA2 genes with the complementation of nonspecific ferredoxin and ferredoxin reductase component of E. coli. Under this condition, these cells exhibited angular dioxygenation of DF and dibenzo-p-dioxin, and monooxygenation of fluorene, but not angular dioxygenation of carbazole, xanthene, and phenoxathiin. Phylogenetic analysis revealed that DbfA1 formed a branch with recently reported large subunits of polycyclic aromatic hydrocarbon (PAH) dioxygenase from gram-positive bacteria but did not cluster with that of other angular dioxygenases, i.e., DxnA1 from Sphingomonas sp. strain RW1 [Armengaud, J., Happe, B., and Timmis, K. N. J. Bacteriol. 180, 3954-3966, 1998] and CarAa from Pseudomonas sp. strain CA10 [Sato, S., Nam, J.-W., Kasuga, K., Nojiri, H., Yamane, H., and Omori, T. J. Bacteriol. 179, 4850-4858, 1997].

Topics: Benzofurans; Cloning, Molecular; Dioxygenases; Genes, Regulator; Gram-Positive Bacteria; Molecular Sequence Data; Open Reading Frames; Oxidoreductases; Oxygenases; Phylogeny; Polymerase Chain Reaction; Protein Subunits; Sequence Analysis, DNA; Sequence Homology, Amino Acid; Substrate Specificity

Induction of cytochrome P4501A (CYP1A) mRNA by polychlorinated dibenzo-p-dioxin (PCDD), polychlorinated dibenzofuran (PCDF), and polychlorinated biphenyl (PCB) congeners was measured in a zebrafish liver (ZF-L) cell line. The ZF-L cells were far less sensitive to PCDD, PCDF, and PCB congeners than were other fish cell lines. The 2,3,7,8-PCDDs, 2,3,7,8-PCDFs, and PCB 126 caused dose-related induction. All other PCBs tested, including other coplanar as well as ortho-substituted congeners, were ineffective at inducing CYP1A. The potency of each congener that gave a response, relative to 2,3,7,8-tetrachlorodibenzo-p-dioxin, was determined. The ZF-L cell-derived relative potency values (REPs) are similar to other in vitro REPs in that the ZF-L cell-derived REPs are generally higher than those derived from in vivo models. Furthermore, the ZF-L cell-derived REPs are generally within fivefold of REPs determined in a variety of rainbow trout systems when the same endpoint in the same tissue are compared. Analysis of these data indicates that REPs based on molecular and biochemical responses in sensitive and insensitive species are similar, but overestimate relative in vivo toxicity in the rainbow trout. The ZF-L cell-derived REPs expand the database of REPs, providing additional information that will be useful in quantifying the uncertainty associated with applying consensus fish-specific toxic equivalency factors in ecological risk assessment.

Topics: Animals; Benzofurans; Cell Line; Cytochrome P-450 Enzyme System; Dioxins; Liver; Polychlorinated Biphenyls; RNA, Messenger; Zebrafish

The attack by the bph-encoded biphenyl dioxygenase of Burkholderia sp. strain LB400 on a number of symmetrical ortho-substituted biphenyls or quasi ortho-substituted biphenyl analogues has been investigated. 2,2'-Difluoro-, 2,2'-dibromo-, 2,2'-dinitro-, and 2,2'-dihydroxybiphenyl were accepted as substrates. Dioxygenation of all of these compounds showed a strong preference for the semisubstituted pair of vicinal ortho and meta carbons, leading to the formation of 2'-substituted 2,3-dihydroxybiphenyls by subsequent elimination of HX (X = F, Br, NO(2), or OH). All of these products were further metabolized by 2,3-dihydroxybiphenyl 1,2-dioxygenases of Burkholderia sp. strain LB400 or of Rhodococcus globerulus P6. Dibenzofuran and dibenzodioxin, which may be regarded as analogues of doubly ortho-substituted biphenyls or diphenylethers, respectively, were attacked at the "quasi ortho" carbon (the angular position 4a) and its neighbor. This shows that an aromatic ring-hydroxylating dioxygenase of class IIB is able to attack angular carbons. The catechols formed, 2,3,2'-trihydroxybiphenyl and 2,3,2'-trihydroxydiphenylether, were further metabolized by 2,3-dihydroxybiphenyl 1,2-dioxygenase. While angular attack by the biphenyl dioxygenase was the main route of dibenzodioxin oxidation, lateral dioxygenation leading to dihydrodiols was the major reaction with dibenzofuran. These results indicate that this enzyme is capable of hydroxylating ortho or angular carbons carrying a variety of substituents which exert electron-withdrawing inductive effects. They also support the view that the conversions of phenols into catechols by ring-hydroxylating dioxygenases, such as the transformation of 2,2'-dihydroxybiphenyl into 2,3,2'-trihydroxybiphenyl, are the results of di- rather than of monooxygenations. Lateral dioxygenation of dibenzofuran and subsequent dehydrogenation and extradiol dioxygenation by a number of biphenyl-degrading strains yielded intensely colored dead-end products. Thus, dibenzofuran can be a useful chromogenic indicator for the activity of the first three enzymes of biphenyl catabolic pathways.

Topics: Benzofurans; Biodegradation, Environmental; Biphenyl Compounds; Burkholderia; Dioxins; Dioxygenases; Escherichia coli; Iron-Sulfur Proteins; Oxygenases; Polybrominated Biphenyls; Polychlorinated Biphenyls; Rhodococcus

The UV absorption spectra structures of carbazole, fluorene and dibenzofurane are studied using the atom monopole-dipole interaction (AMDI) model and atomic dipolar polarisabilities and effective charge given by Fraga. The absorption spectra corresponding to these molecules and their self-associations are presented. The original obtained results are discussed and compared to previous works.

Topics: Benzofurans; Carbazoles; Fluorenes; Molecular Structure; Spectrophotometry, Ultraviolet

The effect of the nonionic surfactant Brij 35 on the bioavailability of solid and Teflon-sorbed dibenzofuran for Sphingomonas sp. strain HH19k was studied in simple model systems. Growth with dibenzofuran and dibenzofuran-specific oxygen uptake in surfactant-free media and with Brij 35 above the critical micelle concentration (cmc) were compared with dissolution and desorption in the absence of bacteria. Brij 35 accelerated dissolution and biodegradation of solid dibenzofuran by a factor of 2. It also enhanced the initial desorption rate of dibenzofuran from Teflon by this factor. Continuously decreasing desorption rates were attributed to slow diffusion of dibenzofuran inside Teflon, leading to depletion of dibenzofuran in the exterior of the Teflon particles. Surprisingly, Brij 35 slowed the initial biodegradation of desorbing dibenzofuran. We propose two processes that led to low bioavailability of sorbed dibenzofuran in the presence of surfactant. First, desorbing dibenzofuran rapidly accumulated in surfactant micelles, leading to reduced truly water-dissolved dibenzofuran concentration as the factor controlling the biodegradation rate. Second, Brij 35 suppressed the contact between bacteria and Teflon. This increased the average diffusion distance of dibenzofuran to the bacteria, which in turn flattened the gradient of the dissolved dibenzofuran concentration between the sorbent and the cells as the driving force for desorption.

Topics: Benzofurans; Biodegradation, Environmental; Biological Availability; Detergents; Diffusion; Polidocanol; Polyethylene Glycols; Solubility; Sphingomonas; Tissue Distribution; Water Pollutants, Chemical

In breast milk, concentrations of polychlorinated biphenyls (PCBs) are higher than those of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), making PCB analyses less time-consuming and expensive. We searched for PCB "markers" of PCDD/DF concentrations, by studying associations between concentrations of PCB and PCDD/DFs (expressed as toxic equivalents, TEQs) in breast milk from 27 women (primiparas, 22-35 years). These women donated breast milk in 1996-1999 together with 183 other primiparas from Uppsala County, Sweden. Regression analyses showed that both dioxin-like and non-dioxin-like penta- to hepta-chlorinated PCBs could be used as markers of TEQ concentrations in this group of women, in some cases after age adjustment of the regressions. The strong positive association between concentrations of dioxin-like PCB/DD/DFs and non-dioxin-like PCBs will in future epidemiological studies make it difficult to separate Ah receptor-dependent effects from non-Ah receptor-dependent effects. With the use of regression equations and concentrations in breast milk samples collected in 1994, TEQ concentrations were estimated in the 1994 samples. Comparisons between estimated and measured concentrations indicated that associations between concentrations of marker substances and TEQs should be determined separately within each study population, in order to obtain reliable TEQ exposure assessments from PCB markers.

Topics: Adult; Age Factors; Benzofurans; Biomarkers; Dioxins; Female; Humans; Milk, Human; Multivariate Analysis; Polychlorinated Biphenyls; Reference Values; Regression Analysis; Reproducibility of Results; Sweden

Two kinds of bacteria having different-structured angular dioxygenases-a dibenzofuran (DF)-utilizing bacterium, Terrabacter sp. strain DBF63, and a carbazole (CAR)-utilizing bacterium, Pseudomonas sp. strain CA10-were investigated for their ability to degrade some chlorinated dibenzofurans (CDFs) and chlorinated dibenzo-p-dioxins (CDDs) (or, together, CDF/Ds) using either wild-type strains or recombinant Escherichia coli strains. First, it was shown that CAR 1,9a-dioxygenase (CARDO) catalyzed angular dioxygenation of all mono- to triCDF/Ds investigated in this study, but DF 4,4a-dioxygenase (DFDO) did not degrade 2,7-diCDD. Secondly, degradation of CDF/Ds by the sets of three enzymes (angular dioxygenase, extradiol dioxygenase, and meta-cleavage compound hydrolase) was examined, showing that these enzymes in both strains were able to convert 2-CDF to 5-chlorosalicylic acid but not other tested substrates to the corresponding chlorosalicylic acid (CSA) or chlorocatechol (CC). Finally, we tested the potential of both wild-type strains for cooxidation of CDF/Ds and demonstrated that both strains degraded 2-CDF, 2-CDD, and 2,3-diCDD to the corresponding CSA and CC. We investigated the sites for the attack of angular dioxygenases in each CDF/D congener, suggesting the possibility that the angular dioxygenation of 2-CDF, 2-CDD, 2,3-diCDD, and 1,2,3-triCDD (10 ppm each) by both DFDO and CARDO occurred mainly on the nonsubstituted aromatic nuclei.

Topics: Actinomycetales; Bacterial Proteins; Benzofurans; Biodegradation, Environmental; Chlorine; Dioxins; Dioxygenases; Escherichia coli; Gas Chromatography-Mass Spectrometry; Oxygenases; Pseudomonas

Topics: Animals; Benzofurans; Biological Assay; Carcinoma, Hepatocellular; Carps; Cytochrome P-450 CYP1A1; Environmental Exposure; Liver; Liver Neoplasms; Polychlorinated Dibenzodioxins; Rats

Two sediment cores collected from the central Venice Lagoon and five from the canals of the nearby industrial area were studied in order to assess the temporal evolution of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) delivery and present trends. The most polluted site is C12, in the Brentella Canal, with a total equivalent (TEQ) concentration of 2858 and 64,130 ng kg-1 at the surface and at 18-20 cm depth, respectively. High values can be also found in the Nord Industrial Canal and in the Salso Canal: 3000 and 2500 ng kg-1, respectively. Lagoon samples are much less contaminated, with TEQ downcore maxima of 22 and 53 ng kg-1, being influenced by pollutants stored in sediments of the canals only occasionally. Sediment chronology, based on 210Pb and 137Cs activity-depth profiles, shows that the highest fluxes occurred in the 1970s and early 1980s, and that pollution is now decreasing. Homologue profiles can distinguish PCDD/Fs from different sources: combustion for octachlorinated dibenzo-p-dioxin (OCDD) and stripping of VCM for octachlorinated dibenzofuran (OCDF) alone, whereas several activities carried out in the past within the industrial area can be responsible of the overall contamination by furans.

Topics: Benzofurans; Environmental Monitoring; Geologic Sediments; Incineration; Industry; Polychlorinated Dibenzodioxins; Soil Pollutants; Water Pollutants, Chemical

Isomer patterns of polychlorinated naphthalenes (PCNs), polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated biphenyls (PCBs), and polychlorinated dibenzofurans (PCDFs) from municipal waste incinerators (MWIs) were predicted by a model based on symmetry numbers and preferential chlorination positions. Fly ash isomer patterns from five stoker and seven fluidized bed incinerators were compared to validate the prediction model. The isomer patterns of the highly chlorinated PCN homologues from stoker type incinerators were successfully predicted. The relative equilibrium concentrations of tetrachloronaphthalenes (TeCNs), calculated by an ab initio method, cannot explain the field isomer patterns. Formation pathways involving chlorophenol precursor condensation reactions should be examined to see whether these isomer patterns provide a better fit to the field PCDD data. The PCB isomer patterns were fit reasonably well, but this finding could merely be an artifact of the limited data and the large number of isomers. The prediction equations of PCDFs, revised from prior work to include a symmetry number for each isomer, represented the field data patterns for the higher chlorinated isomers very well. Successful prediction of isomer patterns for partial homologue ranges suggests that these patterns are determined by a mechanism governed by Cl-position-specific preferences.

Topics: Benzofurans; Environmental Monitoring; Environmental Pollutants; Forecasting; Incineration; Isomerism; Models, Theoretical; Naphthalenes; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Refuse Disposal; Soil Pollutants

In 1999, a campaign of the Flemish Ministry of Health, Belgium was set up to assess pollutant concentrations and related health effect biomarkers in humans living in two regions of Flanders. The study was called the 'Flemish Environment and Health Study' (FLEHS). Concentrations of selected organochiorine pesticides, polychlorinated biphenyls (PCB) and polychlorinated dibenzo-p-dioxins (PCDD) and flirans (PCDF) were measured by gas chromatography-mass spectrometry in 47 pooled human serum samples originating from 200 individual women between 50 and 65 years living in two Flemish regions. The CALUX (Chemical-Activated Luciferase gene eXpression) bioassay was assessed on the same pools. The correlation between CALUX-TEQ and total TEQ (sum of PCDD/PCDF, non- and mono-ortho PCBs) varied from 0.43 to 0.73 for the rural and urban region, respectively. The mean value for the total TBQ (75 pg WHO-TEQ/g fat) was two times higher than the mean TEQ value determined with the CALUX bioassay (36 pg TEQ/g fat). This shows that the assessment of dioxin-like exposure by these two measurements was different. However, regional differences in concentrations were observed for neither total TEQs, nor CALUX-TEQs. It was concluded that the CALUX can be an alternative screening tool for biomonitoring purposes, especially when the objective is to compare different groups of people (e.g. living in different regions).

Topics: Adult; Belgium; Benzofurans; Biological Assay; Blood Chemical Analysis; Environmental Health; Environmental Monitoring; Environmental Pollutants; Female; Humans; Middle Aged; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins

A fast clean-up procedure for the low level analysis of polychlorinated dibenzo-p-dioxins. polychlorinated dibenzofurans and coplanar polychlorinated biphenyls in highly fatty biological matrices using high capacity disposable multi-layer silica columns is presented. Results were compared with gel permeation chromatography for removal of lipids. Analytical criteria such as recovery rates, repeatability, reproducibility and robustness are evaluated through a broad range of biological matrices and reference materials analysis. The final proposed procedure for the complete analysis, including pressurized liquid extraction, Power-Prep system clean-up and GC-high-resolution MS analysis requires only 48 h, and allows the simultaneous preparation of up to 10 samples.

Topics: Benzofurans; Chromatography, Gel; Fats; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Quality Control; Reference Standards; Reproducibility of Results

Sediment from the upper Detroit and lower Rouge Rivers in southeastern Michigan, USA, were analyzed to examine the distribution of polychlorinated naphthalenes (PCNs), biphenyls (PCBs), dibenzo-p-dioxins (PCDDs), and dibenzofurans (PCDFs) as well as polycyclic aromatic hydrocarbons (PAHs) and alkylphenolic compounds such as butylphenol, octylphenol, and nonylphenol (NP). Sediments from a non-point source location in Lake Michigan were also analyzed for target compounds. Concentrations of target compounds in the upper Detroit and lower Rouge Rivers varied considerably among locations, and notable spatial variation existed. Concentrations of PCNs and PCDDs/PCDFs in sediments from the upper Detroit and lower Rouge Rivers ranged from 0.08 to 187 ng/g and 69 to 1420 pg/g dry weight, respectively. Total PCBs, PAHs, and NP concentrations ranged from 8 to 25,000, 17 to 44,000, and < 10 to 60,000 ng/g dry weight, respectively. Concentrations of all target compounds except PCNs were significantly correlated with total organic carbon content of sediments. Similarly, concentrations of PCBs, PCDDs, and PCDFs were significantly correlated with each other. The distribution of organic contaminants in the upper reaches of the Detroit River and lower Rouge River suggested the presence of localized, but multiple, sources of contamination for each compound class. Conners Creek combined sewer overflow has been identified as one of the potential sources for the upper Detroit River, where the highest concentrations PCBs and PCDDs/PCDFs were found. Polycyclic aromatic hydrocarbon and NP concentrations were consistently high in sediment from the lower Rouge River. Analysis of data from selected locations suggested that PCNs contributed a greater proportion of the dioxin-like activity than PCBs and PCDDs/PCDFs contributed.

Topics: Benzofurans; Environmental Monitoring; Environmental Pollutants; Geologic Sediments; Michigan; Naphthalenes; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Polycyclic Aromatic Hydrocarbons; Soil Pollutants; Water Pollutants, Chemical

A cell-associated protein released from Bacillus pumilus PH-01 showed an affinity for some dioxins, like 1,2,3,4-tetrachlorodibenzo-p-dioxin (TCDD) and 1,2,3,4-tetrachlorodibenzofuran (TCDF), and the concentration of the protein increased when B. pumilus PH-01 was boiled in minimal salts medium. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and matrix-assisted laser desorption ionization-mass spectrometry revealed that the boiled culture supernatant contained a major protein with a molecular mass of 5,313.4 Da. The adsorption behavior of the protein for 1,2,3,4-TCDD and 1,2,3,4-TCDF was examined by digesting it with proteinase K and trypsin, showing that the proteolyzed protein lost the ability to adsorb the compounds. The amino acid sequence of the protein was determined by automated Edman degradation and tandem mass spectrometry. A search of the protein databases showed no existence of proteins with an homologous sequence.

Topics: Adsorption; Amino Acid Sequence; Bacillus; Bacterial Proteins; Benzofurans; Dioxins; Polychlorinated Dibenzodioxins

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/DFs) formation by the thermal reactions of phenols with CuCl2 under oxygen flux were carried out in relation to their formation mechanisms. To evaluate the effect of photocatalytic degradation of titanium dioxide (TiO2) thin film prepared by the sol-gel method, the photocatalysis of PCDD/DFs in acetonitrile/water solution by batch-recycle system was conducted. For the thermal reaction system of powder mixtures of 2,4,5-trichlorophenol (2,4,5-TCP) and CuCl2, the formation rates were 8.1 microg/g-2,4,5-TCP/min for total PCDD/DFs and 6.9 microg/g-2,4,5-TCP/min for PCDDs, and total PCDD/DF rate was higher by approximately 40 fold compared to phenol vapor/oxygen/CuCl2 powder system. For the system of 2,4,5-TCP, PCDDs were mainly formed via ortho-phenoxyphenols (POP) intermediate by the condensation of 2,4,5-trichlorophenate. For PCDD/DF photocatalytic degradations, most PCDD congeners photodecomposed rapidly and the rates presented more than 70% (as dechlorination rates of 76% for PCDDs) at 24 h after irradiation, using PCDD/DFs formed with 2,4,5-TCP. The rate constants were in the order of 4.8-6.1 x 10(-3) min(-1), assuming the pseudo-first-order reactions for their low levels.

