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Williamson AJ, Binet M, Sergeant C. Radionuclide biogeochemistry: from bioremediation toward the treatment of aqueous radioactive effluents. Crit Rev Biotechnol 2024; 44:698-716. [PMID: 37258417 DOI: 10.1080/07388551.2023.2194505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 10/07/2022] [Accepted: 01/29/2023] [Indexed: 06/02/2023]
Abstract
Civilian and military nuclear programs of several nations over more than 70 years have led to significant quantities of heterogenous solid, organic, and aqueous radioactive wastes bearing actinides, fission products, and activation products. While many physicochemical treatments have been developed to remediate, decontaminate and reduce waste volumes, they can involve high costs (energy input, expensive sorbants, ion exchange resins, chemical reducing/precipitation agents) or can lead to further secondary waste forms. Microorganisms can directly influence radionuclide solubility, via sorption, accumulation, precipitation, redox, and volatilization pathways, thus offering a more sustainable approach to remediation or effluent treatments. Much work to date has focused on fundamentals or laboratory-scale remediation trials, but there is a paucity of information toward field-scale bioremediation and, to a lesser extent, toward biological liquid effluent treatments. From the few biostimulation studies that have been conducted at legacy weapon production/test sites and uranium mining and milling sites, some marked success via bioreduction and biomineralisation has been observed. However, rebounding of radionuclide mobility from (a)biotic scale-up factors are often encountered. Radionuclide, heavy metal, co-contaminant, and/or matrix effects provide more challenging conditions than traditional industrial wastewater systems, thus innovative solutions via indirect interactions with stable element biogeochemical cycles, natural or engineered cultures or communities of metal and irradiation tolerant strains and reactor design inspirations from existing metal wastewater technologies, are required. This review encompasses the current state of the art in radionuclide biogeochemistry fundamentals and bioremediation and establishes links toward transitioning these concepts toward future radioactive effluent treatments.
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Affiliation(s)
| | - Marie Binet
- EDF R&D, LNHE (Laboratoire National d'Hydraulique et Environnement), Chatou, France
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2
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Hilpmann S, Rossberg A, Steudtner R, Drobot B, Hübner R, Bok F, Prieur D, Bauters S, Kvashnina KO, Stumpf T, Cherkouk A. Presence of uranium(V) during uranium(VI) reduction by Desulfosporosinus hippei DSM 8344 T. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 875:162593. [PMID: 36889400 DOI: 10.1016/j.scitotenv.2023.162593] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 02/27/2023] [Accepted: 02/27/2023] [Indexed: 06/18/2023]
Abstract
Microbial U(VI) reduction influences uranium mobility in contaminated subsurface environments and can affect the disposal of high-level radioactive waste by transforming the water-soluble U(VI) to less mobile U(IV). The reduction of U(VI) by the sulfate-reducing bacterium Desulfosporosinus hippei DSM 8344T, a close phylogenetic relative to naturally occurring microorganism present in clay rock and bentonite, was investigated. D. hippei DSM 8344T showed a relatively fast removal of uranium from the supernatants in artificial Opalinus Clay pore water, but no removal in 30 mM bicarbonate solution. Combined speciation calculations and luminescence spectroscopic investigations showed the dependence of U(VI) reduction on the initial U(VI) species. Scanning transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy showed uranium-containing aggregates on the cell surface and some membrane vesicles. By combining different spectroscopic techniques, including UV/Vis spectroscopy, as well as uranium M4-edge X-ray absorption near-edge structure recorded in high-energy-resolution fluorescence-detection mode and extended X-ray absorption fine structure analysis, the partial reduction of U(VI) could be verified, whereby the formed U(IV) product has an unknown structure. Furthermore, the U M4 HERFD-XANES showed the presence of U(V) during the process. These findings offer new insights into U(VI) reduction by sulfate-reducing bacteria and contribute to a comprehensive safety concept for a repository for high-level radioactive waste.
