Abstract:

         We addressed the individual and combined toxicity of Cu²⁺, Cd²⁺ and Se⁴⁺ to Daphnia magna with a static test method. We also employed additive index method to evaluate their combined toxicity. Individual toxicity experiment shows that the toxicity of Cu²⁺, Cd²⁺ and Se⁴⁺ is degressive. Combined toxicity experiment shows that complex toxicity effect exhibits for different concentration ratios of Cu²⁺, Cd²⁺ and Se⁴⁺. Especially, the combined toxicity effect changed from antagonistic response to synergistic response with the increase of exposure time for equal concentration ratio of Cu²⁺ and Cd²⁺.

Key words: Cu^2+, Cd²⁺, Se⁴⁺, Daphnia magna, combined toxicity