Topics: Air Pollutants; Benzofurans; Catalysis; Coloring Agents; Incineration; Phenols; Photochemistry; Polychlorinated Dibenzodioxins; Refuse Disposal; Soil Pollutants; Temperature; Titanium

Polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/DF) levels in plywood combustion gas were investigated for the effects of ammonium chloride (NH4Cl) and paint. For combustion systems in which neither NH4Cl nor paint were present in the plywood samples, total amounts of PCDD/DFs in the combustion gas were in the order of 35-529 ng/Nm3, and were higher in the systems with softwood trees than broadleaf ones, depending on the Cl concentrations. For the systems with added NH4Cl and no paint, and those without NH4Cl but were painted, higher PCDD/ DF rates were observed at combustion temperatures of 270 degrees C and 500 degrees C, respectively. However, for the systems with both NH4Cl and paint, their amounts in the range of 0.6-13 ng/Nm3 were the lowest in all systems. The PCDD/DF abundance profiles were similar to their patterns in pentachlorophenol (PCP). Furthermore, it was found that the 2,3,7,8-chlorine substituted penta- and hexa-CDDs contributed more than other 2,3,7,8-chlorine substitutes to toxicity equivalency (TEQ).

Topics: Air Pollutants; Ammonium Chloride; Benzofurans; Incineration; Paint; Polychlorinated Dibenzodioxins; Refuse Disposal; Soil Pollutants; Wood

We conducted model simulations of the atmospheric fate and transport of PCDD/F to assess the fraction of emitted PCDD/F that would deposit within 100 km from the source. We considered eight major categories of PCDD/F emission sources and six different locations, to cover a wide range of source characteristics, PCDD/F congener profiles and particle size distributions, meteorological conditions and terrain configurations. These results suggest that for sources that have tall stacks and/or high plume rise (e.g., copper smelters, cement kilns, sinter plants), only a small fraction of PCDD/F emissions is deposited locally (typically, less than 10% within 100 km). Other source categories such as municipal solid waste incinerators, medical waste incinerators and diesel trucks lead to a greater fraction of PCDD/F being deposited locally; nevertheless, the majority of their PCDD/F emissions tends to be transported beyond 100 km. Although local impacts may need to be addressed for these latter source categories, it appears that the long-range potential impacts of PCDD/F need to be addressed for all source categories. Sensitivity studies were conducted to investigate the effect of various key model inputs on simulation results. These studies suggest that an advanced atmospheric dispersion model should be used for cases where PCDD/F emissions may present some local concerns because the results are very sensitive to the treatment of dispersion. Also, it is essential to obtain accurate characterizations of the particle size distribution of particulate PCDD/F because the dry deposition flux is very sensitive to the particle size distribution.

Topics: Air Movements; Air Pollutants; Benzofurans; Environmental Monitoring; Incineration; Industry; Models, Theoretical; Particle Size; Polychlorinated Dibenzodioxins; Refuse Disposal; Soil Pollutants

In order to examine the input of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/PCDFs) from various airborne sources to environmental sinks, the atmospheric deposition of congener-specific PCDDs/PCDFs was investigated. Homologue and congener profiles of atmospheric depositions were compared with those of sources and environmental sinks to identify the relationship among atmospheric depositions, sources, and environmental sinks. Moreover, factor analysis was used to detect similarities, differences, and relationships of the variations in deposition fluxes among congeners within the same and different homologues. The results showed that the congener profiles of the atmospheric depositions were primarily determined by those of combustion emissions. Several congeners in some specific samples showed higher proportions within each homologue compared with representative depositions. This result can be partly explained by the influence of impurities in herbicides, 1,3,5-trichloro-2-(4-nitrophenoxy) benzene (CNP) and pentachlorophenol (PCP). The congener profiles of combustion emissions, representative depositions, and urban soils were very similar although their homologue profiles varied. This implied that PCDDs/PCDFs in the urban soils originate from the deposition of combustion emissions and that all congeners within each homologue behave identically in air and soil. Although the congener profiles of the representative depositions were different from those of the sediments in Tokyo Bay and the soil of a paddy field, the combination of congener profiles of the representative depositions and of the impurities in herbicides. CNP and PCP, can explain the congener profiles of the sediments and the paddy field. This study showed that congener-specific data are useful for source identification.

Topics: Agriculture; Air Pollutants; Benzofurans; Environmental Monitoring; Geologic Sediments; Herbicides; Incineration; Models, Theoretical; Polychlorinated Dibenzodioxins; Refuse Disposal; Soil Pollutants

The gastrointestinal exchange of polychlorinated biphenyls (PCBs), dibenzo-p-dioxins, and dibenzofurans (PCDD/Fs) as well as hexachlorobenzene was measured in five volunteers. The dietary intake and the fecal excretion of the chemicals were quantified and the net absorption/net excretion was calculated as the difference between these two fluxes. Experiments were conducted using an elevated dietary intake and a reduced dietary intake of chemical, and the results were compared with the absorption during normal dietary intake. The net absorption varied widely with the dietary intake for those compounds which bioaccumulate in humans; high dietary intake of chemical resulted in absorption approaching 100% of intake, while low dietary intake resulted in a net excretion several times greater than the dietary intake. In contrast to net absorption, the chemical flux in the feces was largely independent of the dietary intake of chemical for a given individual. Good agreement was found between the feces/blood distribution coefficients measured in this study and in a study with contaminated workers whose blood concentrations were several orders of magnitude higher, indicating that fecal excretion of chemical is linearly proportional to the blood concentration. The results suggest that gastrointestinal exchange can be viewed as two processes operating simultaneously: absorption of contaminant from the diet, and excretion of contaminant from the body's reservoirs via the feces. By subtracting that component of the fecal flux originating from the body, the maximum dietary absorption could be calculated. This was >95% for most of the compounds, decreasing to a minimum of 50-60% for the octachlorinated dioxins and furans. The maximum dietary absorption showed a Kow dependency consistent with the two film model of gastrointestinal absorption of persistent organic chemicals.

Topics: Adult; Benzofurans; Diet; Dioxins; Dose-Response Relationship, Drug; Environmental Pollutants; Feces; Humans; Intestinal Absorption; Male; Middle Aged; Polychlorinated Biphenyls

A method for bioremediation of chlorinated dibenzo-p-dioxins (CDDs) and dibenzofurans (CDFs) by a carbazole-utilizing bacterium, Pseudomonas sp. strain CA10, was developed. CA10 cells transferred to carbon- and nitrogen-free mineral medium supplemented with 1 mg carbazole (CAR)/ml grew rapidly during the first 2 days; and the cells at the end of this rapid growth period showed the highest 2,3-dichlorodibenzo-p-dioxin (2,3-Cl2DD)-degrading activity. The CA10 cells pregrown for 2 days efficiently degraded 2,3-Cl2DD in aqueous solution at either 1 ppm or 10 ppm. The effect of inoculum density on the efficiency of 2,3-Cl2DD degradation was investigated in a soil slurry microcosm [ratio of soil:water = 1:5 (w/v)]. The results showed that a single inoculation with CA10 cells at densities of 10(7) CFU/g soil and 10(9) CFU/g soil degraded 46% and 80% of 2,3-Cl2DD, respectively, during the 7-day incubation. The rate of degradation of each CDD congener, 2-ClDD, 2,3-Cl2DD, and 1,2,3-Cl3DD (1 ppm each) by strain CA10 in the soil slurry system was not significantly influenced by the coexistence of the other congeners. Using this soil slurry system, we tried an experimental bioremediation of the actual dioxin-contaminated soil, which contained mainly tetra- to octochlorinated dioxins. Although the degradation rate of total CDD and CDF congeners by a single inoculation with CA10 cells was 8.3% after a 7-day incubation, it was shown that strain CA10 had a potential to degrade tetra- to hepta-chlorinated congeners including the most toxic compound, 2,3,7,8-tetrachlorinated dibenzo-p-dioxin.

Topics: Benzofurans; Biodegradation, Environmental; Biotechnology; Carbazoles; Culture Media; Dioxins; Pseudomonas; Soil Pollutants

Air samples were taken on board the RRS Bransfield (typically for 24-72 h), during an Atlantic cruise from the U.K. to Antarctica in October-December 1998, to investigate the global scale distribution of PCDD/Fs and coplanar PCBs. Highest concentrations of Cl2-8DD/Fs all occurred between 25 and 52 degrees N; lowest concentrations were measured around approximately 60 degrees S and further south. Cl3DFs showed highest overall concentrations (up to 9800 fg/m3), followed by Cl2DFs (up to 5300 fg/m3) and OCDD (up to 1300 fg/m3). Lowest concentrations, measured in the remote Southern hemisphere, were generally 2 orders of magnitude lower than their highest concentrations over the North Atlantic. Concentrations of PCB-77 were higher in the northern hemisphere, while PCB-126 and PCB-169 exhibited highest concentrations around the equator. Evidence was obtained for substantial emissions of PCDD/Fs off west Africa and while in the port of Montevideo, Uruguay. Shifts in PCDD/F profile distribution were observed on increasing distance from source regions, such that those from the most remote locations were dominated by Cl3DF (approximately 40% of the total) and OCDD (approximately 20%). Gas-particle partition data was obtained for all samples. Cl4-6DD/Fs showed the widest range, varying between 10 and 90% of the total in the gas phase, depending on location/ temperature. The study gave limited evidence for the influence of OH-radical initiated depletion reactions of gaseous PCDD/Fs. The global atmospheric burden is estimated to be on the order of 350 kg sigmaCl4-8DD/Fs and approximately 3 kg sigmaTEQ.

Topics: Air Pollutants; Atlantic Ocean; Benzofurans; Environmental Pollutants; Gases; Particle Size; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Soil Pollutants

From the cultures of the spore-derived mycobionts of the lichen Lecanora cinereocarnea, five dibenzofurans, 3,7-dihydroxy-1,9-dimethyldibenzofuran, 2-chloro-3,7-dihydroxy-1,9-dimethyldibenzofuran, 2,8-dichloro-3,7-dihydroxy-1,9-dimethyldibenzofuran, 3-hydroxy-7-methoxy-1,9-dimethyldibenzofuran, and 2-chloro-7-hydroxy-3-methoxy-1,9-dimethyldibenzofuran, were isolated. Their structures were determined by spectroscopic methods.

Topics: Benzofurans; Lichens; Molecular Structure; Spectrum Analysis

Penicillium canescens oxidises dibenzofuran (DBF) to produce monohydroxylated derivatives and other more hydrophilic metabolites. These substances are water-soluble but unstable in organic solvents such as ethyl acetate, acetone or dichloromethane. Both extraction with ethyl acetate and enzymatic treatment of the aqueous culture filtrate with beta-glucuronidase led to decay of the hydrophilic metabolites and indicated these products to be glycoside conjugates. The glycosyl residue was identified as glucose both by liquid chromatography and by the use of glucose oxidase. The conjugate pattern formed was the same in type and amount, independent of the carbon source used for cultivation of the fungus. Clearly, DBF transformation in P canescens occurred in two phases: first the conversion to 2-, 3-, and 4-hydroxydibenzofuran (phase I), followed by the formation of the corresponding glucosyl conjugates (phase II). In contrast, 2,3-dihydroxydibenzofuran added to the cultures was transformed by ring cleavage producing a muconic acid-like dead-end product.

Topics: Benzofurans; Biotransformation; Chromatography, High Pressure Liquid; Chromatography, Ion Exchange; Gas Chromatography-Mass Spectrometry; Glucose Oxidase; Glucosides; Glucuronidase; Penicillium

An automated clean-up system was evaluated for the simultaneous analysis of polychiorinated dibenzo-p-dioxins (PCDD), dibenzofurans (PCDF), and biphenyls (PCB) in different foods. In addition to the seventeen 2,3,7,8-substituted PCDDIPCDF and four non-ortho PCB, by use of the clean-up system studied, it was possible to collect the eight mono-ortho and two di-ortho PCB and the seven indicator PCB in two separate fractions during the same clean-up run. The study was first performed using standard mixtures containing PCDD, PCDF and PCB, and a certified reference material. The recoveries of the 13C-labeled compounds ranged from 51 to 90%, indicating that the PCDD, PCDF, and PCB clean-up worked satisfactorily. Next, the automated system for PCDD, PCDF, and PCB analysis was evaluated for foods such as milk, egg, meat (beef, chicken, and pork), mussel, and olive oil. The recoveries of the 13C-labeled compounds ranged from 40 to 120% for PCB and from 57 to 113% for PCDD/ PCDF, meeting the requirements of well accepted methods. Thus, the automated clean-up system studied is a suitable alternative to conventional clean-up methods.

Topics: Automation; Benzofurans; Carbon Radioisotopes; Chemical Fractionation; Environmental Exposure; Food; Food Contamination; Mass Spectrometry; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Radioactive Tracers; Reference Standards; Sensitivity and Specificity

Combustion experiments in a laboratory-scale fluidized-bed reactor were performed to elucidate the effects of combustion temperature on PCDD/Fs formation during incineration of model wastes with poly(vinyl chloride) or sodium chloride as a chlorine source and copper chloride as a catalyst. Each temperature of primary and secondary combustion zones in the reactor was set independently to 700, 800, and 900 degrees C using external electric heaters. The PCDD/Fs concentration is reduced as the temperature of the secondary combustion zone increases. It is effective to keep the temperature of the secondary combustion zone high enough to reduce their release during the waste incineration. On the other hand, as the temperature of the primary combustion zone rises, the PCDD/Fs concentration also increases. Lower temperature of the primary combustion zone results in less PCDD/Fs concentration in these experimental conditions. This result is probably related to the devolatilization rate of the solid waste in the primary combustion zone. The temperature decrease slows the devolatilization rate and promotes mixing of oxygen and volatile matters from the solid waste. This contributes to completing combustion reactions, resulting in reducing the PCDD/Fs concentration.

Topics: Benzofurans; Carbon; Clinical Laboratory Techniques; Hot Temperature; Incineration; Polychlorinated Dibenzodioxins; Polyvinyl Chloride; Sodium Chloride; Waste Management

Topics: Animals; Benzofurans; Birds; Dioxins; Eggs; Environmental Exposure; Environmental Pollutants; Female; Male; Polychlorinated Biphenyls; Tissue Distribution

The slow combustion of benzene/phenol gives rise to dibenzofuran (DBF) as major product of incomplete combustion, with negligible proportions of dibenzo-p-dioxin (DBD), or benzofuran (BF). Contrary to a recent proposal that acetylene growth reactions, e.g. BF-->DBF, are important in dioxin formation, co-combustion of benzene/phenol with acetylene--around 550 degrees C--did not alter this product pattern. Also, BF was identified as a product from degradation of DBF.

Topics: Acetylene; Benzene; Benzofurans; Dioxins; Gases; Phenol

The human amyloid disorders, familial amyloid polyneuropathy, familial amyloid cardiomyopathy and senile systemic amyloidosis, are caused by insoluble transthyretin (TTR) fibrils, which deposit in the peripheral nerves and heart tissue. Several nonsteroidal anti-inflammatory drugs and structurally similar compounds have been found to strongly inhibit the formation of TTR amyloid fibrils in vitro. These include flufenamic acid, diclofenac, flurbiprofen, and resveratrol. Crystal structures of the protein-drug complexes have been determined to allow detailed analyses of the protein-drug interactions that stabilize the native tetrameric conformation of TTR and inhibit the formation of amyloidogenic TTR. Using a structure-based drug design approach ortho-trifluormethylphenyl anthranilic acid and N-(meta-trifluoromethylphenyl) phenoxazine 4, 6-dicarboxylic acid have been discovered to be very potent and specific TTR fibril formation inhibitors. This research provides a rationale for a chemotherapeutic approach for the treatment of TTR-associated amyloid diseases.

Topics: Amino Acid Sequence; Amyloid Neuropathies; Anti-Inflammatory Agents, Non-Steroidal; Benzofurans; Binding Sites; Cardiomyopathies; Crystallography, X-Ray; Dicarboxylic Acids; Diclofenac; Drug Design; Flurbiprofen; Humans; Hydrogen Bonding; Models, Molecular; Molecular Sequence Data; ortho-Aminobenzoates; Oxazines; Prealbumin; Protein Structure, Quaternary; Resveratrol; Stilbenes; Structure-Activity Relationship; Thermodynamics

New efficient synthesis of medium- and large-sized ring substituted furans is achieved by 1,3-dicarbonyl compounds with vinyl sulfides in the presence of Ag(2)CO(3)/Celite (Fétizon's reagent) in a one-pot procedure. The synthesized furans can be further converted to biologically interesting compounds such as dibenzofurans, coumestans, benzofuroquinolinone, and 4-pyrone.

Topics: Benzofurans; Coumarins; Furans; Models, Molecular; Molecular Conformation; Pyrones

This study investigated the potency of individual polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) to reduce hepatic vitamin A in the rat. Dose-response relationships were determined following long-term dietary exposure to 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD), 2,3,4,7, 8-pentachlorodibenzofuran, 1,2,3,4,8-pentachlorodibenzofuran, 1,2,3, 7,8-pentachlorodibenzofuran, 1,2,3,6,7,8-hexachlorodibenzofuran, 1,2, 3,7,8-pentachlorodibenzo-p-dioxin, octachlorodibenzo-p-dioxin, octachlorodibenzofuran, or mixtures of some of these congeners. The aim was to estimate vitamin A-related relative potency (REP) values for each congener in relation to that of TCDD and to investigate if these values were in accordance with REP values estimated for the subchronic toxicity observed in the same study. An additional aim was to investigate if the effect on hepatic vitamin A levels was additive compared to the effect of the individual congeners. The obtained results demonstrate that hepatic vitamin A reduction occurs as a consequence of long-term low-level exposure to 2,3,7, 8-substituted but not to non-2,3,7,8-substituted congeners. Female rats were slightly more responsive to this effect as judged from the lower EC50 values for all the congeners in this sex. The vitamin A-related REP values were similar for female and male rats and were in good agreement with the estimated REP values for subchronic toxicity in the same animals. The vitamin A effect of the individual congeners in the mixture tended to be somewhat less than pure additive for male rats and very close to pure additive for female rats. In conclusion, the presented data show that reduction of hepatic vitamin A is a sensitive marker of an altered retinoid homeostasis following long-term low-dose exposure to dioxin-like compounds, which essentially conforms to their assumed additive mechanism of action.

Topics: Animals; Benzofurans; Diet; Dose-Response Relationship, Drug; Drug Interactions; Female; Liver; Male; Polychlorinated Dibenzodioxins; Rats; Rats, Sprague-Dawley; Soil Pollutants; Vitamin A

A new descriptor of molecular structure for use in the derivation of predictive QSAR and QSPR models, electronic eigenvalue (EEVA), is described. This is a modification of the recently proposed EVA approach, but is based on computationally-derived molecular orbital energies instead of vibrational frequencies. Like EVA, it is also invariant as to the alignment of the structures concerned. Its performance has been tested with respect to the Ah receptor binding of PCBs, PCDDs and PCDFs, and its predictive ability has been clearly demonstrated. In particular, it seems to be suitable for 'pure' electronic substituent effects. i.e., for cases in which both hydrophobic and steric factors are of minor importance.

Topics: Algorithms; Benzofurans; Models, Chemical; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Receptors, Aryl Hydrocarbon; Structure-Activity Relationship

Cells of the gram-negative bacterium Ralstonia sp. strain SBUG 290 grown in the presence of biphenyl are able to cooxidize dibenzofuran which has been 1,2-hydroxylated. Meta cleavage of the 1, 2-dihydroxydibenzofuran between carbon atoms 1 and 9b produced 2-hydroxy-4-(3'-oxo-3'H-benzofuran-2'-yliden)but-2-enoic acid, which was degraded completely via salicylic acid. The presence of these intermediates indicates a degradation mechanism for dibenzofuran via lateral dioxygenation by Ralstonia sp. strain SBUG 290.

