title: Dechlorination with sodium thiosulfate affects the toxicity of wastewater contaminated with copper, cadmium, nickel, or zinc.
abstract: Sodium thiosulfate is recommended by U.S. Environmental Protection Agency for dechlorination of the effluent samples containing residual chlorines before the toxicity testing. For samples contaminated with residual chlorine and metals, e.g., Cd(II), Cu(II) and Ni(II); however, metal toxicity as measured with Daphnia magna was reduced even at approximately half the recommended amount of sodium thiosulfate. Formation of metal-thiosulfate complexes that are less bioavailable may explain the apparent reduction of metal toxicity. In contrast, for samples spiked with Zn(II), dechlorination with sodium thiosulfate increased toxicity. The use of sodium thiosulfate for dechlorination should be cautioned when the sample under the bioassay is potentially contaminated with metals.
authors.affiliation: Institute of Health and Environment, Department of Environmental Health, School of Public Health, Seoul National University, 28 Yunkeon, Chongro, Seoul 110-799, Korea.
authors.forename: So-Rin
authors.initials: SR
authors.lastname: Oh
authors.forename: Jung-Kon
authors.initials: JK
authors.lastname: Kim
authors.forename: Min-Jung
authors.initials: MJ
authors.lastname: Lee
authors.forename: Kyungho
authors.initials: K
authors.lastname: Choi
mesh_terms: D000818:Animals; D002713:Chlorine / Q000032:analysis*; D003621:Daphnia / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D013885:Thiosulfates / Q000737:chemistry*; D013997:Time Factors; D023382:Toxicity Tests, Acute; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry / Q000633:toxicity*; D018508:Water Purification / Q000379:methods* / Q000592:standards
chemical_list: D013885:Thiosulfates; D014874:Water Pollutants, Chemical; D002713:Chlorine; C017717:sodium thiosulfate