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The speciation of several tributyltin and triphenyltin compounds under varying salinity conditions (0, 20, 40 and 60%) was studied by Mössbauer spectroscopy in both anaerobic and aerobic Anacostia River sediments. The Mössbauer spectral parameters of the spiked sediments indicated that changes in the salinity did not affect the speciation of the tin compounds in either aerobic or anaerobic sediments. [ABSTRACT FROM AUTHOR]

The effects of pH on the speciation of some tributyltin and triphenyltin compounds in spiked sediments from the Anacostia River were studied. The compounds included tributyltin chloride, oxide, and acetate as well as triphenyltin chloride, hydroxide, and acetate. Mössbauer spectroscopy was used to measure the speciation of the triorganotin compounds in the spiked sediments. In general, for the three pHs (5, 7, and 9) studied, the Mössbauer parameters, quadrupole splitting, and isomer shift, varied depending upon the sediment site and the pH. The ? -values (ratio of quadrupole splitting to isomer shift), which indicate the co-ordination of the tin atom, were greater than 2.1 in all cases, indicating that the co-ordination around the tin atoms in all the spiked sediments is greater than four. The variation in the Mössbauer parameters with pH at different sites in the Anacostia River reflects the variation in the components of the sediments. [ABSTRACT FROM AUTHOR]