Topics: Benzofurans; Biodegradation, Environmental; Biphenyl Compounds; Hydroxylation; Oxidation-Reduction; Proteobacteria

The concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were determined in plasma samples of 20 nonoccupationally exposed subjects living in the vicinity of a new hazardous waste incinerator (HWI), now under construction in Tarragona (Catalonia, Spain). The mean PCDD/F value was 27.0 pg I-TEQ/g lipid with a range from 14.8 to 48.9 pg I-TEQ/g lipid. All samples showed higher PCDD than PCDF levels. Although PCDD/F concentrations were higher in women (27.7 pg I-TEQ/g lipid) than in men (25.2 pg I-TEQ/g lipid), the difference was not statistically significant. While a significant correlation (r = 0.565, p < 0.01) between the age of the subjects and the levels of PCDD/F in plasma could be observed, no significant differences were found in relation to the specific residential area. The plasma concentrations of PCDD/F obtained in the current study are discussed and compared with the results of similar investigations reported in the last two years.

Topics: Adult; Benzofurans; Environmental Exposure; Female; Hazardous Waste; Humans; Incineration; Male; Middle Aged; Polychlorinated Dibenzodioxins; Population Surveillance; Refuse Disposal; Spain; Urban Health

Topics: Animals; Astacoidea; Benzofurans; Carps; Catfishes; Environmental Monitoring; Oregon; Paper; Polychlorinated Dibenzodioxins; Soil Pollutants; Tissue Distribution; Water Pollutants, Chemical; Wood

Removal of dibenzofuran, dibenzo-p-dioxin, and 2-chlorodibenzo-p-dioxin (2-CDD) (10 ppm each) from soil microcosms to final concentrations in the parts-per-billion range was affected by the addition of Sphingomonas sp. strain RW1. Rates and extents of removal were influenced by the density of RW1 organisms. For 2-CDD, the rate of removal was dependent on the content of soil organic matter (SOM), with half-life values ranging from 5.8 h (0% SOM) to 26.3 h (5.5% SOM).

Topics: Benzofurans; Biodegradation, Environmental; Dioxins; Ecosystem; Kinetics; Pseudomonas; Soil Microbiology; Soil Pollutants

The solubilizing effect of humic acids on fluorene and its NSO analogues carbazole, dibenzofuran and dibenzothiophene has been studied. The interaction between these substances and humic acids was found to depend significantly on the actual humic acid concentration. A pronounced decrease in the interaction constant, as well as in the water-organic matter partitioning coefficient was observed with increasing humic acid concentration. The effects are discussed in terms of concentration dependent macromolecular structural changes in the humic acids. A linear free energy relation for the interaction is suggested.

Topics: Benzofurans; Carbazoles; Carbon; Chemical Phenomena; Chemistry, Physical; Fluorenes; Fresh Water; Humic Substances; Solubility; Thiophenes; Water Supply

Food samples from local markets and supermarkets of Tarragona (Catalonia, Spain) were analyzed for PCDD/F concentrations. On lipid basis, PCDD/F levels in meat, fish, eggs, and fats and oils were similar or lower than those found in other countries. By contrast, in general terms PCDD/F levels in milk, vegetables, and cereals showed higher levels than those previously reported. The total dietary PCDD/F intake by the population of Tarragona was estimated to be 210 pg I-TEQ/day. This value is higher than the dietary intake of PCDD/Fs found in a number of surveys from other countries. However, when total dietary intake of PCDD/Fs was calculated including only fish and seafood, meat, milk and dairy products, eggs, and fats and oils, a dietary intake of PCDD/Fs of 117 pg I-TEQ/day was obtained. This intake is in the same range than that reported for different regions and countries. The results of the present study show that food groups such as vegetables, fruits, and cereals should not be excluded to estimate the total dietary intake of PCDD/Fs by general populations, especially in those countries and/or regions in which their consumptions are notable.

Topics: Adult; Aged; Animals; Benzofurans; Dairy Products; Diet; Edible Grain; Female; Food Analysis; Food Contamination; Fruit; Humans; Male; Meat; Middle Aged; Polychlorinated Dibenzodioxins; Seafood; Soil Pollutants; Spain; Vegetables

Transactivation assays were used to compare the potency and efficacy of polychlorinated dibenzo-p-dioxin (PCDD), dibenzofuran (PCDF), and biphenyl (PCB) congeners in activating aryl hydrocarbon receptors (AhRs) from rainbow trout (rtAhR2alpha and rtAhR2beta), zebrafish (zfAhR2), and human (huAhR), respectively. All AhRs were expressed with their species-specific AhR nuclear translocator (ARNT) in COS-7 cells. Transactivation activity was determined for two PCDD, two PCDF, and seven PCB congeners with each of the four AhR/ARNT pairs using prt1Aluc, a luciferase reporter driven by two dioxin-responsive enhancer elements (DREs) from the rainbow trout cyp1A gene. Maximal-fold induction, EC50, and relative potency values were calculated for congeners that exhibited dose-related activity in the assay. Of the four AhR/ARNT pairs tested with PCDD, PCDF, and non-ortho PCB congeners, three exhibited high activity (rainbow trout AhR2alpha, zebrafish AhR2, and human AhR), while rainbow trout AhR2beta had very weak or no activity. Comparisons between these AhRs showed that while mono-ortho PCBs were able to activate the human AhR, they were generally ineffective in activating rainbow trout and zebrafish AhR2s. This supports the hypothesis that structural differences between mammalian and fish AhRs may account for differences in relative potencies of the mono-ortho PCBs between mammals and fish. Another important finding was a significant difference in transactivation activity between the two rainbow trout AhR2 isoforms despite the fact that they are 95% identical at the amino acid level. For all PCDD, PCDF, and PCB agonists tested, rainbow trout AhR2alpha was significantly more active than AhR2beta. However, rainbow trout AhR2beta is active as a 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-activated transcription factor, with enhancer elements from the mouse cyp1A gene. This suggests that AhR2beta may have evolved to serve a different physiological function than AhR2alpha in salmonid fish species.

Topics: Animals; Benzofurans; COS Cells; Dose-Response Relationship, Drug; Environmental Pollutants; Fishes; Humans; Oncorhynchus mykiss; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Receptors, Aryl Hydrocarbon; Soil Pollutants; Species Specificity; Transcriptional Activation; Zebrafish

Selected pyrotechnic articles were set off under laboratory conditions. Residues and vapors of smoke as well as unburnt charges were analyzed for polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/F) and their precursors chlorinated benzenes and phenols. The contamination of the selected products with these organic xenobiotics proved to be very variable. Remains of fireworks contained octachlorinated dioxins and furans up to 142 ng I-TEQ/kg as well as hexachlorobenzene in the range of 0.05 to 1,400 mg/kg. The deflagration of detonating compositions usually resulted in a dispersion of contaminants, whereas continuously burning flare compositions partially led to a thermal decomposition of organic pollutants. A significant rate of formation of polychlorinated dioxins and furans was observed when setting off blue-lightning rockets and fountains. Further investigations revealed that even high temperatures during the deflagration of black powder charges could not suppress the formation of PCDD/F from appropriate precursors.

Topics: Benzofurans; Copper; Environmental Pollutants; Explosions; Germany; Polychlorinated Dibenzodioxins; Polyvinyl Chloride; Smoke

The sediments of Baie des Anglais on the St. Lawrence Estuary have a history of environmental contamination, but no information exists relating to their toxicity. The purpose of the present study was to characterize three sites in and near Baie des Anglais, in terms of sediment toxicity and contaminants. Sites 1 and 2 within the Baie des Anglais are relatively close to local industry and municipal sewage discharge points, while Site 3 is outside the bay. Three microscale bioassays, Microtox, echinoderm fertilization and Toxi-ChromoPad, showed that sediments from Site 1 were the most toxic, followed by Site 2. Site 3 was non-toxic. While the solid phase Microtox test did indicate that Site 1 was most toxic, the absolute response was weak. Liver cytochrome P450 1A1 mRNA in American plaice (Hippoglossoides platessoides), captured at Site 1 in the bay was significantly induced compared to the P450 system of plaice captured at Sites 2 and 3. Hepatic metallothionein mRNA levels were not significantly different between plaice captured at all three sites. Sediment chemical analyses revealed a gradient in polycyclic aromatic hydrocarbons, polychlorinated biphenyls and dibenzofurans (PCDF) with the highest levels recorded at Site 1, about 10-fold less at Site 2 and 100-fold less at Site 3. Amongst the organochlorines the PCDF group were deemed the most important due to their prevalence and known toxicity. Heavy metal concentrations were low and representative of background levels for the St. Lawrence Estuary.

Topics: Animals; Benzofurans; Canada; Cytochrome P-450 CYP1A1; Fertilization; Flatfishes; Luminescent Measurements; Polychlorinated Biphenyls; Polycyclic Aromatic Hydrocarbons; RNA, Messenger; Sea Urchins; Soil Pollutants; Vibrio

The biological degradation of complex mixtures of recalcitrant substances is still a major challenge in environmental biotechnology and the remediation of coal-tar constitutes one such problem area. Biofilm bioreactors offer many advantages and may be successfully used for this purpose. Two stirred-tank reactors and one packed-bed reactor were tested in a continuous mode. Continuous cultivation allows microbial selection to take place whilst adhesive growth provides a high degradation capacity and process stability. The reactors were inoculated with mixed microbial populations to favour complete metabolism and to prevent metabolite accumulation and substrate inhibition effects. Phenol, o-cresol, quinoline, dibenzofuran, acenaphthene and phenanthrene were used as model contaminants and constituted the sole energy and carbon sources. The hydraulic retention time (HRT) was initially set to 2.5 days for a period of several months to allow the establishment of a stable biofilm and was then gradually decreased. All the compounds were found to be degraded by more than 90% at HRT of 3 h or more. Neither substrate inhibition nor metabolite accumulation effects were observed. The stirred-tank configuration was found to be the most efficient for use with high loads. No improvement in the degradation capacity could be achieved by increasing the biofilm surface in these reactors, illustrating that the limiting factor may be the mass transfer limitations rather than the availability of the biofilm surface. Finally, anaerobic treatment was successfully achieved, confirming the potential for remediation of contaminated sites under anaerobic conditions, providing that alternative electron acceptors are present.

Topics: Acenaphthenes; Bacteria, Aerobic; Bacteria, Anaerobic; Benzofurans; Biodegradation, Environmental; Biofilms; Bioreactors; Coal Tar; Cresols; Phenanthrenes; Phenol; Quinolines; Time Factors

Chloracne is caused by exposure to certain halogenated polycyclic hydrocarbons such as polychlorinated dibenzodioxins (PCDDs) and dibenzofurans (PCDFs). In chronic exposure it is not known what level of intoxication, represented by the level in blood lipids, is sufficient to cause chloracne. Blood levels of the congeners of PCDD/Fs were determined in four groups of humans. One group had clinically visible chloracne due to exposure in a hexachlorobenzene workshop of a large chemical factory. A second group was exposed in the same workshop, but had no skin changes. There were two control groups: one non-exposed group of maintenance workers from the same chemical factory, and one group of healthy individuals living elsewhere. Blood levels were converted to toxicity equivalents of tetrachlorodibenzo-p-dioxin (TCDD). In the chloracne group blood levels in toxicity equivalents (TEQs) ranged from 1168 to 22,308 pg/g blood lipid. In the exposed without chloracne this ranged from 424 to 662 pg/g. It is concluded that the level to develop chloracne is between 650 and 1200 pg/g TEQ. The contribution of TCDD was rather small, and the main causative congeners were the hexachlorinated dibenzodioxins and dibenzofurans (HxCDD/Fs); lipid-based blood levels in absolute amounts that may cause chloracne are in the range of 2-3.5 ng/g HxCDD, and 2-5 ng/g HxCDF.

Topics: Acne Vulgaris; Benzofurans; Case-Control Studies; Dermatitis, Occupational; Dioxins; Humans; Lipids

Using the 95% prediction limits of an age-related multiplicative regression model describing the datasets of blood examinations carried out on subjects suspected of having been exposed to lead and to polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/F), it was shown that the relevant curves can be used as an alternative to reference ranges describing the actual background exposure to these pollutants. The upper limit of the actual German background exposure can be estimated by the following equations: PCDD/F as International Toxicity Equivalents in the age range of 10-70 years [pg/g lipid basis] = 1.64.age0.871 and lead in the age range of 15-80 years [microgram/l] = 18.15.age0.3638.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Benzofurans; Child; Dioxins; Environmental Monitoring; Environmental Pollutants; Female; Germany; Humans; Lead; Male; Middle Aged; Models, Statistical; Reference Values

A series of derivatives of dibenzofuran and dibenzosuberol block rhinovirus replication in vitro as judged by their ability to hinder the cytopathic effect in cells infected with HRV14 or HRV16. Both the number and the size of viral plaques were reduced effectively by treatment with these compounds in a dose-dependent fashion, thus affecting viral spread. The compound 2-hydroxy-3-dibenzofuran carboxylic acid was equally effective against HRV16 and HRV14, with IC50 values of 25 microM in cytopathy assays. Dibenzosuberenone showed minor differences in selectivity, with IC50 values of 10 and 30 microM for HRV16 and HRV14 cytopathy, respectively. Likewise, dibenzosuberenone effectively prevented the production of HRV16 proteins, viral RNA, and infectious virus particles when present at concentrations above 30 microM. Time-of-addition experiments show that compounds must be administered before or during the viral adsorption step in order to be effective antivirals. Dibenzosuberenone can block the adsorption of viral particles on to cells, preventing further steps in the replication cycle, but is not effective as a direct inactivating agent. These compounds likely interact with viral capsid proteins, affecting receptor interactions required for attachment and subsequent entry into cells.

Topics: Antiviral Agents; Benzene Derivatives; Benzofurans; Blotting, Western; Cytopathogenic Effect, Viral; Electrophoresis, Polyacrylamide Gel; HeLa Cells; Humans; Reverse Transcriptase Polymerase Chain Reaction; Rhinovirus; Viral Plaque Assay; Virus Replication

We characterized the ability of a yeast to cleave the aromatic structure of the dioxin-like compound dibenzofuran. The yeast strain was isolated from a dioxin-contaminated soil sample and identified as Trichosporon mucoides. During incubation of glucose-pregrown cells with dibenzofuran, six major metabolites were detected by high-performance liquid chromatography. The formation of four different monohydroxylated dibenzofurans was proven by comparison of analytical data (gas chromatography-mass spectrometry) with that for authentic standards. Further oxidation produced 2, 3-dihydroxydibenzofuran and its ring cleavage product 2-(1-carboxy methylidene)-2,3-dihydrobenzo[b]furanylidene glycolic acid, which were characterized by mass spectrometry and 1H nuclear magnetic resonance spectroscopy. These two metabolites are derived from 2-hydroxydibenzofuran and 3-hydroxydibenzofuran, as shown by incubation experiments using these monohydroxylated dibenzofurans as substrates.

Topics: Benzofurans; Biodegradation, Environmental; Chromatography, High Pressure Liquid; Environmental Pollutants; Gas Chromatography-Mass Spectrometry; Hydroxylation; Magnetic Resonance Spectroscopy; Models, Chemical; Oxidation-Reduction; Soil Microbiology; Trichosporon

Cricket frogs (Acris crepitans) from several different sites in Illinois were collected to assess the effects of environmental contamination on the prevalence of intersex gonads. Of 341 frogs collected in 1993, 1994, and 1995, 2.7% were intersex individuals. There was no statistically significant relationship between the chemical compounds detected and cricket frog intersexuality. However, there was an association approaching significance (p = 0.07) between the detection of atrazine and intersex individuals. A comparison of reference sites with sites that had point polychlorinated biphenyl (PCB) and polychlorinated dibenzofuran (PCDF) contamination revealed a significant relationship between sex-ratio reversal and contamination with PCBs and PCDFs. The sex ratio of juvenile frogs studied from three sites with PCB and PCDF point contamination favored males over females, which was the opposite of the sex ratio in control ponds (p = 0.0007). The statistically significant correlation between organochlorine contamination and sex-ratio reversal suggests PCBs and PCDFs can influence cricket frog sexual differentiation. The current study suggests that in cricket frogs, sex ratios and the prevalence of intersex gonads are altered by environmental contamination.

Topics: Aging; Animals; Anura; Benzofurans; Disorders of Sex Development; Environmental Pollutants; Female; Male; Polychlorinated Biphenyls; Prevalence; Sex Distribution

A screening device based on microorganisms immobilised onto a Clark-type oxygen electrode was used to monitor the potential of these microorganisms for the degradation and detection of xenobiotic compounds especially their chlorinated derivatives. The sensitivity and specificity of various species of Pseudomonas, Sphinomonas, Ralstonia, Rhodococcus were characterised in relation to xenobiotic compounds by using biosensor techniques. The following groups of xenobiotics were subjects of investigation: chlorophenols, chlorobenzoates, 2,4-D, PCB, dibenzofurane and their putative intermediates. Using this simple setup it proved possible to screen microbial strains for their potential to catabolize aromatic and chloroaromatic compounds under oxygen consumption. In a kinetic regime, a reproducible signal was obtained within minutes. Based on these results the sensor technique was a suitable method for the rapid characterization of microorganisms and allowed to gather information about the substrate spectrum.

Topics: 2,4-Dichlorophenoxyacetic Acid; Bacteria; Benzofurans; Biosensing Techniques; Chlorine Compounds; Chlorobenzoates; Chlorophenols; Cupriavidus necator; Polychlorinated Biphenyls; Pseudomonas; Rhodococcus; Xenobiotics

The dibenzofuran-degrading bacterial strain DPO360 represents a new species of the genus Terrabacter together with the previously described dibenzofuran-mineralizing bacterial strain DPO1361 (K.-H. Engesser, V. Strubel, K. Christoglou, P. Fischer, and H. G. Rast, FEMS Microbiol. Lett. 65:205-210, 1989; V. Strubel, Ph.D. thesis, University of Stuttgart, Stuttgart, Germany, 1991; V. Strubel, H. G. Rast, W. Fietz, H.-J. Knackmuss, and K.-H. Engesser, FEMS Microbiol. Lett. 58:233-238, 1989). Two 2,3-dihydroxybiphenyl-1,2-dioxygenases (BphC1 and BphC2) and one catechol-2,3-dioxygenase (C23O) were shown to be expressed in Terrabacter sp. strain DPO360 growing with dibenzofuran as a sole source of carbon and energy. These enzymes exhibited strong sensitivity to oxygen. They were purified to apparent homogeneity as homodimers (BphC and BphC2) and as a homotetrameric catechol-2,3-dioxygenase (C23O). According to their specificity constants kcat/Km, both BphC1 and BphC2 were shown to be responsible for the cleavage of 2,2',3-trihydroxybiphenyl, the first metabolite in dibenzofuran mineralization along the angular dioxygenation pathway. With this substrate, BphC2 exhibited a considerably higher kcat/Km, value (183 microM/min) than BphC1 (29 microM/min). Catechol-2,3-dioxygenase was recognized to be not involved in the ring cleavage of 2,2',3-trihydroxybiphenyl (kcat/Km, 1 microM/min). Analysis of deduced amino acid sequence data of bphC1 revealed 36% sequence identity to nahC from Pseudomonas putida PpG7 (S. Harayama and M. Rekik, J. Biol. Chem. 264:15328-15333, 1989) and about 40% sequence identity to various bphC genes from different Pseudomonas and Rhodococcus strains. In addition, another 2,3-dihydroxybiphenyl-1,2-dioxygenase gene (bphC3) was cloned from the genome of Terrabacter sp. strain DPO360. Expression of this gene, however, could not be detected in Terrabacter sp. strain DPO360 after growth with dibenzofuran.

