Soil and Groundwater Investigation at Historical Sawmill

TRC performed extensive environmental investigations and remedial actions at the former sawmill site in Port Gamble, Washington.

TRC conducted a Remedial Investigation/Feasibility Study (RI/FS) and implementation of the selected remedial actions in the uplands soil and groundwater at the former sawmill site. One of the upland source areas had elevated arsenic concentrations in soil and groundwater at a location adjacent to Port Gamble Bay. As part of the remedial action, TRC designed and oversaw excavation and disposal of soil with elevated arsenic concentrations. TRC also determined that groundwater with arsenic at concentrations greater than the site-specific cleanup level was affected by location-specific conditions, a reducing geochemical environment (which increases arsenic solubility), and saline matrix inference in wells close to the bay, which caused artificially elevated arsenic concentrations. TRC worked with analytical laboratories and Ecology to mitigate both matrix interference and geochemical effects and obtained approval from Ecology to use modified analytical methods for arsenic appropriate for those location-specific geochemical conditions.