Geomicrobiological Redox Cycling of the Transuranic Element Neptunium

详细信息    查看全文

• 作者：Gareth T. W. Law ; Andrea Geissler ; Jonathan R. Lloyd ; Francis R. Livens ; Christopher Boothman ; James D. C. Begg ; Melissa A. Denecke ; Jrg Rothe ; Kathy Dardenne ; Ian T. Burke ; John M. Charnock ; Katherine
• 刊名：Environmental Science & Technology
• 出版年：2010
• 出版时间：December 1, 2010
• 年：2010
• 卷：44
• 期：23
• 页码：8924-8929
• 全文大小：210K
• 年卷期：v.44,no.23(December 1, 2010)
• ISSN：1520-5851

文摘

Microbial processes can affect the environmental behavior of redox sensitive radionuclides, and understanding these reactions is essential for the safe management of radioactive wastes. Neptunium, an alpha-emitting transuranic element, is of particular importance because of its long half-life, high radiotoxicity, and relatively high solubility as Np(V)O₂⁺ under oxic conditions. Here, we describe experiments to explore the biogeochemistry of Np where Np(V) was added to oxic sediment microcosms with indigenous microorganisms and anaerobically incubated. Enhanced Np removal to sediments occurred during microbially mediated metal reduction, and X-ray absorption spectroscopy showed this was due to reduction to poorly soluble Np(IV) on solids. In subsequent reoxidation experiments, sediment-associated Np(IV) was somewhat resistant to oxidative remobilization. These results demonstrate the influence of microbial processes on Np solubility and highlight the critical importance of radionuclide biogeochemistry in nuclear legacy management.