The Department of Energy will temporarily suspend some work to contain underground hexavalent chromium contamination at the Los Alamos National Laboratory while talks continue with New Mexico officials over the effectiveness of the treatment, officials said Wednesday night.
The agency’s local Environmental Management field office and its site cleanup contractor will halt injection of clean groundwater along certain points of the underground plume on Friday in keeping with an order from the New Mexico Environment Department, said Troy Thompson, environmental remediation program manager for contractor Newport News Nuclear BWXT Los Alamos (N3B).
By injecting the clean water into the ground, DOE intends to create a hydraulic barrier that can stop the hexavalent chromium plume from spreading. The plume has been contained 500 from the laboratory’s boundary with the Pueblo de San Ildefonso, according to DOE.
Thompson and a DOE Office of Environmental Management supervisor at Los Alamos, discussed the issue during a Wednesday briefing on compliance with a 2016 state-federal consent order on nuclear remediation around the national laboratory. During the meeting a DOE regulatory compliance program manager, Lee Bishop, declined comment on settlement talks to address a state lawsuit over the 2016 consent decree.
The state wants DOE to hold up on the freshwater injections and look at other alternatives until the New Mexico Environment Department is satisfied injections are not actually causing further migration of the underground plume.
“We have had some different technical opinions” on the effectiveness of the injections, Thompson said. “We are continuing to work through that.” The federal government says it has contained the spread of the plume, keeping it inside the laboratory grounds and 500 feet the boundary with the Pueblo de San Ildefonso.
The state and DOE have the same data but look at it differently, said Neelam Dhawan, Los Alamos program manager for the New Mexico Environment Department’s Hazardous Waste Bureau.
The state believes the extraction of the contaminated water is working, but “The injection wells are in the plume and we don’t think that is helping,” she said.
“We are talking … and we are trying to get this resolved and move forward,” Dhawan said.
DOE is scheduled to issue an annual report on the plume to the state at the end of June, according to slides the agency presented at Wednesday’s meeting.
The plume, discovered in 2005, can be traced back to the 1970s when hexavalent chromium was used to clean pipes at a Los Alamos power plant and discharged into the environment.
