1
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Ree SM, Greenwood H, Young JD, Roberts R, Livens FR, Heath SL, Sosabowski JK. Selection of radionuclide(s) for targeted alpha therapy based on their nuclear decay properties. Nucl Med Commun 2024; 45:465-473. [PMID: 38465420 DOI: 10.1097/mnm.0000000000001832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Targeted alpha therapy (TAT) is a promising form of oncology treatment utilising alpha-emitting radionuclides that can specifically accumulate at disease sites. The high energy and high linear energy transfer associated with alpha emissions causes localised damage at target sites whilst minimising that to surrounding healthy tissue. The lack of appropriate radionuclides has inhibited research in TAT. The identification of appropriate radionuclides should be primarily a function of the radionuclide's nuclear decay properties, and not their biochemistry or economic factors since these last two factors can change; however, the nuclear decay properties are fixed to that nuclide. This study has defined and applied a criterion based on nuclear decay properties useful for TAT. This down-selection exercise concluded that the most appropriate radionuclides are: 149 Tb, 211 At/ 211 Po, 212 Pb/ 212 Bi/ 212 Po, 213 Bi/ 213 Po, 224 Ra, 225 Ra/ 225 Ac/ 221 Fr, 226 Ac/ 226 Th, 227 Th/ 223 Ra/ 219 Rn, 229 U, 230 U/ 226 Th, and 253 Fm, the majority of which have previously been considered for TAT. 229 U and 253 Fm have been newly identified and could become new radionuclides of interest for TAT, depending on their decay chain progeny.
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Affiliation(s)
- Samantha M Ree
- National Nuclear Laboratory, Springfields, Salwick, Preston, Lancashire
| | - Howard Greenwood
- National Nuclear Laboratory, Springfields, Salwick, Preston, Lancashire
| | - Jennifer D Young
- School of Biomedical Engineering and Imaging Sciences, King's College London, London
| | - Rachel Roberts
- National Nuclear Laboratory, Springfields, Salwick, Preston, Lancashire
| | | | - Scott L Heath
- Department of Earth and Environmental Sciences, The University of Manchester, Manchester and
| | - Jane K Sosabowski
- Centre for Cancer Biomarkers and Biotherapeutics, Barts Cancer Institute, Queen Mary University of London, London
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2
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Fallon CM, Bower WR, Powell BA, Livens FR, Lyon IC, McNulty AE, Peruski K, Mosselmans JFW, Kaplan DI, Grolimund D, Warnicke P, Ferreira-Sanchez D, Kauppi MS, Vettese GF, Shaw S, Morris K, Law GTW. Vadose-zone alteration of metaschoepite and ceramic UO 2 in Savannah River Site field lysimeters. Sci Total Environ 2023; 862:160862. [PMID: 36521613 DOI: 10.1016/j.scitotenv.2022.160862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 11/25/2022] [Accepted: 12/07/2022] [Indexed: 06/17/2023]
Abstract
Uranium dioxide (UO2) and metaschoepite (UO3•nH2O) particles have been identified as contaminants at nuclear sites. Understanding their behavior and impact is crucial for safe management of radioactively contaminated land and to fully understand U biogeochemistry. The Savannah River Site (SRS) (South Carolina, USA), is one such contaminated site, following historical releases of U-containing wastes to the vadose zone. Here, we present an insight into the behavior of these two particle types under dynamic conditions representative of the SRS, using field lysimeters (15 cm D x 72 cm L). Discrete horizons containing the different particle types were placed at two depths in each lysimeter (25 cm and 50 cm) and exposed to ambient rainfall for 1 year, with an aim of understanding the impact of dynamic, shallow subsurface conditions on U particle behavior and U migration. The dissolution and migration of U from the particle sources and the speciation of U throughout the lysimeters was assessed after 1 year using a combination of sediment digests, sequential extractions, and bulk and μ-focus X-ray spectroscopy. In the UO2 lysimeter, oxidative dissolution of UO2 and subsequent migration of U was observed over 1-2 cm in the direction of waterflow and against it. Sequential extractions of the UO2 sources suggest they were significantly altered over 1 year. The metaschoepite particles also showed significant dissolution with marginally enhanced U migration (several cm) from the sources. However, in both particle systems the released U was quantitively retained in sediment as a range of different U(IV) and U(VI) phases, and no detectable U was measured in the lysimeter effluent. The study provides a useful insight into U particle behavior in representative, real-world conditions relevant to the SRS, and highlights limited U migration from particle sources due to secondary reactions with vadose zone sediments over 1 year.
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Affiliation(s)
- Connaugh M Fallon
- Centre for Radiochemistry Research, Department of Chemistry, The University of Manchester, Manchester M13 9PL, UK,; Research Centre for Radwaste and Decommissioning and Williamson Research Centre, Department of Earth and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK
| | - William R Bower
- Centre for Radiochemistry Research, Department of Chemistry, The University of Manchester, Manchester M13 9PL, UK,; Radiochemistry Unit, Department of Chemistry, University of Helsinki, Helsinki 00014, Finland
| | - Brian A Powell
- Department of Environmental Engineering and Earth Sciences, Department of Chemistry, Clemson University, Clemson, SC 29634, USA
| | - Francis R Livens
- Centre for Radiochemistry Research, Department of Chemistry, The University of Manchester, Manchester M13 9PL, UK,; Research Centre for Radwaste and Decommissioning and Williamson Research Centre, Department of Earth and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK
| | - Ian C Lyon
- Research Centre for Radwaste and Decommissioning and Williamson Research Centre, Department of Earth and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK
| | - Alana E McNulty
- Research Centre for Radwaste and Decommissioning and Williamson Research Centre, Department of Earth and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK
| | - Kathryn Peruski
- Department of Environmental Engineering and Earth Sciences, Department of Chemistry, Clemson University, Clemson, SC 29634, USA
| | | | - Daniel I Kaplan
- Savannah River Ecology Laboratory, University of Georgia, Aiken, SC 29808, USA
| | - Daniel Grolimund
- Swiss Light Source, Paul Scherrer Institute, Villigen CH-5232, Switzerland
| | - Peter Warnicke
- Swiss Light Source, Paul Scherrer Institute, Villigen CH-5232, Switzerland
| | | | - Marja Siitari Kauppi
- Radiochemistry Unit, Department of Chemistry, University of Helsinki, Helsinki 00014, Finland
| | - Gianni F Vettese
- Radiochemistry Unit, Department of Chemistry, University of Helsinki, Helsinki 00014, Finland
| | - Samuel Shaw
- Research Centre for Radwaste and Decommissioning and Williamson Research Centre, Department of Earth and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK
| | - Katherine Morris
- Research Centre for Radwaste and Decommissioning and Williamson Research Centre, Department of Earth and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK
| | - Gareth T W Law
- Radiochemistry Unit, Department of Chemistry, University of Helsinki, Helsinki 00014, Finland.
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3
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Crean DE, Stennett MC, Livens FR, Grolimund D, Borca CN, Hyatt NC. Correction: Multimodal X-ray microanalysis of a UFeO 4 particle: evidence for the environmental stability of ternary U(V) oxides from depleted uranium munitions testing. Environ Sci Process Impacts 2020; 22:1916. [PMID: 32785410 DOI: 10.1039/d0em90027c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Correction for 'Multimodal X-ray microanalysis of a UFeO4 particle: evidence for the environmental stability of ternary U(v) oxides from depleted uranium munitions testing' by Daniel E. Crean et al., Environ. Sci.: Processes Impacts, 2020, DOI: 10.1039/d0em00243g.
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Affiliation(s)
- Daniel E Crean
- Immobilisation Science Laboratory, Department of Materials Science and Engineering, The University of Sheffield, UK.
| | - Martin C Stennett
- Immobilisation Science Laboratory, Department of Materials Science and Engineering, The University of Sheffield, UK.
| | - Francis R Livens
- Centre for Radiochemistry Research, Department of Chemistry, The University of Manchester, UK
| | - Daniel Grolimund
- Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland
| | - Camelia N Borca
- Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland
| | - Neil C Hyatt
- Immobilisation Science Laboratory, Department of Materials Science and Engineering, The University of Sheffield, UK.
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4
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Fuller AJ, Leary P, Gray ND, Davies HS, Mosselmans JFW, Cox F, Robinson CH, Pittman JK, McCann CM, Muir M, Graham MC, Utsunomiya S, Bower WR, Morris K, Shaw S, Bots P, Livens FR, Law GTW. Organic complexation of U(VI) in reducing soils at a natural analogue site: Implications for uranium transport. Chemosphere 2020; 254:126859. [PMID: 32957279 DOI: 10.1016/j.chemosphere.2020.126859] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 04/07/2020] [Accepted: 04/19/2020] [Indexed: 06/11/2023]
Abstract
Understanding the long-term fate, stability, and bioavailability of uranium (U) in the environment is important for the management of nuclear legacy sites and radioactive wastes. Analysis of U behavior at natural analogue sites permits evaluation of U biogeochemistry under conditions more representative of long-term equilibrium. Here, we have used bulk geochemical and microbial community analysis of soils, coupled with X-ray absorption spectroscopy and μ-focus X-ray fluorescence mapping, to gain a mechanistic understanding of the fate of U transported into an organic-rich soil from a pitchblende vein at the UK Needle's Eye Natural Analogue site. U is highly enriched in the Needle's Eye soils (∼1600 mg kg-1). We show that this enrichment is largely controlled by U(VI) complexation with soil organic matter and not U(VI) bioreduction. Instead, organic-associated U(VI) seems to remain stable under microbially-mediated Fe(III)-reducing conditions. U(IV) (as non-crystalline U(IV)) was only observed at greater depths at the site (>25 cm); the soil here was comparatively mineral-rich, organic-poor, and sulfate-reducing/methanogenic. Furthermore, nanocrystalline UO2, an alternative product of U(VI) reduction in soils, was not observed at the site, and U did not appear to be associated with Fe-bearing minerals. Organic-rich soils appear to have the potential to impede U groundwater transport, irrespective of ambient redox conditions.
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Affiliation(s)
- Adam J Fuller
- Centre for Radiochemistry Research, Department of Chemistry, The University of Manchester, Manchester, M13 9PL, UK
| | - Peter Leary
- School of Natural and Environmental Sciences, Newcastle University, Newcastle, NE1 7RU, UK
| | - Neil D Gray
- School of Natural and Environmental Sciences, Newcastle University, Newcastle, NE1 7RU, UK
| | - Helena S Davies
- Research Centre for Radwaste Disposal, and Williamson Centre for Molecular Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, UK
| | | | - Filipa Cox
- Research Centre for Radwaste Disposal, and Williamson Centre for Molecular Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, UK
| | - Clare H Robinson
- Research Centre for Radwaste Disposal, and Williamson Centre for Molecular Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, UK
| | - Jon K Pittman
- Research Centre for Radwaste Disposal, and Williamson Centre for Molecular Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, UK
| | - Clare M McCann
- School of Natural and Environmental Sciences, Newcastle University, Newcastle, NE1 7RU, UK
| | - Michael Muir
- School of Geoscience, University of Edinburgh, Edinburgh, EH9 3FF, UK
| | - Margaret C Graham
- School of Geoscience, University of Edinburgh, Edinburgh, EH9 3FF, UK
| | - Satoshi Utsunomiya
- School of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - William R Bower
- Centre for Radiochemistry Research, Department of Chemistry, The University of Manchester, Manchester, M13 9PL, UK; Radiochemistry Unit, Department of Chemistry, The University of Helsinki, 00014, Finland
| | - Katherine Morris
- Research Centre for Radwaste Disposal, and Williamson Centre for Molecular Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, UK
| | - Samuel Shaw
- Research Centre for Radwaste Disposal, and Williamson Centre for Molecular Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, UK
| | - Pieter Bots
- Research Centre for Radwaste Disposal, and Williamson Centre for Molecular Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, UK
| | - Francis R Livens
- Centre for Radiochemistry Research, Department of Chemistry, The University of Manchester, Manchester, M13 9PL, UK; Research Centre for Radwaste Disposal, and Williamson Centre for Molecular Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, UK
| | - Gareth T W Law
- Centre for Radiochemistry Research, Department of Chemistry, The University of Manchester, Manchester, M13 9PL, UK; Radiochemistry Unit, Department of Chemistry, The University of Helsinki, 00014, Finland.
