Fate of Tributyltin in Estuarine Waters

Abstract

Tributyltin (TBT) degradation rates were determined in water collected from the Skidaway River (estuarine river located near Savannah, Georgia) and the James and Elizabeth Rivers (located near Norfolk, Virginia). Background TBT concentrations were quite low (< 5 ng/liter) for all stations, except the Elizabeth River where high TBT concentrations have been reported. TBT degradation rates were significantly higher in the Elizabeth River compared with the James River. Under sunlit conditions the TBT half-lives in the Elizabeth and James Rivers in June were 6 and 12 days, respectively. The TBT half-lives in the Skidaway River during a year long study varied from 4 to 13 days with degradation always higher in the light relative to dark treatment. Water with a higher phytoplankton population showed higher TBT degradation rates, so TBT half-lives in water with chlorophyll concentrations of 3 and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12 \mu</tex> g/liter were 9 and 4 days, respectively. Our data indicates that microbial degradation is responsible for TBT degradation in estuarine waters.When present in high numbers microalgae can play an important role in TBT degradation.