Use of Mössbauer spectroscopy to determine the effect of salinity on the speciation of triorganotins in Anacostia River sediments

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.     

Tolerance of aggressive and non-aggressive isolates of Ceratocystis ulmi to organotin fungicides

The effect of triorganotin compounds, R₃SnX, on the growth of three wild strains of Ceratocystis ulmi (C. ulmi) fungus, two aggressive and one non-aggressive strains, was evaluated in shake culture. In all cases, the triphenyltins were the more effective organotins for the inhibition of C. ulmi in vitro. The anionic group, X, did not have a significant role in the inhibition, suggesting that the species involved in the inhibition is the triphenyltin moiety (Ph₃Sn⁺) or the hydrated triphenyltin moiety (Ph₃Sn(H₂O)⁺₂). It is further suggested that the triphenyltin species Ph₃SnOH and Ph₃SnOAc are the preferred compounds for the control of Dutch elm disease. The tolerance of aggressive isolates to fungitoxins appears to depend more on the nature of the fungicide than on the type of fungus.