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5
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Crean DE, Stennett MC, Livens FR, Grolimund D, Borca CN, Hyatt NC. Multimodal X-ray microanalysis of a UFeO 4: evidence for the environmental stability of ternary U(v) oxides from depleted uranium munitions testing. Environ Sci Process Impacts 2020; 22:1577-1585. [PMID: 32632425 DOI: 10.1039/d0em00243g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
An environmentally aged radioactive particle of UFeO4 recovered from soil contaminated with munitions depleted uranium (DU) was characterised by microbeam synchrotron X-ray analysis. Imaging of uranium speciation by spatially resolved X-ray diffraction (μ-XRD) and X-ray absorption spectroscopy (μ-XAS) was used to localise UFeO4 in the particle, which was coincident with a distribution of U(v). The U oxidation state was confirmed using X-ray Absorption Near Edge Structure (μ-XANES) spectroscopy as +4.9 ± 0.15. Le-Bail fitting of the particle powder XRD pattern confirmed the presence of UFeO4 and a minor alteration product identified as chernikovite (H3O)(UO2)(PO4)·3H2O. Refined unit cell parameters for UFeO4 were in good agreement with previously published values. Uranium-oxygen interatomic distances in the first co-ordination sphere were determined by fitting of Extended X-ray Absorption Fine Structure (μ-EXAFS) spectroscopy. The average first shell U-O distance was 2.148 ± 0.012 Å, corresponding to a U valence of +4.96 ± 0.13 using bond valence sum analysis. Using bond distances from the published structure of UFeO4, U and Fe bond valence sums were calculated as +5.00 and +2.83 respectively, supporting the spectroscopic analysis and confirming the presence of a U(v)/Fe(iii) pair. Overall this investigation provides important evidence for the stability of U(v) ternary oxides, in oxic, variably moist surface environment conditions for at least 25 years.
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Affiliation(s)
- Daniel E Crean
- Immobilisation Science Laboratory, Department of Materials Science and Engineering, The University of Sheffield, UK.
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6
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Fallon CM, Bower WR, Lyon IC, Livens FR, Thompson P, Higginson M, Collins J, Heath SL, Law GTW. Isotopic and Compositional Variations in Single Nuclear Fuel Pellet Particles Analyzed by Nanoscale Secondary Ion Mass Spectrometry. ACS Omega 2020; 5:296-303. [PMID: 31956776 PMCID: PMC6964264 DOI: 10.1021/acsomega.9b02703] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 10/23/2019] [Indexed: 06/10/2023]
Abstract
The Collaborative Materials Exercise (CMX) is organized by the Nuclear Forensics International Technical Working Group, with the aim of advancing the analytical capabilities of the participating organizations and providing feedback on the best approaches to a nuclear forensic investigation. Here, model nuclear fuel materials from the 5th CMX iteration were analyzed using a NanoSIMS 50L (CAMECA) in order to examine inhomogeneities in the 235U/238U ratio and trace element abundance within individual, micrometer scale particles. Two fuel pellets were manufactured for the exercise and labelled CMX-5A and CMX-5B. These pellets were created using different processing techniques, but both had a target enrichment value of 235U/238U = 0.01. Particles from these pellets were isolated for isotopic and trace element analysis. Fifteen CMX-5A particles and 20 CMX-5B particles were analyzed, with both sample types displaying inhomogeneities in the U isotopic composition at a sub-micrometer scale within individual particles. Typical particle diameters were ∼1.5 to 41 μm for CMX-5A and ∼1 to 61 μm for CMX-5B. The CMX-5A particles were shown to be more isotopically homogeneous, with a mean 235U/238U atom ratio of 0.0130 ± 0.0066. The CMX-5B particles showed a predominantly depleted mean 235U/238U atom ratio of 0.0063 ± 0.0094, which is significantly different to the target enrichment value of the pellet and highlights the potential variation of 235U/238U in U fuel pellets at the micrometer scale. This study details the successful application of the NanoSIMS 50L in a mock nuclear forensic investigation by optimizing high-resolution imaging for uranium isotopics.
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Affiliation(s)
- Connaugh M. Fallon
- Centre for Radiochemistry Research, Department of Chemistry, Department of Earth
and Environmental Sciences and Photon Science Institute, School of Natural
Sciences, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - William R. Bower
- Centre for Radiochemistry Research, Department of Chemistry, Department of Earth
and Environmental Sciences and Photon Science Institute, School of Natural
Sciences, The University of Manchester, Manchester M13 9PL, United Kingdom
- Radiochemistry
Unit, Department of Chemistry, The University
of Helsinki, Helsinki 00014, Finland
| | - Ian C. Lyon
- Centre for Radiochemistry Research, Department of Chemistry, Department of Earth
and Environmental Sciences and Photon Science Institute, School of Natural
Sciences, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Francis R. Livens
- Centre for Radiochemistry Research, Department of Chemistry, Department of Earth
and Environmental Sciences and Photon Science Institute, School of Natural
Sciences, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Paul Thompson
- Atomic
Weapons Establishment, Aldermaston RG7 4PR, United Kingdom
| | | | - Jane Collins
- Atomic
Weapons Establishment, Aldermaston RG7 4PR, United Kingdom
| | - Sarah L. Heath
- Centre for Radiochemistry Research, Department of Chemistry, Department of Earth
and Environmental Sciences and Photon Science Institute, School of Natural
Sciences, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Gareth T. W. Law
- Centre for Radiochemistry Research, Department of Chemistry, Department of Earth
and Environmental Sciences and Photon Science Institute, School of Natural
Sciences, The University of Manchester, Manchester M13 9PL, United Kingdom
- Radiochemistry
Unit, Department of Chemistry, The University
of Helsinki, Helsinki 00014, Finland
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7
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Smith KF, Morris K, Law GTW, Winstanley EH, Livens FR, Weatherill JS, Abrahamsen-Mills LG, Bryan ND, Mosselmans JFW, Cibin G, Parry S, Blackham R, Law KA, Shaw S. Plutonium(IV) Sorption during Ferrihydrite Nanoparticle Formation. ACS Earth Space Chem 2019; 3:2437-2442. [PMID: 32064412 PMCID: PMC7011701 DOI: 10.1021/acsearthspacechem.9b00105] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 09/13/2019] [Accepted: 09/16/2019] [Indexed: 05/06/2023]
Abstract
Understanding interactions between iron (oxyhydr)oxide nanoparticles and plutonium is essential to underpin technology to treat radioactive effluents, in cleanup of land contaminated with radionuclides, and to ensure the safe disposal of radioactive wastes. These interactions include a range of adsorption, precipitation, and incorporation processes. Here, we explore the mechanisms of plutonium sequestration during ferrihydrite precipitation from an acidic solution. The initial 1 M HNO3 solution with Fe(III)(aq) and 242Pu(IV)(aq) underwent controlled hydrolysis via the addition of NaOH to pH 9. The majority of Fe(III)(aq) and Pu(IV)(aq) was removed from solution between pH 2 and 3 during ferrihydrite formation. Analysis of Pu-ferrihydrite by extended X-ray absorption fine structure (EXAFS) spectroscopy showed that Pu(IV) formed an inner-sphere tetradentate complex on the ferrihydrite surface, with minor amounts of PuO2 present. Best fits to the EXAFS data collected from Pu-ferrihydrite samples aged for 2 and 6 months showed no statistically significant change in the Pu(IV)-Fe oxyhydroxide surface complex despite the ferrihydrite undergoing extensive recrystallization to hematite. This suggests the Pu remains strongly sorbed to the iron (oxyhydr)oxide surface and could be retained over extended time periods.
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Affiliation(s)
- Kurt F. Smith
- Research
Centre for Radwaste Disposal and Williamson Research Centre for Molecular
Environmental Science, School of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Katherine Morris
- Research
Centre for Radwaste Disposal and Williamson Research Centre for Molecular
Environmental Science, School of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Gareth T. W. Law
- Centre
for Radiochemistry Research, School of Chemistry, The University of Manchester, Manchester, M13 9PL, United
Kingdom
- Radiochemistry
Unit, Department of Chemistry, The University
of Helsinki, A.I. Virtasen Aukio 1 (PL 55), 00014 Helsinki, Finland
| | - Ellen H. Winstanley
- Research
Centre for Radwaste Disposal and Williamson Research Centre for Molecular
Environmental Science, School of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Francis R. Livens
- Research
Centre for Radwaste Disposal and Williamson Research Centre for Molecular
Environmental Science, School of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, United Kingdom
- Centre
for Radiochemistry Research, School of Chemistry, The University of Manchester, Manchester, M13 9PL, United
Kingdom
| | - Joshua S. Weatherill
- Research
Centre for Radwaste Disposal and Williamson Research Centre for Molecular
Environmental Science, School of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, United Kingdom
| | | | - Nicholas D. Bryan
- National
Nuclear Laboratory, Chadwick House, Warrington, WA3 6AE, United
Kingdom
| | - J. Frederick W. Mosselmans
- Diamond
Light Source Ltd, Diamond House,
Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Giannantonio Cibin
- Diamond
Light Source Ltd, Diamond House,
Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Stephen Parry
- Diamond
Light Source Ltd, Diamond House,
Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | | | - Kathleen A. Law
- Centre
for Radiochemistry Research, School of Chemistry, The University of Manchester, Manchester, M13 9PL, United
Kingdom
| | - Samuel Shaw
- Research
Centre for Radwaste Disposal and Williamson Research Centre for Molecular
Environmental Science, School of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, United Kingdom
- E-mail:
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8
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Lang AR, Engelberg DL, Walther C, Weiss M, Bosco H, Jenkins A, Livens FR, Law GTW. Cesium and Strontium Contamination of Nuclear Plant Stainless Steel: Implications for Decommissioning and Waste Minimization. ACS Omega 2019; 4:14420-14429. [PMID: 31528795 PMCID: PMC6740182 DOI: 10.1021/acsomega.9b01311] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 08/08/2019] [Indexed: 06/10/2023]
Abstract
Stainless steels can become contaminated with radionuclides at nuclear sites. Their disposal as radioactive waste would be costly. If the nature of steel contamination could be understood, effective decontamination strategies could be designed and implemented during nuclear site decommissioning in an effort to release the steels from regulatory control. Here, batch uptake experiments have been used to understand Sr and Cs (fission product radionuclides) uptake onto AISI Type 304 stainless steel under conditions representative of spent nuclear fuel storage (alkaline ponds) and PUREX nuclear fuel reprocessing (HNO3). Solution (ICP-MS) and surface measurements (GD-OES depth profiling, TOF-SIMS, and XPS) and kinetic modeling of Sr and Cs removal from solution were used to characterize their uptake onto the steel and define the chemical composition and structure of the passive layer formed on the steel surfaces. Under passivating conditions (when the steel was exposed to solutions representative of alkaline ponds and 3 and 6 M HNO3), Sr and Cs were maintained at the steel surface by sorption/selective incorporation into the Cr-rich passive film. In 12 M HNO3, corrosion and severe intergranular attack led to Sr diffusion into the passive layer and steel bulk. In HNO3, Sr and Cs accumulation was also commensurate with corrosion product (Fe and Cr) readsorption, and in the 12 M HNO3 system, XPS documented the presence of Sr and Cs chromates.
