Embryotoxicity of butyltin compounds to the sea urchin Paracentrotus lividus

Tributyltin (TBT) has been widely employed in marine anti-fouling paints as a biocide, although it represents a serious risk, particularly in estuarin e and coastal water/sediment ecosystems. In this study, the embryotoxic eff ects of TBT and its degradation products, dibutyltin (DBT) and monobutyltin (MBT), were analyzed during the development of the sea urchin Paracentrotu s lividus from post-fertilization to the pluteus stage, to better clarify e cotoxicological impact. The embryotoxicity of butyltins is concentration-de pendent and increases proportionally with number of butyl groups. Significa nt growth reduction was observed at TBT concentrations as low as 0.01 mug l (-1); 1 mug l(-1) was the maximum concentration allowing embryos to reach t he pluteus stage at 48 h post-fertilization. Development was blocked at the morula or blastula stage with higher TBT concentrations. DBT and MBT are l ess toxic: slowed development and a decrease in pluteus size occurred at 10 mug l(-1) DBT and 0.5 mg l(-1) MET. Effects on both skeletal deposition an d blocked embryonic development are suggested to be due to the interference of organotin compounds with intracellular calcium homeostasis. (C) 2000 El sevier Science Ltd. All rights reserved.