Acute and chronic toxicities of zinc pyrithione alone and in combination with copper to the marine copepod Tigriopus japonicus.

Abstract Irgarol 1051 has been widely used as a booster biocide in combination with copper (Cu) in antifouling paints. The combined toxicity of Irgarol with Cu on marine organisms, however, has not been fully investigated. This study investigated the acute and chronic toxicities of binary mixtures of Irgarol and CuSO 4 to the marine copepod Tigriopus japonicus . The acute combined toxicity of Irgarol and Cu was simple additive as revealed by two response surface models and their contours. However, based on chronic full life-cycle tests, when Irgarol was combined with Cu at an environmentally realistic concentration (10 μg L −1 ), a slightly synergistic effect was observed at a high Irgarol concentration (940 μg L −1 ), as shown by a significant increase in larval mortality. As Cu contamination is widespread in coastal environments, our results entail the importance of considering the combined toxic effect of the booster biocide and Cu for setting ecologically realistic water quality criteria.