title: Predicting the toxicity of metal mixtures.
abstract: The toxicity of single and multiple metal (Cd, Cu, Pb, and Zn) solutions to trout is predicted using an approach that combines calculations of: (1) solution speciation; (2) competition and accumulation of cations (H, Ca, Mg, Na, Cd, Cu, Pb, and Zn) on low abundance, high affinity and high abundance, low affinity biotic ligand sites; (3) a toxicity function that accounts for accumulation and potency of individual toxicants; and (4) biological response. The approach is evaluated by examining water composition from single metal toxicity tests of trout at 50% mortality, results of theoretical calculations of metal accumulation on fish gills and associated mortality for single, binary, ternary, and quaternary metal solutions, and predictions for a field site impacted by acid rock drainage. These evaluations indicate that toxicity of metal mixtures depends on the relative affinity and potency of toxicants for a given aquatic organism, suites of metals in the mixture, dissolved metal concentrations and ratios, and background solution composition (temperature, pH, and concentrations of major ions and dissolved organic carbon). A composite function that incorporates solution composition, affinity and competition of cations for two types of biotic ligand sites, and potencies of hydrogen and individual metals is proposed as a tool to evaluate potential toxicity of environmental solutions to trout.
authors: U.S. Geological Survey, School of Oceanography, University of Washington, Box 355351, Seattle, WA 98195, United States. Electronic address: balistri@usgs.gov.
authors: Laurie S
authors: LS
authors: Balistrieri
authors: Christopher A
authors: CA
authors: Mebane
mesh_terms: D000818:Animals; D002412:Cations / Q000633:toxicity; D003530:Cyprinidae / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004781:Environmental Exposure; D004784:Environmental Monitoring / Q000379:methods*; D005618:Fresh Water / Q000032:analysis / Q000737:chemistry; D007928:Lethal Dose 50; D019216:Metals, Heavy / Q000633:toxicity*; D008954:Models, Biological; D014337:Trout / Q000378:metabolism*; D014707:Vermont; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D002412:Cations; D019216:Metals, Heavy; D014874:Water Pollutants, Chemical
keywords: BLM; Biotic ligand model; Metal mixtures; Metal toxicity; Trout