Microbial Reduction of U(VI) under Alkaline Conditions: Implications for Radioactive Waste Geodisposal.
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| Title: | Microbial Reduction of U(VI) under Alkaline Conditions: Implications for Radioactive Waste Geodisposal. |
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| Authors: | Williamson, Adam J.1, Morris, Katherine1, Law, Gareth T. W.2, Rizoulis, Athanasios1, Charnock, John M.1, Lloyd, Jonathan R.1 jon.lloyd@manchester.ac.uk |
| Source: | Environmental Science & Technology. 11/18/2014, Vol. 48 Issue 22, p13549-13556. 8p. |
| Subjects: | Radioactive waste disposal, Chemical reduction, Microorganisms, Uranium, Chemical speciation, Biogeochemistry, Nitrates, Iron |
| Abstract: | Although there is consensus that microorganisms significantly influence uranium speciation and mobility in the subsurface under circumneutral conditions, microbiologically mediated U(VI) redox cycling under alkaline conditions relevant to the geological disposal of cementitious intermediate level radioactive waste, remains unexplored. Here, we describe microcosm experiments that investigate the biogeochemical fate of U(VI) at pH 10-10.5, using sediments from a legacy lime working site, stimulated with an added electron donor, and incubated in the presence and absence of added Fe(III) as ferrihydrite. In systems without added Fe(III), partial U(VI) reduction occurred, forming a U(IV)-bearing non-uraninite phase which underwent reoxidation in the presence of air (O2) and to some extent nitrate. By contrast, in the presence of added Fe(III), U(VI) was first removed from solution by sorption to the Fe(III) mineral, followed by bioreduction and (bio)magnetite formation coupled to formation of a complex U(IV)-bearing phase with uraninite present, which also underwent air (O2) and partial nitrate reoxidation. 16S rRNA gene pyrosequencing showed that Gram-positive bacteria affiliated with the Firmicutes and Bacteroidetes dominated in the post-reduction sediments. These data provide the first insights into uranium biogeochemistry at high pH and have significant implications for the long-term fate of uranium in geological disposal in both engineered barrier systems and the alkaline, chemically disturbed geosphere. [ABSTRACT FROM AUTHOR] |
| Copyright of Environmental Science & Technology is the property of American Chemical Society and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 100679345 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Microbial Reduction of U(VI) under Alkaline Conditions: Implications for Radioactive Waste Geodisposal. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Williamson%2C+Adam+J%2E%22">Williamson, Adam J.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Morris%2C+Katherine%22">Morris, Katherine</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Law%2C+Gareth+T%2E+W%2E%22">Law, Gareth T. W.</searchLink><relatesTo>2</relatesTo><br /><searchLink fieldCode="AR" term="%22Rizoulis%2C+Athanasios%22">Rizoulis, Athanasios</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Charnock%2C+John+M%2E%22">Charnock, John M.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Lloyd%2C+Jonathan+R%2E%22">Lloyd, Jonathan R.</searchLink><relatesTo>1</relatesTo><i> jon.lloyd@manchester.ac.uk</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Environmental+Science+%26+Technology%22">Environmental Science & Technology</searchLink>. 11/18/2014, Vol. 48 Issue 22, p13549-13556. 8p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Radioactive+waste+disposal%22">Radioactive waste disposal</searchLink><br /><searchLink fieldCode="DE" term="%22Chemical+reduction%22">Chemical reduction</searchLink><br /><searchLink fieldCode="DE" term="%22Microorganisms%22">Microorganisms</searchLink><br /><searchLink fieldCode="DE" term="%22Uranium%22">Uranium</searchLink><br /><searchLink fieldCode="DE" term="%22Chemical+speciation%22">Chemical speciation</searchLink><br /><searchLink fieldCode="DE" term="%22Biogeochemistry%22">Biogeochemistry</searchLink><br /><searchLink fieldCode="DE" term="%22Nitrates%22">Nitrates</searchLink><br /><searchLink fieldCode="DE" term="%22Iron%22">Iron</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Although there is consensus that microorganisms significantly influence uranium speciation and mobility in the subsurface under circumneutral conditions, microbiologically mediated U(VI) redox cycling under alkaline conditions relevant to the geological disposal of cementitious intermediate level radioactive waste, remains unexplored. Here, we describe microcosm experiments that investigate the biogeochemical fate of U(VI) at pH 10-10.5, using sediments from a legacy lime working site, stimulated with an added electron donor, and incubated in the presence and absence of added Fe(III) as ferrihydrite. In systems without added Fe(III), partial U(VI) reduction occurred, forming a U(IV)-bearing non-uraninite phase which underwent reoxidation in the presence of air (O2) and to some extent nitrate. By contrast, in the presence of added Fe(III), U(VI) was first removed from solution by sorption to the Fe(III) mineral, followed by bioreduction and (bio)magnetite formation coupled to formation of a complex U(IV)-bearing phase with uraninite present, which also underwent air (O2) and partial nitrate reoxidation. 16S rRNA gene pyrosequencing showed that Gram-positive bacteria affiliated with the Firmicutes and Bacteroidetes dominated in the post-reduction sediments. These data provide the first insights into uranium biogeochemistry at high pH and have significant implications for the long-term fate of uranium in geological disposal in both engineered barrier systems and the alkaline, chemically disturbed geosphere. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Environmental Science & Technology is the property of American Chemical Society and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1021/es5017125 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 8 StartPage: 13549 Subjects: – SubjectFull: Radioactive waste disposal Type: general – SubjectFull: Chemical reduction Type: general – SubjectFull: Microorganisms Type: general – SubjectFull: Uranium Type: general – SubjectFull: Chemical speciation Type: general – SubjectFull: Biogeochemistry Type: general – SubjectFull: Nitrates Type: general – SubjectFull: Iron Type: general Titles: – TitleFull: Microbial Reduction of U(VI) under Alkaline Conditions: Implications for Radioactive Waste Geodisposal. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Williamson, Adam J. – PersonEntity: Name: NameFull: Morris, Katherine – PersonEntity: Name: NameFull: Law, Gareth T. W. – PersonEntity: Name: NameFull: Rizoulis, Athanasios – PersonEntity: Name: NameFull: Charnock, John M. – PersonEntity: Name: NameFull: Lloyd, Jonathan R. IsPartOfRelationships: – BibEntity: Dates: – D: 18 M: 11 Text: 11/18/2014 Type: published Y: 2014 Identifiers: – Type: issn-print Value: 0013936X Numbering: – Type: volume Value: 48 – Type: issue Value: 22 Titles: – TitleFull: Environmental Science & Technology Type: main |
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