Butyltin Partitioning in Marine Waters and Sediments

Experimental evidence indicates that a small fraction (5% or less) of measurable butyltin species are associated with the particulate fraction separated from whole seawater by filtration. Adsorption experiments have shown that 17% or less of carbon-14 labelled tributyltin added to unfiltered seawater was taken up by suspended particles in a 10-hour period. Butyltin appears to be associated principally with the dissolved fraction of whole seawater, although some particulate associated butyltin is present which permits butyltin transport to marine sediments via particulate settling. Environmental sediment tributyltin concentrations are approximately three orders of magnitude greater than the associated water column levels. Suspended sediment/water partition coefficients (Kp) calculated from recent environmental data are near those previously reported (3000), and are greater than sediment/water partition coefficients in some areas of San DiegoBay.