title: Enhanced transformation of tetrabromobisphenol a by nitrifiers in nitrifying activated sludge.
abstract: The fate of the most commonly used brominated flame retardant, tetrabromobisphenol A (TBBPA), in wastewater treatment plants is obscure. Using a (14)C-tracer, we studied TBBPA transformation in nitrifying activated sludge (NAS). During the 31-day incubation, TBBPA transformation (half-life 10.3 days) was accompanied by mineralization (17% of initial TBBPA). Twelve metabolites, including those with single benzene ring, O-methyl TBBPA ether, and nitro compounds, were identified. When allylthiourea was added to the sludge to completely inhibit nitrification, TBBPA transformation was significantly reduced (half-life 28.9 days), formation of the polar and single-ring metabolites stopped, but O-methylation was not significantly affected. Abiotic experiments confirmed the generation of mono- and dinitro-brominated forms of bisphenol A in NAS by the abiotic nitration of TBBPA by nitrite, a product of ammonia-oxidizing microorganisms (AOMs). Three biotic (type II ipso-substitution, oxidative skeletal cleavage, and O-methylation) and one abiotic (nitro-debromination) pathways were proposed for TBBPA transformation in NAS. Apart from O-methylation, AOMs were involved in three other pathways. Our results are the first to provide information about the complex metabolism of TBBPA in NAS, and they are consistent with a determining role for nitrifiers in TBBPA degradation by initiating its cleavage into single-ring metabolites that are substrates for the growth of heterotrophic bacteria.
authors.affiliation: †State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, 163 Xianlin Avenue, 210023 Nanjing, China.
authors.forename: Fangjie
authors.initials: F
authors.lastname: Li
authors.affiliation: ‡Fujian Provincial Academy of Environmental Science, No. 10, Huan Bei San Cun, Fuzhou 350013, China.
authors.forename: Bingqi
authors.initials: B
authors.lastname: Jiang
authors.affiliation: §Institute for Ecopreneurship, School of Life Sciences, University of Applied Sciences and Arts Northwestern Switzerland, Gründenstrasse 40, Muttenz CH-4132, Switzerland.
authors.forename: Peter
authors.initials: P
authors.lastname: Nastold
authors.affiliation: §Institute for Ecopreneurship, School of Life Sciences, University of Applied Sciences and Arts Northwestern Switzerland, Gründenstrasse 40, Muttenz CH-4132, Switzerland.
authors.forename: Boris Alexander
authors.initials: BA
authors.lastname: Kolvenbach
authors.affiliation: ∥Department of Environmental Science, China Pharmaceutical University, Tongjia Alley 24, 210009 Nanjing, China.
authors.forename: Jianqiu
authors.initials: J
authors.lastname: Chen
authors.affiliation: †State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, 163 Xianlin Avenue, 210023 Nanjing, China.
authors.forename: Lianhong
authors.initials: L
authors.lastname: Wang
authors.affiliation: †State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, 163 Xianlin Avenue, 210023 Nanjing, China.
authors.forename: Hongyan
authors.initials: H
authors.lastname: Guo
authors.affiliation: †State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, 163 Xianlin Avenue, 210023 Nanjing, China.|§Institute for Ecopreneurship, School of Life Sciences, University of Applied Sciences and Arts Northwestern Switzerland, Gründenstrasse 40, Muttenz CH-4132, Switzerland.
authors.forename: Philippe François-Xavier
authors.initials: PF
authors.lastname: Corvini
authors.affiliation: †State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, 163 Xianlin Avenue, 210023 Nanjing, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Ji
mesh_terms: D000641:Ammonia / Q000378:metabolism; D001419:Bacteria / Q000378:metabolism; D001559:Benzhydryl Compounds; D005411:Flame Retardants / Q000378:metabolism; D006207:Half-Life; D054879:Halogenation; D008745:Methylation; D058465:Nitrification; D010636:Phenols; D011075:Polybrominated Biphenyls / Q000737:chemistry / Q000378:metabolism*; D012722:Sewage / Q000382:microbiology*; D013890:Thiourea / Q000031:analogs & derivatives / Q000737:chemistry; D062065:Wastewater; D000098826:Bisphenol A Compounds
chemical_list: D000641:Ammonia; D001559:Benzhydryl Compounds; D005411:Flame Retardants; D010636:Phenols; D011075:Polybrominated Biphenyls; D012722:Sewage; D013890:Thiourea; D062065:Wastewater; C009842:allylthiourea; C020806:tetrabromobisphenol A; C006780:bisphenol A; D000098826:Bisphenol A Compounds