Publication Summary

This is the quality assurance project plan for the Squalicum Harbor Tributyltin (TBT) Investigation.

Six sampling stations in Inner Squalicum Harbor will be evaluated for tributyltin (TBT) concentrations in bulk sediment and pore water. Squalicum Harbor is a small-boat marina on the Bellingham city waterfront in northwestern Washington. Previous sampling showed elevated TBT concentrations in sediment near an area used for boat maintenance activities, including bottom scraping and repainting. TBT was used as an additive in antifouling paints from the 1960s until 1990.

Effects on benthic invertebrates will be assessed at each station with respect to TBT concentrations in sediment and pore water. Invertebrate abundance and diversity in sediment samples will be evaluated and TBT tissue concentrations will be measured at stations where sufficient invertebrate biomass is collected. If insufficient biomass is collected at three or more stations, TBT concentrations will be measured in tissue of clams exposed under laboratory conditions to sediment samples collected from these stations.

Results from this study will be used by the Washington State Department of Ecology (Ecology) Sediment Management Unit, Northwest Regional Office Toxics Cleanup Program and Bellingham Field Office to make recommendations for cleanup of sediments in Inner Squalicum Harbor. The results may also be used by Ecology in developing methods for regulating TBT sediment contamination under the Washington Sediment Management Standards regulation (WAC 173-340).

Link to EIM data for User Study ID NBLA0003