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Affiliation(s)
- Adam R. Lang
- Centre
for Radiochemistry Research, School of Chemistry and Corrosion and
Protection Centre, Materials Performance Centre, School of Materials, The University of Manchester, Manchester M13 9PL, U.K.
| | - Dirk L. Engelberg
- Centre
for Radiochemistry Research, School of Chemistry and Corrosion and
Protection Centre, Materials Performance Centre, School of Materials, The University of Manchester, Manchester M13 9PL, U.K.
| | - Clemens Walther
- Institute
of Radioecology and Radiation Protection, Leibniz-University Hannover, D-30419 Hannover, Germany
| | - Martin Weiss
- Institute
of Radioecology and Radiation Protection, Leibniz-University Hannover, D-30419 Hannover, Germany
| | - Hauke Bosco
- Institute
of Radioecology and Radiation Protection, Leibniz-University Hannover, D-30419 Hannover, Germany
| | - Alex Jenkins
- Sellafield
Ltd., Sellafield, Cumbria CA20 1PG, U.K.
| | - Francis R. Livens
- Centre
for Radiochemistry Research, School of Chemistry and Corrosion and
Protection Centre, Materials Performance Centre, School of Materials, The University of Manchester, Manchester M13 9PL, U.K.
| | - Gareth T. W. Law
- Centre
for Radiochemistry Research, School of Chemistry and Corrosion and
Protection Centre, Materials Performance Centre, School of Materials, The University of Manchester, Manchester M13 9PL, U.K.
- Radiochemistry
Unit, Department of Chemistry, The University
of Helsinki, Helsinki 00014, Finland
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9
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Bower WR, Morris K, Livens FR, Mosselmans JFW, Fallon CM, Fuller AJ, Natrajan L, Boothman C, Lloyd JR, Utsunomiya S, Grolimund D, Ferreira Sanchez D, Jilbert T, Parker J, Neill TS, Law GTW. Metaschoepite Dissolution in Sediment Column Systems-Implications for Uranium Speciation and Transport. Environ Sci Technol 2019; 53:9915-9925. [PMID: 31317743 DOI: 10.1021/acs.est.9b02292] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Metaschoepite is commonly found in U-contaminated environments and metaschoepite-bearing wastes may be managed via shallow or deep disposal. Understanding metaschoepite dissolution and tracking the fate of any liberated U is thus important. Here, discrete horizons of metaschoepite (UO3·nH2O) particles were emplaced in flowing sediment/groundwater columns representative of the UK Sellafield Ltd. site. The column systems either remained oxic or became anoxic due to electron donor additions, and the columns were sacrificed after 6- and 12-months for analysis. Solution chemistry, extractions, and bulk and micro/nano-focus X-ray spectroscopies were used to track changes in U distribution and behavior. In the oxic columns, U migration was extensive, with UO22+ identified in effluents after 6-months of reaction using fluorescence spectroscopy. Unusually, in the electron-donor amended columns, during microbially mediated sulfate reduction, significant amounts of UO2-like colloids (>60% of the added U) were found in the effluents using TEM. XAS analysis of the U remaining associated with the reduced sediments confirmed the presence of trace U(VI), noncrystalline U(IV), and biogenic UO2, with UO2 becoming more dominant with time. This study highlights the potential for U(IV) colloid production from U(VI) solids under reducing conditions and the complexity of U biogeochemistry in dynamic systems.
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Affiliation(s)
- William R Bower
- Centre for Radiochemistry Research, School of Chemistry , The University of Manchester , Manchester , U.K. , M13 9PL
- Research Centre for Radwaste Disposal and Williamson Research Centre, School of Earth and Environmental Sciences , The University of Manchester , Manchester , U.K. , M13 9PL
- Radiochemistry Unit, Department of Chemistry , The University of Helsinki , Helsinki , Finland , 00014
| | - Katherine Morris
- Research Centre for Radwaste Disposal and Williamson Research Centre, School of Earth and Environmental Sciences , The University of Manchester , Manchester , U.K. , M13 9PL
| | - Francis R Livens
- Centre for Radiochemistry Research, School of Chemistry , The University of Manchester , Manchester , U.K. , M13 9PL
- Research Centre for Radwaste Disposal and Williamson Research Centre, School of Earth and Environmental Sciences , The University of Manchester , Manchester , U.K. , M13 9PL
| | | | - Connaugh M Fallon
- Centre for Radiochemistry Research, School of Chemistry , The University of Manchester , Manchester , U.K. , M13 9PL
- Research Centre for Radwaste Disposal and Williamson Research Centre, School of Earth and Environmental Sciences , The University of Manchester , Manchester , U.K. , M13 9PL
- Radiochemistry Unit, Department of Chemistry , The University of Helsinki , Helsinki , Finland , 00014
| | - Adam J Fuller
- Centre for Radiochemistry Research, School of Chemistry , The University of Manchester , Manchester , U.K. , M13 9PL
| | - Louise Natrajan
- Centre for Radiochemistry Research, School of Chemistry , The University of Manchester , Manchester , U.K. , M13 9PL
| | - Christopher Boothman
- Research Centre for Radwaste Disposal and Williamson Research Centre, School of Earth and Environmental Sciences , The University of Manchester , Manchester , U.K. , M13 9PL
| | - Jonathan R Lloyd
- Research Centre for Radwaste Disposal and Williamson Research Centre, School of Earth and Environmental Sciences , The University of Manchester , Manchester , U.K. , M13 9PL
| | - Satoshi Utsunomiya
- Kyushu University , Department of Chemistry , 744 Motooka , Nishi-ku , Fukuoka Japan , 819-0395
| | - Daniel Grolimund
- Swiss Light Source , Paul Scherrer Institute , Villigen , Switzerland , 5232
| | | | - Tom Jilbert
- Ecosystems and Environmental Research Programme, Faculty of Biological and Environmental Sciences , The University of Helsinki , Helsinki , Finland , 00014
| | - Julia Parker
- Diamond Light Source , Harwell Science and Innovation Campus , Didcot , U.K. , OX11 0DE
| | - Thomas S Neill
- Research Centre for Radwaste Disposal and Williamson Research Centre, School of Earth and Environmental Sciences , The University of Manchester , Manchester , U.K. , M13 9PL
| | - Gareth T W Law
- Centre for Radiochemistry Research, School of Chemistry , The University of Manchester , Manchester , U.K. , M13 9PL
- Radiochemistry Unit, Department of Chemistry , The University of Helsinki , Helsinki , Finland , 00014
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10
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Davies HS, Rosas-Moreno J, Cox F, Lythgoe P, Bewsher A, Livens FR, Robinson CH, Pittman JK. Multiple environmental factors influence 238U, 232Th and 226Ra bioaccumulation in arbuscular mycorrhizal-associated plants. Sci Total Environ 2018; 640-641:921-934. [PMID: 30021326 DOI: 10.1016/j.scitotenv.2018.05.370] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 05/16/2018] [Accepted: 05/29/2018] [Indexed: 06/08/2023]
Abstract
Ecological consequences of low-dose radioactivity from natural sources or radioactive waste are important to understand but knowledge gaps still remain. In particular, the soil transfer and bioaccumulation of radionuclides into plant roots is poorly studied. Furthermore, better knowledge of arbuscular mycorrhizal (AM) fungi association may help understand the complexities of radionuclide bioaccumulation within the rhizosphere. Plant bioaccumulation of uranium, thorium and radium was demonstrated at two field sites, where plant tissue concentrations reached up to 46.93 μg g-1 238U, 0.67 μg g-1 232Th and 18.27 kBq kg-1 226Ra. High root retention of uranium was consistent in all plant species studied. In contrast, most plants showed greater bioaccumulation of thorium and radium into above-ground tissues. The influence of specific soil parameters on root radionuclide bioaccumulation was examined. Total organic carbon significantly explained the variation in root uranium concentration, while other soil factors including copper concentration, magnesium concentration and pH significantly correlated with root concentrations of uranium, radium and thorium, respectively. All four orders of Glomeromycota were associated with root samples from both sites and all plant species studied showed varying association with AM fungi, ranging from zero to >60% root colonisation by fungal arbuscules. Previous laboratory studies using single plant-fungal species association had found a positive role of AM fungi in root uranium transfer, but no significant correlation between the amount of fungal infection and root uranium content in the field samples was found here. However, there was a significant negative correlation between AM fungal infection and radium accumulation. This study is the first to examine the role of AM fungi in radionuclide soil-plant transfer at a community level within the natural environment. We conclude that biotic factors alongside various abiotic factors influence the soil-plant transfer of radionuclides and future mechanistic studies are needed to explain these interactions in more detail.
