LONG-TERM SIMULATION OF PCB EXPORT FROM THE FOX-RIVER TO GREEN-BAY

A mass balance approach was used to model long-term PCB transport in t he Fox River (Wisconsin) from Lake Winnebago to Green Bay. The objecti ves of this research were to (1) extend the modeling approach for the Fox River to permit realistic long-term simulations of contaminant tra nsport and fate, (2) forecast long-term PCB export from the Fox River to Green Bay, and (3) develop a rational approach for evaluating sedim ent remediation alternatives. Field data collected as part of the Gree n Bay Mass Balance Study during 1988-90 and additional data collected by the Wisconsin Department of Natural Resources and the U.S. Geologic al Survey during 1992-93 were used to develop the model. A 10-year hin dcast was conducted to confirm long-term model predictions. A series o f 25-year forecasts were then. conducted to explore the potential effe cts of hydrograph structure, extremely high flows, and sediment remedi ation on long-term PCB export from the Fox River to Green Bay. PCB exp ort from the Fox River is forecast to decrease, and most (75%) of the PCB reservoir in Fox River sediment is expected to remain in place. Ho wever, extremely high flows in future years are forecast to cause sign ificant PCB resuspension and export. Model forecasts suggest that long -term PCB export is only mildly sensitive to changes in hydrograph str ucture. Sediment remediation is forecast to reduce but not eliminate P CB export.