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Dai W, Wang Y, Guo W, Wang G, Qiu M. Effects of Fe(II) and humic acid on U(VI) mobilization onto oxidized carbon nanofibers derived from the pyrolysis of bacterial cellulose. Int J Biol Macromol 2024; 266:131210. [PMID: 38552692 DOI: 10.1016/j.ijbiomac.2024.131210] [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: 01/28/2024] [Revised: 03/18/2024] [Accepted: 03/26/2024] [Indexed: 04/02/2024]
Abstract
The effects of Fe(II) and humic acid on U(VI) immobilization onto oxidized carbon nanofibers (Ox-CNFs, pyrolysis of bacterial cellulose) were investigated by batch, spectroscopic and modeling techniques, with results suggesting that, Ox-CNFs exhibited fast adsorption rate (adsorption equilibrium within 3 h), high adsorption performance (maximum adsorption capacity of 208.4 mg/g), good recyclability (no notable change after five regenerations) in the presence of Fe(II) towards U(VI) from aqueous solutions (e.g., 40 % reduction and 10 % adsorption at pH 8.0), which was attributed to the various oxygen-containing functional groups, excellent chemical stability, large specific surface area and high redox effect. U(VI) adsorption increased with increasing pH from 2.0 to 5.0, then high-level plateau and remarkable decrease were observed at 5.0-6.0 and at pH > 6.0, respectively. According to FT-IR and XPS analysis, a negative correlation between U(VI) reduction and organic in the presence of Fe(II) implied that U(VI) reduction was driven by Fe(II) while inhibited by humic acid. The interaction mechanism of U(VI) on Ox-CNFs was demonstrated to be adsorption and ion exchange at low pH and reduction at high pH according to XPS and surface complexation modeling. These findings filled the knowledge gaps pertaining to the effect of Fe(II) on the transformation and fate of U(VI) in the actual environment. This carbon material with distinctive performance and unique topology offers a potential platform for actual application in environmental remediation.
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Affiliation(s)
- Weisheng Dai
- College of Life and Environmental Science, Shaoxing University, Shaoxing 312000, PR China; Shaoxing Raw Water Group Co., LTD., Shaoxing 312000, PR China
| | - Yao Wang
- College of Life and Environmental Science, Shaoxing University, Shaoxing 312000, PR China
| | - Weijuan Guo
- College of Life and Environmental Science, Shaoxing University, Shaoxing 312000, PR China
| | - Guofu Wang
- College of Life and Environmental Science, Shaoxing University, Shaoxing 312000, PR China; School of Architectural Engineering, Shaoxing University Yuanpei College, Shaoxing 312000, PR China.
| | - Muqing Qiu
- College of Life and Environmental Science, Shaoxing University, Shaoxing 312000, PR China.
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2
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Li R, Zhang L, Chen Y, Xia Q, Liu D, Huang Y, Dong H. Oxidation of Biogenic U(IV) in the Presence of Bioreduced Clay Minerals and Organic Ligands. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:1541-1550. [PMID: 38199960 DOI: 10.1021/acs.est.3c07385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
Bioreduction of soluble U(VI) to sparingly soluble U(IV) is proposed as an effective approach to remediating uranium contamination. However, the stability of biogenic U(IV) in natural environments remains unclear. We conducted U(IV) reoxidation experiments following U(VI) bioreduction in the presence of ubiquitous clay minerals and organic ligands. Bioreduced Fe-rich nontronite (rNAu-2) and Fe-poor montmorillonite (rSWy-2) enhanced U(IV) oxidation through shuttling electrons between oxygen and U(IV). Ethylenediaminetetraacetic acid (EDTA), citrate, and siderophore desferrioxamine B (DFOB) promoted U(IV) oxidation via complexation with U(IV). In the presence of both rNAu-2 and EDTA, the rate of U(IV) oxidation was between those in the presence of rNAu-2 and EDTA, due to a clay/ligand-induced change of U(IV) speciation. However, the rate of U(IV) oxidation in other combinations of reduced clay and ligands was higher than their individual ones because both promoted U(IV) oxidation. Unexpectedly, the copresence of rNAu-2/rSWy-2 and DFOB inhibited U(IV) oxidation, possibly due to (1) blockage of the electron transport pathway by DFOB, (2) inability of DFOB-complexed Fe(III) to oxidize U(IV), and (3) stability of the U(IV)-DFOB complex in the clay interlayers. These findings provide novel insights into the stability of U(IV) in the environment and have important implications for the remediation of uranium contamination.
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Affiliation(s)
- Runjie Li
- Center for Geomicrobiology and Biogeochemistry Research, State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China
- School of Water Resources and Environment, China University of Geosciences, Beijing 100083, China
| | - Limin Zhang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yu Chen
- Center for Geomicrobiology and Biogeochemistry Research, State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China
| | - Qingyin Xia
- Center for Geomicrobiology and Biogeochemistry Research, State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China
| | - Dong Liu
- CAS Key Laboratory of Mineralogy and Metallogeny/Guangdong Provincial Key Laboratory of Mineral Physics and Materials, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Ying Huang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Hailiang Dong
- Center for Geomicrobiology and Biogeochemistry Research, State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China
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3
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Xia Q, Jin Q, Chen Y, Zhang L, Li X, He S, Guo D, Liu J, Dong H. Combined Effects of Fe(III)-Bearing Nontronite and Organic Ligands on Biogenic U(IV) Oxidation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:1983-1993. [PMID: 35012308 DOI: 10.1021/acs.est.1c04946] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Bioreduction of soluble U(VI) to sparingly soluble U(IV) solids was proposed as a remediation method for uranium contamination. Therefore, the stability and longevity of biogenic U(IV) are critical to the success of uranium remediation. However, co-occurrence of clay minerals and organic ligands could potentially reoxidize U(IV) to U(VI). Herein, we report a combined effect of Fe(III)-rich nontronite (NAu-2) and environmentally prevalent organic ligands on reoxidation of biogenic U(IV) at circumneutral pH. After 30 days of incubation, structural Fe(III) in NAu-2 oxidized 45.50% U(IV) with an initial rate of 2.7 × 10-3 mol m-2 d-1. Addition of citrate and ethylenediaminetetraacetic acid (EDTA) greatly promoted the oxidative dissolution of U(IV) by structural Fe(III) in NAu-2, primarily through the formation of aqueous ligand-U(IV) complexes. In contrast, a model siderophore, desferrioxamine B (DFOB), partially inhibited U(IV) oxidation due to the formation of stable DFOB-Fe3+ complexes. The resulting U(VI) species intercalated into an NAu-2 interlayer or adsorbed onto an NAu-2 surface. Our results highlight the importance of organic ligands in oxidative dissolution of U(IV) minerals by Fe(III)-bearing clay minerals and have important implications for the design of nuclear waste storage and remediation strategies, especially in clay- and organic-rich environments.