Topics: Amino Acid Sequence; Base Sequence; Benzofurans; Biodegradation, Environmental; Catechol 2,3-Dioxygenase; Chromosome Mapping; Cloning, Molecular; Dioxygenases; Gene Expression; Genes, Bacterial; Gram-Positive Asporogenous Rods; Kinetics; Molecular Sequence Data; Molecular Weight; Oxygenases; Phylogeny; Sequence Analysis; Sequence Homology, Amino Acid

Topics: Benzofurans; China; Molluscacides; Pentachlorophenol; Pest Control; Polychlorinated Dibenzodioxins; Schistosomiasis; Soil Pollutants; Water Pollutants, Chemical

Polychlorinated organic compounds (POCs) accumulate in tissues with a high fat content. Nursed babies are exposed to POCs through the fat in human milk. Exposure levels are estimated to exceed those considered acceptable as a lifelong daily dose. Nevertheless, mothers are still positively advised as to breast-feeding. In 1988, a survey on contamination of human milk with POCs was carried out in The Netherlands. Levels of ten different organochlorine pesticides (OCPs), eight polychlorinated biphenyl (PCB) congeners, and seventeen polychlorinated dibenzodioxin (PCDD) and -dibenzofuran (PCDF) congeners were determined by use of gaschromatographic techniques with either electron-capture or mass-spectrometric detection. Information on some factors potentially influencing the level of contamination of human milk was obtained by questionnaires. The estimated response amounted to 71 percent. Regression analysis was used to investigate associations between determining factors and specific contaminants. It appeared that maternal age was positively associated with POC concentrations. Traditional omnivorous diet was associated with lower concentrations of POCs when compared to all other types of diet. The post-pregnancy Quetelet Index [by definition calculated as weight/(length)2] and the cumulated period of previous breast-feeding were negatively associated with POC concentrations. In conclusion, chemical behavior and environmental distribution patterns of the POCs measured in this study, if translated to factors of human exposure, are in accordance with the study results. Exposure levels will decrease if emissions can be further reduced. Still, in the near future, maternal age will probably rise (Vermunt 1992; Netherlands Central Bureau of Statistics 1992), whereas the duration of lactation in expected to decline. Consequently, there might be an increase in average POC-concentrations in human milk in the forthcoming years.

Topics: Analysis of Variance; Benzofurans; Breast Feeding; Cohort Studies; Data Collection; Environmental Exposure; Female; Humans; Hydrocarbons, Chlorinated; Infant, Newborn; Insecticides; Mass Spectrometry; Milk, Human; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Pregnancy; Quality Control; Regression Analysis; Surveys and Questionnaires

Topics: Adipose Tissue; Adult; Benzofurans; Female; Food Contamination; Humans; Milk, Human; Paris; Polychlorinated Dibenzodioxins; Soil Pollutants; Spain

Use of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxicity equivalents concentration (TEC) assumes that polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) act additively and via a common mechanism to cause toxicity. To test these assumptions, 11 TCDD-like congeners and three non-TCDD-like congeners were combined at ratios typically found in Lake Michigan lake trout. The potency of the mixture, expressed as TEC based on fish-specific toxic equivalency factors, was compared to TCDD for producing lake trout and rainbow trout early life stage mortality. Signs of toxicity following exposure of newly fertilized eggs to the mixture or to TCDD were indistinguishable; sac fry mortality associated with blue-sac disease, and slopes of the dose-response curves for percentage sac fry mortality versus egg TEC or versus egg TCDD were parallel. However, the mixture dose-response curves were significantly shifted to the right of the TCDD dose-response curves by 1.3- and 1.8-fold as illustrated by LD50 values. Following exposure to the mixture or TCDD, LD50S for lake trout early life stage mortality were 97 (89-110) pg TE/g egg and 74 (70-80) pg TCDD/g (LD50, 95% fiducial limits) and for rainbow trout were 362 (312-406) pg TE/g egg and 200 (148-237) pg TCDD/g egg. These data suggest that TCDD-like congeners act via a common mechanism to cause toxicity during trout early development, but may not act strictly additively when combined in a mixture of TCDD- and non-TCDD-like congeners at ratios found in Great Lakes fish. The deviation from additivity, however, is less than current safety factors of 10-fold commonly applied in ecological risk assessments, providing support for the continued use of a TE additivity model for assessing risk posed by complex mixtures of PCDDs, PCDFs, and PCBs to fish.

Topics: Animals; Benzofurans; Dose-Response Relationship, Drug; Drug Combinations; Lethal Dose 50; Oncorhynchus mykiss; Ovum; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Structure-Activity Relationship; Trout; Water Pollutants

The estimated intake of PCDD/Fs and co-planar PCBs associated with an average diet consumed in Spain was investigated. The estimated total average intake for PCDDs and PCDFs from an average spanish diet was found to be 142 pg I-TEQ/day (2.4 pg I-TEQ/Kg b.w./day, for a 60 Kg person). PCDDs provided almost 80% of the total dioxin equivalents. This represents the upper bound estimate. If concentrations less than the LOD are taken as equal to zero, then the estimated average intake would be 81 pg I-TEQ/day which is the lower bound estimate. Data reported are in good agreement with those reported for other countries.

Topics: Benzofurans; Cohort Studies; Diet; Humans; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Reference Values; Soil Pollutants; Spain; Urban Population

Polybrominated and polychlorinated biphenyls (PBBs/PCBs), dibenzo-p-dioxins (PBDDs/PCDDs), dibenzofurans (PBDFs/PCDFs), and diphenyl ethers (PBDEs/PCDEs) are persistent, lipophilic environmental contaminants that may pose a risk to fish early life stage survival. To determine this potential risk, a rainbow trout early life stage mortality bioassay was used in which the potency of individual polybrominated chemicals was compared to the potency of the most potent polychlorinated chemical in these classes, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Following injection of newly fertilized rainbow trout eggs, fish-specific toxic equivalency factors (TEFs) were calculated as the molar ratio of TCDD LD50 to brominated compound LD50. Signs of toxicity were identical to those produced by polychlorinated TCDD-like chemicals and included yolk sac edema, pericardial edema, multifocal hemorrhages, reduced growth, and craniofacial malformations. Polybrominated dibenzo-p-dioxins, dibenzofurans, and biphenyls exhibited decreased potency with increased bromine substitution. Only 2,3,7,8-TBDD was more potent than 2,3,7,8-TCDD, whereas other polybrominated dibenzo-p-dioxins were equipotent or less potent than identically substituted polychlorinated dibenzo-p-dioxins in this assay. Although two PBDF congeners were equipotent to identically substituted PCDFs, 2,3,7,8-TBDF was 9-fold more potent than 2,3,7,8-TCDF. Both 3,3',4,4'-TBB and 3,3',4,4',5,5'-HxBB were 10-fold more potent than identically substituted polychlorinated biphenyls. The halogenated diphenyl ethers and di-ortho polybrominated biphenyls were inactive in this assay. Thus, in this in vivo assay the polybrominated and polychlorinated TCDD-like chemicals were not always equally potent. To assess the risk posed by mixtures of these chemicals to feral fish populations, fish-specific TEFs for both polybrominated and polychlorinated chemicals should be used.

Topics: Animals; Benzofurans; Biphenyl Compounds; Embryo, Nonmammalian; Halogenated Diphenyl Ethers; Hydrocarbons, Brominated; Lethal Dose 50; Oncorhynchus mykiss; Ovum; Phenyl Ethers; Polybrominated Biphenyls; Polychlorinated Dibenzodioxins

Use of fish-specific toxic equivalency factors (TEFs) to estimate the risk that exposure to polybrominated dibenzo-p-dioxins (PBDDs), dibenzofurans (PBDFs), and biphenyls (PBBs) pose to fish early life stage survival depends on validation of the hypothesis that these chemicals act additively to produce mortality. A rainbow trout early life stage bioassay was used to determine how pairs of PBDD, PBDF, and PBB congeners interact to produce 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-like toxicity associated with sac fry mortality. The congener pairs tested were 2,3,7,8-tetrabromodibenzo-p-dioxin (2,3,7,8-TBDD)/1,2,3,7,8-pentabromodibenzo-p-dioxin [correction of pentabromodibenzop-dioxin] (1,2,3,7,8-PBDD); 2,3,7,8-TBDD/1,2,3,7,8-pentabromodibenzofuran (1,2,3,7,8-PBDF); 1,2,3,7,8-PBDD/2,3,4,7,8-pentabromodibenzofuran (2,3,4,7,8-PBDF); and 2,3,4,7,8-PBDF/ 3,3',4,4'-tetrabromobiphenyl (3,3',4,4'-TBB). Graded doses of each congener alone, or graded doses of fixed ratios of paired congeners were injected into newly fertilized rainbow trout eggs. In all cases, interactions between congener pairs were additive as tested by a probit model. Isobolographic analysis also supported the hypothesis that the PBDD, PBDF, and PBB congeners act additively. Thus, the use of fish-specific TEFs to convert fish tissue concentrations of individual PBDD, PBDF, and PBB congeners to TCDD equivalents (TEs) and then adding the TEs contributed by the various congeners to give the total TCDD equivalents concentration (TEC) in the tissue is supported by these results. By comparing the TEC in feral fish eggs to the fish egg TCDD no-observed-effect level (NOEL) and lowest-observed-effect level (LOEL) for early life stage mortality, the risk that complex mixtures of these polybrominated chemicals in eggs pose to sac fry survival can be estimated.

Topics: Animals; Benzofurans; Biphenyl Compounds; Drug Synergism; Embryo, Nonmammalian; Embryonic Development; Oncorhynchus mykiss; Polybrominated Biphenyls; Polychlorinated Dibenzodioxins; Survival Analysis

The regio- and stereospecific oxidation of fluorene, dibenzofuran, and dibenzothiophene was examined with mutant and recombinant strains expressing naphthalene dioxygenase from Pseudomonas sp. strain NCIB 9816-4. The initial oxidation products were isolated and identified by gas chromatography-mass spectrometry and nuclear magnetic resonance spectrometry. Salicylate-induced cells of Pseudomonas sp. strain 9816/11 and isopropyl-beta-D-thiogalactopyranoside-induced cells of Escherichia coli JM109(DE3)(pDTG141) oxidized fluorene to (+)-(3S,4R)-cis-3,4-dihydroxy-3,4-dihydrofluorene (80 to 90% relative yield; > 95% enantiomeric excess [ee]) and 9-fluorenol (< 10% yield). The same cells oxidized dibenzofuran to (1R,2S)-cis-1,2-dihydroxy-1, 2-dihydrodibenzofuran (60 to 70% yield; > 95% ee) and (3S,4R)-cis-3, 4-dihydroxy-3,4-dihydrodibenzofuran (30 to 40% yield; > 95% ee). Induced cells of both strains, as well as the purified dioxygenase, also oxidized dibenzothiophene to (+)-(1R,2S)-cis-1,2-dihydroxy-1, 2-dihydrodibenzothiophene (84 to 87% yield; > 95% ee) and dibenzothiophene sulfoxide (< 15% yield). The major reaction catalyzed by naphthalene dioxygenase with each substrate was stereospecific dihydroxylation in which the cis-dihydrodiols were of identical regiochemistry and of R configuration at the benzylic center adjacent to the bridgehead carbon atom. The regiospecific oxidation of dibenzofuran differed from that of the other substrates in that a significant amount of the minor cis-3,4-dihydrodiol regioisomer was formed. The results indicate that although the absolute stereochemistry of the cis-diene diols was the same, the nature of the bridging atom or heteroatom influenced the regiospecificity of the reactions catalyzed by naphthalene dioxygenase.

Topics: Benzofurans; Biotransformation; Dioxygenases; Escherichia coli; Fluorenes; Magnetic Resonance Spectroscopy; Multienzyme Complexes; Mutation; Oxidation-Reduction; Oxygenases; Pseudomonas; Recombination, Genetic; Stereoisomerism; Substrate Specificity; Thiophenes

This exposure assessment pilot study tested the hypothesis that elevated blood levels of the dioxin congener 2,3,7,8-TCDD ("TCDD"), due to Agent Orange exposure, in American Vietnam veterans could be demonstrated two to three decades after Vietnam service. A second objective was to determine if dioxins, including TCDD, are present in the semen of adult males. In the early 1990s, blood samples from 50 Vietnam veterans and three pooled semen samples from 17 of them were analyzed by high-resolution gas chromatography-mass spectroscopy for dioxins, dibenzofurans, and the dioxin-like PCBs. Fifty volunteers from the Michigan Vietnam veteran bonus list, which documented Vietnam service, were invited to participate based on their self-reported exposure to Agent Orange in Vietnam. Screening of military and medical records was performed by an epidemiologist and a physician to assure that Agent Orange exposure was possible based on job description, location of service in Vietnam, and military Agent Orange spray records. Elevated 2,3,7,8-TCDD levels, over 20 ppt on a lipid basis, could still be detected in six of the 50 veterans in this nonrandomly selected group. The dioxin and dibenzofuran congeners commonly found in the U.S. population, including TCDD, were also detected in the three pooled semen samples. Quantification and comparison on a lipid basis were not possible due to low lipid concentrations where levels were below the detection limit. Therefore, semen samples were measured and reported on a wet-weight basis. Elevated blood TCDD levels, probably related to Agent Orange exposure, can be detected between two and three decades after potential exposure in some American veterans. Original levels were estimated to be 35-1,500-fold greater that that of the general population (4 ppt, lipid) at the time of exposure. In addition, the detection of dioxins in semen suggests a possible mechanism for male-mediated adverse reproductive outcomes following Agent Orange or other dioxin exposure.

Topics: 2,4-Dichlorophenoxyacetic Acid; 2,4,5-Trichlorophenoxyacetic Acid; Adult; Agent Orange; Benzofurans; Defoliants, Chemical; Dioxins; Gas Chromatography-Mass Spectrometry; Humans; Lipids; Male; Michigan; Occupational Exposure; Pilot Projects; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Semen; Teratogens; United States; Veterans; Vietnam

Summaries of first draft of Environmental Health Criteria (EHC), which were circulated for comments by IPCS in the period of 1995-1996, are presented. EHC drafts on 9 compounds were received in this period.

Topics: Aged; Animals; Benzamides; Benzofurans; Boron; Carbon Monoxide; Dioxins; Documentation; Environmental Exposure; Environmental Health; Humans; International Cooperation; Methanol; Organophosphorus Compounds; Organothiophosphates; Phosphines; Reference Standards; Risk Assessment

The 1H NMR spectra of an aromatic ring-cleaving extradiol dioxygenase, 2,2',3-trihydroxybiphenyl dioxygenase of the dibenzofuran-degrading bacterium Sphingomonas sp. strain RW1, are reported. In the catalytically active reduced form of the monomeric enzyme (MW = 32 kDa), three broad strongly downfield shifted signals were observed, two of which disappeared in D2O solution. Their shifts and linewidths are consistent with ring NH and meta-like protons of coordinated histidines. These signals show strong sensitivity to the presence of the substrate. The oxidized form of the enzyme shows no hyperfine shifted signals. It is suggested that the high spin Fe(II) ion present in the active form of the enzyme is coordinated by at least two histidines. This is the first report of hyperfine shifted NMR signals being detected for an extradiol dioxygenase.

Topics: Benzofurans; Binding Sites; Deuterium Oxide; Dioxygenases; Histidine; Iron; Magnetic Resonance Spectroscopy; Molecular Weight; Oxidation-Reduction; Oxygenases; Protein Conformation; Pseudomonas

Concentrations of 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) as well as 16 polychlorinated biphenyls (PCBs) have been determined in pooled samples of breast milk from 10-12 mothers living in three different geographical areas in both Norway and Lithuania. The results indicate no apparent dependency of the PCDD/PCDF levels, expressed as toxic equivalents (TEQs), and total PCB levels on the geographical residence of the donors within a country. This confirms the findings from a corresponding Norwegian study in 1985/1986 where individual samples from the same areas were analyzed. Teh total TEQs, including dioxin-like PCBs, ranged from 31 to 42 pg TEQs/g fat in Norway and from 45 to 49 pg TEQs/g fat in Lithuania. The mean concentration of PCDDs/PCDFs in teh Norwegian samples (10.4 pg TEQs/g fat) was slightly lower than in the Lithuanian samples (14.8 pg TEQs/g fat). Dioxin-like PCBs were found to contribute two to three times more to the total TEQs than the PCDDs and PCDFs. Major contributors among the dioxin-like PCBs were PCBs 126, 156, 114, 118, and 170. Comparison of the present data with those obtained in the Norwegian study in 1985/1986 shows that for PCDDs/PCDFs the mean TEQ levels have decreased by about 37% in the 7-yr time span, while the levels of total PCBs, as determined by packed-column gas chromatography, have remained unchanged or only slightly decreased. Future studies are necessary to confirm this potential temporal trend.

Topics: Animals; Benzofurans; Environmental Exposure; Female; Gas Chromatography-Mass Spectrometry; Humans; Lithuania; Milk, Human; Norway; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Quality Control; Risk Assessment; Time Factors

Blood samples from 34 workers at a pulp and paper mill and from 14 control persons were analysed for 2,3,7,8-substituted PCDDs and PCDFs. There were no statistically significant differences in total lipid-adjusted PCDD/PCDF concentrations, expressed as toxic equivalents, in blood plasma between the potentially exposed bleaching plant or paper mill workers and the controls. The mean level was 61 pg/g I-TEQ in bleaching plant workers, 60 pg/g I-TEQ in paper mill workers and 49 I-TEQ pg/g in controls. Regarding the concentrations of individual isomers, however, there was an indication that the blood plasma concentrations might be affected by the living and working environment.

Topics: Adult; Benzofurans; Humans; Male; Middle Aged; Occupational Exposure; Paper; Polychlorinated Dibenzodioxins

The absorption of polychlorinated biphenyls, dibenzo-p-dioxins and dibenzofurans was studied in four breast-fed infants. The absorption was measured by comparing the estimated total intake and the excretion in faeces, during 48 hours, at three different time points; 1, 2 and 3 months post parta. The levels of the analysed compounds in the human milk are typical for Sweden, i.e approximately 20 ppt toxic equivalents for the dibenzo-p-dioxins and dibenzofurans and for the polychlorinated biphenyls approximately 16 ppt toxic equivalents. For most of the congeners the absorption is found to be over 95%. Higher excretion is noticed for heptachlorinated and octachlorinated dioxins.

Topics: Absorption; Benzofurans; Body Burden; Breast Feeding; Feces; Female; Gas Chromatography-Mass Spectrometry; Humans; Infant, Newborn; Milk, Human; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Risk Assessment

Concentrations of dioxins (PCDD) and dibenzofurans (PCDF) were analysed in adipose tissue from seven patients with malignant lymphoproliferative diseases and 12 surgical patients without a malignant disease. All cases in the first group had reported potential exposure to PCDD and PCDF. Of the analysed congeners significantly higher concentrations of 1,2,3,7,8-pentachlorodioxin, 1,2,3,6,7,8-hexachlorodioxin, and 2,3,4,7,8-pentachlorodibenzofuran were found in the cases with lymphoproliferative diseases compared with the patients in the other group. Higher mean concentration of 2,3,7,8-TCDD was also found in the first group but not significantly so. Toxic equivalents of PCDD and PCDF were significantly higher in the first group (mean 64.7 pg/g, range 19.9-187) than in the second group (mean 29.7 pg/g, range 12.9-53.4). Even if the cases with lymphoproliferative diseases in this case series were potentially exposed to PCDD/PCDF in contrast to the other group, the observed differences may be of may be of interest in relation to the aetiology of these malignancies. Immunosuppression increases the risk for malignant lymphoproliferative diseases, and PCDD/PCDF have established immunotoxic properties.

