Richland, Wash. – Amidst World War II and the Cold War, the federal government produced plutonium to fuel nuclear weapons on the U.S. Department of Energy Hanford Site. During plutonium production, some contaminants were released to the Columbia River and others to the soil at nuclear reactor sites or as unplanned spills or leaks. Contaminants migrated from soil into the groundwater and eventually discharged into the Columbia River. These discharges, known as upwellings, occur where groundwater seeps up into the river bottom in spaces between rocks and sediment. The water in these sediments is called pore water.

Beginning in 2008, Washington Closure Hanford, the Department of Energy’s river corridor contractor, selected Environmental Assessment Services to map groundwater upwelling locations and measure Hanford Site contaminants in sediment, pore water, and surface water in areas where groundwater upwelling occurred. Previous efforts to collect this information had been unsuccessful because the technology did not exist to map upwelling and collect pore water samples offshore in the Columbia’s rocky river beds and turbulent waters.

To solve this problem, Brett Tiller, EAS CEO and principal scientist, collaborated with the developer of the liquid-tip Trident probe to tailor the technology specifically for the Columbia River’s offshore waters and coarse riverbed. Tiller developed an integrated river stage-specified field deployment technique because the river’s stage (level) affects groundwater discharge patterns and contaminant concentrations. This had not been done before.

Information EAS gains from locating and characterizing groundwater upwellings in the Hanford Reach continues to foster a greater understanding of the connection between groundwater and river water. This more precise information is an important component in assessing injury to surface water, groundwater, and aquatic biota from Hanford Site operations.