title: The effect of binary mixtures of zinc, copper, cadmium, and nickel on the growth of the freshwater diatom Navicula pelliculosa and comparison with mixture toxicity model predictions.
abstract: The authors investigated the effect of binary mixtures of zinc (Zn), copper (Cu), cadmium (Cd), and nickel (Ni) on the growth of a freshwater diatom, Navicula pelliculosa. A 7 × 7 full factorial experimental design (49 combinations in total) was used to test each binary metal mixture. A 3-d fluorescence microplate toxicity assay was used to test each combination. Mixture effects were predicted by concentration addition and independent action models based on a single-metal concentration-response relationship between the relative growth rate and the calculated free metal ion activity. Although the concentration addition model predicted the observed mixture toxicity significantly better than the independent action model for the Zn-Cu mixture, the independent action model predicted the observed mixture toxicity significantly better than the concentration addition model for the Cd-Zn, Cd-Ni, and Cd-Cu mixtures. For the Zn-Ni and Cu-Ni mixtures, it was unclear which of the 2 models was better. Statistical analysis concerning antagonistic/synergistic interactions showed that the concentration addition model is generally conservative (with the Zn-Ni mixture being the sole exception), indicating that the concentration addition model would be useful as a method for a conservative first-tier screening-level risk analysis of metal mixtures. Environ Toxicol Chem 2016;35:2765-2773. © 2016 SETAC.
authors.affiliation: National Institute for Agro-Environmental Sciences, Tsukuba, Ibaraki, Japan. nagait@affrc.go.jp.|Laboratory of Environmental Toxicology and Aquatic Ecology, Environmental Toxicology Unit (GhEnToxLab), Ghent University, Ghent, Belgium. nagait@affrc.go.jp.
authors.forename: Takashi
authors.initials: T
authors.lastname: Nagai
authors.affiliation: Laboratory of Environmental Toxicology and Aquatic Ecology, Environmental Toxicology Unit (GhEnToxLab), Ghent University, Ghent, Belgium.
authors.forename: Karel A C
authors.initials: KA
authors.lastname: De Schamphelaere
mesh_terms: D002104:Cadmium / Q000633:toxicity; D045424:Complex Mixtures / Q000633:toxicity*; D003300:Copper / Q000633:toxicity; D017377:Diatoms / Q000187:drug effects*; D005618:Fresh Water / Q000737:chemistry*; D019216:Metals, Heavy / Q000633:toxicity*; D008962:Models, Theoretical; D009532:Nickel / Q000633:toxicity; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D015032:Zinc / Q000633:toxicity
chemical_list: D045424:Complex Mixtures; D019216:Metals, Heavy; D014874:Water Pollutants, Chemical; D002104:Cadmium; D003300:Copper; D009532:Nickel; D015032:Zinc
keywords: Biotic ligand model; Concentration addition; Independent action; Metal; Mixture toxicology