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Affiliation(s)
- Stephan Hilpmann
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - André Rossberg
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany; Rossendorf Beamline (BM20-ROBL), European Synchrotron Radiation Facility, Grenoble, France
| | - Robin Steudtner
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Björn Drobot
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - René Hübner
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Ion Beam Physics and Materials Research, Dresden, Germany
| | - Frank Bok
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Damien Prieur
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany; Rossendorf Beamline (BM20-ROBL), European Synchrotron Radiation Facility, Grenoble, France
| | - Stephen Bauters
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany; Rossendorf Beamline (BM20-ROBL), European Synchrotron Radiation Facility, Grenoble, France
| | - Kristina O Kvashnina
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany; Rossendorf Beamline (BM20-ROBL), European Synchrotron Radiation Facility, Grenoble, France
| | - Thorsten Stumpf
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Andrea Cherkouk
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany.
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Stylo M, Alessi DS, Shao PP, Lezama-Pacheco JS, Bargar JR, Bernier-Latmani R. Biogeochemical controls on the product of microbial U(VI) reduction. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:12351-12358. [PMID: 24102177 DOI: 10.1021/es402631w] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Biologically mediated immobilization of radionuclides in the subsurface is a promising strategy for the remediation of uranium-contaminated sites. During this process, soluble U(VI) is reduced by indigenous microorganisms to sparingly soluble U(IV). The crystalline U(IV) phase uraninite, or UO2, is the preferable end-product of bioremediation due to its relatively high stability and low solubility in comparison to biomass-associated nonuraninite U(IV) species that have been reported in laboratory and under field conditions. The goal of this study was to delineate the geochemical conditions that promote the formation of nonuraninite U(IV) versus uraninite and to decipher the mechanisms of its preferential formation. U(IV) products were prepared under varying geochemical conditions and characterized with X-ray absorption spectroscopy (XAS), scanning transmission X-ray microscopy (STXM), and various wet chemical methods. We report an increasing fraction of nonuraninite U(IV) species with decreasing initial U concentration. Additionally, the presence of several common groundwater solutes (sulfate, silicate, and phosphate) promote the formation of nonuraninite U(IV). Our experiments revealed that the presence of those solutes promotes the formation of bacterial extracellular polymeric substances (EPS) and increases bacterial viability, suggesting that the formation of nonuraninite U(IV) is due to a biological response to solute presence during U(VI) reduction. The results obtained from this laboratory-scale research provide insight into biogeochemical controls on the product(s) of uranium reduction during bioremediation of the subsurface.
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Affiliation(s)
- Malgorzata Stylo
- Environmental Microbiology Laboratory, École Polytechnique Fédérale de Lausanne , CH-1015, Lausanne, Switzerland
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Bacterial Community Structure from the Perspective of the Uranium Ore Deposits of Domiasiat in India. ACTA ACUST UNITED AC 2013. [DOI: 10.1007/s40011-013-0164-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Vidaud C, Bourgeois D, Meyer D. Bone as Target Organ for Metals: The Case of f-Elements. Chem Res Toxicol 2012; 25:1161-75. [DOI: 10.1021/tx300064m] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Claude Vidaud
- CEA, IBEB, LEPC, BP 17171, F-30207
Bagnols-sur-Cèze, France
| | - Damien Bourgeois
- ICSM, UMR 5257/CEA/CNRS/UM2/ENSCM,
BP17171, F-30207 Bagnols-sur-Cèze, France
| | - Daniel Meyer
- ICSM, UMR 5257/CEA/CNRS/UM2/ENSCM,
BP17171, F-30207 Bagnols-sur-Cèze, France
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6
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Deo RP, Rittmann BE. A biogeochemical framework for bioremediation of plutonium(V) in the subsurface environment. Biodegradation 2012; 23:525-34. [DOI: 10.1007/s10532-011-9530-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2011] [Accepted: 12/17/2011] [Indexed: 11/24/2022]
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7
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Bacterial Pu(V) reduction in the absence and presence of Fe(III)–NTA: modeling and experimental approach. Biodegradation 2011; 22:921-9. [DOI: 10.1007/s10532-010-9451-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Accepted: 12/27/2010] [Indexed: 10/18/2022]
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O’Loughlin EJ, Boyanov MI, Antonopoulos DA, Kemner KM. Redox Processes Affecting the Speciation of Technetium, Uranium, Neptunium, and Plutonium in Aquatic and Terrestrial Environments. ACS SYMPOSIUM SERIES 2011. [DOI: 10.1021/bk-2011-1071.ch022] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Edward J. O’Loughlin