Topics: Adipose Tissue; Adult; Aged; Benzofurans; Dioxins; Female; Humans; Lymphoproliferative Disorders; Male; Middle Aged

The concentrations of 2,3,7,8-chlorinated dibenzo-p-dioxins and furans (PCDD/PCDFs) at Finnish contaminated sites associated with chlorophenolic (CP) wood preservatives were measured by isomer-specific GC/HRMS methods, and the implications of the spatial and structural distributions of the isomers and of toxic equivalent (TEF) systems for toxicological risks were investigated. High concentrations (maximum value of over 90 ppb and arithmetic mean value of 19 ppb I-TEQs in dry weight) of PCDD/Fs were found in soil samples from sites where wood preservative consisting of 2346-TeCP, PeCP and 246-TCP have been used. The PCDD/Fs were distributed heterogeneously between soil layers, the concentrations in topsoil samples being generally smaller (mean 9.1 ppb I-TEQ d.w.) than those in subsoil (mean 28 ppb I-TEQ d.w.). Concentrations of PCDD/Fs were unrelated to the CP contents in the soil samples. Hexa-, hepta- and octachlorinated dibenzofurans were the dominant congeners by concentration in these and in most other samples, also in the wood preservative. The isomer distribution differed considerably between study sites, and even between samples of soil and waste at the same site. The relative importance of the samples and isomers was affected by the selection of TEFs; the importance of some of the CP-related samples was increased when applying TEFs based on lethality to juvenile fish, due to the abundance of 123478-HxCDF.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Benzofurans; Chlorophenols; Fishes; Industrial Waste; Isomerism; Polychlorinated Dibenzodioxins; Risk Assessment; Soil Pollutants; Toxicity Tests; Wood

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/DFs) and coplanar polychlorinated biphenyls (Co-PCBs) have been determined in sediment and fish samples from the Er-Jen river in Taiwan. Sediment samples collected near the incineration site show TEQ of PCDD/DFs ranging from 14 pg/g to 14200 pg/g and 2,3,7,8-tetrachlorodibenzo-p-dioxins equivalents (TCDD-EQ) of Co-PCBs ranging from 9 pg/g to 1030 pg/g. The fish samples show TEQ of PCDD/DFs ranging from 37 pg/g to 2084 pg/g and TCDD-EQ of Co-PCBs ranging from 12 pg/g to 120 pg/g. Possible PCDD/DFs sources are discharged PCBs, open-air incineration activities, and pentachlorophenol. PCB#126 was found to degrade more readily than PCB#77. TCDD-EQ of Co-PCBs could be estimated from the total concentration of PCBs. A daily intake value of 28 pg/kg/day to 450 pg/kg/day was estimated when consuming fish caught from the Er-Jen river.

Topics: Animals; Benzofurans; Fishes; Food Contamination; Fresh Water; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Species Specificity; Taiwan; Water Pollutants, Chemical

Our previous reports indicate that polychlorinated biphenyl (PCB) congeners in vitro perturbed cellular Ca2+ homeostasis and protein kinase C (PKC) translocation. We have now studied the structure-activity relationship (SAR) of 3 PCB mixtures, 24 PCB congeners, and 1 dibenzofuran for their effects on PKC translocation by measuring [3H]phorbol ester ([3H]PDBu) binding in cerebellar granule cells (7 days in culture). All the PCB mixtures studied increased [3H]PDBu binding significantly and in a concentration-dependent manner. However, Aroclor 1016 and Aroclor 1254 were more potent than Aroclor 1260. Of the 24 congeners studied, di-ortho congeners such as 2,2',5,5'-tetrachlorobiphenyl (-TeCB), 2,2',4,6,6'-pentachlorobiphenyl (-PeCB), 2,2',4,6-TeCB, and 2,2'-dichlorobiphenyl (-DCB) were the most potent (E50 = 28-43 microM) while non-ortho congeners such as 3,3',4,4'-TeCB and 3,3',4,4'5-PeCB were not effective. The potential contaminant of PCB mixtures, 1,2,3,7,8-pentachlorodibenzofuran had no significant effect on [3H]PDBu binding. The SAR among these congeners revealed: (i) congeners with ortho-chlorine substitution such as 2,2'-DCB (EC50 = 43 +/- 3 microM) or ortho-lateral (meta, para) chlorine substitution such as 2,2',5,5'-TeCB (EC50 = 28 +/- 3 microM) and 2,2'4,6-TeCB (E50 = 41 +/- 6 microM) were most potent; (ii) congeners with only para-substitution such as 4,4'-DCB or high lateral content in the absence of ortho-substitution such as 3,3',4,4',5,5'-HCB were not effective; and (iii) increased chlorination was not clearly related to the effectiveness of these congeners, although hexa- and heptachlorination was less effective than di- and tetrachlorination. Low lateral substitution, especially without para-substitution, or lateral content in the presence of ortho-substitution, may be the most important structural requirement for the in vitro activity of these PCB congeners in neuronal preparations.

Topics: Analysis of Variance; Animals; Aroclors; Benzofurans; Binding Sites; Cells, Cultured; Cerebellum; Chlorodiphenyl (54% Chlorine); Computer Simulation; Dose-Response Relationship, Drug; Female; Phorbol 12,13-Dibutyrate; Polychlorinated Biphenyls; Pregnancy; Protein Kinase C; Rats; Stereoisomerism; Structure-Activity Relationship

The production of magnesium is a well known source of both aliphatic and aromatic chlorinated compounds, among others the polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). The aim of this study was to establish whether increased concentrations of PCDDs and PCDFs could be found in the blood of workers in a magnesium plant.. Blood plasma from 10 workers, employed at a magnesium plant for 10 to 36 years, and from a control group consisting of nine people who had no direct contact with the production were studied. Isomer specific analyses of PCDDs and PCDFs by means of high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS) techniques were performed.. A significant increase was found in the concentrations of some of the congeners, mainly PCDFs, in the workers compared with the control group. Octachlorodibenzofuran (OCDF) is the congener that most strongly correlates with occupational exposure in the magnesium plant. Low concentrations of 1,2,3,4,6,8,9-heptachlorodibenzofuran were found in seven of the workers. Such isomers--that is, not 2,3,7,8-substituted--are rarely found in human samples.. Due to the long biological half lives and lipid solubility of PCDDs and PCDFs, blood analyses may serve as an index of past cumulative occupational exposure and a means of assessing a person's exposure situation.

Topics: Benzofurans; Case-Control Studies; Dioxins; Humans; Industry; Magnesium; Occupational Exposure

A practical method is described for measuring the principal values of the chemical shift tensors in compounds with very long proton spin-lattice relaxation times (T1). This technique involves shortening the effective proton T1. by mixing a compound of interest with another compound having a much shorter T1 value. The doped mixture, partly consisting of a monophasic glass, allows efficient intermolecular spin diffusion between the two compounds. Using a slow magic-angle turning (MAT) experiment, we have successfully used such mixtures to measure the principal values of the chemical shift tensors of all the carbons in dibenzofuran in just four days. Without using this technique the experimental time required for the pure compound would have been several months.

Topics: Benzofurans; Glass; Magnetic Resonance Spectroscopy; Time Factors

Topics: Aged; Benzofurans; Dioxins; Follow-Up Studies; Herbicides; Humans; Male; Middle Aged; Occupational Exposure; Polychlorinated Biphenyls

Consumption of fatty fish species, like salmon and herring, from the Baltic Sea is an important source of human exposure to persistent organochlorine compounds, e.g. polychlorinated dioxins (PCDDs), dibenzofurans (PCDFs) and biphenyls (PCBs). Many of these compounds show immunotoxic and hepatotoxic effects in animals. We have now studied immunological competence, including lymphocyte subsets, in 23 males with a high consumption of fish from the Baltic Sea and in a control group of 20 males with virtually no fish consumption. The high consumers had lower proportions and numbers of natural killer (NK) cells, identified by the CD 56 marker, in peripheral blood than the non-consumers. Weekly intake of fatty fish correlated negatively with proportions of NK cells (rs = -0.32, P = 0.04). There were also, in a subsample of 11 subjects, significant negative correlations between numbers of NK cells and blood levels of a toxic non-ortho-PCB congener (IUPAC 126; rs = -0.68, P = 0.02) and a mono-ortho congener (IUPAC 118; rs = -0.76, P = 0.01). A similar correlation, in 12 subjects, was seen for p,p'-DDT (rs = -0.76, P = 0.01). The corresponding negative correlation, in 13 subjects, with blood levels of PCDD/Fs was not significant (rs = -0.57, P = 0.07). No significant association was seen between organic mercury in erythrocytes and NK cells. Fish consumption was not associated with levels of any other lymphocyte subset. Neither were there any correlations with plasma immunoglobulins or liver enzyme activities. Our study indicates that accumulation of persistent organochlorine compounds in high consumers of fatty fish may adversely affect NK cell levels.

Topics: Adult; Animals; Benzofurans; Dose-Response Relationship, Drug; Fishes; Food Contamination; Humans; Immune Tolerance; Immunocompetence; Immunoglobulins; Killer Cells, Natural; Leukocyte Count; Lymphocyte Activation; Male; Middle Aged; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Sweden; T-Lymphocyte Subsets; Water Pollutants, Chemical

In an earlier study several hydroxylated polychlorinated biphenyls (PCBs), dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) competitively displaced [125I]thyroxine (T4) from transthyretin with different potencies. Transthyretin is the major T4 transport protein in plasma of rodents. In man, however, thyroxine-binding globulin transports most of the T4 in blood. In this study, hydroxylated PCBs, PCDDs and PCDFs were tested in an in vitro competitive binding assay, using purified human thyroxine-binding globulin and [125I]T4 as the displaceable radioligand. None of the tested hydroxylated PCBs, PCDDs and PCDFs inhibited [125I]T4 binding to thyroxine-binding globulin. In addition, some T4 derived compounds, e.g., tyrosine, mono-iodotyrosine, di-iodotyrosine and tri-iodophenol were tested on both transthyretin and thyroxine-binding globulin to investigate possible differences in structural characteristics determining T4 binding to thyroxine-binding globulin and transthyretin. The T4 derived compounds also did not inhibit [125I]T4 binding to thyroxine-binding globulin as tested in the in vitro assay. However, tri-iodophenol and to a lesser extent di-iodotyrosine inhibited [125I]T4-transthyretin binding. These results indicate a marked difference in T4 binding to thyroxine-binding globulin or transthyretin. The hydroxylated PCBs, PCDDs and PCDFs can inhibit T4 binding to transthyretin, but not to thyroxine-binding globulin, and thus may cause different effects in rodents and man.

Topics: Benzofurans; Binding, Competitive; Chromatography, Gel; Humans; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Prealbumin; Protein Binding; Thyroxine; Thyroxine-Binding Proteins

Dibenzofuran uptake-associated kinetic parameters of suspended and attached Sphingomonas sp. strain HH19k cells were compared. The suspended cells were studied in a batch system, whereas glass beads in percolated columns were used as the solid support for attached cells. The maximum specific activities of cells in the two systems were the same. The apparent half-maximum uptake rate-associated concentrations (Kt') of attached cells, however, were considerably greater than those of suspended cells and depended on cell density and on percolation velocity. A mathematical model was developed to explain the observed differences in terms of substrate transport to the cells. This model was based on the assumptions that the intrinsic half-maximum uptake rate-associated concentration (Kt) was unchanged and that deviations of Kt' from Kt resulted from the stereometry and the hydrodynamics around the cells. Our calculations showed that (i) diffusion to suspended cells and to single attached cells is efficient and therefore only slightly affects Kt'; (ii) diffusion to cells located on crowded surfaces is considerably lower than that to single attached cells and greatly increases Kt', which depends on the cell density; (iii) the convective-diffusive transport to attached cells that occurs in a percolated column is influenced by the liquid flow and results in dependency of Kt' on the flow rate; and (iv) higher specific affinity of cells correlates with higher susceptibility to diffusion limitation. Properties of the experimental system which limited quantitative proof of exclusively transport-controlled variations of Kt' are discussed.

Topics: Bacterial Adhesion; Benzofurans; Biodegradation, Environmental; Diffusion; Gram-Negative Aerobic Bacteria; Kinetics; Osmolar Concentration; Solubility

In the State Laboratory of North Rhine-Westphalia for Food, Pharmaceutical and Environmental Chemistry (Chemisches Landesuntersuchungsamt), more than 600 individual human milk samples have been analyzed for polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), and more than 1400 individual milk samples have been analyzed for organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) since 1984. All samples were collected on a voluntary basis from nursing mothers mostly living in North Rhine Westphalia, a federal state in Germany. The samples analyzed so far show a typical pattern of PCDDs and PCDFs. Out of the 210 possible congeners, only those with 2,3,7,8-chlorine substitution were found. While OCDD normally shows the highest concentration, the levels of the other dioxin congeners decrease with decreasing number of chlorine atoms. A different pattern was found for PCDFs. Within this group 2,3,4,7,8-P5CDF is the most abundant congener, followed by the hexachlorodibenzofurans. The mean level of tetrachlorodibenzodioxin (TCDD) was found to be of 3.2 pg/g on a fat basis and for total PCDDs and PCDFs, calculated as I-TEq (NATO/CMMS), 29.3 pg/g on a fat basis. The investigations of the past 2 years have revealed somewhat lower levels compared to former years. This might be an indication that the efforts undertaken to minimize dioxin emissions and to shut down known sources have already had an effect on the body burden of humans. Although mostly banned for a considerable period of time now, some lipophilic persistent pesticides such as DDT, dieldrin, hexachlorobenzene (HCB), and hexachlorocyclohexanes (HCH) can still be found in human milk.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Benzofurans; Body Burden; Female; Food Contamination; Humans; Infant; Infant, Newborn; Insecticides; Milk, Human; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins

For nonoccupationally exposed persons, the daily intake via food consumption has been calculated to be 0.35 pg/kg body weight per day for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 2.3 pg/kg body weight per day for TCDD equivalents (TEqs). As compared to food, other sources and pathways are of minor importance. Food of animal origin contributes most, although human exposure begins with atmospheric emissions depositing these compounds on plant surfaces. In the meantime, a possible additional body burden from cardboard containers for cow's milk and coffee filters has been practically excluded. Of the 210 existing PCDDs and PCDFs, only 15 2,3,7,8-substituted isomers with a characteristic congener pattern can be found in samples of human origin. In adipose tissue and milk samples, mean levels for 2,3,7,8-TCDD of 7.2 and 3.6 pg/g fat, respectively, and of 56 (range 18-122) and 30 (range 10-72) pg TEqs/g fat, respectively, were determined. Human data revealed a dependency of polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDD/PCDF) levels on age. In human milk, levels became reduced with the number of children born to mothers and duration of breast-feeding period. The average daily intake for a breast-fed child has been calculated to be 17 pg 2,3,7,8-TCDD/kg body weight per day and 142 pg TEqs/kg body weight per day, respectively. Levels in adipose tissue of infants, even if breast fed, were distinctly lower compared to human milk. In human milk, adipose tissue, and whole blood, PCDD/PCDF concentrations have been found to be equal on a fat-weight basis. Liver fat accumulated PCDD/PCDF with an alteration in the congener distribution pattern, whereas brain, even on a fat-weight basis, showed the lowest concentrations. Elevated or even high levels were found in occupationally exposed persons working in special chemical plants or involved in specific processes. There are limited data suggesting slightly elevated PCDD/PCDF levels are due to long-term consumption of a large share of food produced near point sources with a heavy emission or ingestion of soil or dust from such areas.

Topics: Adipose Tissue; Adult; Age Factors; Benzofurans; Environmental Exposure; Female; Food Contamination; Germany; Humans; Infant; Infant, Newborn; Male; Middle Aged; Milk, Human; Occupational Exposure; Parity; Polychlorinated Dibenzodioxins; Time Factors; Tissue Distribution

We have measured non-ortho-substituted (coplanar) polychlorinated biphenyl (PCB) levels as well as polychlorinated dibenzo-p-dioxin (PCDD) and polychlorinated dibenzofuran (PCDF) levels in human adipose tissue and serum collected in Atlanta, Georgia. The results show that the concentrations of the coplanar PCBs can be more than an order of magnitude higher than the concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin. Our measurements in pooled serum collected in 1982, 1988, and 1989 show a decrease in coplanar PCB levels from 1982 to 1989. We found that the pattern of relative amounts of coplanar PCBs in adipose tissue varied greatly from person to person unlike the PCDD and PCDF patterns, which were more nearly the same. Age was significantly correlated with the concentrations of 2,3,7,8-TCDD,3,3'4,4'-PCB, 3,3',4,4',5-PCB, and 3,3'4,4',5,5'-PCB in adipose tissue. We also measured levels of the mono- and di-ortho chlorine-substituted PCBs in human serum. The levels for some of these PCB congeners were three orders of magnitude higher than the coplanar PCBs, PCDDs, and PCDFs. We used the international toxicity equivalency factors (TEFs) for PCDDs and PCDFs and the TEFs proposed by Safe for PCBs to calculate the 2,3,7,8-TCDD equivalents. Four PCBs (3,3',4,4',5-; 2,3',4,4',5-;2,3,3',4,4'-;2,3,3',4,4',5-) make a larger contribution than 2,3,7,8-TCDD, while four other PCBs (3,3',4,4'5,5'-; 2,2',3,4,4',5'-;2,2',4,4',5,5'-;2,2',3,4,4',5,5'-) make nearly the same contribution as 2,3,7,8-TCDD. The mono-ortho-chlorine-substituted 2,3',4,4',5-PCB, however, is the major contributor to the total 2,3,7,8-TCDD equivalents in general population samples from the United States, Sweden, and Japan.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adipose Tissue; Adult; Age Factors; Aged; Benzofurans; Female; Humans; Japan; Male; Middle Aged; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Sweden; United States

Two remote maritime populations were evaluated for their biological exposure to organochlorines in 1989-1990. Because of their high intake of seafood, these two populations have high biological levels. One hundred nine breast milk samples from Inuit women from Arctic Québec were analyzed to determine levels of polychlorodibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (PCBs) including non-ortho, mono-ortho, and di-ortho congeners. Total 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEqs) for PCBs were 3.5 times higher in Inuit milk samples than in 96 Caucasian milk samples. Among the 185 fishermen from the Lower North Shore of the Gulf of the St. Lawrence River, we evaluated 10 highly exposed fishermen for their coplanar PCB blood levels. Total TEqs were 900 ng/kg for highly exposed individuals with 36 ng/kg for controls. In these two nonoccupationally exposed populations, coplanar PCBs make a larger contribution to the TEq than PCDDs and PCDFs. However, the mono-ortho penta CB No. 118 is the major contributor for the total toxicity.

Topics: Animals; Benzofurans; Environmental Exposure; Female; Food Contamination; Humans; Inuit; Male; Milk, Human; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Quebec; Seafood

Breast milk samples from 38 women in New Zealand were analyzed for organochlorine pesticides, polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) as part of a World Health Organization collaborative study of breast-milk contaminants. The women were recruited from two urban areas (Auckland and Christchurch) and two rural areas (Northland and North Canterbury) in the North and South Islands of New Zealand. The best predictor of contaminant concentrations in breast milk was found to be the age of the mother. Regional differences were found for hexachlorobenzene, dieldrin, and pp-DDE, reflecting historical use patterns. Urban-rural differences were found for several PCBs, PCDDs, and PCDFs when contaminant concentrations were calculated on a whole-milk basis. However, these differences could be attributed to variation in breast-milk fat concentrations between urban and rural mothers. Urban mothers had about 50% more breast-milk fat than rural mothers. Evidence suggests that breast-milk consumption by babies is regulated by caloric intake. Almost all of the caloric content of milk is in the fat fraction. This suggests that breast-milk contaminant levels calculated on a whole-milk basis do not necessarily reflect the relative levels of exposure of infants to these contaminants. However, the factors that influence breast-milk fat concentration deserve further study.

