Selenate reduction in environmental geomedia

Long-term safety assessment of the underground repository for the high-level and long-lived radioactive waste requires a characterization at the molecular level of the processes that can take place onto the involved solid surfaces and the considered radioactive pollutants. Among them, the 79Se isotope (∼3.27 × 105 years half-life time) is considered as one of the main radionuclides contributing to the dose-to-man after final disposal. Reductive precipitation of oxidized (mobile) species of selenium by redox-active Fe(II)-phases is one of the main mechanisms that can help to decrease the mobility of selenium in these systems. Here, we aim to check whether the presence of sulfate and carbonate, two common ions in the clayey formation hosting the French repository, pose some limitations for the electron transfer from the Fe(II)-bearing solids magnetite (a common corrosion product of steel canisters) and pyrite (a common Fe(II)-solid in the Cox formation).