Unlocking the bentonite microbial diversity and its implications in selenium bioreduction and biotransformation: Advances in deep geological repositories.

Selenium, Se, is one of the most critical radionuclides in radioactive waste disposed in future deep geological repositories (DGRs). Here, we investigate the impact of bentonite microbial communities on the allotropic transformation of Se(IV) bioreduction products under DGR relevant conditions. In addition, Se amendment-dependent shifts in the bentonite microbial populations are assessed.

The Bioreduction of Selenite under Anaerobic and Alkaline Conditions Analogous to Those Expected for a Deep Geological Repository System.

The environmental conditions for the planned geological disposal of radioactive waste -including hyper-alkaline pH, radiation or anoxia-are expected to be extremely harsh for microbial activity. However, it is thought that microbial communities will develop in these repositories, and this would have implications for geodisposal integrity and the control of radionuclide migration through the surrounding environment. Nuclear waste contains radioactive isotopes of selenium (Se) such as Se, which has been identified as one of the main radionuclides in a geodisposal system.