title: Bioassay-directed identification of toxicants in sediments of Liaohe River, northeast China.
abstract: Contaminants accumulated in sediments may directly harm benthic organisms, however, the specific contaminants responsible for adverse effects have been poorly described. In this study, a bioassay-directed analysis combined with toxicity tests and chemistry analysis was conducted to determine the compounds eliciting the greatest toxicological effect in the sediments in Liaohe River, northeast China. A total of 24 sediment samples were examined to determine their acute toxicity to midge Chironomus tentans (C. tentans). Of these samples, 15 exhibited significant toxicity, with a mortality of 23%-93% (p < 0.05). Numerous contaminants, including 16 polycyclic aromatic hydrocarbons, 32 polychlorinated biphenyls, 20 organochlorine pesticides, 6 organophosphate pesticides, 8 pyrethroids, and 5 heavy metals were analyzed. On the basis of toxic unit (TU) analysis results, pyrethroids may contribute to the toxicity of 9 of the 15 toxic samples with concentrations of >1 TU. The significant correlation between the TUs of pyrethroids and the mortality of C. tentans (r2= 0.74, p < 0.01) confirmed the major role of pyrethroids in toxicity. The selected sediment samples responding to piperonyl butoxide and low temperature with the increased toxicity exhibited the characteristics of pyrethroids. The bioassay-based screening framework provided strong evidence that pyrethroids were the primary cause of sediment toxicity in Liaohe River. Further studies should therefore be conducted to regulate this important class of pollutants.
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; College of Water Sciences, Beijing Normal University, Beijing 100012, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: He
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China. Electronic address: xujian@craes.org.cn.
authors.forename: Jian
authors.initials: J
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Changsheng
authors.initials: C
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Jiapei
authors.initials: J
authors.lastname: Lv
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; College of Water Sciences, Beijing Normal University, Beijing 100012, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Meng
mesh_terms: D000818:Animals; D001681:Biological Assay / Q000379:methods*; D002681:China; D002683:Chironomidae / Q000187:drug effects*; D004784:Environmental Monitoring / Q000379:methods*; D019015:Geologic Sediments / Q000737:chemistry*; D015386:Hazardous Substances / Q000032:analysis / Q000633:toxicity; D006843:Hydrocarbons, Chlorinated / Q000032:analysis / Q000633:toxicity; D007306:Insecticides / Q000032:analysis / Q000633:toxicity; D019216:Metals, Heavy / Q000032:analysis / Q000633:toxicity; D011078:Polychlorinated Biphenyls / Q000032:analysis / Q000633:toxicity; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis / Q000633:toxicity; D011722:Pyrethrins / Q000032:analysis / Q000633:toxicity; D045483:Rivers / Q000737:chemistry*; D018675:Toxicity Tests / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000633:toxicity*
chemical_list: D015386:Hazardous Substances; D006843:Hydrocarbons, Chlorinated; D007306:Insecticides; D019216:Metals, Heavy; D011084:Polycyclic Aromatic Hydrocarbons; D011722:Pyrethrins; D014874:Water Pollutants, Chemical; D011078:Polychlorinated Biphenyls
keywords: Bioassay-directed analysis; Chironomus tentans; Liaohe river; Pyrethroids; Toxicity