Adverse effects of dichlofluanid on neotropical marine organisms

This study aimed at evaluating the chronic and acute toxicity of dichlofluanid, an antifouling biocide, on marine invertebrates. Chronic toxicity tests with waterborne dichlofluanid were conducted with embryos of the sea-urchin Echinometra lucunter and ovigerous females of the copepod Nitocra sp. Chronic and acute toxicity tests with sediments spiked with dichlofluanid were performed with Nitocra sp. and the amphipod Tiburonella viscana, respectively, considering sediments with low and high quantities of organic matter. Toxicity was above the environmental concentrations reported in the literature for water. Toxicity to embryos of E. lucunter occurred from 1 μg/L, with effective concentrations to 50% organisms (EC50-40h) estimated as 198.5 (84.6–466.1) μg/L. For the copepod, toxicity started at 100 μg/L, and EC50-7d was 566.4 (304.0–738.4) μg/L. No sediment toxicity was observed to Nitocra sp., while significant effects on the amphipods occurred from 1000 ng/g. Sediments with high organic matter were more toxic. Dichlofluanid may be toxic to marine invertebrates; however, in sediments, its toxicity may be influenced by the amount of OM, since organically enriched sediments exhibited higher toxicity.