Fate and metabolism of the brominated flame retardant tetrabromobisphenol A (TBBPA) in rice cell suspension culture.
Tetrabromobisphenol A (TBBPA) is the brominated flame retardant with the highest production volume and its bioaccumulation in environment has caused both human health and environmental concerns, however the fate and metabolism of TBBPA in plants is unknown. We studied the fate, metabolites, and transformation of (14)C-labeled TBBPA in rice cell suspension culture. During the incubation for 14 days, TBBPA degradation occurred continuously in the culture, accompanied by formation of one anisolic metabolite [2,6-dibromo-4-(2-(2-hydroxy)-propyl)-anisole] (DBHPA) (50% of the degraded TBBPA) and cellular debris-bound residues (46.4%) as well as mineralization (3.6%). The cells continuously accumulated TBBPA in the cytoplasm, while a small amount of DBHPA (2.1% of the initially applied TBBPA) was detectable inside the cells only at the end of incubation. The majority of the accumulated residues in the cells was attributed to the cellular debris-bound residues, accounting for 70-79% of the accumulation after the first incubation day. About 5.4% of the accumulation was associated with cell organelles, which contributed 7.5% to the cellular debris-bound residues. Based on the fate and metabolism of TBBPA in the rice cell suspension culture, a type II ipso-substitution pathway was proposed to describe the initial step for TBBPA degradation in the culture and balance the fate of TBBPA in the cells. To the best of our knowledge, our study provides for the first time the insights into the fate and metabolism of TBBPA in plants and points out the potential role of type II ipso-hydroxylation substitution in degradation of alkylphenols in plants. Further studies are required to reveal the mechanisms for the bound-residue formation (e.g., binding of residues to specific cell wall components), nature of the binding, and toxicological effects of the bound residues and DBHPA.
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Xianlin Avenue 163, 210023 Nanjing, China.
Songfeng
S
Wang
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Xianlin Avenue 163, 210023 Nanjing, China.
Siqi
S
Cao
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Xianlin Avenue 163, 210023 Nanjing, China.
Yongfeng
Y
Wang
Fujian Provincial Academy of Environmental Science, No. 10, Huan Bei San Cun, 350013 Fuzhou, China.
Bingqi
B
Jiang
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Xianlin Avenue 163, 210023 Nanjing, China.
Lianhong
L
Wang
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Xianlin Avenue 163, 210023 Nanjing, China.
Feifei
F
Sun
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Xianlin Avenue 163, 210023 Nanjing, China. Electronic address: ji@nju.edu.cn.
Rong
R
Ji
D001673:Biodegradation, Environmental; D001711:Biotransformation; D002478:Cells, Cultured; D005411:Flame Retardants / Q000378:metabolism*; D012275:Oryza / Q000378:metabolism*; D011075:Polybrominated Biphenyls / Q000378:metabolism*; D013535:Suspensions
D005411:Flame Retardants; D011075:Polybrominated Biphenyls; D013535:Suspensions; C020806:tetrabromobisphenol A
Bound residues; Metabolism; Rice cell suspension culture; TBBPA; Transformation