title: In Vitro Metabolism of Photolytic Breakdown Products of Tetradecabromo-1,4-diphenoxybenzene Flame Retardant in Herring Gull and Rat Liver Microsomal Assays.
abstract: Tetradecabromo-1,4-diphenoxybenzene (TeDB-DiPhOBz) is used as a flame retardant chemical and has been hypothesized to be the precursor of methoxylated polybrominated diphenoxybenzene (MeO-PB-DiPhOBz) contaminants reported in herring gulls from sites across the Laurentian Great Lakes. Here, by irradiating the parent TeDB-DiPhOBz (solution 1) with natural sunlight or UV, we prepared three solutions where solution 2 was dominated by the Br8-11-PB-DiPhOBzs, along with Br5-8-PB-DiPhOBzs (solution 3) and Br4-6-PB-DiPhOBzs (solution 4). The in vitro metabolism of TeDB-DiPhOBz and PB-DiPhOBzs was investigated using harvested wild herring gull (Larus argentatus) and adult male Wister-Han rat liver microsomal assays. After a 90 min incubation period of solution 1 in gull or rat microsomal assays, there was no significant (p > 0.05) depletion of TeDB-DiPhOBz. OH-PB-DiPhOBz metabolites were detectable after gull and rat microsomal assay incubation with solutions 3 or 4, and showed clear species-specific differences. Also detected were two polybrominated hydroxylated metabolites having polybenzofuran structures. Overall, this study suggested that TeDB-DiPhOBz is slowly metabolized in vitro, and also indicated that if wild herring gulls are exposed (e.g., via the diet) to photolytic products of TeDB-DiPhOBz, OH-PB-DiPhOBz and other metabolites could be formed. OH-PH-DiPhOBz are likely precursors to MeO-PB-DiPhOBz contaminants that we reported previously in eggs of wild Great Lakes herring gulls.
authors.affiliation: Ecotoxicology and Wildlife Health Division, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University , Ottawa, Ontario K1A 0H3, Canada.|Department of Chemistry, Carleton University , Ottawa, Ontario K1S 5B6, Canada.
authors.forename: Guanyong
authors.initials: G
authors.lastname: Su
authors.affiliation: Ecotoxicology and Wildlife Health Division, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University , Ottawa, Ontario K1A 0H3, Canada.|Department of Chemistry, Carleton University , Ottawa, Ontario K1S 5B6, Canada.
authors.forename: Alana K
authors.initials: AK
authors.lastname: Greaves
authors.affiliation: AccuStandard , 125 Market Street, New Haven, Connecticut 06513, United States.
authors.forename: Daniel
authors.initials: D
authors.lastname: Teclechiel
authors.affiliation: Ecotoxicology and Wildlife Health Division, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University , Ottawa, Ontario K1A 0H3, Canada.|Department of Chemistry, Carleton University , Ottawa, Ontario K1S 5B6, Canada.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Letcher
mesh_terms: D000818:Animals; D046091:Charadriiformes / Q000378:metabolism*; D005411:Flame Retardants; D060106:Lakes; D008099:Liver / Q000737:chemistry; D010782:Photolysis; D051381:Rats
chemical_list: D005411:Flame Retardants