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Affiliation(s)
- Helena S Davies
- School of Earth and Environmental Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Jeanette Rosas-Moreno
- School of Earth and Environmental Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Filipa Cox
- School of Earth and Environmental Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Paul Lythgoe
- School of Earth and Environmental Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Alastair Bewsher
- School of Earth and Environmental Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Francis R Livens
- School of Earth and Environmental Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, UK; Centre for Radiochemistry Research, School of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Clare H Robinson
- School of Earth and Environmental Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
| | - Jon K Pittman
- School of Earth and Environmental Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
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11
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Al-Qasmi H, Law GTW, Fifield LK, Howe JA, Brand T, Cowie GL, Law KA, Livens FR. Deposition of artificial radionuclides in sediments of Loch Etive, Scotland. J Environ Radioact 2018; 187:45-52. [PMID: 29429873 DOI: 10.1016/j.jenvrad.2018.02.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 10/08/2017] [Accepted: 02/01/2018] [Indexed: 06/08/2023]
Abstract
The nuclear fuel reprocessing plants on the Sellafield site (UK) have released low-level effluents into the Irish Sea under authorisation since 1952. This has led to the labelling of nearby offshore sediments with a range of artificial radionuclides. In turn, these sediments act as a long-term secondary source of both soluble and particle-associated radionuclides to coastal areas. These radionuclides are of interest both in assessing possible environmental impacts and as tracers for marine processes. Here we present results from a study of the geochemistry of natural (234, 238U) and artificial (137Cs, 241Am, 238Pu, 239+240Pu, and 236U) radionuclides and their accumulation in sediments from Loch Etive, Scotland. The data are interpreted in the context of the historical radioactive discharges to the Irish Sea and biogeochemical processes in marine sediments. Loch Etive is divided into two basins; a lower, seaward basin where the sedimentation rate (∼0.6 cm/yr) is about twice that of the more isolated upper basin (∼0.3 cm/yr). These accumulation rates are consistent with the broad distribution of 137Cs in the sediment profiles which can be related to the maximum Sellafield discharges of 137Cs in the mid-1970s and suggest that 137Cs was mainly transported in solution to Loch Etive during that period. Enrichments of Mn, Fe, and Mo in sediment and porewater from both Loch Etive basins result from contemporary biogeochemical redox processes. Enrichments of 238U and 234U in the lower basin may be a result of the cycling of natural U. By contrast, the Sellafield-derived artificial isotope 236U does not seem to be affected by the redox-driven reactions in the lower basin. The 238Pu/239,240Pu ratios suggest contributions from both historical Sellafield discharges and global fallout Pu. The uniform sediment distributions of Pu and Am, which do not reflect Sellafield historical discharges, suggest the existence of a homogenous secondary source. This could be the offshore 'mud patch' in the vicinity of Sellafield from which the supply of radionuclides reflects time-integrated Sellafield discharges. This source could also account for the continuing supply of Cs to Loch Etive, even after substantial reductions in discharge from the Sellafield site.
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Affiliation(s)
- Hamza Al-Qasmi
- Centre for Radiochemistry Research, School of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Gareth T W Law
- Centre for Radiochemistry Research, School of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - L Keith Fifield
- Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200, Australia
| | - John A Howe
- Scottish Association for Marine Science, Oban, Argyll, PA37 1QA, UK
| | - Tim Brand
- Scottish Association for Marine Science, Oban, Argyll, PA37 1QA, UK
| | - Gregory L Cowie
- School of Geosciences, The University of Edinburgh, King's Buildings, Edinburgh, EH9 3FE, UK
| | - Kathleen A Law
- Centre for Radiochemistry Research, School of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Francis R Livens
- Centre for Radiochemistry Research, School of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
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12
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Masters-Waage NK, Morris K, Lloyd JR, Shaw S, Mosselmans JFW, Boothman C, Bots P, Rizoulis A, Livens FR, Law GTW. Impacts of Repeated Redox Cycling on Technetium Mobility in the Environment. Environ Sci Technol 2017; 51:14301-14310. [PMID: 29144125 DOI: 10.1021/acs.est.7b02426] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Technetium is a problematic contaminant at nuclear sites and little is known about how repeated microbiologically mediated redox cycling impacts its fate in the environment. We explore this question in sediments representative of the Sellafield Ltd. site, UK, over multiple reduction and oxidation cycles spanning ∼1.5 years. We found the amount of Tc remobilised from the sediment into solution significantly decreased after repeated redox cycles. X-ray Absorption Spectroscopy (XAS) confirmed that sediment bound Tc was present as hydrous TcO2-like chains throughout experimentation and that Tc's increased resistance to remobilization (via reoxidation to soluble TcO4-) resulted from both shortening of TcO2 chains during redox cycling and association of Tc(IV) with Fe phases in the sediment. We also observed that Tc(IV) remaining in solution during bioreduction was likely associated with colloidal magnetite nanoparticles. These findings highlight crucial links between Tc and Fe biogeochemical cycles that have significant implications for Tc's long-term environmental mobility, especially under ephemeral redox conditions.
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Affiliation(s)
- Nicholas K Masters-Waage
- Centre for Radiochemistry Research, School of Chemistry, The University of Manchester , M13 9PL, Manchester, United Kingdom
- Research Centre for Radwaste Disposal and Williamson Research Centre, School of Earth and Environmental Sciences, The University of Manchester , M13 9PL, Manchester, United Kingdom
| | - Katherine Morris
- Research Centre for Radwaste Disposal and Williamson Research Centre, School of Earth and Environmental Sciences, The University of Manchester , M13 9PL, Manchester, United Kingdom
| | - Jonathan R Lloyd
- Research Centre for Radwaste Disposal and Williamson Research Centre, School of Earth and Environmental Sciences, The University of Manchester , M13 9PL, Manchester, United Kingdom
| | - Samuel Shaw
- Research Centre for Radwaste Disposal and Williamson Research Centre, School of Earth and Environmental Sciences, The University of Manchester , M13 9PL, Manchester, United Kingdom
| | - J Frederick W Mosselmans
- Diamond Light Source Ltd ., Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, United Kingdom
| | - Christopher Boothman
- Research Centre for Radwaste Disposal and Williamson Research Centre, School of Earth and Environmental Sciences, The University of Manchester , M13 9PL, Manchester, United Kingdom
| | - Pieter Bots
- Research Centre for Radwaste Disposal and Williamson Research Centre, School of Earth and Environmental Sciences, The University of Manchester , M13 9PL, Manchester, United Kingdom
| | - Athanasios Rizoulis
- Research Centre for Radwaste Disposal and Williamson Research Centre, School of Earth and Environmental Sciences, The University of Manchester , M13 9PL, Manchester, United Kingdom
| | - Francis R Livens
- Centre for Radiochemistry Research, School of Chemistry, The University of Manchester , M13 9PL, Manchester, United Kingdom
| | - Gareth T W Law
- Centre for Radiochemistry Research, School of Chemistry, The University of Manchester , M13 9PL, Manchester, United Kingdom
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13
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Cherkouk A, Law GTW, Rizoulis A, Law K, Renshaw JC, Morris K, Livens FR, Lloyd JR. Influence of riboflavin on the reduction of radionuclides by Shewanella oneidenis MR-1. Dalton Trans 2016; 45:5030-7. [PMID: 26632613 DOI: 10.1039/c4dt02929a] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Uranium (as UO2(2+)), technetium (as TcO4(-)) and neptunium (as NpO2(+)) are highly mobile radionuclides that can be reduced enzymatically by a range of anaerobic and facultatively anaerobic microorganisms, including Shewanella oneidensis MR-1, to poorly soluble species. The redox chemistry of Pu is more complicated, but the dominant oxidation state in most environments is highly insoluble Pu(IV), which can be reduced to Pu(III) which has a potentially increased solubility which could enhance migration of Pu in the environment. Recently it was shown that flavins (riboflavin and flavin mononucleotide (FMN)) secreted by Shewanella oneidensis MR-1 can act as electron shuttles, promoting anoxic growth coupled to the accelerated reduction of poorly-crystalline Fe(III) oxides. Here, we studied the role of riboflavin in mediating the reduction of radionuclides in cultures of Shewanella oneidensis MR-1. Our results demonstrate that the addition of 10 μM riboflavin enhances the reduction rate of Tc(VII) to Tc(IV), Pu(IV) to Pu(III) and to a lesser extent, Np(V) to Np(IV), but has no significant influence on the reduction rate of U(VI) by Shewanella oneidensis MR-1. Thus riboflavin can act as an extracellular electron shuttle to enhance rates of Tc(VII), Np(V) and Pu(IV) reduction, and may therefore play a role in controlling the oxidation state of key redox active actinides and fission products in natural and engineered environments. These results also suggest that the addition of riboflavin could be used to accelerate the bioremediation of radionuclide-contaminated environments.
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Affiliation(s)
- Andrea Cherkouk
- Research Centre for Radwaste Disposal and Williamson Research Centre for Molecular Environmental Science, School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK.
| | - Gareth T W Law
- Centre for Radiochemistry Research, School of Chemistry, Manchester, M13 9PL, UK
| | - Athanasios Rizoulis
- Research Centre for Radwaste Disposal and Williamson Research Centre for Molecular Environmental Science, School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK.
| | - Katie Law
- Centre for Radiochemistry Research, School of Chemistry, Manchester, M13 9PL, UK
| | - Joanna C Renshaw
- Research Centre for Radwaste Disposal and Williamson Research Centre for Molecular Environmental Science, School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK.
| | - Katherine Morris
- Research Centre for Radwaste Disposal and Williamson Research Centre for Molecular Environmental Science, School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK.
| | - Francis R Livens
- Research Centre for Radwaste Disposal and Williamson Research Centre for Molecular Environmental Science, School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK. and Centre for Radiochemistry Research, School of Chemistry, Manchester, M13 9PL, UK
| | - Jonathan R Lloyd
- Research Centre for Radwaste Disposal and Williamson Research Centre for Molecular Environmental Science, School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK.
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14
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Al-Qasmi H, Law GTW, Fifield LK, Livens FR. Origin of artificial radionuclides in soil and sediment from North Wales. J Environ Radioact 2016; 151 Pt 1:244-249. [PMID: 26529492 DOI: 10.1016/j.jenvrad.2015.10.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 10/15/2015] [Accepted: 10/15/2015] [Indexed: 06/05/2023]
Abstract
During the operations at the Sellafield nuclear fuel reprocessing complex, artificial radionuclides are discharged to the Irish Sea under authorisation, where they are dispersed. In this study, the southern distribution and transport of Sellafield derived radionuclides have been investigated. Both natural and artificial radionuclides have been studied in a soil core from the riverbank of the Afon Goch in Anglesey, North Wales. Particulate input is dominant for all artificial radionuclides (including the more soluble (137)Cs and (236)U) with an estimated lag time of about a decade. The preferential northward seawater movement in the NE Irish Sea limits solution input of (137)Cs and (236)U to the areas south of Sellafield. The relatively long lag time reflects both the water circulation pattern and distance between the study site in north Wales and the source point in Cumbria. Two redox active zones are observed in the top and the bottom of this core, although there is no evidence for any redistribution of Pu and natural uranium by these redox processes. However, (236)U, derived from irradiated uranium, showed variable distribution in the core. This could be a potential response to the geochemical conditions, showing that (236)U may be a promising tracer for the environmental processes and a signature of the Sellafield historical discharges of irradiated uranium.
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Affiliation(s)
- Hamza Al-Qasmi
- Centre for Radiochemistry Research, School of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Gareth T W Law
- Centre for Radiochemistry Research, School of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - L Keith Fifield
- Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200, Australia
| | - Francis R Livens
- Centre for Radiochemistry Research, School of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
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15
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Higginson MA, Thompson P, Marsden OJ, Livens FR, Harwood LM, Lewis FW, Hudson MJ, Heath SL. Rapid selective separation of americium/curium from simulated nuclear forensic matrices using triazine ligands. RADIOCHIM ACTA 2015. [DOI: 10.1515/ract-2015-2403] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
In analysis of complex nuclear forensic samples containing lanthanides, actinides and matrix elements, rapid selective extraction of
Am/Cm for quantification is challenging, in particular due the difficult separation of Am/Cm from
lanthanides. Here we present a separation process for Am/Cm(III) which is achieved using a combination of AG1-X8
chromatography followed by Am/Cm extraction with a triazine ligand. The ligands tested in our process were
CyMe4-BTPhen, CyMe4-BTBP, CA-BTP and CA-BTPhen. Our process allows for purification and quantification of Am and Cm
(recoveries 80% – 100%) and other major actinides in < 2 d without the use of multiple columns or
thiocyanate. The process is unaffected by high level Ca(II)/Fe(III)/Al(III) (10 mg mL
–1) and
thus requires little pre-treatment of samples.
