Photochemistry of a major commercial polybrominated diphenyl ether flame retardant congener: 2,2′,4,4′,5,5′-Hexabromodiphenyl ether (BDE153)

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• 作者：Sierra Rayne ; Peter Wan and Michael Ikonomou
• 关键词：Polybrominated diphenyl ethers (PBDEs) ; Photochemistry ; Environmental fate ; Brominated dibenzofurans ; Brominated 2-hydroxybiphenyls
• 刊名：Environment International
• 出版年：2006
• 出版时间：July 2006
• 年：2006
• 卷：32
• 期：5
• 页码：575-585
• 全文大小：308 K

文摘

The photochemistry of a major commercial polybrominated diphenyl ether (PBDE) flame retardant congener, 2,2′,4,4′,5,5′-hexabromodiphenyl ether (BDE153), was investigated in acetonitrile, distilled water, and seawater. After a short irradiation period in acetonitrile at 302 nm, the major photoproducts of BDE153 included 2,2′,4,4′,5-(BDE99), 2,2′,4,5,5′-(BDE101), and 2,4,4′,5,5′-(BDE118) substituted penta-BDEs as primary photohydrodebromination products, 2,2′,4,4′-(BDE47), 3,3′,4,4′-(BDE77), 2,3′,4,4′-(BDE66), and 2,2′,4,5′-(BDE49) substituted tetra-BDEs as secondary photohydrodebromination products, a suite of non-2,3,7,8-substituted mono- through penta-brominated dibenzofurans, and three tetrabrominated 2-hydroxybiphenyl congeners. By comparison, irradiation in distilled water and seawater gave increased relative photohydrodebromination contributions and no evidence for the formation of brominated dibenzofurans or 2-hydroxybiphenyls. In all solvent systems, subsequent degradation of primary and secondary photoproducts under continuing irradiation led to a steadily decreasing reaction mass balance. The results suggest a short photochemical half-life for BDE153 in aquatic systems, with rapid photohydrodebromination to some of the most prevalent penta- and tetra-brominated diphenyl ether congeners typically observed in environmental matrices.