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Affiliation(s)
- Qingyin Xia
- Center for Geomicrobiology and Biogeochemistry Research, State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China
- School of Earth Science and Resources, China University of Geosciences, Beijing 100083, China
| | - Qusheng Jin
- Department of Earth Sciences, University of Oregon, Eugene, Oregon 97403, United States
| | - Yu Chen
- Center for Geomicrobiology and Biogeochemistry Research, State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China
| | - Limin Zhang
- Center for Geomicrobiology and Biogeochemistry Research, State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiaoxu Li
- The Key Laboratory of Water and Sediment Sciences, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Sheng He
- Beijing Research Institute of Uranium Geology, Beijing 100029, China
| | - Dongyi Guo
- Center for Geomicrobiology and Biogeochemistry Research, State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China
| | - Juan Liu
- The Key Laboratory of Water and Sediment Sciences, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Hailiang Dong
- Center for Geomicrobiology and Biogeochemistry Research, State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China
- School of Earth Science and Resources, China University of Geosciences, Beijing 100083, China
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4
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You X, Liu S, Dai C, Guo Y, Zhong G, Duan Y. Contaminant occurrence and migration between high- and low-permeability zones in groundwater systems: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 743:140703. [PMID: 32758831 DOI: 10.1016/j.scitotenv.2020.140703] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 06/16/2020] [Accepted: 07/01/2020] [Indexed: 06/11/2023]
Abstract
In recent decades, water quality problems that impact human health, especially groundwater pollution, have been intensely studied, and this has contributed to new ideas and policies around the world such as Low Impact Development (LID) and Superfund legislation. The fundamental to many of these problems is pollutant occurrence and migration in saturated porous media, especially in groundwater. Such environments often contain contrasting zones of high and low permeability with significant differences in hydraulic conductivity (~10-4 and 10-8 m/s, respectively). High-permeability zones (HPZs) represent the primary pathways for pollutant transport in groundwater, while low-permeability zones (LPZs) are often diffusion dominated and serve as both sinks and sources (i.e., via back-diffusion) of pollutants over many decades. In this review, concepts and mechanisms of solute source depletion, contaminant accumulation, and back-diffusion in high- and low-permeability systems are presented, and new insights gained from both experimental and numerical studies are analyzed and summarized. We find that effluent monitoring and novel image analysis techniques have been adroitly used to investigate temporal and spatial evolutions of contaminant concentration; simultaneously, mathematical models are constantly upscaled to verify, optimize and extend the experimental data. However, the spatial concentration data during back-diffusion lacks diversity due to the limitations of pollutant species in studies, the microscopic mechanisms controlling pollutant transformation are poorly understood, and the impacts of these reactions on contaminant back-diffusion are rarely considered. Hence, most simulation models have not been adequately validated and are not capable of accurately predicting pollutant fate and cleanup in realistic heterogeneous aquifers. Based on these, some hypotheses and perspectives are mentioned to promote the investigation of contaminant migration in high- and low-permeability systems in groundwater.
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Affiliation(s)
- Xueji You
- Department of Hydraulic Engineering, College of Civil Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China; Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, 301 E. Dean Keeton St., Stop C1786, Austin, TX 78712, USA
| | - Shuguang Liu
- Department of Hydraulic Engineering, College of Civil Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China; The Yangtze River Water Environment Key Laboratory of the Ministry of Education, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Chaomeng Dai
- Department of Hydraulic Engineering, College of Civil Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China.
| | - Yiping Guo
- Department of Civil Engineering, McMaster University, Hamilton, ON, Canada
| | - Guihui Zhong
- Department of Hydraulic Engineering, College of Civil Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Yanping Duan
- School of Environmental and Geographical Sciences, Shanghai Normal University, No. 100 Guilin Road, Shanghai 200234, China.
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5
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Besold J, Eberle A, Noël V, Kujala K, Kumar N, Scheinost AC, Pacheco JL, Fendorf S, Planer-Friedrich B. Antimonite Binding to Natural Organic Matter: Spectroscopic Evidence from a Mine Water Impacted Peatland. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:10792-10802. [PMID: 31436960 DOI: 10.1021/acs.est.9b03924] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Peatlands and other wetlands are sinks for antimony (Sb), and solid natural organic matter (NOM) may play an important role in controlling Sb binding. However, direct evidence of Sb sequestration in natural peat samples is lacking. Here, we analyzed solid phase Sb, iron (Fe), and sulfur (S) as well as aqueous Sb speciation in three profiles up to a depth of 80 cm in a mine water impacted peatland in northern Finland. Linear combination fittings of extended X-ray absorption fine structure spectra showed that Sb binding to Fe phases was of minor importance and observed only in the uppermost layers of the peatland. Instead, the dominant (to almost exclusive) sequestration mechanism was Sb(III) binding to oxygen-containing functional groups, and at greater depths, increasingly Sb(III) binding to thiol groups of NOM. Aqueous Sb speciation was dominated by antimonate, while antimonite concentrations were low, further supporting our findings of much higher reactivity of Sb(III) than Sb(V) toward peat surfaces. Insufficient residence time for efficient reduction of antimonate to antimonite currently hinders higher Sb removal in the studied peatland. Overall, our findings imply that Sb(III) binding to solid NOM acts as an important sequestration mechanism under reducing conditions in peatlands and other high-organic matter environments.
