Full extent of chromium plume unknown
Officials redraw contamination map, but manager says complexity of terrain, hydrology means uncertainty will persist
State lawmakers and members of the public raised concerns Friday about the future safety of Los Alamos County’s water supply after U.S. Department of Energy officials said they were still uncertain about the full extent of a plume of cancer-causing chemicals in the regional aquifer.
Since 2005, Los Alamos National Laboratory has acknowledged there is a significant concentration of hexavalent chromium, a known carcinogen, that is well above state limits pooled in the aquifer under Los Alamos as a result of decades of negligent waste disposal practices by the lab. But in recent months, a map detailing the extent of the plume has been redrawn and now shows a potentially larger circumference of contamination lying closer to a well that pumps drinking water for Los Alamos County residents and the lab.
During a legislative hearing at the Capitol on Friday, lab officials showed state lawmakers the new map, which shows the plume, previously kidney bean-shaped, as a splatter with an arm extending roughly 1,000 feet farther east. The contamination is believed to be a quarter-mile from a county well.
“There has been a history of contamination from the lab hitting the drinking water wells,” said Joni Arends, with Concerned Citizens for Nuclear Safety, referencing perchlorate contamination a decade ago. “There needs to be a contingency plan put together for when Los Alamos County or the Department of Energy will recommend when the well needs to be turned off.”
Energy Department officials said addressing the plume is among their top two priorities. And state officials said that, for now, all of Los Alamos County’s drinking water wells are in compliance with state regulations.
“We hope that is going to continue,” said Bruce Yurdin, director of the New Mexico Environment Department’s Water Protection Division, “and we will certainly be monitoring there.”
Yurdin told lawmakers on the Legislative Radioactive and Hazardous Materials Committee that the county well, called CN 3, “is the one we are
most concerned about.”
The redrawn map of the plume is dotted with question marks along the newly outlined perimeter and along the boundary between the lab and San Ildefonso Pueblo.
“Right now, there is uncertainty,” said Danny Katzman, a program manager with Los Alamos National Security LLC, the private consortium that manages the lab.
Because of the complexity of the terrain and the belowground hydrology, he said, “we had have uncertainty about the concentration in that area for a long time,” and it may never be fully understood.
Katzman said the lab will be doing testing and modeling in coming weeks.
Officials also will inject molasses and sodium dithionite into the plume, testing a technique they hope will show success at reducing the toxic chromium in the groundwater. Still, full remediation could take decades. Katzman declined to wager a completion date.
The uncertainty surrounding the plume includes questions about how much of the chromium has encroached onto tribal land considered culturally sacred to San Ildefonso people. The pueblo has a single well that does not have elevated levels of chromium. But the spread of contamination elsewhere on tribal land is unknown.
No one from San Ildefonso was present at Friday’s hearing.
After hearing about the complexity of the cleanup, state Rep. Stephanie Garcia Richard, D-Los Alamos, said, “I am more nervous than I was before.”
The lab should have informed the community when high levels were detected, she added, but instead she learned about it first in the newspaper.
In the last decade, the lab has drilled roughly a dozen wells in the area where the contamination was expected to be. They were to be used in monitoring the plume and beginning a “pump-and-treat” process of injecting clean water into the perimeter of the contamination to try to prevent it from spreading.
The altered shape and potential spread of the plume was only discovered after the lab drilled a new well earlier this year, which it had believed to be well outside the scope of contamination. But sampling taken in July revealed the well had 270 parts per billion of chromium, more than five times the state limit of 50 parts per billion. Inside the plume, the concentration is significantly higher.
This is because, until the 1970s, coolant from the lab’s power plant, laced with hexavalent chromium, was dumped into canyons by lab workers.
Butch Tongate, secretary of the New Mexico Environment Department, told lawmakers the state was working with the lab on the cleanup and would not require it to drill new wells at this time around the area of the plume.
That spurred criticism from Jay Coghlan, director of the nonprofit Nuclear Watch New Mexico and a long-standing critic of the lab. Coghlan said he was disappointed to hear the secretary say that “there is no urgent requirement to put in new monitoring wells in the near future.”
Outside the hearing room, Tongate accused Coghlan of profiting from his criticism of environmental failures at the lab.
“We think you are in a mode — I would call it a collaborationist — with Los Alamos,” Coghlan fired back, “which we don’t like.”
“Well, I would call it cooperative,” Tongate said of his agency’s relationship with the lab. “I don’t see any benefit in being adversarial,” he said, “the way it was” under the previous administration.