Discovered Microbes Could Help Dispose of Nuclear Waste

Researchers have recently stumbled upon tiny single-celled organisms living underground that could aid in the disposal of radioactive waste, potentially making "green" power plants that are more viable and less harmful to the environment.

While nuclear power plants themselves have always been valued for their extreme efficiency and relatively "green" nature - with little need for fossil fuels or the release of greenhouse gases - the disposal of their dangerous waste has always been a daunting challenge.

It was suggested back in March at the National Meeting of the American Chemical Society that shale and other clay-rich rocks could be used for long-term storage of spent nuclear fuel without much risk of the contaminant spreading. In fact, it would take millions of years for radionuclides to diffuse through shale.

Now researchers at the University of Manchester suggest a way to ensure the safety of a bury-and-forget approach to waste disposal.

Studying solid soil that suffer from severe contamination with highly alkaline lime-kiln wastes, the researchers discovered a specialist "extremophile" bacterium that thrives in these dangerous environments.

Today, nuclear waste is traditionally stored in miles of concrete. However, when groundwater eventually reaches these materials, they react with the surrounding cement and become very alkaline. Resulting chemical reactions also create isosaccharinic acid (ISA) as a product - worrisome acids that can help the radioactive components of the waste escape by becoming more soluble.

However, in the presence of the extremophiles, this could never happen. That's because the bacteria actually use the ISA as a source of food, breaking it down for energy, and stopping its dangerous reactions in their tracks.

Stunningly, this appears to have been a natural adaptation of the organisms, who acclimated themselves to what was thought to be inhabitable conditions.

"We are very interested in these... microorganisms," environmental expert and researcher Jonathan Lloyd said in a statement. "Given that they must have evolved to thrive at the highly alkaline lime-kiln site in only a few decades, it is highly likely that similar bacteria will behave in the same way and adapt to living off ISA in and around buried cement-based nuclear waste quite quickly."

He adds that because waste is expected to be stored underground for thousands of years, these microbes have time to adapt further, potentially even affecting radioactive materials themselves.

These observations were published in The ISME Journal earlier this year.