Degradation of Tributyltin in Marine and Estuarine Waters

Experiments were performed to determine the rate of tributyltin degradation in natural waters. Ambient levels of tributyltin and its degradation products were measured in San Diego Bay. Tributyltin (TBT) degradation rates were measured in microcosms by spiking ambient waters from San Diego Bay, CA and Skidaway Estuary, GA with unlabelled and¹⁴C-labelled TBT. Short degradation half-lives, based on TBT loss, in the range of 7- 15 days were documented. Dibutyltin was the principal degradation product with lesser amounts of monobutyltin formed. Evidence for rapid TBT degradation is supported by environmental measurements which found: [1] elevated levels of mono-and dibutyltin in San Diego Bay waters that tended to co-vary with TBT levels and [2] high percentages of butyltin degradation products were found in regions with long water residence times.