Abstract
Environmental behavior and fate of butyltin compounds in a water-sediment system has been studied.
Following results on butyltin behavior have been obtained experimentally :
1) Sea water-sediment soil partitioning coefficient is 1,500-3,000 (l·kg-1) both for dibutyltin (DBT) and tributyltin (TBT) when the sorption is reversible ;
2) Degradation of TBT in anaerobic sediment seemed to be abiotic and its half life is 460 days ;
4) Flux acorss the water-sediment interface can be represented by the film model for butyltin compounds, and its transport coefficient is order of 10-6(m·s-1) and affected by turbulence of the overlaying water ; and
5) TBT desorbs from sediment soil more easily than DBT : spontaneous desorption ratio are 0.16 and 0.015 (-), and first order desorption kinetic coefficient are 2.3×10-4 and 4.2×10-5 (s-1) respectively.
Fate analysis of TBT in a sea water-sediment system shows ;
1) TBT from paint chips has severer impact (raising concentrations and high persistence) than dissoluted TBT ; and
2) Resuspension of highly contaminated sediment causes recontamination of the overlaying water : a few centimeters of erosion of TBT contaminated sediment will raise the concentration in the overlaying water up to the level of the pore water.
