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Microbially mediated reduction of Np(V) by a consortium of alkaline tolerant Fe(III)-reducing bacteria

Published online by Cambridge University Press:  02 January 2018

Adam J. Williamson ,
Katherine Morris ,
Christopher Boothman ,
Kathy Dardenne ,
Gareth T.W. Law  and
Jonathan R. Lloyd
Adam J. Williamson
Affiliation:
Research Centre for Radwaste Disposal andWilliamson Research Centre forMolecular Environmental Science, School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK
Katherine Morris
Affiliation:
Research Centre for Radwaste Disposal andWilliamson Research Centre forMolecular Environmental Science, School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK
Christopher Boothman
Affiliation:
Research Centre for Radwaste Disposal andWilliamson Research Centre forMolecular Environmental Science, School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK
Kathy Dardenne
Affiliation:
Karlsruhe Institute of Technology, Institut für Nukleare Entsorgung. D-76021-Karlsruhe, Germany
Gareth T.W. Law
Affiliation:
Centre for Radiochemistry Research and Research Centre for Radwaste Disposal, School of Chemistry, The University of Manchester, Manchester M13 9PL, UK
Jonathan R. Lloyd*
Affiliation:
Research Centre for Radwaste Disposal andWilliamson Research Centre forMolecular Environmental Science, School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK
*
*E-mail: [email protected]
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Abstract

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Neptunium-237 will be present in radioactive wastes over extended time periods due to its long half-life (2.13 × 106 years). Understanding its behaviour under conditions relevant to radioactive waste disposal is therefore of particular importance. Here, microcosm experiments were established using sediments from a legacy lime workings with high-pH conditions as an analogue of cementitious intermediate-level radioactive waste disposal. To probe the influence of Fe biogeochemistry on Np(V) in these systems, additional Fe(III) (as ferrihydrite) was added to select experiments. Biogeochemical changes were tracked in experiments with low levels of Np(V) (20 Bq ml–1; 3.3 μM), whilst parallel higher concentration systems (2.5 KBq ml–1; 414 μM) allowed X-ray absorption spectroscopy. As expected, microbial reduction processes developed in microbially-active systems with an initial pH of 10; however, during microbial incubations the pH dropped from 10 to ∼7, reflecting the high levels of microbial metabolism occurring in these systems. In microbially-active systems without added Fe(III), 90% sorption of Np(V) occurred within one hour with essentially complete removal by one day. In the ferrihydrite-amended systems, complete sorption of Np(V) to ferrihydrite occurred within one hour. For higher-activity sediments, X-ray absorption spectroscopy (XAS) at end points where Fe(II) ingrowth was observed confirmed that complete reductive precipitation of Np(V) to Np(IV) had occurred under similar conditions to low-level Np experiments. Finally, pre-reduced, Fe(III)-reducing sediments, with and without added Fe(III) and held at pH 10, were spiked with Np(V). These alkaline pre-reduced sediments showed significant removal of Np to sediments, and XAS confirmed partial reduction to Np(IV) with the no Fe system, and essentially complete reduction to Np(IV) in the Fe(III)-enriched systems. This suggested an indirect, Fe(II)-mediated pathway for Np(V) reduction under alkaline conditions. Microbial analyses using 16S rRNA gene pyrosequencing suggested a role for alkali-tolerant, Gram-positive Firmicutes in coupled Fe(III) reduction and Np immobilization in these experiments.

Keywords

bioreductionNp(V) reductionintermediate-level wastebiomineralizationactinide biogeochemistry
Type
Research Article
Information
Mineralogical Magazine , Volume 79 , Issue 6 , November 2015 , pp. 1287 - 1295
Creative Commons
Creative Common License - CCCreative Common License - BY
Copyright © The Mineralogical Society of Great Britain and Ireland 2015. This is an open access article, distributed under the terms of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2015

