title: Increase of cytotoxicity during wastewater chlorination: Impact factors and surrogates.
abstract: Toxic and harmful disinfection byproducts (DBPs) were formed during wastewater chlorination. It was recently suggested that cytotoxicity to mammalian cells reflects risks posed by chlorinated wastewater. Here, ATP assays were performed to evaluate the cytotoxicity to mammalian cells. Chlorination significantly increased cytotoxicity of treated wastewater. Factors affecting cytotoxicity formation during wastewater chlorination were investigated. Quenching with sodium thiosulfate and ascorbic acid decreased the formed cytotoxicity, while ammonium kept the cytotoxicity stable. The chlorine dose required for the maximum cytotoxicity increase was dramatically affected by DOC and ammonia concentrations. The maximum cytotoxicity increase, defined as the cytotoxicity formation potential (CtFP), occurred when wastewater was treated for 48h with a chlorine dose of 2·DOC+11·NH3N+10 (mg-Cl2/L). During chlorination, the amounts of AOX formation was found to be significantly correlated with cytotoxicity formation when no DBPs were destroyed. AOX formation could be used as a surrogate to estimate cytotoxicity increase during wastewater chlorination. Besides, the CtFP of 14 treated wastewater samples was assessed ranged from 5.4-20.4mg-phenol/L. The CtFP could be estimated from UV254of treated wastewater because CtFP and UV254were strongly correlated.
authors.affiliation: Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China; Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, PR China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Du
authors.affiliation: Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, PR China. Electronic address: wuqianyuan@mail.tsinghua.edu.cn.
authors.forename: Qian-Yuan
authors.initials: QY
authors.lastname: Wu
authors.affiliation: Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China; Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute, Shenzhen 518055, PR China. Electronic address: hyhu@tsinghua.edu.cn.
authors.forename: Hong-Ying
authors.initials: HY
authors.lastname: Hu
authors.affiliation: Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Zhejiang Provincial Key Laboratory of Water Science and Technology, Department of Environment in Yangtze Delta Region Institute of Tsinghua University, Zhejiang, Jiaxing 314006, PR China.
authors.forename: Rui
authors.initials: R
authors.lastname: Liu
authors.affiliation: The Ministry-Province Jointly Constructed Base for State Key Lab-Shenzhen Key Laboratory of Chemical Biology, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, PR China.
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
mesh_terms: D000818:Animals; D016466:CHO Cells; D002470:Cell Survival / Q000187:drug effects; D002713:Chlorine / Q000633:toxicity*; D003412:Cricetulus; D054879:Halogenation; D062065:Wastewater / Q000737:chemistry / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*; D018508:Water Purification / Q000379:methods*
chemical_list: D002713:Chlorine; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: AOX formation; Chlorination; Cytotoxicity; Treated wastewater; UV(254)