Speciation of some triorganotin compounds in sediments from the Anacostia and Potomac Rivers, Washington, DC, using Mossbauer spectroscopy

Triorganotin compounds, namely the tributyltin (TBT) and triphenyltin (TPT) moieties, have been used as the active components in antifoulant marine paints. Mossbauer spectroscopy was used in this work to identify the products of speciation of these triorganotin compounds in various types of sediment from rivers around the Washington, DC, USA, area. Aerobic and anaerobic sediments from several sites in the Anacostia and Potomac Rivers were spiked with tributyl- and triphenyl-tin chloride, bis-(tri-n-butyltin) oxide and triphenyltin hydroxide. Mossbauer spectra were recorded for the resultant interactions of the species produced with the various sediments. The Mossbauer spectra of both types of sediment, aerobic and anaerobic, spiked with tributyltin chloride and bis-(tri-n-butyltin) oxide were the same, suggesting that these compounds were converted to the same species, mostly likely the hydrated tributyltin cation, TBT. The spectra of all triphenyltin chloride and triphenyltin hydroxide spiked sediment samples were the same, indicating again that these compounds were converted to the same species, in this case the hydrated triphenyltin cation, TPT+. Thus the species that interacts with the various sediments are the respective hydrated cations. The results also support the previous conclusion obtained with Chesapeake Bay sediments, that the product of triorganotin speciation depends on the nature of sediment. Copyright (C) 2001 John Wiley Sons, Ltd.