Comparison of the accumulation and effects of copper pyrithione and copper sulphate on rainbow trout larvae.

Copper pyrithione (CuPT) is used as a co-biocide in new antifouling paints but its toxicity remains little known. To compare the toxicity of copper-based compounds, rainbow trout (Oncorhynchus mykiss) larvae were exposed for 8-day to CuPT and CuSO at equivalent copper concentrations. CuPT exposure led to the greatest accumulation of Cu in larvae. Exposure to 10 µg.L CuPT induced 99% larval mortality but only 4% for CuSO-exposed larvae. The larval development and growth were affected by CuPT (from 0.5 µg.L Cu) but not by CuSO. Lipid peroxidation was not induced by either contaminant. The expression of genes involved in oxidative stress defence, detoxification and copper transport was induced in larvae exposed to CuSO and CuPT but at higher concentrations for CuPT. This study highlights the marked toxicity of CuPT for early life stages of fish and raises the question of the possible environmental risks of this antifouling compound.