Sensitivity of Mediterranean amphipods and sea urchins to reference toxicants

Abstract

 Toxicity tests were performed in two amphipod species, Gammarus aequicauda and Microdeutopus gryllotalpa, and three sea urchin species, Arbacia lixula, Paracentrotus lividus and Sphaerechinus granularis. The sensitivity of these marine organisms was evaluated by acute toxicity tests with amphipod juveniles and short chronic embryo-larval tests in sea urchins using the reference toxicants, ammonium chloride (NH₄Cl), cadmium chloride (CdCl₂), potassium dichromate (K₂Cr₂O₇), sodium dodecylsulfate (C₁₂H₂₅NaO₄S) and zinc sulfate (ZnSO₄). The acute toxicity tests in amphipods clearly demonstrated the toxicity gradient of these substances. A two-way ANOVA analysis showed that M. gryllotalpa was more sensitive than G. aequicauda to all the reference toxicants studied (P < 0.0001). The tests conducted with sea urchins also pointed to a toxicant gradient and these organisms were seen to be more sensitive than amphipods. The two-way ANOVA analysis showed no significant differences in the IC25 and IC50 values for each reference toxicant in the three sea urchin species. The interaction of sea urchin species and a reference toxicant had no significant effect (two-way ANOVA, P = 0.9), the sensitivity of these Mediterranean species and groups being similar to that of other amphipod and sea urchin species found in the bibliography. The objective of our study is to provide ecotoxicological tools to evaluate the potential toxicity of Mediterranean benthic ecosystems, and in this work, we characterize the toxicity of reference toxicants towards autochthonous species of amphipods and sea urchins.