title: Precursors of Halobenzoquinones and Their Removal During Drinking Water Treatment Processes.
abstract: Halobenzoquinones (HBQs) widely occur in drinking water treatment plant (DWTP) effluents; however, HBQ precursors and their removal by treatments remain unclear. Thus, we have investigated HBQ precursors in plant influents and their removal by each treatment before chlorination in nine DWTPs. The levels of HBQ precursors were determined using formation potential (FP) tests for 2,6-dichloro-1,4-benzoquinone (DCBQ), 2,3,6-trichloro-1,4-benzoquinone (TCBQ), 2,6-dichloro-3-methyl-1,4-benzoquinone (DCMBQ), and 2,6-dibromo-1,4-benzoquinone (DBBQ). HBQ precursors were present in all plant influents. DCBQ precursors were the most abundant (DCBQ FP up to 205 ng/L). Coagulation removed dissolved organic carbon (DOC) (up to 56%) and HBQ precursors (up to 39% for DCBQ). The level of removal of DOC was significantly greater than the level of removal of HBQ FP, suggesting that organic matter removed by coagulation had a high proportion of non-HBQ-precursor material. Granular activated carbon (GAC) decreased the level of HBQ FPs by 10-20%, where DOC removal was only 0.2-4.7%, suggesting that the GAC was not in the adsorption mode and biodegradation of HBQ precursors may have been occurring. Ozonation destroyed/transformed HBQ FPs by 10-30%, whereas anthracite/sand filtration and UV irradiation appeared to have no impact. The results demonstrated that the combined treatments did not substantially reduce HBQ precursor levels in water.
authors.affiliation: †Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada T6G 2G3.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: †Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada T6G 2G3.
authors.forename: Yichao
authors.initials: Y
authors.lastname: Qian
authors.affiliation: †Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada T6G 2G3.
authors.forename: Lindsay K
authors.initials: LK
authors.lastname: Jmaiff
authors.affiliation: ‡Metropolitan Water District of Southern California, 700 Moreno Avenue, La Verne, California 91750-3399, United States.
authors.forename: Stuart W
authors.initials: SW
authors.lastname: Krasner
authors.affiliation: †Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada T6G 2G3.
authors.forename: Steve E
authors.initials: SE
authors.lastname: Hrudey
authors.affiliation: †Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada T6G 2G3.
authors.forename: Xing-Fang
authors.initials: XF
authors.lastname: Li
mesh_terms: D016227:Benzoquinones / Q000737:chemistry / Q000302:isolation & purification*; D002244:Carbon / Q000032:analysis; D002606:Charcoal / Q000737:chemistry; D060766:Drinking Water / Q000737:chemistry*; D005374:Filtration; D010126:Ozone / Q000737:chemistry; D014466:Ultraviolet Rays; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*; D060753:Water Quality
chemical_list: D016227:Benzoquinones; D060766:Drinking Water; D014874:Water Pollutants, Chemical; D002606:Charcoal; C004532:quinone; D010126:Ozone; D002244:Carbon