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Affiliation(s)
- Johannes Besold
- Department of Environmental Geochemistry, Bayreuth Center for Ecology and Environmental Research (BAYCEER) , Bayreuth University , 95440 Bayreuth , Germany
| | - Anne Eberle
- Department of Environmental Geochemistry, Bayreuth Center for Ecology and Environmental Research (BAYCEER) , Bayreuth University , 95440 Bayreuth , Germany
| | - Vincent Noël
- Stanford Synchrotron Radiation Lightsource , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , United States
| | - Katharina Kujala
- Water Resources and Environmental Engineering Research Unit , University of Oulu , FI-90014 , Oulu , Finland
| | - Naresh Kumar
- Department of Geological Sciences, School of Earth, Energy, and Environmental Sciences , Stanford University , Stanford , California 94305 , United States
- Department of Environmental Geosciences, Centre for Microbiology and Environmental Systems Science , University of Vienna , 1090 Vienna , Austria
| | - Andreas C Scheinost
- The Rossendorf Beamline (ROBL) at ESRF, 38043 Grenoble, France and Helmholtz-Zentrum Dresden-Rossendorf (HZDR) , Institute of Resource Ecology , Bautzner Landstraße 400 , 01328 Dresden , Germany
| | - Juan Lezama Pacheco
- Department of Earth System Science, School of Earth, Energy, and Environmental Sciences , Stanford University , Stanford , California 94305 , United States
| | - Scott Fendorf
- Department of Earth System Science, School of Earth, Energy, and Environmental Sciences , Stanford University , Stanford , California 94305 , United States
| | - Britta Planer-Friedrich
- Department of Environmental Geochemistry, Bayreuth Center for Ecology and Environmental Research (BAYCEER) , Bayreuth University , 95440 Bayreuth , Germany
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6
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Lei P, Nunes LM, Liu YR, Zhong H, Pan K. Mechanisms of algal biomass input enhanced microbial Hg methylation in lake sediments. ENVIRONMENT INTERNATIONAL 2019; 126:279-288. [PMID: 30825746 DOI: 10.1016/j.envint.2019.02.043] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Revised: 02/12/2019] [Accepted: 02/16/2019] [Indexed: 05/25/2023]
Abstract
Eutrophication is a major environmental concern in lake systems, impacting the ecological risks of contaminants and drinking water safety. It has long been believed that eutrophication and thus algal blooms would reduce methylmercury (MeHg) levels in water, as well as MeHg bioaccumulation and trophic transfer (e.g., by growth dilution). In this study, however, we demonstrated that algae settlement and decomposition after algal blooms increased MeHg levels in sediments (54-514% higher), as evidenced by the results from sediments in 10 major lakes in China. These could in turn raise concerns about enhanced trophic transfer of MeHg and deterioration of water quality after algal blooms, especially considering that 9 out of the 10 examined lakes also serve as drinking water sources. The enhanced microbial MeHg production in sediments could be explained by the algal organic matter (AOM)-enhanced abundances of microbial methylators as well as the input of algae-inhabited microbes into sediments, but not Hg speciation in sediments: (1) Several AOM components (e.g., aromatic proteins and soluble microbial by product-like material with generally low molecular weights), rather than the bulk AOM, played key roles in enhancing the abundances of microbial methylators. The copies of Archaea-hgcA methylation genes were 51-397% higher in algae-added sediments; thus, MeHg production was also higher. (2) Input of algal biomass-inhabited microbial methylators contributed to 2-21% of total Archaea-hgcA in the 10 lake sediments with added algal biomass. (3) However, AOM-induced changes in Hg speciation, with implications on Hg availability to microbial methylators, played a minor role in enhancing microbial Hg methylation in sediments as seen in X-ray absorption near edge structure (XANES) data. Our results suggest the need to better understand the biogeochemistry and risks of contaminants in eutrophic lakes, especially during the period of algae settlement and decomposition following algal blooms.
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Affiliation(s)
- Pei Lei
- Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China; Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China; State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210046, China
| | - Luís M Nunes
- Civil Engineering Research and Innovation for Sustainability Center, University of Algarve, Faro, Portugal
| | - Yu-Rong Liu
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Huan Zhong
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210046, China; Environmental and Life Science Program (EnLS), Trent University, Peterborough, Ontario, Canada.
| | - Ke Pan
- Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China.
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7
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Lee JH, Lee BJ. Microbial Reduction of Fe(III) and SO 42- and Associated Microbial Communities in the Alluvial Aquifer Groundwater and Sediments. MICROBIAL ECOLOGY 2018; 76:182-191. [PMID: 29177753 DOI: 10.1007/s00248-017-1119-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 11/21/2017] [Indexed: 06/07/2023]
Abstract
Agricultural demands continuously increased use of groundwater, causing drawdown of water table and need of artificial recharge using adjacent stream waters. River water intrusion into groundwater can alter the geochemical and microbiological characteristics in the aquifer and subsurface. In an effort to investigate the subsurface biogeochemical activities before operation of artificial recharge at the test site, established at the bank of Nakdong River, Changwon, South Korea, organic carbon transported from river water to groundwater was mimicked and the effect on the indigenous microbial communities was investigated with the microcosm incubations of the groundwater and subsurface sediments. Laboratory incubations indicated microbial reduction of Fe(III) and sulfate. Next-generation Illumina MiSeq sequences of V4 region of 16S rRNA gene provided that the shifts of microbial taxa to Fe(III)-reducing and/or sulfate-reducing microorganisms such as Geobacter, Albidiferax, Desulfocapsa, Desulfuromonas, and Desulfovibrio were in good correlation with the sequential flourishment of microbial reduction of Fe(III) and sulfate as the incubations progressed. This suggests the potential role of dissolved organic carbons migrated with the river water into groundwater in the managed aquifer recharge system on the indigenous microbial community composition and following alterations of subsurface biogeochemistry and microbial metabolic activities.
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Affiliation(s)
- Ji-Hoon Lee
- Department of Bioenvironmental Chemistry, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju, 54896, Republic of Korea.
| | - Bong-Joo Lee
- Groundwater Department, Korea Institute of Geoscience and Mineral Resources, Daejeon, Republic of Korea
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8
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Yan S, Boyanov MI, Mishra B, Kemner KM, O'Loughlin EJ. U(VI) Reduction by Biogenic and Abiotic Hydroxycarbonate Green Rusts: Impacts on U(IV) Speciation and Stability Over Time. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:4601-4609. [PMID: 29630355 DOI: 10.1021/acs.est.7b06405] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Green rusts (GRs) are redox active FeII-FeIII minerals that form in the environment via various biotic and abiotic processes. Although both biogenic (BioGR) and abiotic (ChemGR) GRs have been shown to reduce UVI, the dynamics of the transformations and the speciation and stability of the resulting UIV phases are poorly understood. We used carbonate extraction and XAFS spectroscopy to investigate the products of UVI reduction by BioGR and ChemGR. The results show that both GRs can rapidly remove UVI from synthetic groundwater via reduction to UIV. The initial products in the ChemGR system are solids-associated UIV-carbonate complexes that gradually transform to nanocrystalline uraninite over time, leading to a decrease in the proportion of carbonate-extractable U from ∼95% to ∼10%. In contrast, solid-phase UIV atoms in the BioGR system remain relatively extractable, nonuraninite UIV species over the same reaction period. The presence of calcium and carbonate in groundwater significantly increase the extractability of UIV in the BioGR system. These data provide new insights into the transformations of U under anoxic conditions in groundwater that contains calcium and carbonate, and have major implications for predicting uranium stability within redox dynamic environments and designing approaches for the remediation of uranium-contaminated groundwater.
