Industrial Waste Program's pollution source control work in the Lower Duwamish Waterway area

Pollutants of concern

The Industrial Waste Program is helping investigate sources of pollutants in the Lower Duwamish Waterway (LDW) sediments. Investigations have determined that these sediments contain phthalates (plasticizers) as well as polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), metals (arsenic and mercury), and other organic compounds. Understanding and controlling ongoing sources of chemicals to the waterway is very important to help minimize the potential for sediment recontamination following cleanup.

Source tracing phthalates

Phthalates, particularly bis(2-ethylhexyl)phthalate (BEHP), are chemicals of concern in the majority of the early action cleanup sites in the LDW. Sources of the chemicals include historic and contemporary industrial releases, combined sewer overflows, and urban stormwater runoff. The following paragraphs describe some interagency efforts that the Industrial Waste Program and other King County staff have participated in to understand and locate sources of phthalates, particularly those ending up in LDW sediments.

Sediment Phthalates Work Group – 2006 - 07
The cities of Tacoma and Seattle, King County, Washington Department of Ecology, and the U.S. Environmental Protection Agency worked together to better understand how phthalates are reaching Puget Sound sediments and what are the related impacts to humans and animals. The work group evaluated existing information regarding phthalate sediment concentrations, identified data gaps, recommended possible short-term actions and described possible ways to address long-term issues. Washington State Department of Ecology's Sediment Phthalates Work Group Web page contains all meeting notes and group recommendations.

Phthalate Source Study (2003 - 05)
Because the presence of phthalates in the environment is an emerging issue of national and international scope and is beyond any one agency's capability to solve, the Industrial Waste Program, other King County staff and the City of Seattle joined with the City of Tacoma in 2003 to test various commonly used products and materials to help identify the source of these chemicals. Phthalate Source Study work is reported in the following King County and Seattle Public Utilities Source Control Program for the Lower Duwamish Waterway Progress Reports.

For additional information, refer to the "Phthalate Source Study" in the following progress reports:

• June 2005 (pages 15-17; see documents and reports), Initial results of passive air deposition sampling
• January 2005 (pages 11-13; see documents and reports), Phthalate air monitoring -- sampling and analysis plan for passive air deposition sampling
• June 2004 (pages 16-20; see documents and reports), Report on products tested.

Industrial Waste Program source tracing of pollutants of concern in the LDW

• King County Atmospheric Deposition Sampling 2005-07 (PAHs; PCBs; Phthalates)
  • Report (PDF file, 2MB)
• King County Sampling 2003-06 (Phthalates; Benzyl Alcohol)
  • Article  (PDF file, 21KB)
  • Technical memorandum (PDF file, 1.9MB)
• King County International Airport Sampling 2006 (PAHs, PCBs, Phthalates, metals)
  • Report  (PDF file, 340KB)