Topics: Adult; Benzofurans; Female; Humans; Insecticides; Milk, Human; New Zealand; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Rural Population; Urban Population

The present project assessed the effect of environmental contamination with polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) on hepatic microsomal ethoxyresorufin O-deethylase (EROD) activities and morphological parameters in matched double-crested cormorant (Phalacrocorax auritus) hatchlings from egg clutches chosen for chemical analysis. Double-crested cormorant eggs were collected from five colonies across Canada, with differing levels of contamination. Levels of contamination expressed in sum of 2,3,7,8-tetrachlorodibenzo-p-dioxin-toxic equivalents (TCDD-toxic equivalents or TEQ, ng/kg egg; mean +/- SEM) were: Saskatchewan, 250 +/- 50; Chain Islands, 672 +/- 73; Christy Islet, 276 +/- 14; Crofton, 131, n = 1; and Lake Ontario, 1606 +/- 118. In the hatchlings, hepatic EROD activities (pmol/min/mg protein; mean +/- SEM) were: Saskatchewan, 283 +/- 42; Chain Islands, 516 +/- 98; Christy Islet, 564 +/- 91; Crofton, 391 +/- 52; and Lake Ontario, 2250 +/- 156. Hepatic microsomal EROD activity (pmol/min/mg protein) regressed positively on TEQ (r2 = .69; p < .00005; n = 25). Yolk weight (g) regressed negatively on TEQ (r2 = .44; p = .00005). Wing length (mm) regressed negatively on PCB-169 (r2 = .28; p = .007). Monospecific antibodies raised against rat cytochrome P-450 1A1 recognized a protein in the hepatic microsomes of the double-crested cormorant, and also in those of the great blue heron (Ardea herodias), using immunoblotting. The intensity of the stained band increased with increased EROD activity, supporting the assumption that ethoxyresorufin is a suitable substrate for avian cytochrome P-450 1A1. These results validate the use of avian hepatic microsomal EROD activity as an index of cytochrome P-450 1A1 induction by environmental levels of polychlorinated aromatic hydrocarbons and as a useful screening tool to determine the extent of exposure to such chemicals. Furthermore, the induction of cytochrome P-450 1A1 observed in the cormorant indicates that the Ah receptor-mediated process, by which TCDD and related chemicals exert many of their toxicities, has been activated.

Topics: Abnormalities, Drug-Induced; Animals; Benzofurans; Birds; Body Weight; Canada; Cytochrome P-450 CYP1A1; Cytochrome P-450 Enzyme System; Dioxins; Eggs; Microsomes, Liver; Oxidoreductases; Polychlorinated Biphenyls

Isomer-specific determinations of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were performed in 19 surficial sediment samples collected from the lower Passaic River and Newark Bay, New Jersey. Total PCDD and PCDF concentrations ranged from 415 to 23,300 ng/kg (dry wt) and 37 to 8400 ng/kg, respectively. OCDD and OCDF were the predominant congeners in all samples, followed by the hepta-, hexa-, tetra-, and penta-chlorinated compounds. Forty-seven percent (9/19) of the sediment samples contained no detectable levels of 2, 3, 7, 8-TCDD. The concentrations of 2, 3, 7, 8-TCDD and 2, 3, 7, 8-TCDF ranged from nondetect to 510 ng/kg (geometric mean of 5 ng/kg) and from 2.8 to 480 ng/kg (geometric mean of 13 ng/kg), respectively. The composition of PCDD/Fs in sediments was evaluated using chemometric pattern recognition techniques. Principal components analysis and complete linkage:farthest neighbor cluster analysis revealed the presence of at least five distinctive fingerprint patterns in surficial sediments collected from different locations in the Newark Bay estuary. Differences among PCDD/F patterns were attributable to the relative presence or absence of 1, 2, 3, 4, 6, 7, 8-HpCDF and the hepta-, hexa-, and octa-chlorinated congeners. To determine whether the presence of PCDD/Fs in sediments could be associated with a single source, residues in sediments were compared to those found in three soil samples and one sump sediment sample from a former 2, 4, 5-T manufacturing plant. Significant compositional differences were observed between the two data sets. Fingerprint patterns in sediments were dominated by the higher PCDD/F chlorinated congeners and contained significantly lower levels of the tetra-chlorinated congeners, particularly 2, 3, 7, 8-TCDD, than soils from the former 2, 4, 5-T plant. These differences, as well as those observed among surficial sediments from different locations, indicate that there are clearly several different sources of 2, 3, 7, 8-TCDD and other PCDD/Fs to the estuary.

Topics: Benzofurans; Cluster Analysis; Dioxins; Fresh Water; New Jersey; New York; Pattern Recognition, Automated; Seawater; Water Pollutants, Chemical

The concentration-dependent effects of several PCB, PCDD, and PCDF congeners and several commercial PCB preparations as antiestrogens were determined in the aryl hydrocarbon (Ah)-responsive MCF-7 human breast cancer cell lines. The inhibition of the 17 beta-estradiol-induced secretion of the 52-kDa protein (procathepsin D) was measured using a combination of polyacrylamide gel electrophoresis, double-staining of the protein bands with ISS ProBlue and silver stain, and quantitation by densitometric analysis. For the PCBs, the order of antiestrogenic potency was 3,3',4,4',5-pentachlorobiphenyl > 3,3',4,4',5,5'-hexachlorobiphenyl approximately 3,3',4,4'-tetrachlorobiphenyl > 2,3,3',4,4',5'-hexa, 2,3,3',4,4'- and 2,3,4,4',5-pentachlorobiphenyl > Aroclors 1221, 1232, 1248, 1254, and 1260 were inactive as antiestrogens at the highest concentrations used in this study (10(-6) M). For the PCDDs and PCDFs, the order of antiestrogenic potency was 2,3,7,8-tetrachlorodibenzo-p-dioxin > 2,3,7,8-tetrachlorodibenzofuran > 2,3,4,7,8-pentachlorodibenzofuran > 1,2,3,7,9-pentachlorodibenzofuran > 1,3,6,8-tetrachlorodibenzofuran. With few exceptions, the order of potency for all these congeners and mixtures paralleled their relative activities as agonists for other Ah receptor-mediated responses and their competitive binding affinities for the Ah receptor. The results of this study support the role for the Ah receptor in mediating the inhibition of the 17 beta-estradiol-induced secretion of the 52-kDa protein in MCF-7 cells and also points out the utility of this technique as a bioassay for this class of compounds.

Topics: Aroclors; Benzofurans; Breast Neoplasms; Densitometry; Dioxins; Electrophoresis, Polyacrylamide Gel; Estradiol; Estrogen Antagonists; Humans; Neoplasm Proteins; Polychlorinated Biphenyls; Staining and Labeling; Structure-Activity Relationship; Tumor Cells, Cultured

Sphingomonas sp. strain RW1, when grown in salicylate-salts medium, synthesized the enzymes for the degradation of dibenzofuran. The reaction subsequent to meta cleavage of the first benzene ring was found to be catalyzed by two isofunctional hydrolases, H1 and H2, which were purified by chromatography on anion exchange, hydrophobic interaction and gel filtration media. Each enzyme was able to hydrolyze 2-hydroxy-6-oxo-6-(2-hydroxyphenyl)hexa-2,4-dienoate and 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoate to produce salicylate and benzoate, respectively. SDS/PAGE of each purified enzyme showed a single band of M(r) 31,000 (H1) or 29,000 (H2). The N-terminal amino acid sequences of the two proteins showed 50% homology.

Topics: Bacteroidetes; Base Sequence; Benzoates; Benzofurans; Benzoic Acid; Biodegradation, Environmental; Catechols; Fatty Acids, Unsaturated; Hydrolases; Isoenzymes; Molecular Sequence Data; Oxygenases; Salicylates; Salicylic Acid

Topics: Benzofurans; Czechoslovakia; Dioxins; Environmental Health; Environmental Monitoring; Environmental Pollution; Forecasting; Humans; Organizational Objectives; Pesticides; Polychlorinated Biphenyls; Polycyclic Compounds; Research

A key enzyme in the degradation pathways of dibenzo-p-dioxin and dibenzofuran, namely, 2,2',3-trihydroxybiphenyl dioxygenase, which is responsible for meta cleavage of the first aromatic ring, has been genetically and biochemically analyzed. The dbfB gene of this enzyme has been cloned from a cosmid library of the dibenzo-p-dioxin- and dibenzofuran-degrading bacterium Sphingomonas sp. strain RW1 (R. M. Wittich, H. Wilkes, V. Sinnwell, W. Francke, and P. Fortnagel, Appl. Environ. Microbiol. 58:1005-1010, 1992) and sequenced. The amino acid sequence of this enzyme is typical of those of extradiol dioxygenases. This enzyme, which is extremely oxygen labile, was purified anaerobically to apparent homogeneity from an Escherichia coli strain that had been engineered to hyperexpress dbfB. Unlike most extradiol dioxygenases, which have an oligomeric quaternary structure, the 2,2',3-trihydroxybiphenyl dioxygenase is a monomeric protein. Kinetic measurements with the purified enzyme produced similar Km values for 2,2',3-trihydroxybiphenyl and 2,3-dihydroxybiphenyl, and both of these compounds exhibited strong substrate inhibition. 2,2',3-Trihydroxydiphenyl ether, catechol, 3-methylcatechol, and 4-methylcatechol were oxidized less efficiently and 3,4-dihydroxybiphenyl was oxidized considerably less efficiently.

Topics: Amino Acid Sequence; Bacteria; Base Sequence; Benzofurans; Cosmids; Dioxins; Dioxygenases; DNA, Bacterial; Electrophoresis, Polyacrylamide Gel; Genes, Bacterial; Genomic Library; Kinetics; Molecular Sequence Data; Oxygenases; Restriction Mapping; Sequence Homology, Amino Acid; Substrate Specificity

A sample cleanup method for the isolation of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) by solid-phase extraction is described. A C18 bonded silica cartridge is used for the initial extraction and enrichment of the analytes. Subsequent cleanup is achieved with a dual-cartridge arrangement consisting of a bonded benzenesulfonic acid cartridge in series with a silica cartridge. A Florisil cartridge is employed for the final cleanup step. Sample preparation procedures used for blood plasma and animal tissues are described. The precision and accuracy of the method is validated by determining recoveries of 2,3,7,8-substituted PCDD and PCDF congeners spiked at various levels in blood plasma and in animal tissues. The effectiveness of the cleanup method is shown by the analysis of wild bird eggs which are highly contaminated with a variety of pesticides and polychlorinated biphenyls. The application of this cleanup method to human plasma containing PCDDs/PCDFs at parts-per-quadrillion levels and results of analyses by high-resolution mass spectrometry and low-resolution mass spectrometry are presented. The validity of this method is demonstrated by the comparable results obtained from this method and from other established methods.

Topics: Animals; Benzofurans; Birds; Cattle; Chromatography, Ion Exchange; Egg Yolk; Humans; Polychlorinated Dibenzodioxins

The dose-dependent effects of a single acute exposure of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 2,3,4,7,8-pentachlorodibenzofuran (PeCDF), 1,2,3,7,9-PeCDF, 1,3,6,8-tetrachlorodibenzofuran (TCDF), 3,3',4,4',5-pentachlorobiphenyl (pentaCB), and 3,3,',4,4',5,5'-hexaCB on the suppression of the splenic plaque-forming cell (PFC) response to the T-cell-independent antigen trinitrophenyl-lipopolysaccharide were determined in C57BL/6 and DBA/2 mice. In addition, the induction of hepatic microsomal ethoxyresorufin O-deethylase (EROD) activity was also measured in these animals. 2,3,7,8-TCDD and 2,3,4,7,8-PeCDF were the most immunotoxic congeners in both strains of mice and with the exception of the latter congener, the ED50 values for each compound were lower in the C57BL/6 than the DBA/2 mice. 2,3,7,8-TCDD induced hepatic microsomal EROD activity in both strains of mice whereas the other congeners were considerably less active or inactive as inducers. The results of this study demonstrated that for the halogenated aromatic hydrocarbons the immunotoxic response was a more sensitive indicator of exposure than the induction of CYP1A1 activity. The rank order for the immunotoxic potencies of the chlorinated aromatic compounds used in this study was 2,3,7,8-TCDD approximately 2,3,4,7,8-PeCDF > 3,3',4,4',5-pentaCB approximately 3,3',4,4',5,5'-hexaCB > 1,2,3,7,9-PeCDF > 1,3,6,8-TCDF. The order of activity for these congeners was similar for other Ah receptor-mediated responses and these results coupled with the differential responsiveness of the C57BL/6 and DBA/2 mice confirms the role of aryl hydrocarbon (Ah) receptor in mediating the suppression of this T-cell-independent response.

Topics: Animals; Benzofurans; Cytochrome P-450 CYP1A1; Cytochrome P-450 Enzyme System; Dioxins; Enzyme Induction; Immune System; Lipopolysaccharides; Male; Mice; Mice, Inbred C57BL; Mice, Inbred DBA; Microsomes, Liver; Oxidoreductases; Polychlorinated Biphenyls; Spleen; T-Lymphocytes

Sphingomonas sp. strain RW1 synthesized a constitutive enzyme system that oxygenated dibenzofuran (DBF) to 2,2',3-trihydroxybiphenyl (THB). We purified this dibenzofuran 4,4a-dioxygenase system (DBFDOS) and found it to consist of four components which catalyzed three activities. Two isofunctional, monomeric flavoproteins (components A1 and A2; M(r) of about 44,000) transferred electrons from NADH to the second component (B; M(r) of about 12,000), a ferredoxin, which transported electrons to the heteromultimeric (alpha 2 beta 2) oxygenase component (C; M(r) of alpha, 45,000; M(r) of beta, 23,000). DBFDOS consumed 1 mol each of NADH, O2, and DBF, which was dioxygenated to about 1 mol of THB; no intermediate was observed. The reaction was thus the dioxygenation of DBF at the 4 and 4a positions to give a diene-diol-hemiacetal which rearomatized by spontaneous loss of a phenolate group to form THB. Components A1 and A2 each reduced dichlorophenolindophenol but had negligible activity with cytochrome c; each lost the yellow color, observed to be flavin adenine dinucleotide, upon purification. Component B, which transported electrons to the oxygenase or cytochrome c, had an N-terminal amino acid sequence with high homology to the putidaredoxin of cytochrome P-450cam. The oxygenase had the UV spectrum of a Rieske iron-sulfur center. We presume DBFDOS to be a class IIA dioxygenase system (EC 1.14.12.-), functionally similar to pyrazon dioxygenase.

Topics: Amino Acid Sequence; Bacteria; Benzofurans; Ferredoxins; Molecular Sequence Data; Oxidation-Reduction; Oxidoreductases; Oxygenases; Sequence Homology, Amino Acid; Substrate Specificity

Topics: Agriculture; Air Pollutants; Benzofurans; Dioxins; Fires; Oryza; Smoke

Staphylococcus auriculans DBF63, which can grow on dibenzofuran (DBF) or fluorene (FN) as the sole source of carbon and energy, was isolated. Salicylic acid and gentisic acid accumulated in the culture broth of this strain when DBF was supplied as a growth substrate. Also, the formation of 9-fluorenol, 9-fluorenone, 4-hydroxy-9-fluorenone, and 1-hydroxy-9-fluorenone was demonstrated, and accumulation of 1,1a-dihydroxy-1-hydro-9-fluorenone was observed when this strain grew on FN. On the basis of these results, the degradation pathways of DBF and FN were proposed. The analogous oxidation products of dibenzo-p-dioxin were obtained by incubation with DBF-grown S. auriculans DBF63 cells.

Topics: Benzofurans; Biodegradation, Environmental; Catechol 2,3-Dioxygenase; Catechols; Culture Media; Dioxins; Dioxygenases; Fluorenes; Oxidation-Reduction; Oxygenases; Soil Pollutants; Staphylococcus

Crystalline dibenzofuran-d8 has been found to exhibit disorder of the type described previously for dibenzofuran. The disordered molecules are related to the ordered molecules by a 180 degrees rotation about an axis passing through the molecular center of mass and perpendicular to the furan ring. In the present structure 11(2)% of the molecules were found to adopt this alternate orientation. The molecules are bisected by a mirror plane normal to the furan ring and containing the O atom. The average bond length in the benzenoid ring is 1.392 (10) A. The furan ring and the benzenoid ring are separately planar, but form a dihedral angle of 1.45 (9) degrees with each other.

Topics: Benzofurans; Chemical Phenomena; Chemistry, Physical; Crystallization; Molecular Structure; X-Ray Diffraction

Five bulked human adipose tissue samples were analyzed for individual polychlorinated biphenyl (PCB) congeners (including selected non-ortho-substituted compounds) and polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs). Mean sigma PCB and sigma PCDD/F (tetra-through octachlorinated homologues) concentrations were 0.75 microgram/g and 1.22 ng/g adipose tissue respectively. Both the congener patterns and levels detected were similar to those reported by laboratories in other industrialised countries. Each sample comprised of tissue taken from donors within a given locality. However, no obvious relationships were apparent between sampling area, absolute concentrations and congener pattern of PCBs and PCDD/Fs. The contribution of individual PCDD/F and non-ortho-(o), mono-o-, and di-o-substituted PCB congeners to the total calculated toxic equivalent values (sigma TEQ) was assessed for each sample. The main contributions to the sigma TEQ were the mono-o-substituted PCB congeners #118 (TEQ = 42.5 pg/g of lipid), #156 (TEQ = 24.8 pg/g) and #105 (TEQ = 20.7 pg/g), followed by 1,2,3,6,7,8-HxCDD (TEQ = 18.2 pg/g), 2,3,4,7,8-P5CDF (TEQ = 12 pg/g), 1,2,3,7,8-P5CDD (TEQ = 11.5 pg/g), and the non-o-substituted PCB congener #126 (TEQ = 11.3 pg/g). Collectively, these compounds accounted for 80% of the sigma TEQ values. Based on the TEFs proposed by Safe (1990), the overall TEQs calculated for the monitored PCBs, were twice those due to sigma PCDD/Fs.

Topics: Adipose Tissue; Adolescent; Adult; Aged; Benzofurans; Dioxins; Humans; Middle Aged; Polychlorinated Biphenyls; Wales

Dibenzofuran (DF) was reacted with various concentrations of nitrogen oxides (NOx) under light irradiation. The mutagenicities of the reaction mixtures were tested using Salmonella typhimurium strains TA98, TA100, TA98NR and TA98/1,8-DNP6 in the presence or absence of a mammalian metabolic activation system (S9 mix). DF-Nox (molar ratios 1:3, 1:6 and 1:18) reaction mixtures exhibited mutagenic potency in strain TA98 without S9 mix, and their direct-acting mutagenicity was reduced in strains TA98NR and TA98/1,8-DNP6. Four mononitrodibenzofurans and 2 dinitrodibenzofurans, i.e., 1-nitrodibenzofuran (NDF), 2-NDF, 3-NDF, 4-NDF, 2,7-dinitrodibenzofuran (DNDF) and 2,8-DNDF, were identified with authentic samples in the DF-NOx (1:18) reaction mixture by HPLC cochromatography and a gas chromatography/mass spectrometry study. The order of mutagenicity of nitrodibenzofurans in strain TA98 without S9 mix was as follows: 2,7-DNDF greater than 2,8-DNDF greater than 3-NDF greater than 2-NDF greater than 4-NDF greater than 1-NDF. The mutagenic potency of 2,7-DNDF in strains TA98 and TA100 was enhanced by the addition of S9 mix. Since these nitrodibenzofurans were less mutagenic in strains TA98NR and TA98/1,8-DNP6 than in strain TA98 without S9 mix, it was presumed that their mutagenicity was dependent on their activation by the 'classical' bacterial nitroreductase and/or transacetylase, which are absent in strains TA98NR and TA98/1,8-DNP6 but present in strain TA98, respectively. 3-NDF and 4-NDF were mutagenic in strain TA100 without S9 mix. 2-NDF and 3-NDF were determined as corresponding amino derivatives in DF-NOx (1:3), (1:6) and (1:18) reaction mixtures. They contributed about 30-65% of the direct-acting mutagenicity of reaction mixtures in strain TA98.