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Affiliation(s)
- Matthew A. Higginson
- Centre for Radiochemistry Research, School of Chemistry, The University of Manchester, Manchester, M13 9PL, UK
| | | | | | - Francis R. Livens
- Centre for Radiochemistry Research, School of Chemistry, The University of Manchester, Manchester, M13 9PL, UK
| | - Laurence M. Harwood
- Department of Chemistry, University of Reading, Whiteknights, Reading, RG6 6AD, UK
| | | | - Michael J. Hudson
- Department of Chemistry, University of Reading, Whiteknights, Reading, RG6 6AD, UK
| | - Sarah L. Heath
- Centre for Radiochemistry Research, School of Chemistry, The University of Manchester, Manchester, M13 9PL, UK
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16
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Kimber RL, Corkhill CL, Amos S, Livens FR, Lloyd JR. Geochemical association of Pu and Am in selected host-phases of contaminated soils from the UK and their susceptibility to chemical and microbiological leaching. J Environ Radioact 2015; 142:96-102. [PMID: 25659921 DOI: 10.1016/j.jenvrad.2015.01.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 01/06/2015] [Accepted: 01/07/2015] [Indexed: 06/04/2023]
Abstract
Understanding the biogeochemical behaviour and potential mobility of actinides in soils and groundwater is vital for developing remediation and management strategies for radionuclide-contaminated land. Pu is known to have a high Kd in soils and sediments, however remobilization of low concentrations of Pu remains a concern. Here, some of the physicochemical properties of Pu and the co-contaminant, Am, are investigated in contaminated soils from Aldermaston, Berkshire, UK, and the Esk Estuary, Cumbria, UK, to determine their potential mobility. Sequential extraction techniques were used to examine the host-phases of the actinides in these soils and their susceptibility to microbiological leaching was investigated using acidophilic sulphur-oxidising bacteria. Sequential extractions found the majority of (239,240)Pu associated with the highly refractory residual phase in both the Aldermaston (63.8-85.5 %) and Esk Estuary (91.9-94.5%) soils. The (241)Am was distributed across multiple phases including the reducible oxide (26.1-40.0%), organic (45.6-63.6%) and residual fractions (1.9-11.1%). Plutonium proved largely resistant to leaching from microbially-produced sulphuric acid, with a maximum 0.18% leached into solution, although up to 12.5% of the (241)Am was leached under the same conditions. If Pu was present as distinct oxide particles in the soil, then (241)Am, a decay product of Pu, would be expected to be physically retained in the particle. The differences in geochemical association and bioleachability of the two actinides suggest that this is not the case and hence, that significant Pu is not present as distinct particles. These data suggest the majority of Pu in the contaminated soils studied is highly recalcitrant to geochemical changes and is likely to remain immobile over significant time periods, even when challenged with aggressive "bioleaching" bacteria.
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Affiliation(s)
- Richard L Kimber
- Williamson Research Centre for Molecular Environmental Science and Research Centre for Radwaste and Decommissioning, School of Earth, Atmospheric & Environmental Sciences, University of Manchester, M13 9PL, UK; Centre for Radiochemistry Research, School of Chemistry, University of Manchester, Manchester M13 9PL, UK.
| | - Claire L Corkhill
- Williamson Research Centre for Molecular Environmental Science and Research Centre for Radwaste and Decommissioning, School of Earth, Atmospheric & Environmental Sciences, University of Manchester, M13 9PL, UK
| | - Sean Amos
- Atomic Weapons Establishment PLC, Aldermaston, Berkshire RG7 4PR, UK
| | - Francis R Livens
- Williamson Research Centre for Molecular Environmental Science and Research Centre for Radwaste and Decommissioning, School of Earth, Atmospheric & Environmental Sciences, University of Manchester, M13 9PL, UK; Centre for Radiochemistry Research, School of Chemistry, University of Manchester, Manchester M13 9PL, UK
| | - Jonathan R Lloyd
- Williamson Research Centre for Molecular Environmental Science and Research Centre for Radwaste and Decommissioning, School of Earth, Atmospheric & Environmental Sciences, University of Manchester, M13 9PL, UK
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17
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Higginson MA, Kyle ND, Marsden OJ, Thompson P, Livens FR, Heath SL. Synthesis of functionalised BTPhen derivatives – effects on solubility and americium extraction. Dalton Trans 2015; 44:16547-52. [DOI: 10.1039/c5dt01867f] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Separation of the minor actinides (Am/Cm) from spent nuclear fuel post-PUREX process is expected to play a key part in new reprocessing methodologies.
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Affiliation(s)
- Matthew A. Higginson
- Centre for Radiochemistry Research
- School of Chemistry
- The University of Manchester
- Manchester
- UK
| | - Nichola D. Kyle
- Centre for Radiochemistry Research
- School of Chemistry
- The University of Manchester
- Manchester
- UK
| | | | | | - Francis R. Livens
- Centre for Radiochemistry Research
- School of Chemistry
- The University of Manchester
- Manchester
- UK
| | - Sarah L. Heath
- Centre for Radiochemistry Research
- School of Chemistry
- The University of Manchester
- Manchester
- UK
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18
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Siddeeg SM, Bryan ND, Livens FR. Behaviour and mobility of U and Ra in sediments near an abandoned uranium mine, Cornwall, UK. Environ Sci Process Impacts 2015; 17:235-245. [PMID: 25503245 DOI: 10.1039/c4em00230j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Sediment samples were collected from the vicinity of the abandoned South Terras uranium mine in south-west UK and analysed for uranium and (226)Ra to explore their geochemical dispersion. The radioactivity concentrations in the sediment samples were measured using alpha spectrometry for uranium, and gamma spectrometry for radium. Sequential chemical extraction was applied to selected sediments in order to investigate the speciation of the radionuclides and their association with stable elements. The activity ratio of the uranium isotopes was used to explore the mobility of uranium, and scanning electron microscopy (SEM) and electron microprobe analysis (EMPA) were used to characterise the sediments. The radiochemical results identified two locations with enhanced radioactivity, so two samples from these locations were further investigated. The geochemical distribution of the radionuclides in these two samples varies within the five operationally-defined fractions. In one sample, the majority of the uranium was released from the 'carbonate' fraction, followed by the organic fractions. Similarly, in the second sample, the uranium was mainly resealed from the carbonate fraction, although a considerable percentage associated with the resistant fraction. The fractionation trend of radium noticed to show some similarities to that of barium, as expected from the similarity in their chemistries. Geochemical distributions of the stable elements, such as Mn, Ti and As, were different in the enhanced radioactivity samples. The activity ratio of (234)U/(238)U shows different trends in the two sediments, signifying the impact of organic matter and/or the exchange between water and sediment. SEM and EMPA analysis identified uranium-bearing phases in association with potassium, calcium, iron, manganese and arsenic.
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Affiliation(s)
- Saifeldin M Siddeeg
- Centre for Radiochemistry Research, School of Chemistry, The University of Manchester, Manchester, M13 9PL, UK.
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19
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Zhang YJ, Tilley GJ, Martin LR, Collison D, Livens FR, Helliwell M, Malik KA, Hursthouse MB. Controlling Solid State Structure of Uranyl(VI) Complexes: Monomeric Complexes with Malonate and Malonamate. J NUCL SCI TECHNOL 2014. [DOI: 10.1080/00223131.2002.10875506] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
| | | | - Leigh R. Martin
- Centre for Radiochemistry Research, Department of Chemistry, University of Manchester
| | | | - Francis R. Livens
- Centre for Radiochemistry Research, Department of Chemistry, University of Manchester
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20
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Livens FR, Marsden OJ, Keith-Roach MJ, Morris K, Fifield LK, Philip Day J, Good All PS. Geochemistry of artificial actinide isotopes in west Cumbrian sediments. J NUCL SCI TECHNOL 2014. [DOI: 10.1080/00223131.2002.10875623] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Francis R. Livens
- Centre for Radiochemistry Research, Department of Chemistry, University of Manchester, Manchester Ml 3 9PL, England
| | - Olivia J. Marsden
- Centre for Radiochemistry Research, Department of Chemistry, University of Manchester, Manchester Ml 3 9PL, England
| | | | - Katherine Morris
- The Environment Centre, University of Leeds, Leeds LS2 9JT, England
| | - L. Keith Fifield
- Department of Nuclear Physics, Australian National University, Canberra, ACT 0200, Australia
| | - J. Philip Day
- Department of Chemistry, University of Manchester, Manchester Ml 3 9PL, England
| | - Phillip S. Good All
- Research and Technology, BNFL Sellafield, Seascale, Cumbria CA20 1PG, England
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21
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Renshaw JC, Livens FR, Collison D, Robson GD, Trinci APJ, Taylor RJ. Solubilization of α-FeO(OH), ThO2.2H2O and γ-UO3 by hydroxamate and carboxylate Hgands. J NUCL SCI TECHNOL 2014. [DOI: 10.1080/00223131.2002.10875455] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Joanna C. Renshaw
- Centre for Radiochemistry Research, Dept. of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Francis R. Livens
- Centre for Radiochemistry Research, Dept. of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - David Collison
- Dept. of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Geoffrey D. Robson
- School of Biological Sciences, 1.800 Stopford Building, The University of Manchester, Oxford Road, Manchester, M13 9PT, UK
| | - Anthony P. J. Trinci
- School of Biological Sciences, 1.800 Stopford Building, The University of Manchester, Oxford Road, Manchester, M13 9PT, UK
| | - Robin J. Taylor
- Research & Technology, BNFL, Sellafield, Seascale, Cumbria, CA20 9NG, UK
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22
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John GH, Collison D, May I, Livens FR, Helliwell M, McKinney JD. Investigation of the UO22+ / ReO4 / TPPO reaction system; the first characterised actinide-perrhenate complex, [UO2(ReO4)2(TPPO)3]. J NUCL SCI TECHNOL 2014. [DOI: 10.1080/00223131.2002.10875504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Gordon H. John
- Centre for Radiochemistry Research, Department of Chemistry, The University of Manchester, Oxford Road, Manchester, UK M13 9PL
| | - David Collison
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, UK M13 9PL,
| | - Iain May
- Centre for Radiochemistry Research, Department of Chemistry, The University of Manchester, Oxford Road, Manchester, UK M13 9PL
| | - Francis R. Livens
- Centre for Radiochemistry Research, Department of Chemistry, The University of Manchester, Oxford Road, Manchester, UK M13 9PL
| | - Madeleine Helliwell
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, UK M13 9PL,
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23
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Siddeeg SM, Bryan ND, Livens FR. Dispersion of U-series natural radionuclides in stream sediments from Edale, UK. Environ Sci Process Impacts 2014; 16:991-1000. [PMID: 24562972 DOI: 10.1039/c3em00609c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The spatial distribution of (238)U-series radionuclides, specifically 238U, 234U, 230Th and 226Ra, has been determined in stream sediments from Edale, Derbyshire, United Kingdom, to explore the behaviour of U-series radionuclides during weathering. For uranium and thorium, two different extraction methods were used, total dissolution with HNO3/HF in a microwave and leaching with aqua regia. This was followed by radiochemical separation using extraction chromatography, then alpha spectrometry measurement. The total radium contents in the sediments were measured using gamma spectrometry, while the leached fraction was measured in the same way as for uranium and thorium. The total sediment content of uranium and thorium ranges from ∼10 up to ∼200 Bq kg(-1), while the radium specific activity lies between ∼15 and 180 Bq kg(-1). In the aqua regia extractions, the uranium and thorium contents are in the range of ∼5 to ∼100 Bq kg(-1), while the radium specific activities are similar to those measured by total dissolution. All the radionuclides show no correlation with organic matter content. The activity ratios 234U/238U, 230Th/238U and 226Ra/238U were used to determine the degree of radioactive disequilibrium. The data show disequilibrium in most of the sediments, with activity ratios of 234U/238U, 230Th/238U and 226Ra/238U>1, inconsistent with evolution through straightforward weathering processes. Multivariate cluster analysis based on five variables, the specific activities of 238U, 234U, 230Th, 226Ra and loss on ignition, was employed to group the data and identify five distinct clusters. There seems to be a link between high radionuclide concentrations and proximity to landslips.
