title: Assessment of toxic interactions of heavy metals in binary mixtures: A statistical approach
abstract: Toxicity of zinc, copper, cobalt, and chromium ions and their binary interactions were studied at varying test levels by using a battery of two tests, Microtox and duckweed with Vibrio fisheri and Lemna minor as test organisms, respectively. The type of toxic interaction at each test combination was assessed by a statistical approach based on testing the null hypothesis of "additive toxicity" at 95% confidence level. The interactions were called "antagonistic," "additive," or "synergistic" in accordance with the statistical significance and the sign of the difference between the tested hypothesis and the value of the observed toxicity at the binary test level concerned. In the majority of the combinations studied by the two bioassays, the interactions were of antagonistic nature. Additive toxicity was the next frequently predicted interaction in both test results, the frequency being much higher in Microtox responses than in those of duckweed. Finally, synergism was found to be a rare interaction in Microtox results, but totally unlikely in duckweed within the selected test combinations.
authors.affiliation: Institute of Environmental Sciences, Bogazici University, 80815 Bebek-Istanbul, Turkey.
authors.initials: NH
authors.lastname: Ince
authors.initials: N
authors.lastname: Dirilgen
authors.initials: IG
authors.lastname: Apikyan
authors.initials: G
authors.lastname: Tezcanli
authors.initials: B
authors.lastname: Ustun