The New Mexico Environment Department wants the Department of Energy’s cleanup contractor at the Los Alamos National Laboratory to suspend part of its chromium plume mitigation program over concerns it might force contamination deeper underground, a federal official said last week.
The DOE, meanwhile, believes its interim approach is effective and hopes to make that case to the state of New Mexico.
In December, the state sent a letter to Michael Mikolanis, DOE’s field boss for the Office of Environmental Management, and contractor Newport News Nuclear BWXT Los Alamos (N3B), Mikolanis said Feb. 9 during a cleanup presentation. New Mexico wants a halt to injection of clean groundwater “along downgradient side of the plume” by April 1.
The state wants DOE to cease injections until one of two things occur, Mikolanis said. Either DOE completes an action plan, which could take two years, or until “we can definitely prove” through modeling and data that “our operations are not causing further migration of the plume.”
A New Mexico Environment Department spokesperson said by email Wednesday it appears the current procedure “displaces the volume of contaminated groundwater laterally and vertically.”
In recent years, DOE used interim measures “to contain the plume on laboratory land while we get a resolution in place,” Mikolanis said. This involves extracting contaminated groundwater, treating it nearby and then reinjecting the treated or clean groundwater underground. Currently the plume is about 500 feet away from the laboratory’s boundary with the Pueblo de San Ildefonso, according to DOE. The process is meant to help create a hydraulic barrier to prevent further migration of the plume.
The New Mexico Environment Department currently lacks the data required “to determine if plume migration toward Pueblo de San Ildefonso is either more or less likely with the injection operations,” the state spokesperson said. The feds will be “taking steps to fill the data gaps,” about the process, the spokesperson added.
Also, DOE has not yet provided a sufficient analysis “to explain the increasing trends in chromium concentration at the nearby monitoring wells,” the spokesperson said. Data from a monitoring well, R-45, indicates treated water “is diluting the upper portion of the aquifer and is increasing chromium concentrations deeper in the aquifer, according to the spokesperson.
The DOE believes the damage to the aquifer occurred years ago when hexavalent chromium was used to clean pipes at a Los Alamos power plant and was released into the environment. The release started around 1972 and was discovered in 2005, according to the DOE contractor.
“Water is going to move no matter what we do,” so a certain degree of plume migration is inevitable until there is a permanent fix, Mikolanis said.
“Without the ability to re-inject my ability to treat is significantly impaired,” Mikolanis said. The DOE boss hopes an “amicable” solution is reached with the state.The alternative to injection is referred to as “land application,” Mikolanis said.
According to DOE, land application would constitute consumptive use of water under state rules and requires approvals from Los Alamos County, which owns the water rights, as well as the New Mexico Office of the State Engineer.
The lab’s discharge permit with the state would only allow land application in certain locations for up to 10 daylight hours per day and not when the temperature is below-freezing, a DOE spokesperson said in a Thursday email.
This could greatly reduce the amount of chromium DOE pulls out of water, Mikolanis said, “to approximately 10% of current capacity, allowing the plume to advance downgradient,” said the DOE field office boss.
Last year DOE extracted over 100 million gallons and treated it, successfully removing 156 pounds of chromium 6 from the water. Under restrictions sought by the state, DOE would be able to remove 10 million gallons of contaminated water and remove perhaps 16 pounds of chromium, Mikolanis said.
The state agency, however, fears DOE’s approach might be making things worse. The state Environment Department “is not against the injection of treated water, however, we do not approve of the current injection locations and would require that future injection wells be constructed outside the plume boundary,” the New Mexico spokesperson said.
Not returning most of the clean water to the regional aquifer would require DOE’s Office of Environmental Management field office to secure additional approvals from the state, Los Alamos County and the National Nuclear Security Administration, which oversees the lab, Mikolanis said.
