TIME RESPONSE OF THE LAKE-ONTARIO ECOSYSTEM TO VIRTUAL ELIMINATION OFPCBS

This study presents the development, application, and partial validati on of an integrated time-dependent whole ecosystem environmental fate and food-chain bioaccumulation model of the time response of PCB conce ntrations in various media and organisms of Lake Ontario to changes in external PCB loadings to the lake. The model and observed PCB concent ration time trends in herring gull eggs, lake trout, sculpins, smelt, water, and sediment data are used to reconstruct the time response and PCB loading history for Lake Ontario and to assess the past and futur e time response of PCB concentrations in the Lake Ontario food web to PCB inputs. Estimates of loadings, concentrations, half-lifetimes, and changes in PCB composition over time are discussed.