Distribution and Fate of Butyltin Compounds in the Sediment of San Diego Bay

Mono-, di- and tributyltin compound concentrations were determined by the hydride derivatization/atomic absorption technique for twelve sediment cores recovered from San Diego Bay, CA. Tri-, di- and monobutyltin were found to be present in significant concentrations (up to 551 ug/kg dry-weight total butyltin in areas of restricted tidal flushing and high marine craft density as well as areas adjacent to active drydock facilities). Low to non-detectable ( 2 ug/kg each butyltin species) concentrations were found in well flushed areas (San Diego Bay entrance as well as recently dredged, newly built basin 5th Avenue Marina). Total butyltin concentrations decreased with depth in the cores. Results from a laboratory tank experiment with organotin contaminated sediment documented that tributyltin was debutylated primarily to monobutyltin with a half-life of approximately 162 days.