Photochemistry of a major commercial polybrominated diphenyl ether flame retardant congener: 2,2',4,4',5,5'-Hexabromodiphenyl ether (BDE153) [An article from: Environment International]

This digital document is a journal article from Environment International, published by Elsevier in 2006. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
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 302nm, 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.