A Little Help from Below: Naturally Occurring Microbes Ready to Lend a Hand Trapping Radioactivity Underground

Microbes living underground at the Department of Energy's Idaho National Engineering and Environmental Laboratory can do a little chemistry, which means they may be able to help researchers trap a radioactive contaminant found in the groundwater beneath the lab.

Microbes isolated from groundwater drawn at the lab site break down the compound urea through a process called urea hydrolysis, researchers from INEEL, Idaho State University, and the University of Toronto reported today at the American Geophysical Union meeting in San Francisco. The INEEL specializes in subsurface science as part of its environmental mission.

That means the naturally occurring microbes may be able to change the chemistry of the groundwater so calcite, a mineral found naturally in the rock the water flows through, will accumulate faster than normal. The growing calcite deposits will trap radioactive strontium-90 in their crystal structures.

Researchers hope to inject urea into a contaminated area and let the native microorganisms go to work breaking it down. The resulting buildup of calcite should keep the strontium-90 from spreading. The buildup will remain limited to the area around the injection well and will not interfere with groundwater flow.

"If we can trap strontium-90 in the subsurface, it's not going to keep moving with the groundwater," said INEEL microbiologist Yoshiko Fujita, who reported the results in the Hydrology: Environmental Geochemistry poster session. "We want to stop it in place."

Trapping strontium-90 underground should be cheaper and safer than extracting it, said INEEL geochemist Bob Smith who leads the project. "If you were to do some sort of treatment where you brought it to the surface, you'd have to expose workers, you'd have to ship it, you'd have to pack it," he said.

The research
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Contact: Mary Beckman
beckmt@inel.gov
208-526-0061
DOE/Idaho National Laboratory
15-Dec-1999