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The Lower Duwamish Waterway Group (LDWG), a partnership between King County, the Port of Seattle, City of Seattle and The Boeing Company, has been actively cleaning up waterway pollution.

LDWG has invested nearly $200 million on studies and cleanup of early action areas. We are now working on the cleanup design for the upper/southern third of the waterway. View design documents .

King County’s work with LDWG so far

Additional environmental work in the Duwamish

Activated Carbon Pilot Study

The Lower Duwamish Waterway Group partners conducted a pilot study (February 2017) to determine if activated carbon, a common purifier in household water filters, traps contaminants in waterway sediments. The study was designed to see how much polychlorinated biphenyls (PCBs) and other pollutants can be prevented from entering the food chain. The pollutants are trapped by activated carbon that is mixed in a thin layer of clean material (either sand or gravely sand) and placed over existing contaminated sediments. This method, if successful, could be used in the cleanup of the Lower Duwamish Waterway