EXTENSIVE BUTYLTIN CONTAMINATION IN SOUTHWESTERN COASTAL BRITISH-COLUMBIA, CANADA

Fish, shellfish, and sediment samples from 10 sites in southwestern coastal British Columbia were analysed for contamination by butyltin, phenyltin and cyclohexyltin compounds. No cyclohexyltin or phenyltin compounds were detected, but all coastal and lower Fraser River samples contained tributyltin (TBT) and its metabolites dibutyltin (DBT) and monobutyltin (MBT). The highest concentration recorded was 314 ng g-1 TBT-Sn in Mytilus edulis collected at the mouth of the Fraser River. Butyltin compounds were detected in benthic sediments collected at a water depth of 377 m from Ballenas Basin, Strait of Georgia. This exploratory survey suggests that TBT is a widespread contaminant in the marine environment of southwestern B.C., and is a continuing cause for concern despite restrictions on the use of organotin-based marine antifouling paints imposed in 1989.