Puget Sound Regional Toxics Model: Evaluation of PCBs, PBDEs, PAHs, Copper, Lead, and Zinc

The PSRTM is a model of contaminant fate, transport, and bioaccumulation in Puget Sound. We found that sediments are a major sink for toxic contaminants in Puget Sound. In this study, Ecology (1) incorporated recent data and loading estimates and (2) expanded the model to simulate PCBs, PBDEs, PAHs, copper, lead, and zinc. Fate and transport modeling results suggested that current estimates of contaminant loading from the watershed, the ocean, or both, may be too low. Such uncertainties limited the utility of the model for evaluating contaminant source-control strategies. The updated bioaccumulation model had good skill for predicting PCB and PBDE concentrations in Puget Sound biota. The model identified areas where organisms would be expected to bioaccumulate contaminants to harmful levels, and then estimated how low sediment and water concentrations would need to be at these locations to ensure that contaminants in biota do not exceed harmful-effects thresholds