About Us

Sediment Phthalates Work Group

What are "phthalates"?

Phthalates (“thal-ates”) are pollutants found in our air, soil, and water. Phthalates are plasticizers used widely in consumer products such as cosmetics, vinyl flooring, children’s toys, flexible plastics, lubricants, and adhesives. Each chemical has different characteristics and potential effects.

Why are we concerned about phthalates in sediments?


We have several concerns about phthalates. For example:

  • Sediments in urban areas of Puget Sound frequently contain phthalates above the Washington Department of Ecology cleanup levels, which are set to protect aquatic organisms.
  • Research shows phthalates wind up in marine sediments and can cause harm to organisms that live there.
  • Phthalates are pervasive in the environment because they are contained in hundreds of common products found in everyday life.
  • Phthalates enter waters through many ways, so identifying precise sources of contamination is difficult.
  • We know little about how to control or treat phthalate contamination.

What's being done?

The cities of Tacoma and Seattle, King County, Washington Department of Ecology, and U.S. Environmental Protection Agency are working together to better understand how phthalates are reaching Puget Sound sediments and what are the related impacts to humans and animals. A work group has been voluntarily created with representatives from each public agency. The work group recognizes the challenges that municipal governments face regarding phthalates in sediments at important cleanup sites such as the Thea Foss Waterway and Lower Duwamish River. The group also will study the occurrence of phthalates in other areas of Puget Sound.

Work group goals

The work group is starting to evaluate existing information regarding phthalate sediment concentrations, identify data gaps, and recommend possible short-term actions. They also will describe possible ways to address long-term issues such as:

  • Defining phthalate concerns within current regulations.
  • Placing sediment phthalate concerns in perspective with other sediment contamination risks and within the broader issue of phthalate risks from all exposure pathways.
  • Documenting where phthalates occur and identify potential sources.
  • Identifying source control and treatment options.
  • Examining data collected by work group members and providing recommendations on next steps.
  • Sharing findings with the public.

Information sharing and outreach

The work group will develop public messages and recommendations using a collaborative approach in which ideas are shared openly. During 2007, the work group anticipates presenting draft recommendations to stakeholders for review and comment. Work group members also will use existing community and stakeholder forums to discuss the group’s process and receive feedback.

Work group recommendations

The work group intends to develop recommendations to address phthalate sediment contamination for regulatory agencies and the community to consider. However, any regulatory decisions will be made by state and federal agencies. Possible types of recommendations may include:
  • Further study to fill any key information gaps.
  • Source identification and control measures applicable to Puget Sound.
  • How to address uncertainty and risks due to potential for phthalate contamination following cleanups.
  • Policy and regulatory changes to address human health and environmental risks from sediment phthalate contamination.