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Multiple Metabolic Pathways of 2,4,6-Tribromophenol in Rice Plants
Journal article   Open access   Peer reviewed

Multiple Metabolic Pathways of 2,4,6-Tribromophenol in Rice Plants

Qing Zhang, Yanwei Liu, Yongfeng Lin, Wenqian Kong, Xingchen Zhao, Ting Ruan, Jiyan Liu, Jerald L Schnoor and Guibin Jiang
Environmental science & technology, Vol.53(13), pp.7473-7482
07/02/2019
DOI: 10.1021/acs.est.9b01514
PMCID: PMC6931395
PMID: 31244074
url
https://www.ncbi.nlm.nih.gov/pmc/articles/6931395View
Open Access

Abstract

Bromophenols occur naturally and are used globally as man-made additives in various industrial products. They are decomposition products of many emerging organic pollutants, such as tetrabromobisphenol A, polybrominated dibenzo- p-dioxin (PBDD), polybrominated diphenyl ethers (PBDE), and others. To characterize their biotransformation pathways, bromophenol congener 2,4,6-tribromophenol, being used most frequently in the synthesis of brominated flame retardants and having the greatest environmental abundance, was selected to hydroponically expose rice plants. After exposure for 5 days, 99.2% of 2,4,6-tribromophenol was metabolized by rice. Because of the lack of relative reference standards, an effective screening strategy was used to screen for potential metabolites that were further qualitatively identified by gas and liquid chromatography combined with high-resolution mass spectrometry. Forty transformation products were confirmed or tentatively identified at different confidence levels, including 9 phase I and 31 phase II metabolites. A large number of metabolites (39) were found in rice root, and 10 of them could be translocated and detected in rice stems or leaves. Many transformation pathways were proposed, including debromination, hydroxylation, methylation, coupling reactions, sulfation, and glycosylation. It was remarkable that a total of seven hydrophobic, persistent, and toxic OH-PBDEs and PBDD/Fs were found, indicating the biotic dimeric reactions of 2,4,6-tribromophenol that occurred in the rice plants. These results improve our understanding of the transformation and environmental fates of bromophenols, and they indicate new potential sources for OH-PBDEs and PBDD/Fs in the environment, especially in food chains.
Phenols Oryza Metabolic Networks and Pathways Halogenated Diphenyl Ethers

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