Assessing Impacts of Organotin Paint Use

The U.S. EPA must determine whether uses of tributyltin antifouling paints pose an unreasonable risk to the environment. Quantitative assessments of impacts from paint use are desirable, but these assessments would require detailed information on potential aquatic organisms exposed to TBT, exposure levels and regimes, and effects of exposures on organisms and ecosystems. A nationwide quantitative assessment is not practical; therefore, other impact assessment approaches must be considered. This paper discusses the objectives, benefits, limitations, and data needs of the various approaches. Lessons learned from assessing the potential effects of the Navy's proposed use of TBT paints provide insight to the larger problem facing the EPA. Ultimate selection of impact assessment methodology will depend on the EPA's working definition of "unreasonable adverse effects."