title: Comparative hepatic microsomal biotransformation of selected PBDEs, including decabromodiphenyl ether, and decabromodiphenyl ethane flame retardants in Arctic marine-feeding mammals.
abstract: The present study assessed and compared the oxidative and reductive biotransformation of brominated flame retardants, including established polybrominated diphenyl ethers (PBDEs) and emerging decabromodiphenyl ethane (DBDPE) using an in vitro system based on liver microsomes from various arctic marine-feeding mammals: polar bear (Ursus maritimus), beluga whale (Delphinapterus leucas), and ringed seal (Pusa hispida), and in laboratory rat as a mammalian model species. Greater depletion of fully brominated BDE209 (14-25% of 30 pmol) and DBDPE (44-74% of 90 pmol) occurred in individuals from all species relative to depletion of lower brominated PBDEs (BDEs 99, 100, and 154; 0-3% of 30 pmol). No evidence of simply debrominated metabolites was observed. Investigation of phenolic metabolites in rat and polar bear revealed formation of two phenolic, likely multiply debrominated, DBDPE metabolites in polar bear and one phenolic BDE154 metabolite in polar bear and rat microsomes. For BDE209 and DBDPE, observed metabolite concentrations were low to nondetectable, despite substantial parent depletion. These findings suggested possible underestimation of the ecosystem burden of total-BDE209, as well as its transformation products, and a need for research to identify and characterize the persistence and toxicity of major BDE209 metabolites. Similar cause for concern may exist regarding DBDPE, given similarities of physicochemical and environmental behavior to BDE209, current evidence of biotransformation, and increasing use of DBDPE as a replacement for BDE209.
authors: Carleton University, Ottawa, Ontario, Canada.
authors: Melissa A
authors: MA
authors: McKinney
authors: Rune
authors: R
authors: Dietz
authors: Christian
authors: C
authors: Sonne
authors: Sylvain
authors: S
authors: De Guise
authors: Karl
authors: K
authors: Skirnisson
authors: Karl
authors: K
authors: Karlsson
authors: Egill
authors: E
authors: Steingrímsson
authors: Robert J
authors: RJ
authors: Letcher
mesh_terms: D000818:Animals; D001110:Arctic Regions; D050643:Beluga Whale / Q000378:metabolism; D001711:Biotransformation; D001969:Bromobenzenes / Q000378:metabolism*; D004784:Environmental Monitoring; D005411:Flame Retardants / Q000378:metabolism*; D055768:Halogenated Diphenyl Ethers / Q000378:metabolism*; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D046048:Seals, Earless / Q000378:metabolism; D001503:Ursidae / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: C477694:2,2',4,4',5-brominated diphenyl ether; D001969:Bromobenzenes; D005411:Flame Retardants; D055768:Halogenated Diphenyl Ethers; D014874:Water Pollutants, Chemical; C491509:decabromodiphenyl ethane; C010902:decabromobiphenyl ether