State committee discuses chromium plume cleanup

-A A +A
By Tris DeRoma

A state legislative committee met with Los Alamos National Laboratory officials in Los Alamos Thursday, focusing mainly on cleaning up a decades-old hazardous waste spill on lab property.


The legislators were members of the Radioactive and Hazardous Materials Committee.

The lab is treating the ground plume, which is on an aquifer below Mortandad Canyon that is part of a regional aquifer used by Los Alamos Santa Fe and other communities.

The plume is 1,000 feet below the ground, and some has made its way into the regional aquifer below.

LANL discovered the plume in 2005, and has been installing a series of wells to define where the boundaries of the plume are, so it can be stopped and the area inside the well boundary cleaned or rendered harmless to the environment.

The chromium 6 was used as a corrosion inhibitor at a LANL power plant from the mid-‘50s to the early ‘70s. The chromium was regularly flushed out into the canyons. There is approximately 160,000 pounds of chromium in the plume.

Officials believe the plume is about 20 to 50 feet deep, and a mile long by a half a mile wide.

In a presentation to the committee, Doug Hintze, manager of the Environmental Management Los Alamos Field Office, disputed recent newspaper reports that the plume was spreading and growing in size.

Since 2004, LANL has taken measures to halt the chromium spill, which is located in an aquifer 900 to 1,000 feet below

Mortandad Canyon. Contractors for the lab have been installing a network of injection and monitoring wells within the plume and around its projected boundary to keep it from spreading into nearby San Ildefonso Pueblo and elsewhere.

The new data shows seven samples taken at the well over a two-day period in July were higher than expected. Levels of chromium ranged from 247.24 ug/L to 259 ug/L. ug/L is a unit of density, micrograms per liter. “1” ug/L means “one part per billion.” The EPA defines a part in this case as one drop of water in a billion drops of water, about what an average swimming pool contains. The acceptable state limit for chromium is 50 parts per billion. Measurements taken at the plume have ranged as high as 1,000 parts per billion.

Contractors for EM sampled a newly drilled well in July, expecting to see a low amount of chromium in the sample. Instead the sample showed chromium 6 levels five-times higher than levels allowed by the state.

“We did not do a good job in all of our discussions over the last couple of years to explain what folks would see on the maps that were modeled based on assumptions using the limited data that we have,” Hintze said. “This latest well that we drilled gave us more data.”

Sen. Carlos Cisneros wanted to know if any of the drinking water sources on San Ildefonso Pueblo were contaminated by the chromium plume. Hintze said the plume is still some distance from pueblo boundary, and that there is a large amount of hunting land starting from the pueblo boundary to the first drinking well on the pueblo. He also told Cisneros that no drinking water wells in Los Alamos County have been contaminated.

Cisneros also wanted to know how frequently the wells on the pueblo and Los Alamos County are tested for contamination.

“It’s continuous from a multitude of organizations,” Hintze said. He added that sampling is done at various times by Environmental Management the New Mexico Environment Department San Ildefonso Pueblo and Los Alamos County does sampling.

Rep. Carl Trujillo, D-46, wanted to know if the EM Office had enough federal funding devote to cleaning and stopping the spread of the plume before it damaged any water sources.

Hintze said that they receive no extra funding to remediate the plume, that it is included in their annual budget, which is $194 million every year.

Sen. Jeff Steinborn (D-36), chairman of the committee, said they will be recommending to their congressional delegation more funding for the Los Alamos EM Office to help remediate the plume more quickly.

“Because of the focus of the committee, we really wanted to key in on some of these environmental issues,” Steinborn said. “Clearly, the chromium issue is one the committee is concerned about, and feels needs more resources and need to be expanded to get our arms around the extent of this problem.”