Oxidative dissolution of biogenic uraninite in groundwater at Old Rifle, CO

Kate M. Campbell; Harish Veeramani; Kai-Uwe Ulrich; Lisa Y. Blue; Dianiel E. Giammar; Rizlan Bernier-Latmani; Joanne E. Stubbs; Elena Suvorova; Steve Yabusaki; Juan S. Lezama-Pacheco; Apurva Mehta; Philip E. Long; John R. Bargar

doi:10.1021/es200482f

USGS · 70006304

Oxidative dissolution of biogenic uraninite in groundwater at Old Rifle, CO

Kate M. Campbell·Harish Veeramani·Kai-Uwe Ulrich·Lisa Y. Blue·Dianiel E. Giammar·Rizlan Bernier-Latmani·Joanne E. Stubbs·Elena Suvorova·Steve Yabusaki·Juan S. Lezama-Pacheco·Apurva Mehta·Philip E. Long·John R. Bargar

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Abstract

Reductive bioremediation is currently being explored as a possible strategy for uranium-contaminated aquifers such as the Old Rifle site (Colorado). The stability of U(IV) phases under oxidizing conditions is key to the performance of this procedure. An in situ method was developed to study oxidative dissolution of biogenic uraninite (UO 2 ), a desirable U(VI) bioreduction product, in the Old Rifle, CO, aquifer under different variable oxygen conditions. Overall uranium loss rates were 50–100 times slower than laboratory rates. After accounting for molecular diffusion through the sample holders, a reactive transport model using laboratory dissolution rates was able to predict overall uranium loss. The presence of biomass further retarded diffusion and oxidation rates. These results confirm the importance of diffusion in controlling in-aquifer U(IV) oxidation rates. Upon retrieval, uraninite was found to be free of U(VI), indicating dissolution occurred via oxidation and removal of surface atoms. Interaction of groundwater solutes such as Ca 2+ or silicate with uraninite surfaces also may retard in-aquifer U loss rates. These results indicate that the prolonged stability of U(IV) species in aquifers is strongly influenced by permeability, the presence of bacterial cells and cell exudates, and groundwater geochemistry.

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Environmental Science & Technology Article

Source-reported bounding extent: 39.36137794996196° to 39.68076911511416° latitude; -108.05259704589842° to -107.49229431152342° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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Kate M. Campbell, Harish Veeramani, Kai-Uwe Ulrich, Lisa Y. Blue, Dianiel E. Giammar, Rizlan Bernier-Latmani, Joanne E. Stubbs, Elena Suvorova, Steve Yabusaki, Juan S. Lezama-Pacheco, Apurva Mehta, Philip E. Long, John R. Bargar. 2011-09-27. Oxidative dissolution of biogenic uraninite in groundwater at Old Rifle, CO. https://doi.org/10.1021/es200482f

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