Washington, Sep 9 (IANS) The Lost Orphan Mine below the Grand Canyon hasn’t produced uranium since the sixties, but radioactive residue still contaminates the area. Now a study is examining how sulphate-reducing bacteria can convert radioactive metal to inert substances.
Cleaning the region takes an expensive process that is only done in extreme cases, but Judy Wall of the University of Missouri (U-M) College of Agriculture, is studying bacteria that are bio-corrosives and can change the solubility of heavy metals.

Wall, a bio-chemistry professor, and researchers from the Lawrence Berkley National Lab in California are investigating the bacterium’s basic genetics and hope to determine its growth limits and activity in natural settings, including how to make its interactions with metals sustainable.

They have already identified a few genes that are critical to converting uranium. They can take uranium and convert it to uraninite, a nearly insoluble substance that will sink to the bottom of a lake or stream.

Wall is looking into the bacteria’s water cleansing ability and how long the changed material would remain inert.

The research could also be beneficial to heavy metal pollution from storage tanks and industrial waste. The bacteria are already present in more than 7,000 heavy metal contaminated sites, but they live in a specific range of oxygen and temperature, making them difficult to control.

“Our research must be done in the absence of air,” Wall said. “Obviously, none but the most committed - and stubborn - will work with them.”

Even if an oxygen-tolerant strain were developed, there are still multiple factors that would make applying the bacteria challenging, and these microbes can contribute to massive iron corrosion, according to an university release.

“Knowledge of the way bacteria live in the environment, in microbial communities, is still in its infancy,” Wall said. “We just don’t know a lot about the communication systems among microbes.”

Wall’s research has been published in Applied and Environmental Microbiology, Nucleic Acids Research and Environmental Microbiology.