Developing ecosystem based sediment quality guidelines in British Columbia

Sediment Quality Guidelines (SQG) that do not account for biomagnification of chemicals in marine food chains, may be insufficiently protective of upper trophic level organisms. Biota-Sediment Accumulation Factors (BSAF=Cbiota/Csediment) quantify the relationship between concentrations in organisms and the sediment and can be applied to derive SQGs that account for biomagnification. PCB data for four sites on the B.C. coast were used to derive BSAFs. BSAF were used to assess risks to upper trophic level populations from current SQG and to derive new SQG. Bioaccumulation modeling derived BSAFs for additional species and human health risk assessment. Applying BSAFs shows that current guidelines fail to protect Orca whale, Steller sea lion and harbor seal populations or human health. SQGs back-calculated from relevant endpoints for human health, marine mammal, birds and salmon population health were all under 1 μg/kg dw – substantially lower than the current B.C. SQG of 20 μg/kg dw.