Diagenetic formation of uranium-silica polymers in lake sediments over 3,300 years.

ABSTRACT: The long-term fate of uranium-contaminated sediments, especially downstream former mining areas, is a widespread environmental challenge. Essential for their management is the proper understanding of uranium (U) immobilization mechanisms in reducing environments. In particular, the long-term behavior of noncrystalline U(IV) species and their possible evolution to more stable phases in subsurface conditions is poorly documented, which limits our ability to predict U long-term geochemical reactivity. Here, we report direct evidence for the evolution of U speciation over 3,300 y in naturally highly U-enriched sediments (350-760 µg ⋅ g^-1 U) from Lake Nègre (Mercantour Massif, Mediterranean Alps, France) by combining U isotopic data (δ²³⁸U and (²³⁴U/²³⁸

SUBMITTER: Lefebvre P 

PROVIDER: S-EPMC7848604 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature