Occurrence of butyltin species in sewage and sludge in Canada

Samples of sewage treatment influent, effluent and sludges collected monthly from five Canadian cities over the period from July 1990 to January 1991 were analysed for butyltin and octyltin species. Monobutyltin was found in all influent samples, but dibutyltin and tributyltin were found only infrequently, and octyltin species were not found at all. In the case of monobutyltin, there was significant reduction in its concentration by degradation and adsorption to sludge during passage through the sewage treatment plant. The average reduction was 40%. The monobutyltin found in the effluent likely came from its use as a poly (vinyl chloride) stabilizer, and from the degradation of tributyltin, which is used as a slimicide. No butyltin or octyltin species was found in five landfill leachate samples in southern Ontario during the same period.