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Affiliation(s)
- Sen Yan
- School of Earth Sciences , China University of Geosciences , Wuhan , 430074 , China
- Biosciences Division , Argonne National Laboratory , Argonne , Illinois 60439 , United States
| | - Maxim I Boyanov
- Biosciences Division , Argonne National Laboratory , Argonne , Illinois 60439 , United States
- Institute of Chemical Engineering , Bulgarian Academy of Sciences , Sofia , 1113 , Bulgaria
| | - Bhoopesh Mishra
- Biosciences Division , Argonne National Laboratory , Argonne , Illinois 60439 , United States
- School of Chemical and Process Engineering , University of Leeds , Leeds , LS2 9JT , U.K
| | - Kenneth M Kemner
- Biosciences Division , Argonne National Laboratory , Argonne , Illinois 60439 , United States
| | - Edward J O'Loughlin
- Biosciences Division , Argonne National Laboratory , Argonne , Illinois 60439 , United States
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9
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Wu Y, Li J, Wang Y, Xie X. Variations of uranium concentrations in a multi-aquifer system under the impact of surface water-groundwater interaction. JOURNAL OF CONTAMINANT HYDROLOGY 2018; 211:65-76. [PMID: 29559163 DOI: 10.1016/j.jconhyd.2018.03.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Revised: 01/24/2018] [Accepted: 03/05/2018] [Indexed: 06/08/2023]
Abstract
Understanding uranium (U) mobility is vital to minimizing its concentrations in potential drinking water sources. In this study, we report spatial-seasonal variations in U speciation and concentrations in a multi-aquifer system under the impact of Sanggan River in Datong basin, northern China. Hydrochemical and H, O, Sr isotopic data, thermodynamic calculations, and geochemical modeling are used to investigate the mechanisms of surface water-groundwater mixing-induced mobilization and natural attenuation of U. In the study site, groundwater U concentrations are up to 30.2 μg/L, and exhibit strong spatial-seasonal variations that are related to pH and Eh values, as well as dissolved Ca2+, HCO3-, and Fe(III) concentrations. For the alkaline aquifers of this site (pH 7.02-8.44), U mobilization is due to the formation and desorption of Ca2UO2(CO3)30 and CaUO2(CO3)32- caused by groundwater Ca2+ elevation via mineral weathering and Na-Ca exchange, incorporated U(VI) release from calcite, and U(IV) oxidation by Fe(OH)3. U immobilization is linked to the adsorption of CaUO2(CO3)32- and UO2(CO3)34- shifted from Ca2UO2(CO3)30 because of HCO3- elevation and Ca2+ depletion, U(VI) co-precipitation with calcite, and U(VI) reduction by adsorbed Fe2+ and FeS. Those results are of great significance for the groundwater resource management of this and similar other surface water-groundwater interaction zones.
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Affiliation(s)
- Ya Wu
- School of Environmental Studies, China University of Geosciences, 430074 Wuhan, China.
| | - Junxia Li
- School of Environmental Studies, China University of Geosciences, 430074 Wuhan, China
| | - Yanxin Wang
- School of Environmental Studies, China University of Geosciences, 430074 Wuhan, China.
| | - Xianjun Xie
- School of Environmental Studies, China University of Geosciences, 430074 Wuhan, China
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10
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Liu Y, Xu F, Liu C. Coupled Hydro-Biogeochemical Processes Controlling Cr Reductive Immobilization in Columbia River Hyporheic Zone. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:1508-1517. [PMID: 27996242 DOI: 10.1021/acs.est.6b05099] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
An experiment and modeling study was conducted to investigate coupled hydro-biogeochemical processes controlling reductive immobilization of groundwater Cr in the hyporheic zone (HZ) at the U.S. Department of Energy's Hanford Site, where dynamic surface water-groundwater exchange occurs on a daily basis. Experiments were performed to calibrate kinetic models, and the calibrated models were incorporated into a multicomponent reactive transport model to simulate Cr redox transformation and immobilization under field hydrological conditions. The results revealed that the rates of Cr(VI) reduction, Cr(III) accumulation, and Cr(VI) release to the river are mostly affected by dynamic sediment redox conditions represented by Fe(II) reactivity, which is controlled by its cyclic interaction with O2 carried by river water, microbial activities, and the supply and bioavailability of organic carbon (OC) that is present in the HZ and/or carried by transport. In addition, the HZ geophysical properties including hydraulic conductivity and the thickness of the top alluvial layer have a significant influence on Cr reactive transport and immobilization by controlling residence times for reactions and the supply rates of O2, Cr, and OC into the HZ. The results provide important insights into the dynamic redox environments in the HZ that can reductively immobilize contaminants.
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Affiliation(s)
- Yuanyuan Liu
- Pacific Northwest National Laboratory , Richland, Washington 99354, United States
| | - Fen Xu
- Pacific Northwest National Laboratory , Richland, Washington 99354, United States
- School of Environmental Studies, China University of Geosciences , Wuhan 430074, China
| | - Chongxuan Liu
- Pacific Northwest National Laboratory , Richland, Washington 99354, United States
- School of Environmental Science and Engineering, Southern University of Science and Technology , Shenzhen 518055, China
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11
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Kwon MJ, O’Loughlin EJ, Boyanov MI, Brulc JM, Johnston ER, Kemner KM, Antonopoulos DA. Impact of Organic Carbon Electron Donors on Microbial Community Development under Iron- and Sulfate-Reducing Conditions. PLoS One 2016; 11:e0146689. [PMID: 26800443 PMCID: PMC4723079 DOI: 10.1371/journal.pone.0146689] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 12/21/2015] [Indexed: 11/23/2022] Open
Abstract
Although iron- and sulfate-reducing bacteria in subsurface environments have crucial roles in biogeochemical cycling of C, Fe, and S, how specific electron donors impact the compositional structure and activity of native iron- and/or sulfate-reducing communities is largely unknown. To understand this better, we created bicarbonate-buffered batch systems in duplicate with three different electron donors (acetate, lactate, or glucose) paired with ferrihydrite and sulfate as the electron acceptors and inoculated them with subsurface sediment as the microbial inoculum. Sulfate and ferrihydrite reduction occurred simultaneously and were faster with lactate than with acetate. 16S rRNA-based sequence analysis of the communities over time revealed that Desulfotomaculum was the major driver for sulfate reduction coupled with propionate oxidation in lactate-amended incubations. The reduction of sulfate resulted in sulfide production and subsequent abiotic reduction of ferrihydrite. In contrast, glucose promoted faster reduction of ferrihydrite, but without reduction of sulfate. Interestingly, the glucose-amended incubations led to two different biogeochemical trajectories among replicate bottles that resulted in distinct coloration (white and brown). The two outcomes in geochemical evolution might be due to the stochastic evolution of the microbial communities or subtle differences in the initial composition of the fermenting microbial community and its development via the use of different glucose fermentation pathways available within the community. Synchrotron-based x-ray analysis indicated that siderite and amorphous Fe(II) were formed in the replicate bottles with glucose, while ferrous sulfide and vivianite were formed with lactate or acetate. These data sets reveal that use of different C utilization pathways projects significant changes in microbial community composition over time that uniquely impact both the geochemistry and mineralogy of subsurface environments.
