Decision Time Coming on Duwamish Superfund Cleanup

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Duwamish River and Industrial District, 1999

The four major parties involved in completing technical studies of the cleanup program for the Duwamish Superfund site (King County, City of Seattle, Port of Seattle, and the Boeing Company) have submitted their comments on cleanup strategies to the United States Environmental Protection Agency (USEPA), which will now select a final cleanup plan.  The four parties, known as the Lower Duwamish Waterway Group (LDWG), have been implementing early action cleanup projects and conducting scientific studies for ten years.

The menu of alternatives under consideration range from extensive dredging to capping contaminated sediments and a series of mix-and-match options in between.  LDWG is recommending that EPA develop a strategy that combines the best approaches for each area of the River to meet the following three key objectives:

  • Reduce health risks to people as quickly as possible;
  • Reduce cleanup construction impacts to neighborhoods, businesses, and the environment by completing construction within 5 years;
  • Minimize uncertainty and ensure a permanent and effective cleanup.

The strategy would include:

  • Focusing on the areas with the worst contamination first;
  • Using a limited amount of dredging, only for the most contaminated areas, so that less pollution will be stirred up from the sediment;
  • Adding carbon to bottom mud, which will rapidly lower the level of contaminants in fish and shellfish;
  • Relying on “natural recovery”, allowing cleaner sediment to settle naturally in the river in areas where this might be successful, while monitoring and reserving the option of dredging such areas if this does not succeed;
  • Keeping options flexible and preserving uses, while moving as rapidly as possible in order to achieve the goal of completing major work within 5 years;
  • Accelerating several studies needed for cleanup design, so cleanup can start faster.

USEPA will now take this recommendation into account, along with input from the public, businesses, and organizations, and will decide on a proposed plan in early 2012, which will then go out for a final round of public comment.

The challenge of finding a way to clean up this busy site – with a dozen or so salmonid runs passing through every year – is extraordinary.  The cleanup elements identified by LDWG, combined with work to reduce upstream recontamination, offers a path that is innovative, rapid, and draws on experience with adaptive management to provide flexibility.  As with any plan, there will be challenges in ensuring that it meets all public objectives in the best possible manner.  There are no perfect or easy solutions for these kinds of problems.

In the interim, the LDWG partners have completed or are completing a series of early action projects that address sites that may become a threat to people or the environment before the full cleanup can be completed.    The City-led cleanup of Slip 4 is starting this October. 

The City has also entered into an innovative agreement with a company called Bluefield Holdings.  Bluefield Holdings plans to create habitat improvements in the Duwamish that can contribute to environmental restoration before, during, and after cleanup activities.  Cleaning up the pollution is one side of the problem – restoring the ecosystems is the other side, and both tasks must be accomplished in order to have the Duwamish River truly revitalized.  Bluefield Holdings finances these restoration projects, and then plans to sell the credits to those responsible for Duwamish contamination, who are also responsible for Natural Resources Damage Assessments (NRDA) settlements.  Jump-starting ecological restoration by using the flexibility and expertise of a private company is a creative complement to the cleanup work and will go a long way towards achieving our long range goals for this important natural resource.