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Affiliation(s)
- Saifeldin M Siddeeg
- Centre for Radiochemistry Research, School of Chemistry, University of Manchester, Manchester, M13 9PL, UK.
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24
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Marshall T, Morris K, Law GTW, Livens FR, Mosselmans JFW, Bots P, Shaw S. Incorporation of Uranium into Hematite during crystallization from ferrihydrite. Environ Sci Technol 2014; 48:3724-3731. [PMID: 24580024 PMCID: PMC4059770 DOI: 10.1021/es500212a] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 02/26/2014] [Accepted: 03/02/2014] [Indexed: 05/28/2023]
Abstract
Ferrihydrite was exposed to U(VI)-containing cement leachate (pH 10.5) and aged to induce crystallization of hematite. A combination of chemical extractions, TEM, and XAS techniques provided the first evidence that adsorbed U(VI) (≈3000 ppm) was incorporated into hematite during ferrihydrite aggregation and the early stages of crystallization, with continued uptake occurring during hematite ripening. Analysis of EXAFS and XANES data indicated that the U(VI) was incorporated into a distorted, octahedrally coordinated site replacing Fe(III). Fitting of the EXAFS showed the uranyl bonds lengthened from 1.81 to 1.87 Å, in contrast to previous studies that have suggested that the uranyl bond is lost altogether upon incorporation into hematite. The results of this study both provide a new mechanistic understanding of uranium incorporation into hematite and define the nature of the bonding environment of uranium within the mineral structure. Immobilization of U(VI) by incorporation into hematite has clear and important implications for limiting uranium migration in natural and engineered environments.
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Affiliation(s)
- Timothy
A. Marshall
- Research
Centre for Radwaste Disposal and Williamson Research Centre for Molecular
Environmental Science, School of Earth, Atmospheric and Environmental
Sciences, The University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Katherine Morris
- Research
Centre for Radwaste Disposal and Williamson Research Centre for Molecular
Environmental Science, School of Earth, Atmospheric and Environmental
Sciences, The University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Gareth T. W. Law
- Centre
for Radiochemistry Research and Research Centre for Radwaste Disposal,
School of Chemistry, The University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Francis R. Livens
- Centre
for Radiochemistry Research and Research Centre for Radwaste Disposal,
School of Chemistry, The University of Manchester, Manchester, M13 9PL, United Kingdom
| | - J. Frederick W. Mosselmans
- Diamond
Light Source Ltd, Diamond House, Harwell
Science and Innovation Campus, Didcot, Oxfordshire OX11
0DE, United Kingdom
| | - Pieter Bots
- Research
Centre for Radwaste Disposal and Williamson Research Centre for Molecular
Environmental Science, School of Earth, Atmospheric and Environmental
Sciences, The University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Samuel Shaw
- Research
Centre for Radwaste Disposal and Williamson Research Centre for Molecular
Environmental Science, School of Earth, Atmospheric and Environmental
Sciences, The University of Manchester, Manchester, M13 9PL, United Kingdom
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25
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Crean DE, Livens FR, Stennett MC, Grolimund D, Borca CN, Hyatt NC. Microanalytical X-ray imaging of depleted uranium speciation in environmentally aged munitions residues. Environ Sci Technol 2014; 48:1467-1474. [PMID: 24451034 DOI: 10.1021/es403938d] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Use of depleted uranium (DU) munitions has resulted in contamination of the near-surface environment with penetrator residues. Uncertainty in the long-term environmental fate of particles produced by impact of DU penetrators with hard targets is a specific concern. In this study DU particles produced in this way and exposed to the surface terrestrial environment for longer than 30 years at a U.K. firing range were characterized using synchrotron X-ray chemical imaging. Two sites were sampled: a surface soil and a disposal area for DU-contaminated wood, and the U speciation was different between the two areas. Surface soil particles showed little extent of alteration, with U speciated as oxides U3O7 and U3O8. Uranium oxidation state and crystalline phase mapping revealed these oxides occur as separate particles, reflecting heterogeneous formation conditions. Particles recovered from the disposal area were substantially weathered, and U(VI) phosphate phases such as meta-ankoleite (K(UO2)(PO4) · 3H2O) were dominant. Chemical imaging revealed domains of contrasting U oxidation state linked to the presence of both U3O7 and meta-ankoleite, indicating growth of a particle alteration layer. This study demonstrates that substantial alteration of DU residues can occur, which directly influences the health and environmental hazards posed by this contamination.
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Affiliation(s)
- Daniel E Crean
- Immobilisation Science Laboratory, Department of Materials Science and Engineering, The University of Sheffield , Mappin Street, Sheffield S11 7GL, United Kingdom
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Crean DE, Livens FR, Sajih M, Stennett MC, Grolimund D, Borca CN, Hyatt NC. Remediation of soils contaminated with particulate depleted uranium by multi stage chemical extraction. J Hazard Mater 2013; 263 Pt 2:382-390. [PMID: 23998894 DOI: 10.1016/j.jhazmat.2013.08.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 07/09/2013] [Accepted: 08/02/2013] [Indexed: 06/02/2023]
Abstract
Contamination of soils with depleted uranium (DU) from munitions firing occurs in conflict zones and at test firing sites. This study reports the development of a chemical extraction methodology for remediation of soils contaminated with particulate DU. Uranium phases in soils from two sites at a UK firing range, MOD Eskmeals, were characterised by electron microscopy and sequential extraction. Uranium rich particles with characteristic spherical morphologies were observed in soils, consistent with other instances of DU munitions contamination. Batch extraction efficiencies for aqueous ammonium bicarbonate (42-50% total DU extracted), citric acid (30-42% total DU) and sulphuric acid (13-19% total DU) were evaluated. Characterisation of residues from bicarbonate-treated soils by synchrotron microfocus X-ray diffraction and X-ray absorption spectroscopy revealed partially leached U(IV)-oxide particles and some secondary uranyl-carbonate phases. Based on these data, a multi-stage extraction scheme was developed utilising leaching in ammonium bicarbonate followed by citric acid to dissolve secondary carbonate species. Site specific U extraction was improved to 68-87% total U by the application of this methodology, potentially providing a route to efficient DU decontamination using low cost, environmentally compatible reagents.
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Affiliation(s)
- Daniel E Crean
- Immobilisation Science Laboratory, Department of Materials Science and Engineering, The University of Sheffield, UK; Centre for Radiochemistry Research, School of Chemistry, The University of Manchester, UK
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27
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Doudou S, Vaughan DJ, Livens FR, Burton NA. Atomistic simulations of calcium uranyl(VI) carbonate adsorption on calcite and stepped-calcite surfaces. Environ Sci Technol 2012; 46:7587-7594. [PMID: 22642750 DOI: 10.1021/es300034k] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Adsorption of actinyl ions onto mineral surfaces is one of the main mechanisms that control the migration of these ions in environmental systems. Here, we present computational classical molecular dynamics (MD) simulations to investigate the behavior of U(VI) in contact with different calcite surfaces. The calcium-uranyl-carbonate [Ca(2)UO(2)(CO(3))(3)] species is shown to display both inner- and outer-sphere adsorption to the flat {101̅4} and the stepped {314̅8} and {31̅2̅16} planes of calcite. Free energy calculations, using the umbrella sampling method, are employed to simulate adsorption paths of the same uranyl species on the different calcite surfaces under aqueous condition. Outer-sphere adsorption is found to dominate over inner-sphere adsorption because of the high free energy barrier of removing a uranyl-carbonate interaction and replacing it with a new uranyl-surface interaction. An important binding mode is proposed involving a single vicinal water monolayer between the surface and the sorbed complex. From the free energy profiles of the different calcite surfaces, the uranyl complex was also found to adsorb preferentially on the acute-stepped {314̅8} face of calcite, in agreement with experiment.
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Affiliation(s)
- Slimane Doudou
- School of Chemistry, University of Manchester, Manchester, M13 9PL, UK
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28
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Deli D, Law K, Liu Z, Crouch DJ, Livens FR, Yeates SG. Selective removal of 90Sr and 60Co from aqueous solution using N-aza-crown ether functional poly(NIPAM) hydrogels. REACT FUNCT POLYM 2012. [DOI: 10.1016/j.reactfunctpolym.2012.03.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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29
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Long M, Thornthwaite DW, Rogers SH, Livens FR, Rannard SP. Controlled synthesis of radiolabelled amine methacrylate water-soluble polymers with end-groups of varying hydrophobicity and studies of adsorption behaviour. Polym Chem 2012. [DOI: 10.1039/c1py00397f] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Radioactive initiators of increasing hydrophobicity, including fluorescent initiators, have been used to conduct the ambient ATRP of poly(2-(diethylamino)ethyl methacrylate) and the behaviour of the resultant polymers has been monitored with respect to surface adsorption using radio-techniques; considerable effects of end group type were observed.
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Affiliation(s)
- Mark Long
- Unilever Research and Development Port Sunlight Laboratories
- Bebington
- UK
| | | | - Suzanne H. Rogers
- Unilever Research and Development Port Sunlight Laboratories
- Bebington
- UK
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Doudou S, Arumugam K, Vaughan DJ, Livens FR, Burton NA. Investigation of ligand exchange reactions in aqueous uranyl carbonate complexes using computational approaches. Phys Chem Chem Phys 2011; 13:11402-11. [DOI: 10.1039/c1cp20617f] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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31
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Long M, Rogers SH, Thornthwaite DW, Livens FR, Rannard SP. Monitoring Atom Transfer Radical Polymerisation using14C-radiolabelled initiators. Polym Chem 2011. [DOI: 10.1039/c0py00275e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Law GTW, Geissler A, Lloyd JR, Livens FR, Boothman C, Begg JDC, Denecke MA, Rothe J, Dardenne K, Burke IT, Charnock JM, Morris K. Geomicrobiological redox cycling of the transuranic element neptunium. Environ Sci Technol 2010; 44:8924-8929. [PMID: 21047117 DOI: 10.1021/es101911v] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
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)O(2)(+) 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.
