Evolution of noncrystalline uranium in lake sediments over 3,300 years

Abstract : The long-term behavior of U in contaminated soils and sediments downstream former U-mines is a widespread environmental challenge. Although reducing subsurface environments are generally considered as favorable for U immobilization, it has been shown that U is often present in the form of potentially labile non-crystalline U(IV) species in contaminated anoxic sediments [e.g. 1-3] and soils [e.g. 4-6]. The fate of such mononuclear or polymeric U(IV) species and their ability to eventually transform into less soluble minerals at the century or millennial scale remains poorly documented, which thus deserves further research to better constrain contaminated sites management.