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Affiliation(s)
- Man Jae Kwon
- Biosciences Division, Argonne National Laboratory, Argonne, IL, 60439, United States of America
- Korea Institute of Science and Technology (KIST) – Gangneung Institute, Gangneung, 210–340, S. Korea
| | - Edward J. O’Loughlin
- Biosciences Division, Argonne National Laboratory, Argonne, IL, 60439, United States of America
| | - Maxim I. Boyanov
- Biosciences Division, Argonne National Laboratory, Argonne, IL, 60439, United States of America
| | - Jennifer M. Brulc
- Institute for Genomics and Systems Biology, Argonne National Laboratory, Argonne, IL, 60439, United States of America
| | - Eric R. Johnston
- Institute for Genomics and Systems Biology, Argonne National Laboratory, Argonne, IL, 60439, United States of America
| | - Kenneth M. Kemner
- Biosciences Division, Argonne National Laboratory, Argonne, IL, 60439, United States of America
| | - Dionysios A. Antonopoulos
- Biosciences Division, Argonne National Laboratory, Argonne, IL, 60439, United States of America
- Institute for Genomics and Systems Biology, Argonne National Laboratory, Argonne, IL, 60439, United States of America
- * E-mail:
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12
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Yan S, Liu Y, Liu C, Shi L, Shang J, Shan H, Zachara J, Fredrickson J, Kennedy D, Resch CT, Thompson C, Fansler S. Nitrate bioreduction in redox-variable low permeability sediments. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 539:185-195. [PMID: 26363392 DOI: 10.1016/j.scitotenv.2015.08.122] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2015] [Revised: 08/21/2015] [Accepted: 08/21/2015] [Indexed: 06/05/2023]
Abstract
Lowpermeability zone (LPZ) can play an important role as a sink or secondary source in contaminant transport in groundwater system. This study investigated the rate and end product of nitrate bioreduction in LPZ sediments. The sedimentswere fromthe U.S. Department of Energy's Hanford Site,where nitrate is a groundwater contaminant as a by-product of radionuclide waste discharges. The LPZ at the Hanford site consists of two layerswith an oxidized layer on top and reduced layer below. The oxidized layer is directly in contact with the overlying contaminated aquifer, while the reduced layer is in contact with an uncontaminated aquifer below. The experimental results showed that nitrate bioreduction rate and end-product differed significantly in the sediments. The bioreduction rate in the oxidized sediment was significantly faster than that in the reduced one. A significant amount of N2O was accumulated in the reduced sediment; while in the oxidized sediment, N2O was further reduced to N2. RT-PCR analysis revealed that nosZ, the gene that codes for N2O reductase, was below detection limit in the reduced sediment. Batch experiments and kinetic modeling were performed to provide insights into the role of organic carbon bioavailability, biomass growth, and competition between nitrate and its reducing products for electrons fromelectron donors. The results revealed that it is important to consider sediment redox conditions and functional genes in understanding and modeling nitrate bioreduction in subsurface sediments. The results also implied that LPZ sediments can be important sink of nitrate and a potential secondary source of N2O as a nitrate bioreduction product in groundwater.
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Affiliation(s)
- Sen Yan
- China University of Geosciences, Wuhan 430074, China; Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Yuanyuan Liu
- Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Chongxuan Liu
- China University of Geosciences, Wuhan 430074, China; Pacific Northwest National Laboratory, Richland, WA 99354, USA.
| | - Liang Shi
- Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Jianying Shang
- Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Huimei Shan
- China University of Geosciences, Wuhan 430074, China; Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - John Zachara
- Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Jim Fredrickson
- Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - David Kennedy
- Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Charles T Resch
- Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | | | - Sarah Fansler
- Pacific Northwest National Laboratory, Richland, WA 99354, USA
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13
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Brookshaw DR, Pattrick RAD, Bots P, Law GTW, Lloyd JR, Mosselmans JFW, Vaughan DJ, Dardenne K, Morris K. Redox Interactions of Tc(VII), U(VI), and Np(V) with Microbially Reduced Biotite and Chlorite. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:13139-13148. [PMID: 26488884 DOI: 10.1021/acs.est.5b03463] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Technetium, uranium, and neptunium are contaminants that cause concern at nuclear facilities due to their long half-life, environmental mobility, and radiotoxicity. Here we investigate the impact of microbial reduction of Fe(III) in biotite and chlorite and the role that this has in enhancing mineral reactivity toward soluble TcO4(-), UO2(2+), and NpO2(+). When reacted with unaltered biotite and chlorite, significant sorption of U(VI) occurred in low carbonate (0.2 mM) buffer, while U(VI), Tc(VII), and Np(V) showed low reactivity in high carbonate (30 mM) buffer. On reaction with the microbially reduced minerals, all radionuclides were removed from solution with U(VI) reactivity influenced by carbonate. Analysis by X-ray absorption spectroscopy (XAS) confirmed reductive precipitation to poorly soluble U(IV) in low carbonate conditions and both Tc(VII) and Np(V) in high carbonate buffer were also fully reduced to poorly soluble Tc(IV) and Np(IV) phases. U(VI) reduction was inhibited under high carbonate conditions. Furthermore, EXAFS analysis suggested that in the reaction products, Tc(IV) was associated with Fe, Np(IV) formed nanoparticulate NpO2, and U(IV) formed nanoparticulate UO2 in chlorite and was associated with silica in biotite. Overall, microbial reduction of the Fe(III) associated with biotite and chlorite primed the minerals for reductive scavenging of radionuclides: this has clear implications for the fate of radionuclides in the environment.
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Affiliation(s)
- Diana R Brookshaw
- Research Centre for Radwaste Disposal and Williamson Research Centre for Molecular Environmental Science, School of Earth, Atmospheric and Environmental Sciences, The University of Manchester , Oxford Road, Manchester M13 9PL, United Kingdom
| | - Richard A D Pattrick
- Research Centre for Radwaste Disposal and Williamson Research Centre for Molecular Environmental Science, School of Earth, Atmospheric and Environmental Sciences, The University of Manchester , Oxford Road, Manchester M13 9PL, 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 , Oxford Road, 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
| | - 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 , Oxford Road, Manchester M13 9PL, United Kingdom
| | - J Fredrick W Mosselmans
- Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - David J Vaughan
- Research Centre for Radwaste Disposal and Williamson Research Centre for Molecular Environmental Science, School of Earth, Atmospheric and Environmental Sciences, The University of Manchester , Oxford Road, Manchester M13 9PL, United Kingdom
| | - Kathy Dardenne
- Karlsruhe Institute of Technology, Institut fur Nukleare Entsorgung , D-76021 Karlsruhe, Baden-Württemberg, Germany
| | - 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 , Oxford Road, Manchester M13 9PL, United Kingdom
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14
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Converse BJ, McKinley JP, Resch CT, Roden EE. Microbial mineral colonization across a subsurface redox transition zone. Front Microbiol 2015; 6:858. [PMID: 26379637 PMCID: PMC4551860 DOI: 10.3389/fmicb.2015.00858] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 08/06/2015] [Indexed: 11/13/2022] Open
Abstract
This study employed 16S rRNA gene amplicon pyrosequencing to examine the hypothesis that chemolithotrophic Fe(II)-oxidizing bacteria (FeOB) would preferentially colonize the Fe(II)-bearing mineral biotite compared to quartz sand when the minerals were incubated in situ within a subsurface redox transition zone (RTZ) at the Hanford 300 Area site in Richland, WA, USA. The work was motivated by the recently documented presence of neutral-pH chemolithotrophic FeOB capable of oxidizing structural Fe(II) in primary silicate and secondary phyllosilicate minerals in 300 Area sediments and groundwater (Benzine et al., 2013). Sterilized portions of sand+biotite or sand alone were incubated in situ for 5 months within a multilevel sampling (MLS) apparatus that spanned a ca. 2-m interval across the RTZ in two separate groundwater wells. Parallel MLS measurements of aqueous geochemical species were performed prior to deployment of the minerals. Contrary to expectations, the 16S rRNA gene libraries showed no significant difference in microbial communities that colonized the sand+biotite vs. sand-only deployments. Both mineral-associated and groundwater communities were dominated by heterotrophic taxa, with organisms from the Pseudomonadaceae accounting for up to 70% of all reads from the colonized minerals. These results are consistent with previous results indicating the capacity for heterotrophic metabolism (including anaerobic metabolism below the RTZ) as well as the predominance of heterotrophic taxa within 300 Area sediments and groundwater. Although heterotrophic organisms clearly dominated the colonized minerals, several putative lithotrophic (NH4 (+), H2, Fe(II), and HS(-) oxidizing) taxa were detected in significant abundance above and within the RTZ. Such organisms may play a role in the coupling of anaerobic microbial metabolism to oxidative pathways with attendant impacts on elemental cycling and redox-sensitive contaminant behavior in the vicinity of the RTZ.
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Affiliation(s)
| | | | | | - Eric E. Roden
- Department of Geoscience, University of Wisconsin-MadisonMadison, WI, USA
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15
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Lee JH, Fredrickson JK, Plymale AE, Dohnalkova AC, Resch CT, McKinley JP, Shi L. An autotrophic H2 -oxidizing, nitrate-respiring, Tc(VII)-reducing Acidovorax sp. isolated from a subsurface oxic-anoxic transition zone. ENVIRONMENTAL MICROBIOLOGY REPORTS 2015; 7:395-403. [PMID: 25558059 DOI: 10.1111/1758-2229.12263] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 12/19/2014] [Indexed: 06/04/2023]
Abstract
Increasing concentrations of H2 with depth were observed across a geologic unconformity and associated redox transition zone in the subsurface at the Hanford Site in south-central Washington, USA. An opposing gradient characterized by decreasing O2 and nitrate concentrations was consistent with microbial-catalysed biogeochemical processes. Sterile sand was incubated in situ within a multilevel sampler placed across the redox transition zone to evaluate the potential for Tc(VII) reduction and for enrichment of H2 -oxidizing denitrifiers capable of reducing Tc(VII). H2 -driven TcO4 (-) reduction was detected in sand incubated at all depths but was strongest in material from a depth of 17.1 m. Acidovorax spp. were isolated from H2 -nitrate enrichments from colonized sand from 15.1 m, with one representative, strain JHL-9, subsequently characterized. JHL-9 grew on acetate with either O2 or nitrate as electron acceptor (data not shown) and on medium with bicarbonate, H2 and nitrate. JHL-9 also reduced pertechnetate (TcO4 (-) ) under denitrifying conditions with H2 as the electron donor. H2 -oxidizing Acidovorax spp. in the subsurface at Hanford and other locations may contribute to the maintenance of subsurface redox gradients and offer the potential for Tc(VII) reduction.
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Affiliation(s)
- Ji-Hoon Lee
- Pacific Northwest National Laboratory, Richland, WA, 99352, USA
| | | | | | | | - Charles T Resch
- Pacific Northwest National Laboratory, Richland, WA, 99352, USA
| | | | - Liang Shi
- Pacific Northwest National Laboratory, Richland, WA, 99352, USA
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16
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Percak-Dennett EM, Roden EE. Geochemical and microbiological responses to oxidant introduction into reduced subsurface sediment from the Hanford 300 Area, Washington. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:9197-9204. [PMID: 25014732 DOI: 10.1021/es5009856] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Pliocene-aged reduced lacustrine sediment from below a subsurface redox transition zone at the 300 Area of the Hanford site (southeastern Washington) was used in a study of the geochemical response to introduction of oxygen or nitrate in the presence or absence of microbial activity. The sediments contained large quantities of reduced Fe in the form of Fe(II)-bearing phyllosilicates, together with smaller quantities of siderite and pyrite. A loss of ca. 50% of 0.5 M HCl-extractable Fe(II) [5-10 mmol Fe(II) L(-1)] and detectable generation of sulfate (ca. 0.2 mM, equivalent to 10% of the reduced inorganic sulfur pool) occurred in sterile aerobic reactors. In contrast, no systematic loss of Fe(II) or production of sulfate was observed in any of the other oxidant-amended sediment suspensions. Detectable Fe(II) accumulation and sulfate consumption occurred in non-sterile oxidant-free reactors. Together, these results indicate the potential for heterotrophic carbon metabolism in the reduced sediments, consistent with the proliferation of known heterotrophic taxa (e.g., Pseudomonadaceae, Burkholderiaceae, and Clostridiaceae) inferred from 16S rRNA gene pyrosequencing. Microbial carbon oxidation by heterotrophic communities is likely to play an important role in maintaining the redox boundary in situ, i.e., by modulating the impact of downward oxidant transport on Fe/S redox speciation. Diffusion-reaction simulations of oxygen and nitrate consumption coupled to solid-phase organic carbon oxidation indicate that heterotrophic consumption of oxidants could maintain the redox boundary at its current position over millennial time scales.
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Affiliation(s)
- Elizabeth M Percak-Dennett
- Department of Geoscience, University of Wisconsin-Madison , 1215 West Dayton Street, Madison, Wisconsin 53706, United States
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17
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Fan D, Anitori RP, Tebo BM, Tratnyek PG, Lezama Pacheco JS, Kukkadapu RK, Kovarik L, Engelhard MH, Bowden ME. Oxidative remobilization of technetium sequestered by sulfide-transformed nano zerovalent iron. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:7409-7417. [PMID: 24884124 DOI: 10.1021/es501607s] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Our previous study showed that formation of TcS2-like phases is favored over TcO2 under sulfidic conditions stimulated by nano zerovalent iron. This study further investigates the stability of Tc(IV) sulfide upon reoxidation by solution chemistry, solid phase characterization, and X-ray absorption spectroscopy. Tc dissolution data showed that Tc(VII) reduced by sulfide-transformed nZVI has substantially slower reoxidation kinetics than Tc(VII) reduced by nZVI only. The initial inhibition of Tc(IV) dissolution at S/Fe = 0.112 is due to the redox buffer capacity of FeS, which is evidenced by the parallel trends in oxidation-reduction potentials (ORP) and Tc dissolution kinetics. The role of FeS in inhibiting Tc oxidation is further supported by the Mössbauer spectroscopy and micro X-ray diffraction data at S/Fe = 0.112, showing persistence of FeS after 24-h oxidation but complete oxidation after 120-h oxidation. X-ray absorption spectroscopy data for S/Fe = 0.011 showed significantly increasing percentages of TcS2 in the solid phase after 24-h oxidation, indicating stronger resistance of TcS2 to oxidation. At S/Fe = 0.112, the XAS results revealed significant transformation of Tc speciation from TcS2 to TcO2 after 120-h oxidation. Given that no apparent Tc dissolution occurred during this period, the speciation transformation might play a secondary role in hindering Tc oxidation. Collectively, the results indicate that sequestrating Tc as TcS2 under stimulated sulfate reduction is a promising strategy to improve the long-term stability of reduced Tc in subsurface remediation.
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Affiliation(s)
- Dimin Fan
- Institute of Environmental Health, Oregon Health & Science University , 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
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18
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19
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Luan F, Gorski CA, Burgos WD. Thermodynamic controls on the microbial reduction of iron-bearing nontronite and uranium. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:2750-2758. [PMID: 24512199 DOI: 10.1021/es404885e] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Iron-bearing phyllosilicate minerals help establish the hydrogeological and geochemical conditions of redox transition zones because of their small size, limited hydraulic conductivity, and redox buffering capacity. The bioreduction of soluble U(VI) to sparingly soluble U(IV) can promote the reduction of clay-Fe(III) through valence cycling. The reductive precipitation of U(VI) to uraninite was previously reported to occur only after a substantial percentage of clay-Fe(III) had been reduced. Using improved analytical techniques, we show that concomitant bioreduction of both U(VI) and clay-Fe(III) by Shewanella putrefaciens CN32 can occur. Soluble electron shuttles were previously shown to enhance both the rate and extent of clay-Fe(III) bioreduction. Using extended incubation periods, we show that electron shuttles enhance only the rate of reduction (overcoming a kinetic limitation) and not the final extent of reduction (a thermodynamic limitation). The first 20% of clay-Fe(III) in nontronite NAu-2 was relatively "easy" (i.e., rapid) to bioreduce; the next 15% of clay-Fe(III) was "harder" (i.e., kinetically limited) to bioreduce, and the remaining 65% of clay-Fe(III) was effectively biologically unreducible. In abiotic experiments with NAu-2 and biogenic uraninite, 16.4% of clay-Fe(III) was reduced in the presence of excess uraninite. In abiotic experiments with NAu-2 and reduced anthraquinone 2,6-disulfonate (AH2DS), 18.5-19.1% of clay-Fe(III) was reduced in the presence of excess and variable concentrations of AH2DS. A thermodynamic model based on published values of the nonstandard state reduction potentials at pH 7.0 (E'H) showed that the abiotic reactions between NAu-2 and uraninite had reached an apparent equilibrium. This model also showed that the abiotic reactions between NAu-2 and AH2DS had reached an apparent equilibrium. The final extent of clay-Fe(III) reduction correlated well with the standard state reduction potential at pH 7.0 (E°'H) of all of the reductants used in these experiments (AH2DS, CN32, dithionite, and uraninite).
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Affiliation(s)
- Fubo Luan
- Department of Civil and Environmental Engineering, The Pennsylvania State University , University Park, Pennsylvania 16802-1408, United States
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20
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Benzine J, Shelobolina E, Xiong MY, Kennedy DW, McKinley JP, Lin X, Roden EE. Fe-phyllosilicate redox cycling organisms from a redox transition zone in Hanford 300 Area sediments. Front Microbiol 2013; 4:388. [PMID: 24379809 PMCID: PMC3863755 DOI: 10.3389/fmicb.2013.00388] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 11/26/2013] [Indexed: 02/01/2023] Open
Abstract
Microorganisms capable of reducing or oxidizing structural iron (Fe) in Fe-bearing phyllosilicate minerals were enriched and isolated from a subsurface redox transition zone at the Hanford 300 Area site in eastern Washington, USA. Both conventional and in situ “i-chip” enrichment strategies were employed. One Fe(III)-reducing Geobacter (G. bremensis strain R1, Deltaproteobacteria) and six Fe(II) phyllosilicate-oxidizing isolates from the Alphaproteobacteria (Bradyrhizobium japonicum strains 22, is5, and in8p8), Betaproteobacteria (Cupriavidus necator strain A5-1, Dechloromonas agitata strain is5), and Actinobacteria (Nocardioides sp. strain in31) were recovered. The G. bremensis isolate grew by oxidizing acetate with the oxidized form of NAu-2 smectite as the electron acceptor. The Fe(II)-oxidizers grew by oxidation of chemically reduced smectite as the energy source with nitrate as the electron acceptor. The Bradyrhizobium isolates could also carry out aerobic oxidation of biotite. This is the first report of the recovery of a Fe(II)-oxidizing Nocardioides, and to date only one other Fe(II)-oxidizing Bradyrhizobium is known. The 16S rRNA gene sequences of the isolates were similar to ones found in clone libraries from Hanford 300 sediments and groundwater, suggesting that such organisms may be present and active in situ. Whole genome sequencing of the isolates is underway, the results of which will enable comparative genomic analysis of mechanisms of extracellular phyllosilicate Fe redox metabolism, and facilitate development of techniques to detect the presence and expression of genes associated with microbial phyllosilicate Fe redox cycling in sediments.
