Comparison of trends in tributyltin concentrations among three monitoring programs in the United States

Abstract

The results of three national monitoring programs in the United States (U.S.) that measure concentrations of tributyltin (TBT) are compared. Regional and site comparisons are made of changes in TBT concentrations since passage of the Organotin Antifouling Paint Control Act (OAPCA) in 1988. The monitoring programs compared are the U.S. LongTerm Monitoring Program conducted by a consortium of tributyltin manufacturers, the National Oceanic and Atmospheric Administration's National Status and Trends Mussel Watch project, and the U.S. Navy's TBT monitoring program. All of the monitoring results demonstrate declining TBT concentrations over time. These declines have occurred rapidly (within a few years) and are considerable (56%–71% decrease in TBT concentrations in water, 47%–55% decrease in sediments, and 40%–82% decrease in bivalve tissues). Mean TBT concentrations in water are generally below the current U.S. Environmental Protection Agency marine chronic water quality criterion of 10ng/L. These results indicate that the OAPCA has been effective in reducing TBT concentrations in the aquatic environment.