benzofurans and 2-4-6-trichlorophenol

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

The thermal reactions of 2,4,6-T(3)CP in the presence and absence of DEHP in a dry air stream was investigated using a silica flow reactor at a residence time of 10s and a temperature range from 450 degrees C to 850 degrees C. Two isomers of T(4)CDDs (1,3,6,8- and 1,3,7,9-T(4)CDDs) were the most abundant products during the combustion of 2,4,6-T(3)CP alone and were observed at temperatures ranging from 550 degrees C to 800 degrees C. In the presence of DEHP, we observed a remarkable decrease in the yields of T(4)CDDs during the combustion of 2,4,6-T(3)CP. The suppression ratio of the T(4)CDDs formation was more than 90% in the case of the co-combustion with 10% DEHP in molar ratio. Other PCDD/Fs except for 2,7-/2,8-DCDD and 2,8-DCDF also decreased upon the combustion of 2,4,6-T(3)CP in the presence of DEHP. During the co-combustion of 2,4,6-T(3)CP and DEHP, the residual ratio of 2,4,6-T(3)CP increased slightly and formations of lower chlorinated phenols were observed. The suppression of the T(4)CDDs was strongly dependent on the DEHP ratio in the starting material. The prospective pathways of the suppressions of the T(4)CDDs formations during the combustion of 2,4,6-T(3)CP in the presence of DEHP were proposed.

Topics: Air Pollutants; Benzofurans; Chlorophenols; Diethylhexyl Phthalate; Incineration; Polychlorinated Dibenzodioxins; Polymers

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

In order to obtain information on thermochemical reactions of chlorophenols, which are well known as dioxin precursors, occurring during the combustion of municipal solid wastes, the combustion of 2,4,6-trichlorophenol (2,4,6-T(3)CP) in an air stream was investigated over a temperature range of 500-800 degrees C for a residence time of 1-20s using a quartz flow reactor. Gas chromatographic/mass spectrometric (GC/MS) analysis of the gaseous products and residues showed that 2,4,6-T(3)CP began to decompose at 500 degrees C and produced several compounds, with 1,3,6,8- and 1,3,7,9-tetrachlorodibenzo-p-dioxins (T(4)CDD) as the major products. In addition, more than fifty organic products were observed in our experimental conditions. The yields of polychlorinated benzenes, phenols, dibenzofurans, and dibenzo-p-dioxins formed during the combustion of 2,4,6-T(3)CP were plotted as a function of temperature and residence time. Furthermore, it was found that the yields and the compositions of these gaseous products were strongly dependent on the residence time in the flow reactor.

Topics: Benzofurans; Chlorophenols; Dibenzofurans, Polychlorinated; Environmental Pollutants; Gas Chromatography-Mass Spectrometry; Hot Temperature; Incineration; Polychlorinated Dibenzodioxins; Time Factors

In this paper results of various measurement campaigns at different municipal waste incineration (MWI) plants concerning the change of the PCDD/PCDF isomer distribution in the crude gas during transiently impaired combustion conditions are presented. The focus is on the Cl4DD isomer distributions exemplarily for all other homologue groups to demonstrate the change in PCDD/PCDF formation mechanism at transient combustion conditions. Additionally to crude gas samples, at one plant filter and boiler ash were investigated simultaneously to determine if there is any difference in the isomer distribution between the matrices. For the ash from an electrostatic precipitator (ESP ash), the boiler ash and the corresponding crude gas sample, nearly identical changes in the Cl4DD isomer distribution under transient combustion conditions in relation to the normal operation process could be detected. By comparing the Cl4DD isomer distributions from different incineration plants (two municipal waste incinerators and one little incinerator burning wood chips for heating domestic household) under transient combustion conditions, in all cases the 1,3,6,8- and 1,3,7,9-Cl4DD were dominating the isomer distribution, whereas under normal operation other isomers were predominant. Obviously PCDD/PCDF formation mechanisms under transient combustion conditions are independent from the type of incinerator and of the burned fuel, respectively. Data sets were analyzed with respect to the possible reaction mechanism via chlorophenols and a good correlation of 2,4,6-trichlorophenol during the second phase of a start-up process and during a CO experiment was found. To get more detailed information about possible formation mechanisms, at one plant the dependence of the PCDD/PCDF isomer distribution on the different matrices was studied. Separate analysis of fly ash collected at the boiler exit, subsequent gas phase, ESP ash and boiler ash under normal operation conditions showed that, apart from the fly ash, the Cl4DD isomer distributions are nearly the same in the different matrices. Surprisingly, the Cl4DD isomer distribution of the fly ash was more similar to the distributions found under transient combustion conditions.

Topics: Air Pollutants; Benzofurans; Carbon Monoxide; Chlorophenols; Cities; Dibenzofurans, Polychlorinated; Environmental Monitoring; Incineration; Isomerism; Polychlorinated Dibenzodioxins; Waste Products; Wood

The influence of aluminium cation as a strong electrophilic centre on the thermolysis of chlorophenols chemisorbed on Al(OH)3 surface was investigated. If thermolysis is carried out at 300 degrees C the spontaneous rupture of the bond between aluminium and oxygen of phenol takes place in the temperature range of 260-280 degrees C. The thermolysis of chlorophenoxy aluminium compounds occurs through homolytic and heterolytic bond cleavage. In the case of heterolytic cleavage the leaving chlorophenoxy anion causes a simultaneous formation of the aluminium cation, which is the driving force for the rearrangement of the unstable intermediate. By homolytic cleavage of the Al-O bond the chlorophenoxy radical is formed. The isolation of reaction products of the thermolysis of the system AI(OH)3/2,4,6-trichlorophenol gave five isomers of dimeric compounds of resonance stabilised 2,4,6-trichlorophenoxy radical. The compounds are stable in nonaqueous, aprotic solution, but they are very sensitive to acid catalysis. They quickly transform into aromatic hydroxydiphenyl ethers. The process of dechlorination and aromatisation of cyclohexadienone dimers gives PCDD/PCDF.

Topics: Adsorption; Aluminum; Benzofurans; Catalysis; Chlorophenols; Dibenzofurans, Polychlorinated; Incineration; Mass Spectrometry; Mutagens; Polychlorinated Dibenzodioxins; Refuse Disposal; Soil Pollutants; Temperature