LOWER DUWAMISH EPA Region 10 King SITE Seattle

WASHINGTON 09 Congressional District EPA ID# WA0002329803 Other Names:

Last Update: April, 2001 Site Description

Sediments in the lower Duwamish River are contaminated with polychlorinated biphenyls (PCBs), polynuclear aromatic hydrocarbons (PAHs), phthalates, inorganics, and organotins. To address the long-term threat these contaminants pose to the human food chain and sensitive environments in the river, EPA proposed this site to the National Priorities or "Superfund" List on December 1, 2000. The Duwamish River originates at the confluence of the Green and Black Rivers near Tukwila, Washington, then flows northeast for approximately 21 kilometers, dividing at the southern end of Harbor Island to form the East and West Waterways prior to discharging into Elliot Bay at Seattle, Washington. The segment of the river down channel from Turning Basin #3 is maintained by the U.S. Army Corps of Engineers as a federal navigation channel. Most of the shoreline along the Duwamish Waterway has been developed for industrial and commercial purposes. Much of the upland area is heavily industrialized. In addition, this reach of the river receives discharges from over 100 storm drains, combined sewer overflows (CSOs), and other outfalls. Historical or current commercial and industrial operations on the waterway include cargo handling and storage; marine construction; boat manufacturing; marina operations; paper and metals fabrication; food processing; and airplane parts manufacturing. Contaminants may have entered the river via spillage during product shipping and handling, direct disposal or discharge, contaminated groundwater discharge, surface water runoff, storm water discharge, or contaminated soil erosion.

Site Responsibility: This site is being addressed through an administrative order on consent with potentially responsible parties. NPL Listing History Dates Proposed Date: 12/01/2000 Final Date: 09/13/2001 Deleted Date:

Threats and Contaminants

Media Affected: sediments A number of investigations within the Duwamish Waterway have documented sediment contamination with PCBs, PAHs, phthalates, inorganics, and organotins. In 1997, the natural resource trustees for the Duwamish River initiated an investigation to evaluate the extent and severity of PCB and polychlorinated terphenyl (PCT) contamination in the sediments of the Duwamish Waterway. In total, the trustees collected 328 sediment samples within the waterway. The analytical results for this study were compared to Washington State sediment quality standards (SQS). The major findings of the sediment characterization indicate that almost 71 of the 350 acres sampled, or just under 20 percent of the waterway, were estimated to have PCB contaminant levels that exceed the SQS. Concentrations of PCBs at many sample points in the middle portion of the waterway (north of Slip 6 and south of Slip 2) were 10 to 100 times the SQS. The report also concluded that the quantity and concentrations of PCBs found in Duwamish Waterway sediments could potentially injure natural resources.

In 1997, the King County Department of Natural Resources Wastewater Treatment Division and the Water and Land Resources Division performed a CSO Water Quality Assessment for the Duwamish River and Elliott Bay to better understand the risk to aquatic life, wildlife, and people who use the resources of the estuary. King County concluded that clear evidence of potential risks to aquatic life, wildlife, and people exists under the conditions in the estuary. Several City of Seattle or King County CSOs exist in the lower Duwamish River. Seven of these outfalls discharge 318 million gallons of raw untreated sewage annually to the lower Duwamish River.

In October 1997, The Boeing Company performed a Phase I Surface Sampling Screening to generate information that could be used as a first step in evaluating potential chemical releases to the Duwamish Waterway that could be attributable exclusively to Boeing. A total of 88 three-part composite surface (0 to 10 centimeters) sediment samples were collected at stations adjacent to Boeing facilities. Sample results indicated the presence of PCBs, mercury, and semivolatile organic compound contamination to surface sediments throughout the river segment.

In August and September 1998, consultants for EPA conducted site inspection sampling in the lower Duwamish Waterway. Sampling activities included the collection of 312 surface (0 to 10 centimeter) sediment samples and 35 subsurface (0 to 0.6 meter) sediment samples from the lower Duwamish Waterway. Surface sediment sample results documented PAH, phthalate, PCB, inorganic, and organotin contamination in the lower Duwamish Waterway. Further, subsurface sample results indicate that organic, inorganic, and organotin contamination exists up to a depth of 1.2 meters (4 feet) at some locations.

The lower Duwamish River is fished for recreational, commercial, and subsistence purposes. Three salmon hatcheries within the Green-Duwamish River system release approximately 10 million juvenile salmon each year. The Duwamish River is part of the traditional fishing grounds for the Muckleshoot and Suquamish Indian tribes.

For several species of Pacific salmon, the lower Duwamish River serves as a nursery, migratory route, and transition zone from freshwater to saltwater. Puget Sound Chinook salmon are federally listed as threatened and utilize the lower Duwamish River during a critical stage of their migration from a freshwater to a saltwater environment. The federal candidate species Coho salmon also occurs in this area, as does a nesting territory for the federally listed threatened bald eagle, and a wetland. The National Marine Fisheries Service has conducted numerous studies on the effects of contaminated sediments on biotic resources in the Duwamish River and elsewhere in Puget Sound. This research has shown that juvenile salmon from the Duwamish River exhibit reduced growth and immune system function relative to salmon from uncontaminated areas. Cleanup Progress

On December 20, 2000, EPA and Ecology signed an agreement called an administrative order on consent with four parties to investigate the nature and extent of chemical contamination in Lower Duwamish Waterway sediments. The four parties are the City of Seattle, King County, the Port of Seattle, and The Boeing Company. Under the agreement, the parties will collect existing information, evaluate potential risks to human health and the environment due to the contamination, and recommend areas that warrant early cleanup action. They will then do any necessary additional sampling, and prepare a final remedial investigation report and an evaluation of options for long-term cleanup.

The parties are compiling the data from past studies of the waterway and preparing the scoping phase human health and environmental risk assessments based on existing data. The scoping phase risk assessments should be completed in the fall of 2001. The parties will also identify candidate sites for early cleanup actions in the fall of 2001. The parties will prepare a Phase I Remedial Investigation Report and will identify areas where additional data is needed. These reports will be submitted to the agencies at the end of 2001. If EPA and Ecology agree that these proposed early action sites should be addressed separately, they will negotiate administrative orders for further study and cleanup of these sites prior to completion of the remedial investigation.

EPA and Ecology have been interviewing community members in order to prepare a community involvement plan for the site. EPA has advertised the availability of a technical assistance grant to help community groups review and disseminate information about the site to community members, and has received one grant application, which is currently under review. EPA and Ecology are also developing a source control strategy to ensure that upland sources of contamination are adequately addressed prior to sediment cleanup.

Regional Contacts SITE MANAGER(S): Allison Hiltner E-MAIL ADDRESS: [email protected] PHONE NUMBER: 206-553-2140 COMMUNITY INVOLVEMENT Cindy Schuster COORDINATOR: E-MAIL ADDRESS [email protected] PHONE NUMBER: 206-553-1815 Information pertaining to this site is housed at the following location(s): South Park Community Center 8319 Eighth Avenue South Seattle, WA 98101

EPA Region 10 Records Center 1200 Sixth Ave. Seattle, WA 98101