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Toxics Cleanup Program

Lower Duwamish Waterway
Latest Information

Ecology, the City of Seattle, King County and the EPA work continuously on source control.  Ecology posts the latest source control information on this page, including reports and updates on work underway. 

June 2017

Ecology partners with zoo to study PCBs in river otter scat, and you can help!
Ecology provided funding to Michelle Wainstein, a researcher at Woodland Park Zoo, to analyze PCBs in river otter scat (poop). Her team collected samples from West Seattle, Duwamish River, Des Moines, east of Auburn, and Black Diamond. They found higher levels of PCBs in samples collected from the Duwamish, and lower levels in samples from upstream areas. View the final report here.

The North American River Otter can serve as an indicator of the Green-Duwamish River’s health. Studying the otter population and the toxins in their scat can help us understand how contamination moves through the ecosystem. In fact, the Duwamish cleanup plan specifically includes a cleanup level for PCBs to protect river otters.

If you’d like to help with this research, sign up with the Zoo to be an “Otter Spotter”! Anyone can participate by recording observations of otters and their behavior along the length of the Green-Duwamish River.

May 2017

Duwamish River Long-term Stewardship: Request for Proposals
The Elliott Bay/Duwamish River Restoration Program is a program that oversees a natural resource damage settlement with the City of Seattle and King County. They are seeking a stewardship partner to provide habitat stewardship services for four habitat restoration sites on the Duwamish River near Seattle, Washington. Funding is available for regular inspections, maintenance activities, qualitative monitoring, adaptive management activities and community involvement on these Duwamish restoration sites. 

The first phase in the process is a request for information from interested parties to see if they are eligible for funding.  During the second phase, eligible parties submit detailed proposals. The eligibility information and proposals will be reviewed by the program members including NOAA, US Fish and Wildlife Service, Ecology, Muckleshoot Tribe, the Suquamish Tribe, City of Seattle, and King County. 

The request for proposals is available here:  The deadline for submissions of answers to Phase One eligibility questions is Thursday, July 6, 2017. For more information, please contact or

For more information about Natural Resource Damage Assessment and Restoration in Washington, visit our website at:

April 2017

New groundwater pilot studies to begin for Burlington-Environmental Georgetown site*
Starting in May, contractors working for Stericycle will study methods that would enhance the breakdown of 1,4 dioxane found in groundwater under Georgetown (east of 4th Ave). The studies will test two different below ground cleanup methods. The studies will be done along 6th Avenue South and near the intersection of Maynard Avenue South and South Lucile Street.

Questions? Contact Ed Jones, Ecology’s PSC-Georgetown site manager, with questions about these studies or other aspects of the cleanup. Email him at, or call 425-649-4449.

Learn more at our website and check out our handouts available in English, Spanish (en español), and Chinese  (用中文(表达).

*Burlington Environmental LLC, a wholly owned subsidiary of PSC Environmental Services, LLC (PSC), which is a wholly owned subsidiary of Stericycle Environmental Solutions, Inc. (Stericycle).

Ecology is sampling groundwater on cleanup sites for low levels of PCBs
Ecology’s Toxic Cleanup Program sampled groundwater and surface water for polychlorinated biphenyls (PCBs) at 14 cleanup sites in March. This is part of the larger Green-Duwamish River Watershed PCB Congener Study, to determine what types of PCBs are found and where.

In this study, we are using a method that can detect PCB congeners (specific PCB molecules) at very low levels. Previous analytical methods could not measure low enough concentrations to determine if groundwater meets water quality standards.

For more information, see the Sampling Analysis Plan (SAP) and Quality Assurance Project Plan (QAPP).

March 2017

Green-Duwamish Pollutant Loading Assessment meeting for interested parties was held March 15, 2017
For more information on the Pollutant Loading Assessment, visit

Seattle metal recycler fined $64,000 for pollution discharges to Duwamish River
Ecology fined Seattle Iron and Metals Corporation $64,000 for discharging stormwater with excessive levels of several pollutants into the Duwamish River. The company’s monitoring records showed 27 violations of pollutant limits from February 2015 through December 2016. On June 20 and 21, 2016, stormwater was allowed to bypass the treatment system, which resulted in four additional violations. Seattle Iron and Metals Corporation also failed to submit monitoring reports for the fourth quarter in 2015.  The company paid the fine.

Ecology’s water quality penalties go to the state’s Coastal Protection Fund which issues grants to public agencies and tribes for water quality restoration projects.

Site Work begins for the Georgetown Wet Weather Treatment Station
King County is beginning site demolition and soil remediation work at the home of the future Georgetown Wet Weather Treatment Station. The station will treat combined sewage and stormwater flows from the Michigan and Brandon combined sewer overflow basins.  Ecology’s Water Quality Program reviewed the plans for this project to ensure that it meets the state’s water quality laws.  Ecology is reviewing the 90% design documents for the treatment facility, conveyance system improvements, and the facility’s outfall in the Duwamish River (where treated wastewater will discharge). King County’s project website:

City of Seattle has begun testing stormwater treatment technologies at Riverside Drive as part of the South Park Water Quality project.
This stormwater treatment facility will treat runoff from the 7th Avenue storm drain basin in South Park. The project is part of Seattle’s Integrated Plan to protect Seattle’s waterways, approved by Ecology and EPA, which addresses control of combined sewer overflows (CSOs) and includes stormwater projects.