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Affiliation(s)
- Gareth T W Law
- Research Centre for Radwaste and Decommissioning, School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester, M13 9PL, UK
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33
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Sajih M, Livens FR, Alvarez R, Morgan M. Physicochemical characterisation of depleted uranium (DU) particles at a UK firing test range. Sci Total Environ 2010; 408:5990-5996. [PMID: 20855109 DOI: 10.1016/j.scitotenv.2010.07.075] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Revised: 07/21/2010] [Accepted: 07/28/2010] [Indexed: 05/29/2023]
Abstract
Depleted uranium (DU) particles were isolated from soils at Eskmeals, UK, where DU munitions have been tested against hard targets and unfired DU buried in soils for corrosion studies. Using electron microscopy and X-ray analyses, three classes of particles were identified: (1) DU aerosols and fragments, typically 1-20 μm diameter, composed mainly of uranium as UO(2) and U(3)O(8), (2) solidified molten particles, typically 200-500 μm diameter, composed of U, mixed with Fe from target materials and (3) deposits and coatings, often of metaschoepite on sand grains up to 500 μm diameter. The first two particle types are derived from firing impacts, the last from corrosion of buried uranium metal. Alpha and mass spectrometry allowed quantitative elemental and isotopic characterisation of DU-containing particulate environmental samples.
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Affiliation(s)
- Mustafa Sajih
- Centre for Radiochemistry Research, School of Chemistry, University of Manchester, Manchester, M13 9PL, UK.
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Lear G, McBeth JM, Boothman C, Gunning DJ, Ellis BL, Lawson RS, Morris K, Burke IT, Bryan ND, Brown AP, Livens FR, Lloyd JR. Probing the biogeochemical behavior of technetium using a novel nuclear imaging approach. Environ Sci Technol 2010; 44:156-162. [PMID: 20039746 DOI: 10.1021/es802885r] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Dynamic gamma-camera imaging of radiotracer technetium ((99m)Tc) was used to assess the impact of biostimulation of metal-reducing bacteria on technetium mobility at 10(-12) mol L(-1) concentrations in sediments. Addition of the electron donor acetate was used to stimulate a redox profile in sediment columns, from oxic to Fe(III)-reducing conditions. When (99m)Tc was pumped through the columns, real-time gamma-camera imaging combined with geochemical analyses showed technetium was localized in regions containing biogenic Fe(II). In parallel experiments, electron microscopy with energy-dispersive X-ray (EDX) mapping confirmed sediment-bound Tc was associated with iron, while X-ray absorption spectroscopy (XAS) confirmed reduction of Tc(VII) to poorly soluble Tc(IV). Molecular analyses of microbial communities in these experiments supported a direct link between biogenic Fe(II) accumulation and Tc(VII) reductive precipitation, with Fe(III)-reducing bacteria more abundant in technetium immobilization zones. This offers a novel approach to assessing radionuclide mobility at ultratrace concentrations in real-time biogeochemical experiments, and confirms the effectiveness of biostimulation of Fe(III)-reducing bacteria in immobilizing technetium.
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Affiliation(s)
- Gavin Lear
- Williamson Centre for Molecular Environmental Science, School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, M13 9PL, UK
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Law GTW, Geissler A, Boothman C, Burke IT, Livens FR, Lloyd JR, Morris K. Role of nitrate in conditioning aquifer sediments for technetium bioreduction. Environ Sci Technol 2010; 44:150-155. [PMID: 20039745 DOI: 10.1021/es9010866] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Here we examine the bioreduction of technetium-99 in sediment microcosm experiments with varying nitrate and carbonate concentrations added to synthetic groundwater to assess the influence of pH and nitrate on bioreduction processes. The systems studied include unamended-, carbonate buffered-, low nitrate-, and high nitrate-groundwaters. During anaerobic incubation, terminal electron accepting processes (TEAPs) in the circumneutral pH, carbonate buffered system progressed to sulfate reduction, and Tc(VII) was removed from solution during Fe(III) reduction. In the high-nitrate system, pH increased during denitrification (pH 5.5 to 7.2), then TEAPs progressed to sulfate reduction. Again, Tc(VII) removal was associated with Fe(III) reduction. In both systems, XAS confirmed reduction to hydrous Tc(IV)O(2) like phases on Tc removal from solution. In the unamended and low-nitrate systems, the pH remained low, Fe(III) reduction was inhibited, and Tc(VII) remained in solution. Thus, nitrate can have complex influences on the development of the metal reducing conditions required for radionuclide treatment. High nitrate concentrations stimulated denitrification and caused pH neutralization facilitating Fe(III) reduction and Tc(VII) removal; acidic, low nitrate systems showed no Fe(III)-reduction. These results have implications for Tc-cycling in contaminated environments where nitrate has been considered undesirable, but where it may enhance Fe(III)-reduction via a novel pH "conditioning" step.
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Affiliation(s)
- Gareth T W Law
- Earth System Science Institute, School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK
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36
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Handley-Sidhu S, Bryan ND, Worsfold PJ, Vaughan DJ, Livens FR, Keith-Roach MJ. Corrosion and transport of depleted uranium in sand-rich environments. Chemosphere 2009; 77:1434-1439. [PMID: 19783278 DOI: 10.1016/j.chemosphere.2009.08.053] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Revised: 08/24/2009] [Accepted: 08/28/2009] [Indexed: 05/28/2023]
Abstract
The firing of depleted uranium (DU) weapons during conflicts and military testing has resulted in the deposition of DU in a variety of sand-rich environments. In this study, DU-amended dune sand microcosm and column experiments were carried out to investigate the corrosion of DU and the transport of corrosion products. Under field-moist conditions, DU corroded to metaschoepite ((UO(2))(8)O(2)(OH)(12).(H(2)O)(10)) at a rate of 0.10+/-0.012 g cm(-2)y(-1). This loosely bound corrosion product detached easily from the coupon and became distributed heterogeneously within the sand. The corrosion of DU caused significant changes in the geochemical environment, with NO(3)(-) and Fe(III) reduction observed. Column experiments showed that transport of metaschoepite was mainly dependent on its dissolution and the subsequent interaction of the resulting dissolved uranyl (UO(2)(2+)) species with sand particles. The modelling results predict that the transport of U released from metaschoepite dissolution is retarded, due to a slowly desorbing surface species (first order desorption rate constant=5.0 (+/-1.0)x10(-8)s(-1)). The concentrations of U eluting from the metaschoepite column were orders of magnitude higher than the World Health Organisation's recommended maximum admissible concentration for U in drinking water of 15 microg L(-1). Therefore, a relatively high level of mobile U contamination would be expected in the immediate proximity of a corroding penetrator in a sand-rich environment.
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Affiliation(s)
- Stephanie Handley-Sidhu
- Biogeochemistry and Environmental Analytical Chemistry Research Group, School of Earth, Ocean and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK.
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Handley-Sidhu S, Worsfold PJ, Livens FR, Vaughan DJ, Lloyd JR, Boothman C, Sajih M, Alvarez R, Keith-Roach MJ. Biogeochemical controls on the corrosion of depleted uranium alloy in subsurface soils. Environ Sci Technol 2009; 43:6177-6182. [PMID: 19746710 DOI: 10.1021/es901276e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Military activities have left a legacy of depleted uranium (DU) penetrator waste in the near-surface terrestrial environment. To understand the fate of this DU alloy, the mechanisms and controlling factors of corrosion need to be determined. In this study, field-moist and waterlogged microcosms were used to investigate the effect of redox conditions and soil water content on the corrosion and fate of DU in subsurface soil, and the impact of corroding DU on the soil microbial population. The mechanism of corrosion and the corrosion products formed were highly dependent on the water status of the soil. Under field-moist conditions, DU corroded at a rate of 0.49 +/- 0.06 g cm(-2) y(-1) and the main U input to surrounding soil was large metaschoepite [(UO2)8O2(OH)12 x (H2O)10] particles. However, underwaterlogged conditions the rate of corrosion was significantly slower at 0.01-0.02 g cm(-2) y(-1) and occurred with the release of dissolved species to the surrounding environment. Corrosion ceases under reducing conditions, thus redox conditions are important in determining the persistence of penetrators in the environment. Corroding DU alters the redox conditions in the surrounding environment and both mechanisms of corrosion impact the microbial community.
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Affiliation(s)
- Stephanie Handley-Sidhu
- Biogeochemistry and Environmental Analytical Chemistry Research Group, School of Earth, Ocean and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK
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Walton RC, McCrohan CR, Livens FR, White KN. Tissue accumulation of aluminium is not a predictor of toxicity in the freshwater snail, Lymnaea stagnalis. Environ Pollut 2009; 157:2142-2146. [PMID: 19285770 DOI: 10.1016/j.envpol.2009.02.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2008] [Revised: 02/03/2009] [Accepted: 02/08/2009] [Indexed: 05/27/2023]
Abstract
The amount of toxic metal accumulated by an organism is often taken as an indicator of potential toxicity. We investigated this relationship in the freshwater snail, Lymnaea stagnalis, exposed to 500 microg l(-1) Al over 30 days, either alone or in the presence of phosphate (500 microg l(-1) P) or a fulvic acid surrogate (FAS; 10 mg l(-1) C). Behavioural activity was assessed and tissue accumulation of Al quantified. Lability of Al within the water column was a good predictor of toxicity. FAS increased both Al lability and behavioural dysfunction, whereas phosphate reduced Al lability, and completely abolished Al-induced behavioural toxicity. Tissue accumulation of Al was not linked to toxicity. Higher levels of Al were accumulated in snails exposed to Al + P, compared to those exposed to Al alone, whereas FAS reduced Al accumulation. These findings demonstrate that the degree of tissue accumulation of a metal can be independent of toxicity.
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Affiliation(s)
- Rachel C Walton
- Faculty of Life Sciences, The University of Manchester, Oxford Road, Manchester M13 9PT, UK.
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Handley-Sidhu S, Worsfold PJ, Boothman C, Lloyd JR, Alvarez R, Livens FR, Vaughan DJ, Keith-Roach MJ. Corrosion and fate of depleted uranium penetrators under progressively anaerobic conditions in estuarine sediment. Environ Sci Technol 2009; 43:350-355. [PMID: 19238963 DOI: 10.1021/es8021842] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The testing of armor-piercing depleted uranium (DU) "penetrators" has resulted in the deposition of DU in the sediments of the Solway Firth, UK. In this study, DU-amended, microcosm experiments simulating Solway Firth sediments under high (31.5) and medium (16.5) salinity conditions were used to investigate the effect of salinity and biogeochemical conditions on the corrosion and fate of DU, and the impact of the corroding DU on the microbial population. Under suboxic conditions, the average corrosion rates were the same forthe 31.5 and 16.5 salinity systems at 0.056 +/- 0.006 g cm(-2) y(-1), implying that complete corrosion of a 120 mm penetrator would take approximately 540 years. Under sulfate-reducing conditions, corrosion ceased due to passivation of the surface. Corroding DU resulted in more reducing conditions and decreased microbial diversity as indicated by DNA sequencing and phylogenetic analysis. The lack of colloidal and particulate DU corrosion products, along with measurable dissolved U and a homogeneous association of U with the sediment, suggest that U was transported from the penetrator surface into the surrounding environment through dissolution of U(VI), with subsequent interactions resulting in the formation of secondary uranium species in the sediment.
