octabromobiphenyl and decabromobiphenyl-ether

Three commercial polybrominated diphenyl oxide flame retardants (PBDPO, PBDE) are manufactured: decabromodiphenyl oxide (DBDPO), octabromodiphenyl oxide (OBDPO) and pentabromodiphenyl oxide (PeBDPO). The composition, production volumes, uses and toxicology of the three products differ. In 1999, DBDPO accounted for approximately 82% of the global PBDPO usage. DBDPO has been extensively tested. DBDPO was not acutely toxic, was not irritating to the skin or eye, and did not induce skin sensitization. No evidence of genotoxic effects was detected in the Ames Salmonella, chromosome aberration, mouse lymphoma, or sister chromatid exchange tests. No cytogenic changes were observed in the bone marrow of rats (parents and offspring) undergoing a one-generation reproduction test. DBDPO did not adversely affect development or reproduction in rats. DBDPO's no-adverse-effect-level (NOAEL) in repeated dose studies was > or = 1000 mg/kg body weight. No, equivocal, or some evidence of carcinogenicity, dependent on genus and sex, was found in mice and rats at 2.5% and 5% of the diet administered for 2 years. DBPDO was poorly absorbed from the gastrointestinal tract (< 0.3-2% oral dose), had a short half-life (< 24 h) compared to PCB 153 (only 2% of an oral dose eliminated by rats in 21 days), and was rapidly eliminated via the feces (> 99% in 72 h). In contrast, components of the PeBDPO product were well absorbed and slowly eliminated, OBDPO's effect level in a 90-day study was approximately 100 mg/kg, PeBDPO's no-effect-level (NOEL) in a 30-day study was 1 mg/kg, and OBDPO induced developmental toxicity in the rat. In aquatic species, neither DBDPO nor OBDPO were toxic to aquatic organisms or bioconcentrating. Components of the PeBDPO product bioconcentrated in fish but produced little evidence of adverse effects.

Topics: Administration, Oral; Animals; Bromobenzenes; Dose-Response Relationship, Drug; Female; Fishes; Flame Retardants; Half-Life; Halogenated Diphenyl Ethers; Hydrocarbons, Brominated; Male; Mice; Neoplasms; No-Observed-Adverse-Effect Level; Phenyl Ethers; Polybrominated Biphenyls; Rabbits; Rats; Reproduction; Tissue Distribution

Polybrominated diphenyl ethers (PBDEs), a type of brominated flame retardant chemically and toxicologically similar to polychlorinated biphenyls (PCBs), are a class of emerging environmental and human contaminants. They have recently been detected in U.S. milk, blood, and food at the highest levels in the world. This pilot study was undertaken with the aim of determining levels of PBDE in the U.S. indoor environment, to assess the potential exposure to PBDEs from computer surfaces and carpets. Food of animal origin is the usual source of polychlorinated dibenzo-p-dioxin (PCDD), polychlorinated dibenzofurans (PCDF), and PCBs in humans, but there may also be environmental sources for intake of PBDEs. It was also our aim to characterize the PBDE congener profile in these indoor environmental samples. Four computer wipe samples and 9 domestic vacuum-sweeping samples were analyzed for 13 PBDE congeners, PBDEs 17 (2,2',4), 28 (2,4,4'?), 47 (2,2',4,4'?), 66 (2,3',4,4'?), 77 (3,3',4,4'?), 85 (2,2',3,4,4'?), 99 (2,2'4,4',5), 100 (2,2',4,4',6), 138 (2,2',3,4,4',5'?), 153 (2,2',4,4',5,5'?), 154 (2,2',4,4',5,6'?), 183 (2,2',3,4,4',5',6), and 209 (2,2',3,3',4,4',5,5',6,6'?). All samples tested positive for PBDEs. PBDE 209 was the dominant congener in all 4 computer wipe samples and in 7 out of the 9 vacuum dust samples. The congener profiles observed in this study varied considerably, a finding that has been observed previously. However these congener profiles differ from the pattern seen in U.S. human milk, human blood and in food, where PBDEs 47 and 99 predominate.

Topics: Computers; Dust; Environmental Exposure; Environmental Monitoring; Environmental Pollutants; Flame Retardants; Floors and Floorcoverings; Halogenated Diphenyl Ethers; Humans; Molecular Structure; Phenyl Ethers; Polybrominated Biphenyls; United States

Decabromodiphenyl oxide (DBDPO) and octabromobiphenyl (OBBP) perform well as fire-retardant additives for thermoplastics. Both compounds have low acute oral toxicity and low skin absorption toxicity. They are neither primary skin irritants or skin sensitizers and are only mildly irritating to the eyes. A 30-day dietary feeding study in rats established 8 mg DBDPO/kg-day as an unequivocal no-effect level and 80 mg/kg-day as a marginal effect level. A no-effect level was not established for OBBP in a comparative study. A 2-yr rat study providing 0.1 mg DBDPO/kg-day in the diet revealed the bromine concentration reached a plateau in the liver within 30 days, while the concentration in adipose tissue slowly increased. A comparable OBBP study revealed bromine concentration in the liver and adipose tissue increased steadily and rapidly with no attainment of a plateau during 180 days of the study. Neither compound produced an accumulation of bromine in other tissues. After administration of 14C DBDPO, all 14C activity was eliminated via the feces within 2 days. After administration of 14C OBBP, 62% was eliminated with a half-life of less than 24 hr; the half-life for the remainder was greater than 16 days. In a teratology study, 10, 100, or 1000 mg DBDPO/kg-day had no effect in rats. Reproductive capacity of rats was not effected at 3, 30, or 100 mg DBDPO/kg-day. No effects were observed on cytogenetic examination of bone marrow cells of parents and weanlings from the reproduction study.

Topics: Abnormalities, Drug-Induced; Acne Vulgaris; Adipose Tissue; Animals; Biphenyl Compounds; Bromine; Bromobenzenes; Chemical Phenomena; Chemistry; Diet; Erythema; Eye; Female; Fetus; Halogenated Diphenyl Ethers; Intubation, Gastrointestinal; Liver; Male; Phenyl Ethers; Polybrominated Biphenyls; Pregnancy; Rabbits; Rats; Reproduction