- Biosciences Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439
- The Institute for Genomics and Systems Biology, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439
| | - Maxim I. Boyanov
- Biosciences Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439
- The Institute for Genomics and Systems Biology, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439
| | - Dionysios A. Antonopoulos
- Biosciences Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439
- The Institute for Genomics and Systems Biology, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439
| | - Kenneth M. Kemner
- Biosciences Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439
- The Institute for Genomics and Systems Biology, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439
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Contribution to interpretation of metal uptake dependence upon the growth phase of microorganisms. The case of uranium (VI) uptake by common yeasts, cultivated at different temperatures, with or without aeration. J Radioanal Nucl Chem 2010. [DOI: 10.1007/s10967-010-0811-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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10
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Deo RP, Songkasiri W, Rittmann BE, Reed DT. Surface complexation of Neptunium(V) onto whole cells and cell components of Shewanella alga: modeling and experimental study. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:4930-4935. [PMID: 20521812 DOI: 10.1021/es9035336] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We systematically quantified surface complexation of Np(V) onto whole cells, cell wall, and extracellular polymeric substances (EPS) of Shewanella alga strain BrY. We first performed acid and base titrations and used the mathematical model FITEQL to estimate the concentrations and deprotonation constants of specific surface functional groups. Deprotonation constants most likely corresponded to a carboxyl group not associated with amino acids (pK(a) approximately 5), a phosphoryl site (pK(a) approximately 7.2), and an amine site (pK(a) > 10). We then carried out batch sorption experiments with Np(V) and each of the S. alga components as a function of pH. Since significant Np(V) sorption was observed on S. alga whole cells and its components in the pH range 2-5, we assumed the existence of a fourth site: a low-pK(a) carboxyl site (pK(a) approximately 2.4) that is associated with amino acids. We used the SPECIATE submodel of the biogeochemical model CCBATCH to compute the stability constants for Np(V) complexation to each surface functional group. The stability constants were similar for each functional group on S. alga bacterial whole cells, cell walls, and EPS, and they explain the complicated sorption patterns when they are combined with the aqueous-phase speciation of Np(V). For pH < 8, the aquo NpO(2)(+) species was the dominant form of Np(V), and its log K values for the low-pK(a) carboxyl, mid-pK(a) carboxyl, and phosphoryl groups were 1.8, 1.8, and 2.5-3.1, respectively. For pH greater than 8, the key surface ligand was amine >XNH(3)(+), which complexed with NpO(2)(CO(3))(3)(5-). The log K for NpO(2)(CO(3))(3)(5-) complexed onto the amine groups was 3.1-3.9. All of the log K values are similar to those of Np(V) complexes with aqueous carboxyl and N-containing carboxyl ligands. These results help quantify the role of surface complexation in defining actinide-microbiological interactions in the subsurface.
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Affiliation(s)
- Randhir P Deo
- Center for Environmental Biotechnology, Biodesign Institute, Arizona State University, Tempe, Arizona 85287-5701, USA
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11
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Reed DT, Lucchini JF, Aase SB, Kropf AJ. Reduction of plutonium(VI) in brine under subsurface conditions. RADIOCHIM ACTA 2009. [DOI: 10.1524/ract.2006.94.9-11.591] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The redox stability of PuO2
2+ was investigated in brine under subsurface conditions. In simulated brines, when no reducing agent was present, 0.1 mM concentrations of plutonium(VI) were stable as regards to reduction for over two years, which was the duration of the experiments performed. In these systems, the plutonyl existed as a carbonate or hydroxy-chloride species. The introduction of reducing agents (e.g. steel coupons, and aqueous Fe2+) typically present in a subsurface repository, however, led to the destabilization of the plutonium(VI) complexes and the subsequent reduction to Pu(IV) under most conditions investigated. X-ray Absorption Near-Edge Spectroscopy (XANES) confirmed that the final oxidation state in these systems was Pu(IV). This reduction lowered the overall steady state concentration of plutonium in the brine by 3−4 orders of magnitude. These results show the importance of considering repository constituents in evaluating subsurface actinide solubility/mobility and provide further evidence of the effectiveness of reduced iron species in the reduction and immobilization of higher-valent plutonium species.
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Abstract
We studied the interaction of Pu(VI) withPseudomonas stutzeriATCC 17588 andBacillus sphaericusATCC 14577, representatives of the main aerobic groups of soil bacteria present in the upper soil layers. The biosorption studies have shown that these soil bacteria accumulate high amounts of Pu(VI). The relative sorption efficiency toward Pu(VI) related to the amount of biomass used decreased with increasing biomass concentration due to increased agglomeration of the bacteria resulting in a decrease of the number of available complexing groups. Spores ofBacillus sphaericusshowed a higher biosorption than the vegetative cells at low biomass concentration which decreased significantly with increasing biomass concentration. At higher biomass concentrations (>0.7 g/L), the vegetative cells of both strains and the spores ofB. sphaericusshowed comparable sorption efficiencies. Investigations on the pH dependency of the biosorption and extraction studies with 0.01 M EDTA solution have shown that the biosorption of plutonium is a reversible process and the plutonium is bound by surface complexation. Optical absorption spectroscopy showed that one third of the initially present Pu(VI) was reduced to Pu(V) after 24 hours. Kinetic studies and solvent extraction to separate different oxidation states of Pu after contact with the biomass provided further information on the yield and the kinetics of the bacteria-mediated reduction. Long-term studies showed that also 16% of Pu(IV) was formed after one month. The slow kinetics of this process indicate that under our experimental conditions the Pu(IV) was not a produced by microbial reduction but seemed to be rather the result of the disproportionation of the formed Pu(V) or autoreduction of Pu(VI).
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Abstract
SummaryPlutonium has no known biological utility, yet it has the potential to interact with bacterial cellular and extracellular structures that contain metal-binding groups, to interfere with the uptake and utilization of essential elements, and to alter cell metabolism. These interactions can transform plutonium from its most common forms, solid, mineral-adsorbed, or colloidal Pu(IV), to a variety of biogeochemical species that have much different physico-chemical properties. Organic acids that are extruded products of cell metabolism can solubilize plutonium and then enhance its environmental mobility, or in some cases facilitate plutonium transfer into cells. Phosphate- and carboxylate-rich polymers associated with cell walls can bind plutonium to form mobile biocolloids or Pu-laden biofilm/mineral solids. Bacterial membranes, proteins or redox agents can produce strongly reducing electrochemical zones and generate molecular Pu(III/IV) species or oxide particles. Alternatively, they can oxidize plutonium to form soluble Pu(V) or Pu(VI) complexes. This paper reviews research on plutonium-bacteria interactions and closely related studies on the biotransformation of uranium and other metals.
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Hu QH, Zavarin M, Rose TP. Effect of reducing groundwater on the retardation of redox-sensitive radionuclides. GEOCHEMICAL TRANSACTIONS 2008; 9:12. [PMID: 19077277 PMCID: PMC2615433 DOI: 10.1186/1467-4866-9-12] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2008] [Accepted: 12/12/2008] [Indexed: 05/27/2023]
Abstract
Laboratory batch sorption experiments were used to investigate variations in the retardation behavior of redox-sensitive radionuclides. Water-rock compositions were designed to simulate subsurface conditions at the Nevada Test Site (NTS), where a suite of radionuclides were deposited as a result of underground nuclear testing. Experimental redox conditions were controlled by varying the oxygen content inside an enclosed glove box and by adding reductants into the testing solutions. Under atmospheric (oxidizing) conditions, radionuclide distribution coefficients varied with the mineralogic composition of the sorbent and the water chemistry. Under reducing conditions, distribution coefficients showed marked increases for 99Tc (from 1.22 at oxidizing to 378 mL/g at mildly reducing conditions) and 237Np (an increase from 4.6 to 930 mL/g) in devitrified tuff, but much smaller variations in alluvium, carbonate rock, and zeolitic tuff. This effect was particularly important for 99Tc, which tends to be mobile under oxidizing conditions. A review of the literature suggests that iodine sorption should decrease under reducing conditions when I- is the predominant species; this was not consistently observed in batch tests. Overall, sorption of U to alluvium, devitrified tuff, and zeolitic tuff under atmospheric conditions was less than in the glove-box tests. However, the mildly reducing conditions achieved here were not likely to result in substantial U(VI) reduction to U(IV). Sorption of Pu was not affected by the decreasing Eh conditions achieved in this study, as the predominant sorbed Pu species in all conditions was expected to be the low-solubility and strongly sorbing Pu(OH)4. Depending on the aquifer lithology, the occurrence of reducing conditions along a groundwater flowpath could potentially contribute to the retardation of redox-sensitive radionuclides 99Tc and 237Np, which are commonly identified as long-term dose contributors in the risk assessment in various radionuclide environmental contamination scenarios. The implications for increased sorption of 99Tc and 237Np to devitrified tuff under reducing conditions are significant as the fractured devitrified tuff serves as important water flow path at the NTS and the horizon for a proposed repository to store high-level nuclear waste at Yucca Mountain.
