Researchers involved in a study at the University of Manchester have come across a species of tiny single-cell organisms living underground that could help dispose off nuclear waste by feeding on it. Prior to this discovery, bacteria with waste-eating properties were discovered in relatively pristine soils, but this is the first time that microbes with survival capacity expected in radioactive waste disposal sites have been found.
Scientists working on soil samples from a highly alkaline industrial site in Peak District, England discovered ‘extremophile’ bacteria that have the potential to survive under alkaline conditions expected in cement-based radioactive waste. The industrial site, though, was not radioactive. Disposing off nuclear waste is very challenging. The waste has to be first encased in concrete before it could be buried in deep underground vaults. However, the real challenge begins when ground waters eventually reach these waste materials and start reacting with cement to become highly alkaline. It leads to a series of chemical reactions, triggering breakdown of various 'cellulose' based materials that are present in these complex wastes. At such a juncture, these organisms use the ‘isosaccharinic acid’ (ISA; formed during the production of nuclear power and make up the radioactive component of nuclear waste) as a source of food and energy under conditions that imitate those expected in and around intermediate level radioactive waste disposal sites.
ISA upon binding with radionuclide such as uranium becomes far more soluble and are more likely to flow out of the underground vaults to surface environments. Chances are that it could enter drinking water or even food chain. Scientists expect these organisms to naturally degrade ISA by their dietary habits.