The Oregon Department of Environmental Quality (DEQ) is proposing cleanup action for East Whitaker Pond, located within the Columbia Slough watershed.
The proposed remedial action includes a combination of soil removal, dredging of contaminated sediments and placing a thin layer of clean material across the majority of the pond.
In some locations, the clean material will include an activated carbon amendment, the Department stated.
The proposed remedial action for the sediment includes:
- Excavation and off-site disposal of soils above ecological risk based concentrations;
- Excavation and off-site disposal of sediment located in the eastern 170 feet of the pond;
- Placement of activated carbon-amended material between 170 and 800 feet from the east end of the pond to address moderate concentrations of PCBs remaining after dredging;
- Placement of a thin layer of clean material across the remainder of the pond bottom to enhance natural recovery;
- Confirmation sampling and long-term monitoring to evaluate the effectiveness of the remedial action.
Once the comment period closes on November 30, 2015, DEQ will consider any comments and select the cleanup approach for East Whitaker Pond.