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Affiliation(s)
- QH Hu
- Department of Earth and Environmental Sciences, University of Texas at Arlington, Arlington, TX 76019, USA
| | - M Zavarin
- Lawrence Livermore National Laboratory, 7000 East Avenue, MS L-231, Livermore, CA 94550, USA
| | - TP Rose
- Lawrence Livermore National Laboratory, 7000 East Avenue, MS L-231, Livermore, CA 94550, USA
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Keith-Roach MJ. The speciation, stability, solubility and biodegradation of organic co-contaminant radionuclide complexes: a review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2008; 396:1-11. [PMID: 18384838 DOI: 10.1016/j.scitotenv.2008.02.030] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2007] [Revised: 02/14/2008] [Accepted: 02/20/2008] [Indexed: 05/26/2023]
Abstract
The potential migration of radionuclides is of concern at contaminated land sites and, in the long term, waste repositories. Pathways of migration need to be characterised on a predictive level so that management decisions can be made with confidence. A pathway that is relatively poorly understood at present is radionuclide solubilisation due to complexation by organic complexing agents that are present in mixed radioactive wastes, and at radioactively contaminated land sites. Interactions of the complexing agents with radionuclides and the host environment, and the response to changes in the physicochemical conditions make their role far from simple to elucidate. In addition, chemical and biodegradation of the organic materials may be important. In this paper, key co-contaminant organics are reviewed with emphasis on their environmental fate and impact on radionuclide migration.
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Affiliation(s)
- Miranda J Keith-Roach
- Biogeochemistry and Environmental Analytical Chemistry Group/Consolidated Radio-isotope Facility, School of Earth, Ocean and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK.
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Francis AJ, Dodge CJ, Gillow JB. Reductive dissolution of Pu(IV) by Clostridium sp. under anaerobic conditions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:2355-2360. [PMID: 18504965 DOI: 10.1021/es072016w] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
An anaerobic, gram positive, spore-forming bacterium Clostridium sp., common in soils and wastes, capable of reduction of Fe(III) to Fe(II), Mn(IV) to Mn(II), Tc(VII) to Tc(IV), and U(VI) to U(IV), reduced Pu(IV) to Pu(III). Addition of 242Pu (IV)-nitrate to the bacterial growth medium at pH 6.4 resulted in the precipitation of Pu as amorphous Pu(OH)4 due to hydrolysis and polymerization reactions. The Pu (1 x 10(-5) M) had no effect upon growth of the bacterium as evidenced by glucose consumption; carbon dioxide and hydrogen production; a decrease in pH of the medium from 6.4 to 3.0 due to production of acetic and butyric acids from glucose fermentation; and a change in the Eh of the culture medium from +50 to -180 mV. Commensurate with bacterial growth, Pu was rapidly solubilized as evidenced by an increase in Pu concentration in solution which passed through a 0.03 microm filtration. Selective solvent extraction of the culture by thenoyltrifluoroacetone (TTA) indicated the presence of a reduced Pu species in the soluble fraction. X-ray absorption near edge spectroscopic (XANES) analysis of Pu in the culture sample at the Pu LIII absorption edge (18.054 keV) showed a shift of -3 eV compared to a Pu(IV) standard indicating reduction of Pu(IV) to Pu(III). These results suggestthat, although Pu generally exists as insoluble Pu(IV) in the environment, under appropriate conditions, anaerobic microbial activity could affect the long-term stability and mobility of Pu by its reductive dissolution.
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Affiliation(s)
- Arokiasamy J Francis
- Environmental Sciences Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
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Simonoff M, Sergeant C, Poulain S, Pravikoff MS. Microorganisms and migration of radionuclides in environment. CR CHIM 2007. [DOI: 10.1016/j.crci.2007.02.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Icopini GA, Boukhalfa H, Neu MP. Biological reduction of Np(V) and Np(V) citrate by metal-reducing bacteria. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2007; 41:2764-9. [PMID: 17533836 DOI: 10.1021/es0618550] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Oxidized actinide species are often more mobile than reduced forms. Bioremediation strategies have been developed to exploit this chemistry and stabilize actinides in subsurface environments. We investigated the ability of metal-reducing bacteria Geobacter metallireducens and Shewanella oneidensis to enzymatically reduce Np(V) and Np(V) citrate, as well as the toxicity of Np(V) to these organisms. A toxic effect was observed for both bacteria at concentrations of > or = 4.0 mM Np(V) citrate. Below 2.0 mM Np(V) citrate, no toxic effect was observed and both Fe(III) and Np(V) were reduced. Cell suspensions of S. oneidensis were able to enzymatically reduce unchelated Np(V) to insoluble Np(IV)(s), but cell suspensions of G. metallireducens were unable to reduce Np(V). The addition of citrate enhanced the Np(V) reduction rate by S. oneidensisand enabled Np(V) reduction by G. metallireducens. The reduced form of neptunium remained soluble, presumably as a polycitrate complex. Growth was not observed for either organism when Np(V) or Np(V) citrate was provided as the sole terminal electron acceptor. Our results show that bacteria can enzymatically reduce Np(V) and Np(V) citrate, but that the immobilization of Np(IV) may be dependent on the abundance of complexing ligands.
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Affiliation(s)
- Gary A Icopini
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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Perevalov SA, Kulyako YM, Myasoedov BF, Fujiwara A, Tochiyama O. Solubility of mixed-valence U(IV–VI) and Np(IV–V) hydroxides in simulated groundwater and 0.1 M NaClO4 solutions. RADIOCHEMISTRY 2006. [DOI: 10.1134/s1066362206050122] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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20
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Keith-Roach MJ, Buratti MV, Worsfold PJ. Thorium Complexation by Hydroxamate Siderophores in Perturbed Multicomponent Systems Using Flow Injection Electrospray Ionization Mass Spectrometry. Anal Chem 2005; 77:7335-41. [PMID: 16285683 DOI: 10.1021/ac051069y] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Flow injection electrospray ionization mass spectrometry has been shown to produce simple, characteristic m/z signals for Th-hydroxamate siderophore (desferrioxamine and ferrichrome) complexes, with Th complexed as a simple 4+ ion in the environmentally relevant pH range investigated (pH 5-9). All species of interest for this study were identified optimally in the positive mode; thus, multiple species were analyzed concurrently in a single spectrum. Complexation of Th by the two siderophores was rapid in 1:1 molar aqueous solution, reaching equilibrium before the first measurement was possible at 2 min. However, a significant proportion of the equimolar siderophore remained uncomplexed. Both siderophores rapidly exchanged Th for Fe when equimolar Fe(III) was added to the Th complexes, and only a small proportion of each siderophore remained complexed with Th at equilibrium (7-30 min). The results show a difference in the affinities of the two siderophores for the metals; ferrichrome has a 5-fold higher affinity than desferrioxamine for Th and a 5-fold lower affinity than desferrioxamine for Fe. Also, siderophore-complexed Th interacted strongly with a cation-exchange resin suggesting that, even when complexed by trianionic siderophores, Th mobility will be impeded by interactions with negatively charged binding sites in subsurface environmental matrixes. These results have important implications regarding siderophore-enhanced actinide(IV) mobility in the terrestrial environment.