Topics: Animals; Benzofurans; Biotransformation; Chromatography, High Pressure Liquid; Light; Male; Microsomes, Liver; Mutagenicity Tests; Mutagens; Nitro Compounds; Nitrogen Oxides; Rats; Rats, Inbred Strains; Salmonella typhimurium; Structure-Activity Relationship

It was found that the differences between the frontier molecular orbital energies (epsilon homo - epsilon lumo = delta epsilon) in polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) have a correlationship with the magnitude of the biological activity which is influenced by both the number and position of chlorine atom substituents on PCDFs and PCBs skeletons. Moreover, it was found that the delta epsilon's values of PCBs are classified into two types which coincide with the well-known classification of PCBs to types of 3-methylcholanthrene and phenobarbital according to their biological activities. The relationship between delta epsilon and biological activity in these xenobiotics suggests that the congeners having small delta epsilon values as 2,3,4,7,8-pentaCDF, 2,3,4,6,7-pentaCDF, 3,4,5,3',4'-pentaCB, and 3,4,5,3',4',5'-hexaCB form stable molecular complexes with an Ah-receptor, e.g. (2,3,4,7,8-PentaCDF-Ah-receptor), while the congeners having large delta epsilon values are strongly suggested to be unstable in a complex formation. Thus, this work presents an explanatory method to help understand the structure-activity relationship of the xenobiotics PCDFs and PCBs.

Topics: Animals; Benzofurans; Benzopyrenes; Chlorine; Cytochrome P-450 Enzyme System; Dihydrolipoamide Dehydrogenase; Hydrocarbons, Chlorinated; Liver; Mathematics; Polychlorinated Biphenyls; Rats; Structure-Activity Relationship

In December 1990 the U.S. Environmental Protection Agency sponsored a workshop to discuss the applicability of an interim "toxicity equivalency factor" (TEF) approach to assessing risks posed by exposures to complex mixtures of polychlorinated biphenyls (PCBs). The group concluded that application of the TEF approach to PCBs would be less straightforward than it was in the case of chlorinated dibenzo-p-dioxins and dibenzofurans (CDDs/CDFs). It appears that "dioxin"-like properties of some PCB congeners are amenable to a TEF treatment that is compatible with that used for CDDs/CDFs. Such a scheme also seems to have utility in assessing risks to wildlife. Other non-"dioxin"-like toxic endpoints (e.g., neurotoxicity) appear to have a different structure-activity-related mechanism-of-action that requires a separate TEF scheme. The workshop identified data gaps in toxicology and analytical chemistry that hinder adoption of proposed TEF schemes for PCBs at this time.

Topics: Benzofurans; Dioxins; Environmental Exposure; Feasibility Studies; Polychlorinated Biphenyls; Risk Factors; Toxicology; United States; United States Environmental Protection Agency

The H-4-II E enzyme induction bioassay was used for testing both pure reference substances and extracts of wildlife samples. Polychlorinated naphthalenes were found to be as active as enzyme inducers as certain coplanar polychlorinated biphenyls (PCBs). Also a mixture of polybrominated diphenyl ethers (Bromkal 70-5DE) was shown to induce enzyme activity. In extracts of herring, containing polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), bioassay and chemically derived TCDD-equivalents (TEQs) were nearly identical. When extracts containing other types of dioxin-like compounds as well were tested, the bioassay TEQs for most of them agreed well with chemical TEQs calculated for PCDDs, PCDFs and non-ortho PCBs. However, for ringed seal and whitefish, TEQs obtained from the bioassay were higher than those from the chemical analysis. Our results indicate that this bioassay is an excellent complement to chemical residue analysis and a useful tool in understanding the complex interactions of halogenated hydrocarbons. For risk assessment, such results should, however, be used most carefully as they are measured in vitro.

Topics: Animals; Benzofurans; Biological Assay; Cytochrome P-450 CYP1A1; Cytochrome P-450 Enzyme System; Environmental Monitoring; Environmental Pollutants; Enzyme Induction; Fishes; Oxidoreductases; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Reference Standards; Reindeer

Topics: Animals; Benzofurans; Dioxins; Gas Chromatography-Mass Spectrometry; Humans; Microchemistry; Polychlorinated Dibenzodioxins

Capillary column gas chromatography/high-resolution mass spectrometry was used in two different selected-ion monitoring modes to analyze trace levels of monobromopolychlorodibenzo-p-dioxins and dibenzofurans (BPCDD/Fs) in municipal waste incinerator (MWI) flyash. The mass profile monitoring mode is well-suited for identification of unknown compounds in uncharacterized matrices because it has superior diagnostic capability. Owing to its high sensitivity, conventional peak top monitoring was used to quantify, on the basis of polychlorodibenzo-p-dioxin and dibenzofuran (PCDD/F) standards, the BPCDD/Fs in the sample. The results were compared with those obtained by using two commercial BPCDDs as standards, and the latter results are 4 times greater, indicating the need for appropriate standards. The high certainty and sensitivity obtained from these two mass spectrometric techniques combined with the resolving power of capillary gas chromatography enabled us to compare for the first time the isomer distribution patterns between BPCDD/Fs and their PCDD/F analogues at a high confidence level. The comparison indicates BPCDD/Fs and PCDD/Fs found in MWI flyash are closely related and that many BPCDD/Fs with a 2,3,7,8-substitution configuration may be present in MWI flyash.

Topics: Benzofurans; Carbon; Coal Ash; Environmental Pollutants; Particulate Matter; Polychlorinated Dibenzodioxins; Refuse Disposal; Waste Products

Topics: Benzofurans; Carcinogens, Environmental; Dioxins; Environmental Exposure; Humans

In some regions, including the Baltic Sea, fatty fish such as salmon and herring contain high levels of polychlorinated dibenzodioxins and dibenzofurans. We investigated human exposure to these potentially toxic substances in relation to the consumption of fish from the Baltic Sea.. Plasma levels of 10 different dibenzofurans and 7 dioxins were analyzed in three groups of Swedish men: one group with a high intake of fish (fish eaten almost daily; n = 11), one with a moderate intake of fish (about once per week; n = 9), and one with no consumption of fish (usually because of allergy; n = 9).. Plasma levels of several of the compounds we measured were higher in the men with a high intake of fish than in those who consumed moderate amounts, and the levels were higher in those who ate moderate amounts of fish than in those who ate none. The median amounts of the most toxic dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin) were 8.0 pg per gram of plasma lipid (range, 2.0 to 13) in the high-intake group, 2.6 pg per gram (range, 1.2 to 4.2) in the moderate-intake group, and 1.8 pg per gram (range, 1.0 to 2.5) in the nonconsumers (P = 0.001 and 0.02, respectively). There were consistent and statistically significant associations between the reported amount of fish eaten and the plasma levels of several of the dibenzofurans and dioxins.. Contaminated fish such as those from the Baltic Sea are an important source of exposure to polychlorinated dibenzofurans and dibenzodioxins in persons who eat fish regularly. However, the clinical consequences of such exposure remain uncertain.

Topics: Adult; Animals; Benzofurans; Dioxins; Feeding Behavior; Fishes; Food Contamination; Humans; Lipids; Male; Middle Aged; Polychlorinated Biphenyls; Salmon; Sweden

Topics: Animals; Benzofurans; Dioxins; Disasters; Environmental Pollution; Humans; Polychlorinated Biphenyls

The primary reason for concern about the adverse effects of exposure to Agent Orange is attributable to its toxic contaminant, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or dioxin. We studied adipose tissues from 36 Vietnam veterans, a similar group of 79 non-Vietnam veterans, and 80 civilians; the tissue specimens were selected from the 8,000 archived tissues collected from the non-institutionalized general population by the US Environmental Protection Agency. The geometric mean (+/- standard deviation) dioxin levels in adipose tissue for Vietnam veterans, non-Vietnam veterans, and civilian controls were 11.7 (+/- 1.7), 10.9 (+/- 1.7), and 12.4 (+/- 1.9) parts per trillion on a lipid weight basis, respectively. The mean levels for these groups were not significantly different from each other with or without adjustment for age of individuals, body mass index, and specimen collection year. In addition, none of the surrogate measures of Agent Orange exposure such as military branch, service within specific geographic region, military occupation, and troop location in relation to recorded Agent Orange spray was associated with the dioxin levels in adipose tissue of Vietnam veterans. Our results suggest that heavy exposure to Agent Orange or dioxin for most US troops was unlikely.

Topics: Adipose Tissue; Benzofurans; Dioxins; Environmental Exposure; Humans; Military Personnel; United States; Veterans; Vietnam

Mutagenicities of 3-nitrodibenzofuran and 3-aminodibenzofuran were examined using Salmonella typhimurium TA98 and TA100. Strong mutagenicity was found in both compounds. The mutagenic potency of 3-nitrodibenzofuran was approximately 3.5-fold stronger in TA98 and twice stronger in TA100 than that of benzo[a]pyrene. Mutagenicity of 3-aminodibenzofuran was observed under metabolic activation and was 10 times stronger in TA98 and about 5 times stronger in TA100 than that of benzo[a]pyrene.

Topics: Benzofurans; Mutagenicity Tests; Mutagens; Salmonella typhimurium

Brevibacterium sp. strain DPO 1361 oxygenates dibenzofuran in the unusual angular position. The 3-(2-hydroxyphenyl)catechol thus generated is subject to meta ring cleavage in the proximal position, yielding 2-hydroxy-6-(2-hydroxyphenyl)-6-oxo-2,4-hexadienoic acid, which is hydrolyzed to 2-oxo-4-pentenoate and salicylate by 2-hydroxy-6-oxo-6-phenyl-2,4-hexadienoic acid hydrolase. The proximal mode of ring cleavage is definitely established by isolation and unequivocal structural characterization of a cyclization product of 2-hydroxy-6-(2-hydroxyphenyl)-6-oxo-2,4-hexadienoic acid, i.e., 3-(chroman-4-on-2-yl)pyruvate.

Topics: Benzofurans; Brevibacterium; Catechols; Chromatography, Ion Exchange; Hydrolysis; Magnetic Resonance Spectroscopy

Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were measured in various source and environmental samples obtained from eight chemical manufacturers producing agricultural chemicals, synthetic dye, or resin and eight chemical waste disposal facilities. The concentrations of PCDDs and PCDFs ranged from 3.0 to 3504 ng/g for PCDDs and from 1.2 to 1668 ng/g for PCDFs in fly ash. Their concentrations in emission were in the ranges of 21.8 to 3205 ng/m3 for PCDDs and not detected to 4344 ng/m3 for PCDFs. PCDD and PCDF concentrations were higher in fly and bottom ashes and in emissions from two manufacturers that incinerate waste plastics than in those from other manufacturers. For emission and liquid samples from the manufacturers. For emission and liquid samples from the manufacturers of agricultural chemicals, significantly high concentrations of tetra-CDDs were detected. Furthermore, the high concentrations of PCDFs, especially hepta- and octa-CDF congeners, existed in emissions from waste incinerators that manufacture rubber. Among manufacturers and disposal facilities, the total emission equivalent (2.94 ng/m3) of PCDDs and PCDFs was highest for a certain manufacturer of agricultural chemicals, showing that more 2,3,7,8-chlorine-substituted PCDDs and PCDFs were present in their emissions.

Topics: Benzofurans; Chemical Industry; Industrial Waste; Japan; Polychlorinated Dibenzodioxins; Refuse Disposal; Waste Disposal, Fluid; Waste Products

In 1979, rice oil accidentally contaminated with a mixture of polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) was ingested by a large number of individuals in Taiwan. Placentas obtained from women four years after the exposure had occurred contained several PCB congeners known to be present in the rice oil as well as two toxic PCDF congeners: 2,3,4,7,8-pentachlorodibenzofuran (2,3,4,7,8-PCDF) and 1,2,3,4,7,8-hexachlorodibenzofuran (1,2,3,4,7,8-HCDF). Placentas from exposed women had markedly elevated activities of two cytochrome P1-450 dependent enzymes, arylhydrocarbon hydroxylase and ethoxyresorufin O-deethylase. The average magnitude of enzyme induction was 100-fold, but much interindividual variation was evident. Binding properties of epidermal growth factor (EGF) to its receptor were not altered by PCB-PCDF exposure. However, EGF-stimulated autophosphorylation of the EGF receptor was decreased significantly in placentas from exposed women and this effect was strongly correlated with decreased birth weight. Species comparisons of effects on EGF receptor actions and cytochrome P-450 isoenzymes, coupled with data on tissue concentrations of PCDFs, suggest that humans are more sensitive than rats to some of the biochemical effects of PCDFs and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The data are discussed in relation to key issues in the risk assessment of the toxic halogenated aromatics.

Topics: Animals; Aryl Hydrocarbon Hydroxylases; Benzofurans; Biomarkers, Tumor; Carcinogens, Environmental; Cytochrome P-450 CYP1A1; Cytochrome P-450 Enzyme System; Female; Food Contamination; Humans; Liver; Oryza; Oxidoreductases; Placenta; Plant Oils; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Rats; Risk; Species Specificity

Topics: Accidents, Home; Acne Vulgaris; Adult; Benzofurans; Child; Child, Preschool; Dioxins; Family; Female; Hexachlorobenzene; Humans; Hydrocarbons, Chlorinated; Infant; Male; Oils; Pentachlorophenol

Polychlorinated dibenzodioxins (PCDD) and polychlorinated dibenzofurans (PCDF) are globally distributed, are persistent in the environment, and tend to accumulate in human tissues. Several 2,3,7,8-substituted PCDD and PCDF have been found at parts-per-trillion levels in human milk and adipose tissue. Food is the major source for the general population. Above-average exposures may be caused by the incineration of various wastes, certain industries (eg, metal and paper and pulp), and traffic exhaust. PCDD and PCDF have been of great public concern because one of the congeners, 2,3,7,8-tetrachlorodibenzodioxin, is an extremely potent carcinogen and teratogen in rodents. Although epidemiologic studies on cancer are too few for conclusions, animal studies and documented human exposure suggest that humans may be at increased risk. Human exposure is generally low when compared with the effective levels for rodents. However, part of the population can be more exposed and, consequently, also be potentially at higher risk.

Topics: Air Pollutants; Air Pollutants, Occupational; Benzofurans; Dioxins; Humans; Risk Factors; Vehicle Emissions

Numerous laboratory simulations and real-world events have demonstrated the thermal conversion of neat or high concentration of PCBs into the much more toxic PCDFs. Since millions of mineral oil transformers currently in service contain PCB concentrations in the 50 to 5000 ppm range, the thermal behavior of dilute PCB solutions is of practical and regulatory significance. In this work, neat Aroclor 1254 and 5000 ppm Aroclor 1254 in mineral oil were subjected to pyrolysis and combustion under a range of experimental conditions to define parameters resulting in maximal PCDF yields. The dependence of PCDF yield on Aroclor 1254 concentrations was then investigated in the 5000 to 50 ppm range. Combustion experiments demonstrated that PCDF yields expressed as micrograms PCDF/gram PCB were independent of concentration range, confirming that the process is kinetically first order in PCB. Much lower yields of PCDF were observed in the open tube pyrolysis experiments, as compared to combustion experiments and to earlier and concurrent sealed tube experiments. Slightly improved yields were observed in the pyrolysis experiments at lower concentrations, suggesting the existence of a PCB or PCDF destruction process of higher than first order kinetics. In all cases, yields expressed as micrograms PCDF/gram mixture were sharply and monotonically lower as concentrations decreased between neat or 5000 ppm Aroclor 1254 and 50 ppm Aroclor 1254.

Topics: Aroclors; Benzofurans; Chemical Phenomena; Chemistry; Chlorodiphenyl (54% Chlorine); Hot Temperature; Mineral Oil; Polychlorinated Biphenyls

Topics: Benzofurans; Dioxins; Graphite; Hydrocarbons, Chlorinated; Polychlorinated Biphenyls

Multiresidue digestion-extraction procedures for the determination of chlorinated dioxins and furans in a wide variety of products are presented. Procedure selection is dependent upon the residue(s) of interest, and on the fat content of the product. Additional cleanup is accomplished using column chromatography and a Florisil trap. The separation of residues is achieved by fraction collection off of two high-performance liquid chromatographic systems. Capillary gas chromatography employing electron-capture detection is used for quantitation. The extracts are suitable for gas chromatography mass spectrometry or gas chromatography with Hall electrolytic conductivity detection. Results of analysis, recovery data, and interlaboratory comparisons are presented. Spike recoveries will typically average 90% +/- 10%.

Topics: Benzofurans; Chlorine; Chromatography, Gas; Chromatography, High Pressure Liquid; Dioxins; Food Analysis; Isomerism; Methylene Chloride; Potassium

Two dibenzofuran degrading bacteria, Brevibacterium strain DPO 1361 and strain DPO 220, were found to utilize fluorene as sole source of carbon and energy. Cells which were grown on dibenzofuran, transformed fluorene into a number of products. For five of the seven metabolites isolated, the structure could be established unequivocally. Accumulation of one metabolite, 1,10-dihydroxy-1,10-dihydrofluoren-9-one, indicated the presence of a novel type of dioxygenase, attacking polynuclear aromatic systems in the unusual angular position. Debenzofuran degradation is proposed to likewise proceed via initial angular dioxygenation. One aryl oxygen ether bond, which normally is extremely stable, is thus transformed to a hemiacetal. After spontaneous cleavage and subsequent rearomatization by dehydration, 2,2',3-trihydroxybiphenyl [3-(2-hydroxyphenyl)-catechol] thus results as the immediate product of the first enzymatic reaction in the degradation sequence.

Topics: Benzofurans; Biodegradation, Environmental; Brevibacterium; Chemical Phenomena; Chemistry, Physical; Fluorenes; Magnetic Resonance Spectroscopy; Molecular Structure

The disposition and elimination of 1,2,3,6,7,8-HxCDF (HxCDF), 1,2,3,7,8-PnCDF (1-PnCDF), and 2,3,4,7,8-PnCDF (4-PnCDF) were studied in liver of female Sprague-Dawley rats after administration of a single oral dose of 3.5-6.3 micrograms/kg. The disposition of these PCDF congeners was structure and vehicle dependent. Administration in peanut oil caused the highest liver retention, compared with administration through the standard diet. Half-lives in liver for 1-PnCDF, 4-PnCDF, and HxCDF were 3.3, 108, and 73 days, respectively. 4-PnCDF showed very high liver retention: greater than or equal to 70% of the dose in the first days after administration. To study kinetic interaction in the liver, mixtures of 1-PnCDF and 4-PnCDF (Experiment I) and of 4-PnCDF and HxCDF (Experiment II) were administered. The presence of 4-PnCDF in Experiment I did not significantly influence the half-life of 1-PnCDF. In Experiment II the estimated half-life of 4-PnCDF was again 108 days, but for HxCDF an increased half-life was found, 156 days. It is concluded that PCDFs with a chlorine substituent(s) adjacent to the oxygen bridge (4- and 6-positions) are eliminated very slowly with t1/2 much greater than that of TCDD.

Topics: Animals; Benzofurans; Chemical Phenomena; Chemistry; Female; Liver; Rats; Rats, Inbred Strains

Dibenzofuran degrading bacteria were enriched from various environmental sources. A mutualistic mixed culture of strain DPO 220 and strain DPO 230 was characterized. Strain DPO 220 alone showed limited growth with dibenzofuran as sole source of carbon and energy (td greater than or equal to 4.5 h). A labile degradation product, C12H10O5, and salicylate were isolated from the culture fluid. Salicylate was found to be a central intermediate of DBF-degradation. Strain DPO 220 co-metabolized a wide range of anellated aromatics as well as heteroaromatics. High rates of co-oxidation of dibenzodioxin demonstrate analogue-enrichment to be a powerful technique for selecting enzymatic activities for otherwise non-degradable substrates.

