NEW MEXICO (KRQE) – Nearly 20 years after a large chromium plume contamination was identified near Los Alamos National Laboratory, state and federal officials are still trying to figure out the best way to clean it up. Disagreement over rising levels of chromium has led to the cleanup effort being halted.
“The plume that we currently know is about a mile and a half long and about half a mile wide,” explained Resource Protection Division of the New Mexico Environment Department Director Rick Shean, “It was discovered in 2005. However, at this point, the full nature and extent hasn’t been fully determined.”
In 2016, the U.S. Department of Energy (DOE) was given a consent order to clean up the chromium plume. The nearly 160,000 pounds of chromium comes from a non-nuclear power plant at Los Alamos National Laboratory. The plant flushed contaminated water into Sandia Canyon between 1956 and 1972. The DOE reported the chromium has seeped into the ground above the aquifer.
The DOE has a plan to clean it up: “It installed five extraction wells, one treatment system, and five wells to reinject the treated water back into the aquifer,” said DOE Los Alamos Field Office Manager Michael Mikolanis. This operation to clean up the chromium began in 2018.
In that time, the DOE said the plume moved back 500 feet on the southern edge, and they’ve managed to extract 700 pounds of chromium from the ground; a drop in the bucket compared to the 160,000 pounds leaked, but progress, officials said.
However, late last year the New Mexico Environment Department (NMED) told the DOE to stop injecting the clean water back into the ground by April 1, 2023.
“We started seeing rising contaminants in one of the wells, one of the lower screens of the wells,” Shean said. The NMED is worried they were injecting clean water back into the plume, mixing it contaminated water. “This will cause problems in the future when you’re trying to design a full cleanup plan and full cleanup system in order to address all of the contamination,” Shean explained.
The NMED wants the DOE to put the clean water someplace else, but the DOE argued that will get rid of a ‘hydraulic barrier’ they’ve created as they’ve been re-injecting the clean water to keep the plume from spreading into surrounding communities. Mikolanis said, in the three months since they stopped their cleanup efforts, they’ve seen chromium levels rise again.
“Effectively, in the three and a half years we operated the well, we reduced chromium concentration by 170 parts per billion. In the last three months, the chromium in this extraction well has increased 80 parts per billion. That’s nearly half of the gains we’ve made in the past three years, and at this rate and at this trending, we will have erased completely the three and half years’ worth of work sometime in October,” Mikolanis said.
Right now, the DOE and the NMED are at an impasse of what to do. The NMED said extraction activities can continue, but the DOE stated they can’t unless they are also injecting the water somewhere else, and don’t want to do that at the risk of contaminating water elsewhere.
The interim legislative committee—the Radioactive and Hazardous Materials Committee—is encouraging both parties in the form of a letter to use a third party to resolve their technical issues and find a solution to finally clean up the plume.
Right now, this plume is not affecting the Espanola Aquifer Basin. An NMED spokesperson sent News 13 the following statement:
The hexavalent chromium plume is in the regional aquifer under the Pajarito Plateau, beneath Los Alamos National Laboratory and near the boundary with the Pueblo de San Ildefonso. The water source for Los Alamos County comes from groundwater pumped by twelve wells, which all draw on the regional aquifer beneath the Pajarito Plateau.
Although hexavalent chromium contamination is found in one part of the aquifer, the Los Alamos County supply wells are regularly sampled to ensure that contamination has not migrated to the drinking water supply. Additionally, NMED monitors a nearby groundwater monitoring well, R-35, that is located closer to the contamination plume and will detect increases in chromium concentration before reaching the nearest Los Alamos County supply well, PM-3. Chromium concentrations in the groundwater monitoring well R-35 have not increased and do not indicate there is contamination of the Los Alamos County drinking water supply.
Los Alamos County utilizes a wellhead protection program to treat the water with a disinfectant and routinely monitors the drinking water quality. The Los Alamos County Department of Public Utilities produces and distributes drinking water to more than 25,000 users in the Los Alamos townsite, White Rock, Bandelier National Monument and the Los Alamos National Laboratory.