IDAHO FALLS — A naturally occurring bacteria is being used to clean up a hazardous waste plume in the aquifer under the Idaho National Laboratory.
The plume was caused when an organic solvent called trichloroethylene, or TCE, was used to degrease machinery at the 890-square-mile federal nuclear research area in eastern Idaho.
The TCE-laden waste was then put into the ground because scientists at the time thought that soil and water would filter and dilute the chemical.
According to the U.S. Department of Energy, anywhere from 350 to 35,000 gallons of TCE were pumped into a site injection well at INL's Test Area North between 1953 and 1972.
Environmental monitors discovered TCE-contaminated groundwater in 1987. By the 1990s, the plume of polluted water had expanded to two miles with a zone of high contamination within 500 yards of the well. The chemical can damage kidneys, livers and immune systems.
Bacteria native to the underground basalt in the area is breaking down the organic solvent and turning it into harmless byproducts, scientists say. Scientists are considering other areas where the bacteria could help.
"The natural bacteria are solving the problem," Ron Crawford, a University of Idaho professor who is studying the bacteria, told the Post Register.
The DOE has plans to clean up other areas with the bacteria that can break down TCE, and use a method that makes the bacteria "breathe" TCE when oxygen is removed.
Lee Nelson is the stewardship manager for CWI, the contractor for the Department of Energy's Idaho Cleanup Project at INL.
He said that near the original injection site, scientists have been pouring a solution into the ground since 1999 that starves the bacteria of oxygen and forces them to metabolize TCE.
In that area, TCE levels have dropped from 10 parts per billion to zero, Nelson said.
Officials at the Snake River Alliance said they liked the natural TCE cleanup but were concerned about other contaminants.
"It looks like it's working," said Beatrice Brailsford, the groups program director. "But TCE is not the only contaminant of concern there."