Smeaton,C.M., Weisener,C.G., Burns,P.C., Fryer,B.J. and Fowle,D.A.(2008): Bacterially enhanced dissolution of meta-autunite. American Mineralogist, 93, 1858-1864.

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wAbstract
@The release of U from the mineral meta-autunite {Ca[(UO2)(PO2)](H2O)6} was evaluated using spectroscopy, aqueous geochemistry, and electron microscopy in a minimal media with the dissimilatory metal-reducing bacterium Shewanella putrefaciens 200R. The onset of anaerobic conditions resulted in the rapid release of U and phosphate to solution followed by the reprecipitation of meta-autunite. Spectroscopy measurements (XANES) indicated that the U was not released via reduction during the bacterial incubations, but instead dissolution was promoted by uptake and immobilization of P by the bacterial cells.Our results suggest that U(VI) in grefractoryh P mineral phases may be mobilized from U mill tailings and/or U disposal sites and that the nutrient status (P) of the geologic setting may be a predictor for the lability of U in these environments.

Keywords: Uranium; autunite; phosphate; Shewanella putrefaciens; weathering; XANESx

Introduction
Materials and methods
@Mineral preparation
@Bacteria and cultivation methods
@Experimental and sampling methods
@Solid phase characterization
@XANES experiments
Results and discussion
Acknowledgments
References cited



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