Monohydroxylated Polybrominated Diphenyl Ethers (OH-PBDEs) and Dihydroxylated Polybrominated Biphenyls (Di-OH-PBBs): Novel Photoproducts of 2,6-Dibromophenol
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- 作者：Hongxia Zhao ; Jingqiu Jiang ; Yanli Wang ; Hans-Joachim Lehmler ; Garry R. Buettner ; Xie Quan ; Jingwen Chen
- 刊名：Environmental Science & Technology
- 出版年：2015
- 出版时间：December 15, 2015
- 年：2015
- 卷：49
- 期：24
- 页码：14120-14128
- 全文大小：490K
- ISSN：1520-5851
文摘
Hydroxylated polybromodiphenyl ethers (OH-PBDEs) are emerging aquatic pollutants, but their origins in the environment are not fully understood. There is evidence that OH-PBDEs are formed from bromophenols, but the underlying transformation processes remain unknown. Here, we investigate if the photoformation of OH-PBDEs from 2,6-dibromophenol in aqueous solution involves 2,6-bromophenoxyl radicals. After the UV irradiation of an aqueous 2,6-dibromophenol solution, HPLC鈥揕TQ-Orbitrap MS and GC鈥揗S analysis revealed the formation of a OH-PBDE and a dihydroxylated polybrominated biphenyl (di-OH-PBB). Both dimeric photoproducts were tentatively identified as 4鈥?OH-BDE73 and 4,4鈥?di-OH-PBB80. In addition, three debromination products (4-OH-BDE34, 4鈥?OH-BDE27, and 4,4鈥?di-OH-PBBs) were observed. Electron paramagnetic resonance spectroscopy revealed the presence of a 2,6-dibromophenoxyl radical with a six-line spectrum (aH (2 meta) = 3.45 G, aH (1 para) = 1.04 G, g = 2.0046) during irradiation of a 2,6-dibromophenol solution in water. The 2,6-dibromophenoxyl radical had a relatively long half-life (122 卤 5 渭s) according to laser flash photolysis experiments. The para鈥損ara C鈥揅 and O鈥?i>para-C couplings of these 2,6-dibromophenoxyl radicals are consistent with the observed formation of both dimeric OH-PBDE and di-OH-PBB photoproducts. These findings show that bromophenoxyl radical-mediated phototransformation of bromophenols is a source of OH-PBDEs and di-OH-PBBs in aqueous environments that requires further attention.