Impact assessment of organotin chemicals in harbor environments

The use of organotin chemicals in antifouling paints is expected to increase as the new polymer-based tins provide exceptionally long protection against fouling for marine vessels. Environmental modeling studies of New York Harbor and Chesapeake Bay were undertaken to determine whether the anticipated increase in use of organotins poses a risk to estuarine biota. The inputs of antifouling toxicant were estimated from vessel traffic data provided by the U.S. Coast Guard. Environmental chemistry parameters were derived generally from previously published reports. The model results indicate that tributyltin toxicants are likely to be transported to the open ocean or decay before significant quantities accumulate in harbor waters or sediments. Water column concentrations, for the harbors studied, are shown not to exceed 5.0 nanograms per liter (ng/l) even with 100 percent of the commercial vessels using organotin antifouling paints. Published studies suggest this level will have no adverse effects on vertebrate estuarine life.