title: Bioassay-directed identification of organic toxicants in water and sediment of Tai Lake, China.
abstract: The government of China has invested large amounts of money and manpower into revision of water quality standards (WQS). Priority organic pollutants have been screened for WQS establishment using the potential hazard index method, however, some unsuspected chemicals that could cause adverse effects might have been ignored. A large number of chemicals exist in environment and there might be interactions between or among chemicals especially those with the same mode of action. Therefore, a toxicity-directed analysis, based on acute toxicity to Daphnia magna, was conducted for organic extracts of water and sediment from Tai Lake (Ch: Taihu) to determine toxicants responsible for adverse effects. Extracts of five of twelve samples of water and all extracts of sediment were acutely toxic. Based on toxic units, water from location L1 in July and sediments from locations L1 and L4 during several months would be expected to result in some toxicity. Twenty one (21) organophosphorus pesticides, 25 organophosphorus pesticides and 10 pyrethroids were detected in samples, extracts of which caused toxicity to D. magna. Chlorpyrifos and cyfluthrin were identified as predominant pollutants in organic extracts of sediments, accounting for up to 71% and 57% of bioassay-derived toxicity equivalents (BEQs), respectively. Chlorpyrifos was identified as the major contributor to toxicity of organic extracts of surface water, accounting for 71% to 83 % of BEQs. The putative causative agents were confirmed by use of three lines of evidence, including statistical correlation, addition of key pollutants or synergists. Greater attention should be paid to chlorpyrifos and cyfluthrin, neither of which is currently on the list of priority pollutants in China. Bioassay-directed analysis should be added for screening for the presence of priority organic pollutants in environmental media.
authors: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, People's Republic of China; Shandong Academy of Environmental Science, Jinan, People's Republic of China.
authors: Xinxin
authors: X
authors: Hu
authors: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, People's Republic of China. Electronic address: njushiwei@nju.edu.cn.
authors: Wei
authors: W
authors: Shi
authors: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, People's Republic of China.
authors: Nanyang
authors: N
authors: Yu
authors: Key Laboratory of Environmental Protection of Lake Pollution Control, Chinese Research Academy of Environmental Science, Beijing, People's Republic of China.
authors: Xia
authors: X
authors: Jiang
authors: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, People's Republic of China.
authors: Shuhang
authors: S
authors: Wang
authors: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, People's Republic of China; Department of Veterinary Biomedical Sciences and Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan, Canada; Department of Zoology, Center for Integrative Toxicology, Michigan State University, East Lansing, MI, USA; School of Biological Sciences, University of Hong Kong, Hong Kong, China; Department of Biology and Chemistry and State Key Laboratory for Marine Pollution, City University of Hong Kong, Hong Kong, China.
authors: John P
authors: JP
authors: Giesy
authors: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, People's Republic of China.
authors: Xiaowei
authors: X
authors: Zhang
authors: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, People's Republic of China.
authors: Si
authors: S
authors: Wei
authors: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, People's Republic of China. Electronic address: yuhx@nju.edu.cn.
authors: Hongxia
authors: H
authors: Yu
mesh_terms: D000818:Animals; D002681:China; D003621:Daphnia / Q000187:drug effects*; D019015:Geologic Sediments / Q000032:analysis; D060106:Lakes / Q000032:analysis; D009930:Organic Chemicals / Q000032:analysis / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*
chemical_list: D009930:Organic Chemicals; D014874:Water Pollutants, Chemical
keywords: Chlorpyrifos; Cyfluthrin; Organic extract; Predominant pollutants; Tai Lake; Toxicity-directed analysis