January 2017

2017 Lower Duwamish Cleanup Sites Update
Ecology is mailing an update on cleanup sites managed by our Toxics Cleanup Program in the LDW. It explains the status of each site and how these cleanups fit into Ecology’s Source Control Strategy. If you would like to receive a paper copy of such mailings in the future, contact Amy White at 425-649-7052 or

Save the Date: March 15, 2017 is the next Green-Duwamish Pollutant Loading Assessment meeting for interested parties

  • Where: Tukwila Community Center Banquet Hall, 12424 42nd Avenue South, Tukwila
  • When: 1pm to 4pm.
  • What: Update on the status of watershed model set-up and results from the PCB Congener Assessment Phase 2.

For more information on the Pollutant Loading Assessment, visit

Waste Management’s Duwamish Reload facility is ready to accept dredged sediments
Waste Management (WM) has all necessary permits to transfer contaminated soils and sediments from trucks and barges to railcars on the property known as the Crowley 8th Avenue Cleanup Site. WM has been accepting contaminated soils since October. They plan to load contaminated dredged sediments from barges to the facility in early 2017. Ecology and other local regulatory agencies will continue to inspect the facility regularly for compliance.

Byproduct PCBs Study
In November, Ecology released the second of three planned studies looking at the presence of byproduct PCBs in common consumer products, such as paper and packaging. The study looked for detectable levels of PCBs in 201 products. Read the full report, or download the focus sheet.

PCBs in Sampling Equipment
Ecology has posted a technical memo about the potential for PCB contamination from sampling equipment tubing materials. This factor should be considered when planning to conduct laboratory analyses using Method 1668 (for low-level PCB congener analyses).

Carbon Amendment Pilot Study
The Lower Duwamish Waterway Group (LDWG) is conducting an Enhanced Natural Recovery (ENR) Activated Carbon pilot study. Construction started on November 28, 2016 and is expected to complete in January 2017. 

ENR means covering contaminated sediments (river mud) with a thin layer of sand to speed up the process of natural recovery – the natural deposition of cleaner sediments to cover contaminated sediments. The goal of the pilot study is to determine whether adding activated carbon to the sand layer can reduce PCB bioavailability in sediment as part of ENR. PCB bioavailability is the amount of PCBs that can be taken up by fish and other living things in the river.

Monitoring will continue for three years following construction. For more information, see the Design Report and Quality Assurance Project Plan.

September 2016

Phase 3 Begins for USGS Green River Loading Study
The purpose of this research project is to find out how much suspended sediment and chemical pollution is coming down the river into the cleanup site. Phase 1 and 2 seem to show that the sediments coming downstream have lower levels of PCBs than previous estimates, and there is less total material coming down than other previous estimates. The Phase 3 Quality Assurance Project Plan (QAPP) has been approved. USGS will continue collection of water and suspended sediment samples at River Mile 10.8 (Foster Golf Links) until April 2017. Additionally in this phase, they will analyze the samples to estimate the concentration of PCBs dissolved in the water.

August 2016

Whitehead Tyee Agreed Order Signed
In August 2016, Ecology entered into a legal agreement called an Agreed Order (AO) with Seattle Iron & Metals Corporation and 730 Myrtle LLC (the Potentially Liable Parties or PLPs) for the site located at 730 South Myrtle Street in the Georgetown area of Seattle. Click here to view the web page for the Whitehead Tyee Cleanup Site.

Phase I Municipal Stormwater Permit Modified
Ecology’s modification to the Phase I Municipal Stormwater Permit took effect in August 2016. It includes requirements for Seattle to adaptively manage their municipal stormwater discharges to the Lower Duwamish Waterway. 

June 2016

Ecology Updates Source Control Strategy
Ecology made significant updates to their Source Control Strategy for the Lower Duwamish Waterway, which include developing a procedure to let EPA know when source control is sufficient for river cleanup to begin, and requesting Source Control Implementation Plans from other local regulatory agencies.

City of Seattle Publishes Draft Final Source Control Implementation Plan
Seattle’s Draft Final Source Control Implementation Plan describes their planned activities to control sources within their authorities over a five year period (2015-2020).  See their website for the Plan, Appendices, and Map Atlas, along with a video that highlights their source control activities.

Progress Report: USGS Green River Loading Study
The U.S. Geological Survey submitted a Progress Report and Data Tables to document the status of the project, which was suspended in autumn 2015 due to a funding shortfall.

April 2016

Green-Duwamish River Watershed PCB Congener Study: Phase 1 
Ecology published a summary of available information on PCB congeners and Aroclors, dated April 27, 2016. The report identifies important issues to consider when evaluating historical PCB congener and/or Aroclor data or when collecting new data.

March 2016

Technical Memo on Groundwater Cleanup Levels
Ecology produced a technical memorandum, revised March 1, 2016, for establishing groundwater cleanup levels for upland sites along the Lower Duwamish Waterway Waterway.

January 2016

Phase 2 Report:  USGS Green River Loading Study
Between November 2013 and March 2015, the U.S. Geological Survey collected representative samples of water, suspended sediment, or bed sediment from the Duwamish River upstream of the Superfund site. Samples were analyzed for a large suite of compounds, including metals, dioxins/furans, polycyclic aromatic hydrocarbons, pesticides, polychlorinated biphenyl (PCB) Aroclors and the 209 PCB congeners, and other chemicals. For more information see the Phase 2 Report  and its Appendices.

Older Reports

Phase 1 Report: USGS Green River Loading Study
Between February and June 2013, the U.S. Geological Survey collected representative samples of whole water, suspended sediment, and (or) bed sediment from a single strategically located site on the Duwamish River, during seven periods of different flow conditions. For more information, see the Phase 1 Report.

Stakeholders' Meeting Presentations:

This page created March 6, 2017