Bacteria Clean Up Nuclear Waste

In the search for ways to limit the dangers of nuclear waste in the past 40 years, microbial processes have always seemed a likely solution. When microbiologists first discovered microorganisms that could live in extreme alkaline environments, the idea began to spread that perhaps bacteria could be found that could withstand conditions at nuclear disposal sites. Surprisingly, many bacteria seem to thrive in the presence of high radiation levels.

One big problem is uranium's tendency to leak out of its containment repository, thanks to a reaction with isosaccharinic acid (ISA). Cellulose, which is often found in nuclear waste, can break down into ISA in the presence of an alkaline environment, which are common at waste sites. The soluble complex formed is much more likely to leak from the receptacle. Some bacteria however, use ISA as a source of carbon, keeping it from mixing with the uranium at all.

Yucca Mountain Tunnel.

Another major contamination concern is leakage due to excess hydrogen buildups. Reactions inside repositories can produce hydrogen gases which pose a danger for cracks and explosions as pressure builds.But microbes can help out here too, not only by using the excess hydrogen for their own metabolism, but also by sealing fractures and openings with biofilm layers.

Most recently, Russian scientists discovered a new bacteria in a Siberian nuclear waste storage site that shows much promise in the creation of barriers for liquid waste. The bacteria was found while performing groundwater studies at the Seversky deep radiation burial site, where waste from uranium enrichment is stored. Radionuclides like uranium and plutonium can take the place of oxygen for this species, where they are rendered insoluble and much less likely to spread.

Low-level radioactive waste storage pit, Nevada.

Hopefully these discoveries will soo be put to widespread use in deep burial sites containing liquid radioactive waste.
By adding a biological element to the physical and chemical containment models in current use, we could go a long way toward preventing ecological disaster.