Sublethal growth effects and mortality to marine bivalves from long-term exposure to tributyltin

Condition indices expressed as the whole body wet weight divided by the internal shell volume indicated a significant decrease in body weight in oysters exposed to 0.73-1.89 ug/liter tributyltin, while specimens exposed to 0.04-0.31 ug/liter showed no significant decreases. Mortality was evident in bay mussel specimens after long-term exposure to tributyltin with a 66-day LC50 value or 0.97 ug/liter tributyltin determined by probit analysis. The data clearly indicate that sublethal growth effects and mortality to some marine species occur at tributyltin concentrations of 1 ug/liter and less.