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Affiliation(s)
- Jason Benzine
- Department of Geoscience, University of Wisconsin Madison Madison, WI, USA
| | | | - Mai Yia Xiong
- Department of Geoscience, University of Wisconsin Madison Madison, WI, USA
| | | | | | - Xueju Lin
- School of Biology, Georgia Institute of Technology Atlanta, GA, USA
| | - Eric E Roden
- Department of Geoscience, University of Wisconsin Madison Madison, WI, USA
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Zachara JM, Long PE, Bargar J, Davis JA, Fox P, Fredrickson JK, Freshley MD, Konopka AE, Liu C, McKinley JP, Rockhold ML, Williams KH, Yabusaki SB. Persistence of uranium groundwater plumes: contrasting mechanisms at two DOE sites in the groundwater-river interaction zone. JOURNAL OF CONTAMINANT HYDROLOGY 2013; 147:45-72. [PMID: 23500840 DOI: 10.1016/j.jconhyd.2013.02.001] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 01/10/2013] [Accepted: 02/06/2013] [Indexed: 05/22/2023]
Abstract
We examine subsurface uranium (U) plumes at two U.S. Department of Energy sites that are located near large river systems and are influenced by groundwater-river hydrologic interaction. Following surface excavation of contaminated materials, both sites were projected to naturally flush remnant uranium contamination to levels below regulatory limits (e.g., 30 μg/L or 0.126 μmol/L; U.S. EPA drinking water standard), with 10 years projected for the Hanford 300 Area (Columbia River) and 12 years for the Rifle site (Colorado River). The rate of observed uranium decrease was much lower than expected at both sites. While uncertainty remains, a comparison of current understanding suggests that the two sites have common, but also different mechanisms controlling plume persistence. At the Hanford 300 A, the persistent source is adsorbed U(VI) in the vadose zone that is released to the aquifer during spring water table excursions. The release of U(VI) from the vadose zone and its transport within the oxic, coarse-textured aquifer sediments is dominated by kinetically-limited surface complexation. Modeling implies that annual plume discharge volumes to the Columbia River are small (<one pore volume). At the Rifle site, slow oxidation of naturally reduced, contaminant U(IV) in the saturated zone and a continuous influx of U(VI) from natural, up-gradient sources influence plume persistence. Rate-limited mass transfer and surface complexation also control U(VI) migration velocity in the sub-oxic Rifle groundwater. Flux of U(VI) from the vadose zone at the Rifle site may be locally important, but it is not the dominant process that sustains the plume. A wide range in microbiologic functional diversity exists at both sites. Strains of Geobacter and other metal reducing bacteria are present at low natural abundance that are capable of enzymatic U(VI) reduction in localized zones of accumulated detrital organic carbon or after organic carbon amendment. Major differences between the sites include the geochemical nature of residual, contaminant U; the rates of current kinetic processes (both biotic and abiotic) influencing U(VI) solid-liquid distribution; the presence of detrital organic matter and the resulting spatial heterogeneity in microbially-driven redox properties; and the magnitude of groundwater hydrologic dynamics controlled by river-stage fluctuations, geologic structures, and aquifer hydraulic properties. The comparative analysis of these sites provides important guidance to the characterization, understanding, modeling, and remediation of groundwater contaminant plumes influenced by surface water interaction that are common world-wide.
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Affiliation(s)
- John M Zachara
- Pacific Northwest National Laboratory, Richland, WA 99354, USA.
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22
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Ahmed B, Cao B, Mishra B, Boyanov MI, Kemner KM, Fredrickson JK, Beyenal H. Immobilization of U(VI) from oxic groundwater by Hanford 300 Area sediments and effects of Columbia River water. WATER RESEARCH 2012; 46:3989-3998. [PMID: 22683408 DOI: 10.1016/j.watres.2012.05.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 05/08/2012] [Accepted: 05/15/2012] [Indexed: 06/01/2023]
Abstract
Regions within the U.S. Department of Energy Hanford 300 Area (300 A) site experience periodic hydrologic influences from the nearby Columbia River as a result of changing river stage, which causes changes in groundwater elevation, flow direction and water chemistry. An important question is the extent to which the mixing of Columbia River water and groundwater impacts the speciation and mobility of uranium (U). In this study, we designed experiments to mimic interactions among U, oxic groundwater or Columbia River water, and 300 A sediments in the subsurface environment of Hanford 300 A. The goals were to investigate mechanisms of: 1) U immobilization in 300 A sediments under bulk oxic conditions and 2) U remobilization from U-immobilized 300 A sediments exposed to oxic Columbia River water. Initially, 300 A sediments in column reactors were fed with U(VI)-containing oxic 1) synthetic groundwater (SGW), 2) organic-amended SGW (OA-SGW), and 3) de-ionized (DI) water to investigate U immobilization processes. After that, the sediments were exposed to oxic Columbia River water for U remobilization studies. The results reveal that U was immobilized by 300 A sediments predominantly through reduction (80-85%) when the column reactor was fed with oxic OA-SGW. However, U was immobilized by 300 A sediments through adsorption (100%) when the column reactors were fed with oxic SGW or DI water. The reduced U in the 300 A sediments fed with OA-SGW was relatively resistant to remobilization by oxic Columbia River water. Oxic Columbia River water resulted in U remobilization (∼7%) through desorption, and most of the U that remained in the 300 A sediments fed with OA-SGW (∼93%) was in the form of uraninite nanoparticles. These results reveal that: 1) the reductive immobilization of U through OA-SGW stimulation of indigenous 300 A sediment microorganisms may be viable in the relatively oxic Hanford 300 A subsurface environments and 2) with the intrusion of Columbia River water, desorption may be the primary process resulting in U remobilization from OA-SGW-stimulated 300 A sediments at the subsurface of the Hanford 300 A site.
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Affiliation(s)
- Bulbul Ahmed
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Spokane St, PO Box 642710, Pullman, WA 99164-2710, United States
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