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Affiliation(s)
- Miranda J Keith-Roach
- School of Earth, Ocean and Environmental Sciences, University of Plymouth, Drake Circus, UK.
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Ruggiero CE, Boukhalfa H, Forsythe JH, Lack JG, Hersman LE, Neu MP. Actinide and metal toxicity to prospective bioremediation bacteria. Environ Microbiol 2005; 7:88-97. [PMID: 15643939 DOI: 10.1111/j.1462-2920.2004.00666.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Bacteria may be beneficial for alleviating actinide contaminant migration through processes such as bioaccumulation or metal reduction. However, sites with radioactive contamination often contain multiple additional contaminants, including metals and organic chelators. Bacteria-based bioremediation requires that the microorganism functions in the presence of the target contaminant, as well as other contaminants. Here, we evaluate the toxicity of actinides, metals and chelators to two different bacteria proposed for use in radionuclide bioremediation, Deinococcus radiodurans and Pseudomonas putida, and the toxicity of Pu(VI) to Shewanella putrefaciens. Growth of D. radiodurans was inhibited at metal concentrations ranging from 1.8 microM Cd(II) to 32 mM Fe(III). Growth of P. putida was inhibited at metal concentrations ranging from 50 microM Ni(II) to 240 mM Fe(III). Actinides inhibited growth at mM concentrations: chelated Pu(IV), U(VI) and Np(V) inhibit D. radiodurans growth at 5.2, 2.5 and 2.1 mM respectively. Chelated U(VI) inhibits P. putida growth at 1.7 mM, while 3.6 mM chelated Pu(IV) inhibits growth only slightly. Pu(VI) inhibits S. putrefaciens growth at 6 mM. These results indicate that actinide toxicity is primarily chemical (not radiological), and that radiation resistance does not ensure radionuclide tolerance. This study also shows that Pu is less toxic than U and that actinides are less toxic than other types of metals, which suggests that actinide toxicity will not impede bioremediation using naturally occurring bacteria.
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Li W, Wang R, Si S, Li Y. Synthesis, structures and properties of series lanthanide nitrilotriacetates. J Mol Struct 2004. [DOI: 10.1016/j.molstruc.2004.01.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Lloyd JR, Lovley DR, Macaskie LE. Biotechnological application of metal-reducing microorganisms. ADVANCES IN APPLIED MICROBIOLOGY 2004; 53:85-128. [PMID: 14696317 DOI: 10.1016/s0065-2164(03)53003-9] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Jonathan R Lloyd
- Williamson Research Centre for Molecular Environmental Studies, Department of Earth Sciences, University of Manchester, Manchester M13 9PL, United Kingdom
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Abstract
The microbial reduction of metals has attracted recent interest as these transformations can play crucial roles in the cycling of both inorganic and organic species in a range of environments and, if harnessed, may offer the basis for a wide range of innovative biotechnological processes. Under certain conditions, however, microbial metal reduction can also mobilise toxic metals with potentially calamitous effects on human health. This review focuses on recent research on the reduction of a wide range of metals including Fe(III), Mn(IV) and other more toxic metals such as Cr(VI), Hg(II), Co(III), Pd(II), Au(III), Ag(I), Mo(VI) and V(V). The reduction of metalloids including As(V) and Se(VI) and radionuclides including U(VI), Np(V) and Tc(VII) is also reviewed. Rapid advances over the last decade have resulted in a detailed understanding of some of these transformations at a molecular level. Where known, the mechanisms of metal reduction are discussed, alongside the environmental impact of such transformations and possible biotechnological applications that could utilise these activities.
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Affiliation(s)
- Jonathan R Lloyd
- The Williamson Research Centre for Molecular Environmental Studies, Department of Earth Sciences, The University of Manchester, Manchester M13 9PL, UK.
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Chapter 4 Biogeochemical cycles and remobilisation of the actinide elements. ACTA ACUST UNITED AC 2002. [DOI: 10.1016/s1569-4860(02)80033-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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26
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Chapter 12 Microbial interactions with radioactive wastes and potential applications. ACTA ACUST UNITED AC 2002. [DOI: 10.1016/s1569-4860(02)80041-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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