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Biofilms protect nuclear waste

While biofilms can corrode metals and speed up rock dissolution, it looks like the assemblies of bacteria could actually help to protect nuclear waste. Jean-Louis Crovisier of the Centre National de Recherche in Strasbourg, France, has found that A. Thiobacillus thiooxidans bacteria can reduce the amount of elements such as strontium and caesium dissolving from nuclear glass into a solution of water in the laboratory.

Speaking at the EGU meeting, Crovisier explained that scientists who believe biofilms damage glass and concrete-based materials are finding bacteria or biofilms in holes and assuming that they have caused the hole. He reckons that’s equivalent to finding early humans living in caves and deducing that they made the cave.

The real test, according to Crovisier, is comparing changes in materials in the presence and absence of bacteria. He has found that both Pseudonomas bacteria and A. Thiobacillus thiooxidans lowered the concentration of caesium and strontium entering water from a nuclear glass, compared to sterile conditions. This indicates that the presence of a biofilm is actually protective, potentially trapping the elements.

As to whether biofilms could be used to protect nuclear waste in the field - it’s still early days. Research so far has only taken place in the laboratory and much more is needed before any application - for example, scientists would need to find out the effects of a consortium of bacteria rather than just one species at a time. The species making up a biofilm would also be likely to change over the hundreds of years that the waste remains radioactive.

Posted by Liz Kalaugher on April 23, 2009 9:02 AM | Permalink