EXTENSIVE BUTYLTIN CONTAMINATION IN SOUTHWESTERN COASTAL BRITISH-COLUMBIA, CANADA

Fish, shellfish, and sediment samples from 10 sites in southwestern co astal British Columbia were analysed for contamination by butyltin, ph enyltin and cyclohexyltin compounds. No cyclohexyltin or phenyltin com pounds were detected, but all coastal and lower Fraser River samples c ontained tributyltin (TBT) and its metabolites dibutyltin (DBT) and mo nobutyltin (MBT). The highest concentration recorded was 314 ng g-1 TB T-Sn in Mytilus edulis collected at the mouth of the Fraser River. But yltin compounds were detected in benthic sediments collected at a wate r depth of 377 m from Ballenas Basin, Strait of Georgia. This explorat ory survey suggests that TBT is a widespread contaminant in the marine environment of southwestern B.C., and is a continuing cause for conce rn despite restrictions on the use of organotin-based marine antifouli ng paints imposed in 1989.