The Department of Energy and its legacy cleanup contractor at the Los Alamos National Laboratory said Tuesday an interim groundwater pump-and-treat system to contain a hexavalent chromium plume is now fully operational.
Three extraction wells and two injection wells that came online this month are part of what DOE dubbed an “interim measure” to control the mile-long chromium plume, the agency said in a Tuesday press release. The interim setup now has five extraction and five injection wells overseen by environmental contractor Newport News Nuclear BWXT-Los Alamos (N3B).
An N3B official told the online Waste Management Symposia in March he was relieved to see the chromium plume did not grow worse during about three months during the first half of 2020 when Los Alamos operations scaled back significantly due to COVID-19 precautions.
Thus far, the interim measure has been successful in pushing the plume back about 500 feet from the laboratory’s border with the Pueblo de San Ildefonso tribal lands, according to the DOE release.
“While we have a number of environmental remediation activities underway as part of the Consent Order with NMED [New Mexico Environment Department], the effort to pull back the plume from the laboratory’s boundary with the Pueblo de San Ildefonso has been our highest Consent Order priority,” the DOE Office of Environmental Management’s federal cleanup director at Los Alamos, Cheryl Rodriguez, said in the agency release.
The chromium plume was discovered in 2005 about 1,000 feet belowground. Chromium was often used to slow corrosion at Los Alamos between the 1950s and the 1970s and was occasionally flushed from the plant’s cooling towers into Sandia Canyon, according to DOE. Over time the chromium seeped into the regional aquifer beneath Sandia and Mortandad canyons.
The DOE and its contractor expects to identify a “final remedy” for the chromium plume next year and submit it for regulatory approval, the agency recently said in a set of 10-year goals for the Environmental Management office.