Redox-active phases and radionuclide equilibrium valence state in subsurface environments – new insights from 6th EC FP IP FUNMIG

Within the 6th EC FP Integrated Project ‘‘Fundamental Processes of Radionuclide Migration’’ (FUNMIG), progress has been made to improve knowledge about the phases and reaction mechanisms involved in complex reduction processes of radionuclide contaminants in natural subsurface environments. This review paper gives an overview of the achievements made by the research groups involved in this project, and puts the scope and results of the studies in a more global context. The paper focuses on three aspects: 1) presence of green rust in subsurface groundwaters, 2) reduction of Se(IV) by Fe(II)-bearing minerals and 3) influence of bicarbonate and organic ligands on the uptake and reduction of U(VI) on Fe(II)-bearing minerals.