Bacteria a potential threat to nuclear waste repositories

By interacting with the radioactive waste and the materials used to contain it, underground microorganisms may affect the safety of nuclear waste repositories, for better or for worse. Underground, time appears to stand still. That is one of the reasons why deep geological formations are considered the safest place to dispose of nuclear waste. But now, scientists are finding out that human activities such as the excavation of tunnels can lead to a blooming of underground bacterial activity. In an ongoing research project, scientists from EPFL are cataloguing subterranean microbial life and studying its potential to affect the performance of the protective barriers - canisters, concrete and adjacent rock - that are used to contain nuclear waste. Knowing what bacteria are present at such depths, what chemical transformations they are capable of, and even how they might evolve, have to be considered to assess the long-term safety of potential waste disposal sites. "We will use DNA sequencing and bio-informatics to identify the microbes trapped in the rock," explains Rizlan Bernier-Latmani, head of EPFL's Environmental Microbiology Laboratory and director of the project.