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Affiliation(s)
- Stephanie Handley-Sidhu
- Biogeochemistry and Environmental Analytical Chemistry Research Group, School of Earth, Ocean and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK
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Long M, Thornthwaite DW, Rogers SH, Bonzi G, Livens FR, Rannard SP. Utilising 14C-radiolabelled atom transfer radical polymerisation initiators. Chem Commun (Camb) 2009:6406-8. [DOI: 10.1039/b913294e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Talbot-Eeckelaers C, Pope SJA, Hynes AJ, Copping R, Jones CJ, Taylor RJ, Faulkner S, Sykes D, Livens FR, May I. Luminescence from neptunyl(VI) species in solution. J Am Chem Soc 2007; 129:2442-3. [PMID: 17295490 DOI: 10.1021/ja068522n] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Catherine Talbot-Eeckelaers
- Centre for Radiochemistry Research, School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K
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Burke IT, Boothman C, Lloyd JR, Livens FR, Charnock JM, McBeth JM, Mortimer RJG, Morris K. Reoxidation behavior of technetium, iron, and sulfur in estuarine sediments. Environ Sci Technol 2006; 40:3529-35. [PMID: 16786690 DOI: 10.1021/es052184t] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Technetium is a redox active radionuclide, which is present as a contaminant at a number of sites where nuclear fuel cycle operations have been carried out. Recent studies suggest that Tc(VII), which is soluble under oxic conditions, will be retained in sediments as Fe(III)-reducing conditions develop, due to reductive scavenging as hydrous TcO2. However, the behavior of technetium during subsequent reoxidation of sediments remains poorly characterized. Here, we describe a microcosm-based approach to investigate the reoxidation behavior of reduced, technetium-contaminated sediments. In reoxidation experiments, the behavior of Tc was strongly dependent on the nature of the oxidant. With air, reoxidation of Fe(II) and, in sulfate-reducing sediments, sulfide occurred accompanied by approximately 50% remobilization of Tc to solution as TcO4-. With nitrate, reoxidation of Fe(II) and, in sulfate-reducing sediments, sulfide only occurred in microbially active experiments where Fe(II) and sulfide oxidation coupled to nitrate reduction was occurring. Here, Tc was recalcitrant to remobilization with <10% Tc remobilized to solution even when extensive Fe(II) and sulfide reoxidation had occurred. X-ray absorption spectroscopy on reoxidized sediments suggested that 15-50% of Tc bound to sediments was present as Tc(VII). Overall, these results suggest that Tc reoxidation behavior is not directly coupled to Fe or S oxidation and that the extent of Tc remobilization is dependent on the nature of the oxidant.
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Affiliation(s)
- Ian T Burke
- Institute of Geological Sciences, School of Earth & Environment, University of Leeds, Leeds, LS2 9JT, UK
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Khijniak TV, Slobodkin AI, Coker V, Renshaw JC, Livens FR, Bonch-Osmolovskaya EA, Birkeland NK, Medvedeva-Lyalikova NN, Lloyd JR. Reduction of uranium(VI) phosphate during growth of the thermophilic bacterium Thermoterrabacterium ferrireducens. Appl Environ Microbiol 2005; 71:6423-6. [PMID: 16204572 PMCID: PMC1265970 DOI: 10.1128/aem.71.10.6423-6426.2005] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The thermophilic, gram-positive bacterium Thermoterrabacterium ferrireducens coupled organotrophic growth to the reduction of sparingly soluble U(VI) phosphate. X-ray powder diffraction and X-ray absorption spectroscopy analysis identified the electron acceptor in a defined medium as U(VI) phosphate [uramphite; (NH4)(UO2)(PO4) . 3H2O], while the U(IV)-containing precipitate formed during bacterial growth was identified as ningyoite [CaU(PO4)2 . H2O]. This is the first report of microbial reduction of a largely insoluble U(VI) compound.
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Affiliation(s)
- T V Khijniak
- The Williamson Research Centre for Molecular Environmental Science and The School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester M13 9PL, United Kingdom
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Abstract
The interaction between two contrasting examples of lake sediments and small concentrations of mercury added to the sediments in solution has been studied using X-ray absorption spectroscopy. Whereas one lake (Esthwaite Water) is biologically productive, with a seasonal cycle of phytoplankton activity, including stratification and Fe(III) reduction, and a mineralogy involving quartz, muscovite, and clinochlore, the other (Botany Pond) remains oxic throughout the year. In the latter case, the sediment is predominantly quartz and calcite. Chemical analyses of these two lake sediments reflectthe differences in mineralogy and showthat both contain significant organic carbon (approximately 10-12 wt %) and smaller amounts of S (approximately 0.2-1.7 wt %) and Cl (approximately 0.4-1.1 wt %). Despite the substantial amounts of organic matter in both sediments, the spectroscopic data show that the mercury occurs as a sulfide phase with a local structural environment akin to that in cinnabar. Parallel spectroscopic studies conducted on Hg either coprecipitated or sorbed onto FeS (mackinawite), and on oxidized mackinawite, provide supporting information; the possibility of Hg forming a chloride was eliminated by careful mapping of the relevant elements by an electron microprobe. It appears, therefore, that the high affinity of Hg for S predominates even in substantially oxic environments.
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Affiliation(s)
- Steven Wolfenden
- School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester, United Kingdom
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Renshaw JC, Butchins LJC, Livens FR, May I, Charnock JM, Lloyd JR. Bioreduction of uranium: environmental implications of a pentavalent intermediate. Environ Sci Technol 2005; 39:5657-60. [PMID: 16124300 DOI: 10.1021/es048232b] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The release of uranium and other transuranics into the environment, and their subsequent mobility, are subjects of intense public concern. Uranium dominates the inventory of most medium- and low-level radioactive waste sites and under oxic conditions is highly mobile as U(VI), the soluble uranyl dioxocation (UO2)2+. Specialist anaerobic bacteria are, however, able to reduce U(VI)to insoluble U(IV), offering a strategy for the bioremediation of uranium-contaminated groundwater and a potential mechanism for the biodeposition of uranium ores. Despite the environmental importance of U(VI) bioreduction, there is little information on the mechanism of this transformation. In the course of this study we used X-ray absorption spectroscopy (XAS) to show that the subsurface metal-reducing bacterium Geobacter sulfurreducens reduces U(VI) by a one-electron reduction, forming an unstable (UO2)+ species. The final, insoluble U(IV) product could be formed either through further reduction of U(V) or through its disproportionation. When G. sulfurreducens was challenged with the chemically analogous (NpO2)+, which is stable with respect to disproportionation, it was not reduced, suggesting that it is disproportionation of U(V) which leads to the U(IV) product. This surprising discrimination between U and Np illustrates the need for mechanistic understanding and care in devising in situ bioremediation strategies for complex wastes containing other redox-active actinides, including plutonium.
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Affiliation(s)
- Joanna C Renshaw
- Williamson Research Centre for Molecular Environmental Science, School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester, United Kingdom
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Burke IT, Boothman C, Lloyd JR, Mortimer RJG, Livens FR, Morris K. Effects of progressive anoxia on the solubility of technetium in sediments. Environ Sci Technol 2005; 39:4109-16. [PMID: 15984789 DOI: 10.1021/es048124p] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Technetium is a significant radioactive contaminant from nuclear fuel cycle operations. It is highly mobile in its oxic form (as Tc(VII)O4-) but is scavenged to sediments in its reduced forms (predominantly Tc(IV)). Here we examine the behavior of Tc at low concentrations and as microbial anoxia develops in sediment microcosms. A cascade of stable-element terminal-electron-accepting processes developed in microcosms due to indigenous microbial activity. TcO4- removal from solution occurred during active microbial Fe(III) reduction, which generated Fe(II) in the sediments and was complete before sulfate reduction began. Microbial community analysis revealed a similar and complex microbial population at all three sample sites. At the intermediate salinity site, PauII, a broad range of NO3-, Mn(IV), Fe(III), and SO4(2-) reducers were present in sediments including microbes with the potential to reduce Fe(III) to Fe(II), although no differences in the microbial population were discerned as anoxia developed. When sterilized sediments were incubated with pure cultures of NO3(-)-, Fe(III)-, and sulfate-reducing bacteria, TcO4- removal occurred during active Fe(III) reduction. X-ray absorption spectroscopy confirmed that TcO4- removal was due to reduction to hydrous Tc(IV)O2 in Fe(III)- and sulfate-reducing estuarine sediments.
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Affiliation(s)
- Ian T Burke
- School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK
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Bhatt AI, du Fou de Kerdaniel E, Kinoshita H, Livens FR, May I, Polovov IB, Sharrad CA, Volkovich VA, Charnock JM, Lewin RG. Uranium Oligomerization in Chloride-Based High Temperature Melts: In Situ XAS Studies. Inorg Chem 2004; 44:2-4. [PMID: 15627351 DOI: 10.1021/ic048617v] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In situ EXAFS spectroscopic studies of uranium compounds in high temperature alkali chloride melts indicate the presence of oligomeric species. An investigation into UCl(3) and UCl(4) dissolved in LiCl reveals long range ordering of uranium atoms in the molten state which is not maintained on quenching. Studies of uranium dioxide dissolved in LiCl-KCl eutectic with HCl exhibit long range ordering in both molten and quenched states, and the EXAFS data can be modeled using multiple coordination shells.
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Affiliation(s)
- Anand I Bhatt
- Centre for Radiochemistry Research, Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
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Livens FR, Jones MJ, Hynes AJ, Charnock JM, Mosselmans JFW, Hennig C, Steele H, Collison D, Vaughan DJ, Pattrick RAD, Reed WA, Moyes LN. X-ray absorption spectroscopy studies of reactions of technetium, uranium and neptunium with mackinawite. J Environ Radioact 2004; 74:211-219. [PMID: 15063549 DOI: 10.1016/j.jenvrad.2004.01.012] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Technetium, uranium and neptunium may all occur in the environment in more than one oxidation state (IV or VII, IV or VI and IV or V respectively). The surface of mackinawite, the first-formed iron sulfide phase in anoxic conditions, can promote redox changes so a series of laboratory experiments were carried out to explore the interactions of Tc, U and Np with this mineral. The products of reaction were characterised using X-ray absorption spectroscopy. Technetium, added as TcO4(-), is reduced to oxidation state IV and forms a TcS(2)-like species. On oxidation of the mackinawite in air to form goethite, Tc remains in oxidation state IV but in an oxide, rather than a sulfide environment. At low concentrations, uranium forms uranyl surface complexes on oxidised regions of the mackinawite surface but at higher concentrations, the uranium promotes surface oxidation and forms a mixed oxidation state oxide phase. Neptunium is reduced to oxidation IV and forms a surface complex with surface sulfide ions. The remainder of the Np coordination sphere is filled with water molecules or hydroxide ions.
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Affiliation(s)
- Francis R Livens
- Centre for Radiochemistry Research, Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
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