Hanford and Lander Sediment Remediation Project
The Hanford and Lander Combined Sewer Overflows (CSOs) are two locations indentified under the County's Sediment Management Plan that have contaminated sediments in the vicinity of county CSOs requiring cleanup. The cleanup project at these sites involves a combination of approaches.
King County and the Port of Seattle removed 19,000 cubic yards of contaminated sediment in the vicinity of Lander CSO in 2009. The project was part of a berth deepening at Terminal 30 to allow deeper draft container vessels to use the pier. The dredged sediment was transported to a subtitle D landfill for disposal and the new sediment surface was sampled to verify that it passed state sediment standards.
The areas in the vicinity of both the Lander and Hanford CSOs are also being evaluated to determine what additional sediment remediation is necessary as part of the East Waterway Superfund project described below. Once the Superfund Cleanup is completed, the actions needed for the Hanford and Lander sediment remediation project will be complete.
East Waterway - Harbor Island Superfund Site
The East Waterway is a portion of the Harbor Island Superfund site, which the US Environmental Protection Agency (EPA) added to its Superfund list in 1983. The EPA is overseeing the cleanup which will target contamination in sediments, addressing unacceptable human health and environmental risks in the waterway.
With EPA oversight, the Port of Seattle has already removed over 200,000 cubic yards of contaminated material from the waterway. The Port and EPA are now studying the waterway to better understand the remaining contamination and risks and to develop a cleanup plan. The Port is partnering with the King County and the City of Seattle to identify the extent of the chemical contamination and the risks to human health and the environment posed by this contamination. Site investigations have included sediment and fish tissue sampling. This work resulted in a draft Supplemental Remedial Investigation report being submitted to EPA in March, 2012.
The Port, County and City will also complete a draft feasibility study (in approximately 2013) that will present various cleanup alternatives to address unacceptable human health and environmental risks. The EPA will then select a proposed cleanup plan for public review, finalize the plan and then will start the cleanup.
The Port, County and City are also undertaking source control actions in the drainage basins to identify, trace and reduce chemical inputs to the waterway. The County is also working to control the overflows from the County's Hanford and Lander CSOs.
The East Waterway flows by the east side of Harbor Island that is at the mouth of the Duwamish Waterway on the southern edge of Elliott Bay. Lead smelting, shipbuilding and maintenance, metal recycling, oil terminals and bulk fuel storage facilities, discharge of raw sewage (up until 1958), and other industrial activities contaminated the island or the waterways beside it with polychlorinated biphenyls (PCBs), metals, and other chemicals.