PCB removal from the Duwamish River estuary: implications to the management alternative for the Hudson River PCB cleanup.

The results of the Duwamish River PCB cleanup and recovery project are discussed as a basis for comparison in selecting potential management alternatives for removing PCB residues in the Hudson River. Application of the Pneuma dredge system at the Duwamish River spill site removed approximately 92% of the PCBs spilled. No significant changes in the PCB load of suspended matter and water column were observed. These results suggest that a carefully planned dredge/disposal operation can be effective in minimizing environmental impacts in the Hudson River. On the basis of observations of the Duwamish case, the existing baseline data on the distribution of PCBs in the Hudson River, and the removal alternatives and associated environmental tradeoffs, hot spot dredging is recommended as the best practical alternative.