References

Bassil, N.M., Bryan, N. and Lloyd, J.R. (2014) Microbial degradation of isosaccharinic acid at high pH. The ISME Journal, 1-11.Google Scholar
Bassil, N.M., Bewsher, A.D., Thompson, O.R. and Lloyd, J.R. (2015) Microbial degradation of cellulosic material under ILW-simulated conditions. Mineralogical Magazine, 79, DOI: 10.1180/minmag.2015.079.6.18.CrossRefGoogle Scholar
Clark, D.L., Conradson, S.D., Ekberg, S.A., Hess, N.J., Neu, M.P., Palmer, P.D., Runde, W. and Tait, C.D. (1996) EXAFS studies of pentavalent neptunium carbonato complexes. Structural elucidation of the principal constituents of neptunium in groundwater environments. Journal of the American Chemical Society, 118, 2089–2090.CrossRefGoogle Scholar
Combes, J.-M., Chisholme-Brause, Catherine, J., Brown Jr, G.E., Parks, G.A., Conradson, S.D., Eller, P.G., Trlay, I.R., Hobart, D.E. and Meljer, A. (1992) EXAFS spectroscopic study of neptunium(V) sorption at the α-FeOOH water interface. Environmental Science & Technology, 26, 376–382.CrossRefGoogle Scholar
Daims, H., Brühl, A., Amann, R., Schleifer, K.H. and Wagner, M. (1999) The domain-specific probe EUB338 is insufficient for the detection of all bacteria: development and evaluation of a more comprehensive probe set. Systematic and Applied Microbiology, 22, 434–4.CrossRefGoogle ScholarPubMed
Girvin, D.C., Ames, L.L., Schwab, A.P. andMcGarrah, J.E. (1991) Neptunium adsorption on synthetic amorphous iron oxyhydroxide. Journal of Colloid and Interface Science, 141, 67–78.CrossRefGoogle Scholar
Gorman-Lewis, D., Jensen, M.P., Harrold, Z.R. and Hertel, M.R. (2013) Complexation of neptunium(V) with Bacillus subtilis endo spore surfaces and their exudates. Chemical Geology, 341, 75–83.CrossRefGoogle Scholar
Hennig, C. (2007) Evidence for double-electron excita-tions in the L3-edge X-ray absorption spectra of actinides. Physical Review B, 75, 1–7.CrossRefGoogle Scholar
Kaszuba, J.P. and Runde, W.H. (1999) The aqueous geochemistry of neptunium: Dynamic control of soluble concentrations with applications to nuclear waste disposal. Environmental Science & Technology, 33, 4427–4433.CrossRefGoogle Scholar
Lane, D.J. (1991) 16S/23S rRNA sequencing. Pp. 115-175 in: Nucleic Acid Techniques in Bacterial Systematics (E. Stackebrandt and M. Goodfellow, editors). New York: John Wiley and Sons.Google Scholar
Law, G.T.W., Geissler, A., Lloyd, J.R., Livens, F.R., Boothman, C., Begg, J.D.C., Denecke, M.A., Rothe, J., Dardenne, K., Burke, I.T., Charnock, J.M. and Morris, K. (2010) Geomicrobiological redox cycling of the transuranic element neptunium. Environmental Science & Technology, 44, 8924–8929.CrossRefGoogle ScholarPubMed
Lin, B., Hyacinthe, C., Bonneville, S., Braster, M., Van Cappellen, P. and Röling, W.F.M. (2007) Phylogenetic and physiological diversity of dissimilatory ferric iron reducers in sediments of the polluted Scheldt estuary, northwest Europe. Environmental Microbiology, 9, 1956–68.CrossRefGoogle ScholarPubMed
Lloyd, J. and Renshaw, J. (2005) Microbial transformations of radionuclides: fundamental mechanisms and biogeochemical implications. Pp. 205–240 in: Metal Ions in Biological Systems (A. Siegal and R.K.O. Siegal, editors). New York: M. Dekker.Google Scholar
Lloyd, J.R., Yong, P. and Macaskie, L.E. (2000) Biological reduction and removal of Np(V) by two microorganisms. Environmental Science & Technology, 34, 1297–1301.CrossRefGoogle Scholar
Lovley, D.R. and Phillips, E.J. (1987) Rapid assay for microbially reducible ferric iron in aquatic sediments. Applied and Environmental Microbiology, 53, 1536–1540.CrossRefGoogle ScholarPubMed
Ravel, B. and Newville, M. (2005) ATHENA, ARTEMIS, HEPHAESTUS: data analysis for X-ray absorption spectroscopy using IFEFFIT. Journal of Synchrotron Radiation, 12, 537–541.CrossRefGoogle ScholarPubMed
Reed, D.T., Deo, R.P. and Rittmann, B.E. (2010) Subsurface interactions of actinide species with microorganisms. Pp. 3595-3663 in: Chemistry of the Actinides, 4th edition (L.R. Morse, N.M. Edelstein and J. Fuger, editors) Netherlands, Springer.Google Scholar
Renshaw, J.C., Butchins, L.J.C., Livens, F.R., May, I., Charnock, J.M. and Lloyd, J.R. (2005) Bioreduction of uranium: environmental implications of a pentavalent intermediate. Environmental Science & Technology, 39, 5657–5660.CrossRefGoogle ScholarPubMed
Rizoulis, A., Steele, H.M., Morris, K. and Lloyd, J.R. (2012) The potential impact of anaerobic microbial metabolism during the geological disposal of inter-mediate-level waste. Mineralogical Magazine, 76, 3261–3270.CrossRefGoogle Scholar
Rossberg, A., Scheinost, A.C., Schmeisser, N., Rothe, J., Kaden, P., Schild, D., Wiss, T and Daehn, R. (2014) AcReDaS, an Actinide Reference Database for XAS, EELS, IR, Raman and NMR Spectroscopy. Available at: https://www.hzdr.de/acredas.Google Scholar
Songkasiri, W., Reed, D.T and Rittmann, B.E. (2002) Bio-sorption of neptunium (V) by Pseudomonas fluorescens. Radiochimica Acta, 90, 785–789.Google Scholar
Williamson, A.J., Morris, K., Shaw, S., Byrne, J.M., Boothman, C. and Lloyd, J.R. (2013) Microbial reduction of Fe(III) under alkaline conditions relevant to geological disposal. Applied and Environmental Microbiology, 79, 3320–3326.CrossRefGoogle ScholarPubMed
Williamson, A.J., Morris, K., Charnock, J.M., Law, G.T. W, Rizouliz, A. and Lloyd, J.R. (2014) Microbial reduction of U(VI) under alkaline conditions; implications for radioactive watse disposal. Environmental Science & Technology, 48, 13549–13556.CrossRefGoogle Scholar