Topics: Bacteria; Benzofurans; Biodegradation, Environmental; Dioxins; Salicylates; Salicylic Acid

Topics: Benzofurans; Biotransformation; Dioxins; Kinetics; Pseudomonas

Some possible intermediates or by-products in the synthesis of polychlorodibenzo-p-dioxins and dibenzofurans in municipal waste incinerators are presented. In stack gas samples from two different incinerators, the following compounds were tentatively identified: polychloromonobenzofurans, polychloromonobenzodioxins, monobromo-polychlorobenzenes and polychlorothiophenes. The occurrence of complete series of homologues and isomers with an increasing degree of chlorination suggests an analogous formation mechanism with common precursors. The presence of these compounds in the vapour phase, the non-regiospecific character of these reactions and the high reaction temperature and speed confirm a radical mechanism of formation.

Topics: Air Pollutants, Occupational; Benzofurans; Dioxins; Gas Chromatography-Mass Spectrometry; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Polycyclic Compounds

Vietnam veterans who were heavily exposed to Agent Orange exceeded matched control subjects in both blood and adipose tissue levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) but not in the levels of the 12 other 2,3,7,8-substituted dioxins and dibenzofurans that were detected. Since only TCDD among these compounds was present in Agent Orange but all are present in the population of the industrialized world, it is likely that the elevated TCDD levels arose from wartime exposure. The high correlation (r = +.89) of blood with adipose tissue level suggests that there may be a mobile equilibrium between them and that blood measurement could replace adipose tissue measurement of TCDD levels, making the collection of human data less invasive.

Topics: 2,4-Dichlorophenoxyacetic Acid; 2,4,5-Trichlorophenoxyacetic Acid; Adipose Tissue; Agent Orange; Benzofurans; Body Burden; Dioxins; Half-Life; Humans; Male; Pilot Projects; Polychlorinated Dibenzodioxins; Veterans

Structure-antitumor activity relationships are reported for a number of different examples (acridine, phenazine, anthracene, acridone, xanthenone, thioxanthenone, anthraquinone, pyridoquinazoline, dibenzodioxin, thianthrene, phenothiazine, phenoxazine, dibenzofuran, carbazole, and pyridoindole) of the general class of N-[2-(dimethylamino)ethyl] linear tricyclic carboxamides. Only the compounds containing coplanar chromophores intercalated DNA. There is an absolute requirement for an oxygen or aromatic nitrogen (possibly as hydrogen-bond acceptors) peri to the carboxamide, together with a planar ring geometry for biological activity. In addition to further delineating the nature of the pharmacophore for this class of compounds, the work has also identified dibenzo[1,4]dioxin as a novel DNA-intercalating chromophore with in vivo antitumor activity.

Topics: Aminacrine; Animals; Antineoplastic Agents; Benzofurans; Chemical Phenomena; Chemistry, Physical; Dioxins; DNA; Heterocyclic Compounds; Hydrogen-Ion Concentration; Intercalating Agents; Leukemia, Experimental; Structure-Activity Relationship; Tyramine

Microchlorination of 1,4,9[3H]dibenzofuran gave several polychlorinated dibenzofuran (PCDF) products and 2,3,7,8-[3H]tetrachlorodibenzofuran (TCDF), 1,2,3,7,8-[3H]pentachlorodibenzofuran (PeCDF), and 1,2,3,6,7,8-/1,2,3,4,7,8-hexachlorodibenzofuran (HCDF) of high specific activity (57, 34, and 32.5 Ci/mmol, respectively) were purified by preparative high-pressure liquid chromatography. These compounds were investigated as radioligands for the rat liver cytosolic aryl hydrocarbon (Ah) receptor protein. Like 2,3,7,8-[3H]tetrachlorodibenzo-p-dioxin (TCDD), the radiolabeled PCDF congeners exhibited saturable binding with the receptor protein and sucrose density gradient analysis of the radiolabeled ligand-receptor complexes gave specific binding peaks with comparable sedimentation profiles. The rank order of radioligand binding affinities (Kd values) was 2,3,7,8-TCDD greater than 2,3,7,8-TCDF greater than 1,2,3,6,7,8-HCDF greater than 1,2,3,7,8-PeCDF and the maximum difference in Kd values for the four radioligands was less than 13-fold (0.44-5.9 nM). The interactions of the PCDF radioligands with the cytosolic receptor all exhibited saturable binding curves and linear Scatchard plots and the slopes of their Hill plots were in the range 1.0-1.1, thus indicating that cooperativity was not a factor in these binding interactions. The relative stabilities and dissociation kinetics of the radioligand-receptor complexes were highly dependent on the structure of the radioligand. The dissociation curves of the 2,3,7,8-[3H]TCDD and PCDF receptor complexes were biphasic and this suggests that there may be a temporal shift in ligand binding affinities. However, the rates of dissociation did not correlate with the rank order of ligand binding affinities. The stabilities of the radioligand-receptor complexes were also dependent on the structures of the radioligands; for example, the 2,3,7,8-[3H]TCDD-receptor complex degraded more rapidly than the PCDF-receptor complex and these relative stabilities were clearly not related to the Kd values or the relative in vivo or in vitro biologic potencies of these halogenated aryl hydrocarbons.

Topics: Animals; Benzofurans; Hydrocarbons; Indicators and Reagents; Kinetics; Liver; Male; Rats; Rats, Inbred Strains; Receptors, Aryl Hydrocarbon; Receptors, Drug; Structure-Activity Relationship; Tritium

Topics: Benzofurans; Cause of Death; Chlorobenzenes; Female; Food Contamination; Japan; Male; Mortality; Oryza; Plant Oils; Polychlorinated Biphenyls

Topics: Animals; Benzofurans; Catalysis; Cattle; Chlorophenols; Chromatography, Gas; Dioxins; Lactoperoxidase; Mass Spectrometry; Peroxidases; Polychlorinated Dibenzodioxins

A fly ash extract from a municipal incinerator, containing polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), was orally administered to rats on Days 10 to 17 of the pregnancy and during the first 10 days of the lactation period. PCDD and PCDF congeners retained in the fetuses and livers of the offspring had a 2,3,7,8-chlorine substitution pattern. The only non-2,3,7,8-substituted congener retained in the liver of the offspring and females was 2,3,4,6,7-pentachlorodibenzofuran (PnCDF). In the fetuses 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) had the highest retention (0.13% of total dose) and a decrease in retention was found with increasing number of chlorine atoms. In the livers of the offspring, the highest retention was found for 2,3,7,8-TCDD and the three 2,3,7,8-substituted hexachlorodibenzo-p-dioxins (HxCDDs) (5.26-8.12%). In the livers of the pregnant and lactating females penta- and hexachlorinated congeners had the highest retention (53.91-80.20%). For both groups the liver retention of the tetra- to octachlorinated congeners was similar, but the lactating females stored less PCDDs and PCDFs in their adipose tissue. A linear relationship was found between the retention of congeners in the livers of the females and offspring.

Topics: Adipose Tissue; Animals; Animals, Newborn; Benzofurans; Dioxins; Female; Fetus; Lactation; Maternal-Fetal Exchange; Polychlorinated Dibenzodioxins; Pregnancy; Rats; Rats, Inbred Strains

A synthetic method for the preparation of aci-reductone 6-chloro-3,4-dihydroxy-2H-1-benzopyran-2-one (3) from 5-chlorosalicylate is presented. In human platelets, the benzopyranone derivative 3, clofibric acid (1), and the 2,3-dihydrobenzofuran analogue 4 inhibited aggregation and serotonin secretory responses to adenosine diphosphate (ADP) with a rank order of potency 3 greater than or equal to 4 greater than 1. Only analogues 3 and 4 consistently blocked the aggregatory responses (greater than 50%) to arachidonic acid (AA) and U46619, a thromboxane A2 agonist. Further, the rank order of inhibitory potency against U46619-induced serotonin secretion was 4 greater than 3 greater than 1. Benzopyranone 3 is of interest since it was the most potent inhibitor of thrombin-induced [3H]AA release (3 much greater than 4 = 1) and more potent than 1 or 4 for the blockade of the ADP- or AA-mediated pathway of platelet aggregation.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Arachidonic Acid; Arachidonic Acids; Benzofurans; Blood Platelets; Clofibrate; Clofibric Acid; Coumarins; Humans; In Vitro Techniques; Platelet Aggregation; Prostaglandin Endoperoxides, Synthetic; Serotonin; Structure-Activity Relationship

Binding energies to human plasma prealbumin using the energy minimization program AMBER are found for a series of polychlorinated biphenyls, dibenzodioxins, and dibenzofuran. Corrections for solvation free energies of the chlorinated analogues lead to estimates of the differential free energies of complex formation. These are compared in a number of cases to known experimental log (KPCB/Kref) values. The theory correctly separates strong, intermediate, and nonbinders. On the basis of calculations, 2,3,7,8-tetrachlorodibenzodioxin and 2,3,7,8-tetrachlorodibenzofuran are predicted to be strong binders, 3,3',5,5'-tetrachlorodiphenoquinone is predicted to be a weak binder, and octachlorodibenzodioxin is predicted to not bind at all. This theoretical model for prealbumin interactions may be of use in estimating the toxic potential of PCBs and related halogenated aromatic hydrocarbons of environmental importance.

Topics: Benzofurans; Dioxins; Humans; Kinetics; Models, Molecular; Molecular Conformation; Polychlorinated Biphenyls; Prealbumin; Protein Binding; Structure-Activity Relationship; Thermodynamics

Dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin, TCDD) is a highly toxic contaminant produced in the manufacture of phenoxy herbicides. Despite its high TCDD content, soil from a contaminated area associated with a 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) manufacturing site in Newark, New Jersey, did not induce acute toxicity when administered to guinea pigs (the most sensitive species) by gavage. Analysis of liver samples demonstrated low bioavailability of TCDD from this soil. A comparative analysis of soils showed that Soxhlet extraction was necessary for the determination of TCDD on Newark soil, whereas solvent extraction was sufficient for soil from Times Beach, Missouri. The difference in the bioavailability of TCDD from these soils is correlated with TCDD extractability and may be related to the different compositions of the soils.

Topics: 2,4,5-Trichlorophenoxyacetic Acid; Animals; Benzofurans; Biological Availability; Chemical Industry; Dioxins; Female; Guinea Pigs; Male; New Jersey; Polychlorinated Dibenzodioxins; Soil; Soil Pollutants

EPA is faced with the need to perform health risk assessments of environmental materials containing mixtures of chlorinated dioxins and -dibenzofurans. Preferably, such an assessment must be based on the direct evaluation of chronic health effects of the mixture or on a knowledge of the toxic effects of each of the components. In the absence of such data, the authors have developed two pragmatic approaches that can reasonably be applied to mixtures such as flyash or contaminated soil. The details of these approaches, viewed as interim procedures, are compared and contrasted with those used by other regulatory and public health authorities.

Topics: Animals; Benzofurans; Dioxins; Humans; Industrial Waste; Polychlorinated Dibenzodioxins; Risk; Stereoisomerism; United States; United States Environmental Protection Agency

The interactions of 2,3,7,8-tetrachlorodibenzo-p-dioxin and related compounds with prealbumin, a model for the nuclear thyroid hormone receptor, have been studied with use of computer graphics and predictions made regarding relative binding affinities for such structures. These modeling predictions were tested by experimentally measuring the binding affinities of dioxin and furan analogues. The results were in general agreement with the modeling predictions and demonstrated that such compounds could be effective competitive binding ligands for thyroxine-specific binding sites in prealbumin. The computer modeling work also demonstrates the importance of lateral chlorine substitution in the binding of these toxic compounds. The prealbumin interaction model should be of use in investigating the structure-toxicity relationships of these classes of toxic compounds. Thus, if prealbumin is a model for the nuclear thyroid hormone receptor, this work would also have major implications bearing on the mechanism of dioxin toxicity and the potential of these compounds to function as potent and persistent thyroxine agonists. A new cooperative receptor mechanism for dioxin toxic action is proposed.

Topics: Benzofurans; Binding Sites; Dioxins; Models, Molecular; Polychlorinated Dibenzodioxins; Prealbumin; Protein Binding; Solubility; Structure-Activity Relationship; Thyroxine-Binding Proteins

Topics: Adipose Tissue; Benzofurans; Chromatography, Gas; Dioxins; Female; Humans; Isomerism; Mass Spectrometry; Polychlorinated Dibenzodioxins

Topics: Benzofurans; Body Burden; Dioxins; Female; Humans; Hydrocarbons, Chlorinated; Metals; Milk, Human; Mycotoxins; Nitrates; Nitrites; Nitrosamines; Pharmaceutical Preparations; Polycyclic Compounds; Pregnancy; Risk

Topics: Animals; Benzofurans; Birds; Dioxins; Environmental Pollutants; Polychlorinated Biphenyls; Salmon; Soil Pollutants

Liver is extracted with chloroform-methanol to give essentially quantitative transfer of endogenous chlorinated dibenzo-p-dioxins (CDDs) and dibenzofurans (CDFs) into the organic phase. A new procedure involving LH-20 Sephadex is used to remove most of the lipids from the extract. Soil is extracted by a simple, rapid and economical procedure giving very high recoveries of CDDs and CDFs from sandy soil, various types of clay, and humus-rich loam. Subsequent cleanup on basic and acidic alumina complete the preparation for gas chromatography-mass spectrometric analysis. The use of propylene glycol as a "keeper" and of 2,3,7-trichlorodibenzo-p-dioxin as a carrier minimizes losses during evaporation of solvents and on glass surfaces. Interactions of 2,3,7,8-CDD with organic material in loam slightly reduce recovery but there is no indication of high affinity binding sites, the losses being apparently associated with simple distribution coefficients. Special precautions needed to avoid losses of CDFs on alumina chromatography are described, and the effect of "aging" spiked soil is discussed.

Topics: Animals; Benzofurans; Chlorine; Dioxins; Gas Chromatography-Mass Spectrometry; Liver; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Rats; Rats, Inbred F344; Rats, Inbred Strains; Soil; Solvents

Topics: Benzofurans; Chemical Industry; Chlorophenols; Herbicides; Hot Temperature; Hydrocarbons, Chlorinated; Poland

The hepatic acid-soluble thiol content of striped mullet (Mugil cephalus) exposed to cadmium (10 mg/liter seawater), mercury (200 micrograms/liter), fluorene (100 micrograms/liter), dibenzofuran (750 micrograms/liter), or a 20% water-soluble fraction of a No. 2 fuel oil, and of winter flounder (Pseudopleuronectes americanus) exposed to pentachlorophenol (200 micrograms/liter) for up to 3 weeks was determined. Exposure to these chemicals caused an elevation of hepatic acid-soluble thiol content over control values. Similarly, the acid-soluble thiol content was 1.75 times control values 24 hr after injection with acetaminophen (40 mg/100 g body wt, ip). In contrast, hepatic acid-soluble thiol concentrations did not fluctuate after feeding or during short-term starvation, or after acute or chronic physical trauma. Thus, the increase in hepatic acid-soluble thiols observed in mullet appears to be a specific response to chemical insult. The effect of chemical exposure on specific thiols can vary with the compound under investigation. Glutathione accounted for most of the acid-soluble thiol increase observed in mullet exposed to oil, whereas other acid-soluble thiols were also elevated after exposure to cadmium. Injection of [14C]glycine into cadmium- and oil-treated mullet showed that hepatic uptake of this amino acid substrate and its incorporation into hepatic glutathione increased after chemical exposure. The proportion of the total [14C]glycine in the liver incorporated into glutathione was unchanged after oil exposure, but was significantly increased in cadmium-exposed fish. These results suggest that chemicals may elevate glutathione content by enhancing the hepatic uptake of amino acid substrates and also the activity of biosynthetic enzymes.

Topics: Acetaminophen; Animals; Benzofurans; Cadmium; Cysteine; Fishes; Fluorenes; Food Deprivation; Fuel Oils; Glutathione; Glycine; Liver; Mercury; Pentachlorophenol; Sulfhydryl Compounds

Topics: Benzofurans; Chlorophenols; Drug Contamination; Herbicides; Hydrocarbons, Chlorinated; Poland

Topics: Animals; Benzofurans; Carcinogens; Cattle; Dibenzofurans, Polychlorinated; Dioxins; Environmental Exposure; Female; Fishes; Humans; Male; Meat; Mice; Neoplasms; Polychlorinated Biphenyls; Poultry

A series of polyaromatic hydrocarbons (PAHs) has been used to calibrate the retention times of chlorinated dibenzo-p-dioxins (dioxins) and chlorinated dibenzofurans (furans) on high-performance liquid chromatography (HPLC) in the ultra-trace analysis of biological samples. Fraction collection is then based on the HPLC retention times of the PAHs without the need for the dioxins or furans. Because of the variety of PAHs, a particular one can be chosen that will co-chromatograph near any given dioxin or furan. It has been shown that the effect of solvent changes and sample co-extractives on the HPLC eluting properties of the PAHs is minimal. The use of PAHs as secondary standards for HPLC calibration in dioxin trace analysis diminishes both the potential for contamination of the sample by the standard and the handling of the chlorinated dioxins and furans. The PAH standards could also be useful for those laboratories who are limited in their safety facilities or in the number and amount of dioxin-furan standards available to them.

Topics: Animals; Benzofurans; Chromatography, High Pressure Liquid; Dioxins; Environmental Pollutants; Fishes; Hydrocarbons, Chlorinated; Liver; Polycyclic Compounds; Reference Standards

The hepatic tumor-promoting activity of a commercial polychlorinated biphenyl mixture, Aroclor 1254 (AR 1254), with and without its intrinsic polychlorinated dibenzofuran (PCDF) impurities, was investigated. Male Sprague-Dawley non-inbred albino rats were treated with 66 microgram diethylnitrosamine (DENA)/ml drinking water for 5 weeks and subsequently given a control diet or a diet supplemented (100 ppm for 18 wk) with either AR 1254 or AR 1254 from which the PCDF moieties were removed (AR 1254-PCDF). Of those animals receiving DENA alone, 16% exhibited hepatocellular carcinomas. Of those rats treated with DENA followed by administration of AR 1254 or AR 1254-PCDF, 64 or 84%, respectively, developed hepatocellular carcinomas. Thus promotion with either AR 1254 or AR 1254-PCDF significantly (P less than 0.05) increased the incidence of DENA-initiated hepatocellular carcinomas. Administration of AR 1254 or AR 1254-PCDF alone did not induce hepatic tumors. Therefore, PCDF impurities were not necessary for the promoting activity of AR 1254.

Topics: Animals; Aroclors; Benzofurans; Body Weight; Carcinogens; Chlorodiphenyl (54% Chlorine); Cocarcinogenesis; Diet; Diethylnitrosamine; Liver; Liver Neoplasms; Liver Neoplasms, Experimental; Male; Polychlorinated Biphenyls; Rats

The effect of polychlorinated biphenyl (PCB), dibenzofuran (CDF) and dibenzo-p-dioxin (CDD) on endotoxin sensitivity was studied in male mice. The oral administration of CDF and CDD, once a week for 4 weeks, increased endotoxin sensitivity, whereas, PCB was not affective. On the other hand, residual levels of PCB were detected in thymus but CDF and CDD were not.

Topics: Adipose Tissue; Animals; Atrophy; Benzofurans; Dioxins; Endotoxins; Immunosuppression Therapy; Liver; Male; Mice; Organ Size; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Spleen; Thymus Gland

Topics: Anti-Bacterial Agents; Bacteria; Benzofurans; Furans; Lichens

Topics: Anti-Bacterial Agents; Bacteria; Benzofurans; Furans; Lichens; Structure-Activity Relationship

Topics: Anti-Bacterial Agents; Bacteria; Benzofurans; Furans; Lichens