Butyltins in estuarine sediments two years after tributyltin use was restricted

The highly toxic compound tributyltin (TBT) is the active agent in many effective antifouling paints. In 1988 the U.S. regulated its use in such paints. Sediments taken from four sites in Boston Harbor, MA., USA in the summer of 1990 were assayed for organotins. There was significantly less TBT at all sites in 1990 than there was in 1988. Dibutyltin (DBT) and monobutyltin (MBT), were also detected, confirming that TBT degradation occurs in the estuary. It is suggested that the decreases are due to biological and/or chemical mechanisms rather than to photochemical reactions or transport away from the sites on resuspended particulate matter.