title: Formation of brominated disinfection byproducts during Chloramination of drinking water: new polar species and overall kinetics.
abstract: The formation of brominated disinfection byproducts (Br-DBPs), which are generally significantly more cytotoxic and genotoxic than their chlorinated analogues, in chloramination has not been fully examined. In this work, the formation of new polar Br-DBPs in simulated drinking waters was examined using state-of-the-art ultraperformance liquid chromatography/electrospray ionization-triple quadrupole mass spectrometry. As many as 29 aliphatic, aromatic, or nitrogenous polar Br-DBPs were detected in chloramination, and five of them (including 2,4,6-tribromoresorcinol, 2,6-dibromo-4-nitrophenol, 2,2,4-tribromo-5-hydroxy-4-cyclopentene-1,3-dione, 2,2,4-dibromochloro-5-hydroxy-4-cyclopentene-1,3-dione, and 2,2,4-bromodichloro-5-hydroxy-4-cyclopentene-1,3-dione) were tentatively identified. Unlike chlorination, chloramination favored the formation of aromatic and nitrogenous polar Br-DBPs and was mild enough to allow polar intermediate Br-DBPs to accumulate. To further explore the formation mechanism of Br-DBPs in chloramination, a quantitative empirical model involving 33 major reactions was developed to describe the overall kinetics. According to the modeling results, bromochloramine and monobromamine were the major species responsible for 54.2-58.1% and 41.7-45.7%, respectively, of the formed Br-DBPs, while hypobromous acid accounted for only 0.2% of the formed Br-DBPs; direct reactions between monochloramine and natural organic matter accounted for the majority of the formed chlorinated DBPs (93.7-95.1%); hypochlorous acid and hypobromous acid in the chloramination were at ng/L or subng/L levels, which were not enough to cause polar intermediate Br-DBPs to decompose.
authors: School of Environmental Science and Engineering, Tianjin University , No. 92 Weijin Road, Nankai District, Tianjin, China.
authors: Hongyan
authors: H
authors: Zhai
authors: Xiangru
authors: X
authors: Zhang
authors: Xiaohu
authors: X
authors: Zhu
authors: Jiaqi
authors: J
authors: Liu
authors: Min
authors: M
authors: Ji
mesh_terms: D002700:Chloramines / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D004203:Disinfection / Q000379:methods*; D060766:Drinking Water / Q000737:chemistry* / Q000592:standards; D054879:Halogenation; D006842:Hydrocarbons, Brominated / Q000032:analysis* / Q000737:chemistry; D008956:Models, Chemical; D021241:Spectrometry, Mass, Electrospray Ionization; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D002700:Chloramines; D060766:Drinking Water; D006842:Hydrocarbons, Brominated; D014874:Water Pollutants, Chemical; C030816:chloramine