The Upper Columbia River Site is currently the subject of a remedial investigation / feasibility study (RI/FS) to investigate contamination along the Upper Columbia River from the Grand Coulee Dam to the United States (U.S.)-Canada border related to historical smelting operations. The residential properties and tribal allotments are located on land that is historically and culturally significant to both the Confederated Tribes of the Colville Reservation (Colville Confederated Tribes) and the Spokane Tribe of Indians.
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As part of the RI/FS, in 2014 EPA collected and analyzed soil samples from residential properties and tribal allotments in the Columbia River valley north of Northport, WA to the U.S.-Canada border to investigate potential airborne metals contamination from a smelter located in Trail, B.C., Canada and the former LeRoi Smelter that had historically operated in Northport. A total of 74 properties along both sides of the river were sampled. At each property, EPA identified representative decision units that had high human contact with soil (i.e., yards, gardens, play areas, etc.). Once the sampling areas were identified, EPA used an incremental composite (IC) sampling approach to collect IC samples from each decision unit (“DU”). A DU is an identified area within a property that is distinguishable from other areas by factors such as location or use and include areas within a property with a high likelihood of exposure to humans from contaminated soil. Examples of decision units are play areas, gardens, or lawns. Most DUs had three IC samples collected. Each IC sample was collected from shallow surface soil (usually 0-1” deep), except gardens which went to tilling depth (usually 0-12” deep). A total of 237 DUs were sampled. Lead concentrations at fourteen residential properties and three tribal allotments exceeded site action levels.
In May 2015, the EPA Region 10 Removal Program conducted a removal site evaluation. During this removal site evaluation, EPA prepared for the proposed removal action by documenting the condition and layout at each of the 14 residential properties designated for cleanup and coordinated with each of the property owners. At some of the properties, EPA either extended the size of some DUs, or added new DUs, based on additional observations of property use and interviews with the landowners that indicated areas of the property with a high likelihood of exposure to humans from contaminated soil. EPA also collected and analyzed soil samples from the original DUs to better delineate the horizontal and vertical extent of contamination and to assist in removal planning (i.e., measuring quantities and depths of contaminated soil for logistics, disposal, and cost estimating).
Sampling conducted in 2014 and 2015 also identified three tribal allotments where lead and arsenic concentrations exceed action levels; however, this removal action does not include those three tribal allotments because the benefits of alternative removal or remedial techniques are being further evaluated for potential future cleanup actions.
In August 2015, EPA and Teck Metals Limited and Teck American Incorporated (collectively "Teck") entered into an Administrative Settlement and Order on Consent whereby Teck and its contractors will conduct a removal action on 14 residential properties, under EPA's oversight. Teck also agreed to conduct a removal action at another tribal allotment (different from the three that were previously identified) that was of particular cultural significance and currently in frequent use by CCT members.
The removal action began in August 2015 and is expected to continue until late October 2015.