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Wang H, Zhu Y, Lu Y, Bu X, Zhu Q, Yuan S. Reduction capacity in the transmissive zones fueled by the embedded low-permeability lenses: Implications for contaminant transformation in heterogeneous aquifers. WATER RESEARCH 2024; 260:121955. [PMID: 38909424 DOI: 10.1016/j.watres.2024.121955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 06/13/2024] [Accepted: 06/16/2024] [Indexed: 06/25/2024]
Abstract
Redox conditions play a decisive role in regulating contaminant and nutrient transformation in groundwater. Here we quantitatively described and interpreted the temporal and spatial variations of aquifer reduction capacity formation in lens-embedded heterogeneous aquifers in 1-D columns. Experimental results indicated that the aquifer reduction capacity exported from the low-permeability lens permeated into the downstream sandy zones, where it subsequently accumulated and extended. Reactive transport modeling suggested that reduction capacity within the lens preferentially diffused to the transmissive zones around the lens-sand interface, and was then transported via convection to downstream transmissive zones. A low-permeability lens of the same volume, but more elongated in the flow direction, led to less concentrated reduction capacity but extended further downgradient from the lens. The increased flow velocity attenuated the maintenance of aquifer reduction capacity by enhancing mixing and diluting processes in the transmissive zones. The reduction zones formed downstream from the low-permeability lens were hotpots for resisting the oxidative perturbation by O2. This study highlights the important role of low-permeability lenses as large and long-term electron pools for the transmissive zones, and thus providing aquifer reduction capacity for contaminant transformation and remediation in heterogeneous aquifers.
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Affiliation(s)
- Hong Wang
- School of Environmental Studies, China University of Geosciences, No. 68 Jincheng Street, East Lake High-Tech Development Zone, Wuhan, 430078, PR China
| | - Yonghui Zhu
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, No. 68 Jincheng Street, East Lake High-Tech Development Zone, Wuhan 430078, PR China
| | - Yuxi Lu
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, No. 68 Jincheng Street, East Lake High-Tech Development Zone, Wuhan 430078, PR China
| | - Xiaochuang Bu
- Ecohydrology Research Group, Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Qi Zhu
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, No. 68 Jincheng Street, East Lake High-Tech Development Zone, Wuhan 430078, PR China
| | - Songhu Yuan
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, No. 68 Jincheng Street, East Lake High-Tech Development Zone, Wuhan 430078, PR China; Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, No. 68 Jincheng Street, East Lake High-Tech Development Zone, Wuhan, 430078, PR China.
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2
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Kent RD, Johnson RH, Laase AD, Nyman JL. Modeling evaluation of the impact of residual source material on remedial time frame at a former uranium mill site. JOURNAL OF CONTAMINANT HYDROLOGY 2024; 261:104298. [PMID: 38242064 DOI: 10.1016/j.jconhyd.2024.104298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 12/14/2023] [Accepted: 01/09/2024] [Indexed: 01/21/2024]
Abstract
Groundwater contamination at legacy uranium processing sites is an ongoing global challenge. Plumes at many uranium-contaminated sites are more persistent than originally predicted by groundwater modeling. Previous investigations of uranium plume persistence identified residual and secondary sources that contribute to plume longevity, but there is a remaining need to revise forecasted cleanup times using information about these ongoing sources. The purpose of this study is to investigate the quantitative impact of residual vadose zone sources of uranium on groundwater remediation time frame. This objective was approached by applying numerical uranium transport simulations and uncertainty analysis to a former uranium mill site in the southwestern United States. Information from recent site investigations provided details about the distribution and release characteristics of uranium accumulations in the vadose zone. The residual uranium characteristics were incorporated as decaying source terms in the transport model. A stochastic approach using an iterative ensemble smoother was applied for history matching, and the transport model was used to assess the impact of multiple remedial alternatives on forecasted time frame. The forecasted time frame to achieve the groundwater remediation goal for uranium by monitored natural attenuation is on the order of thousands of years, and treatment of the dissolved plume does not reduce the projected time frame. The large proportion of residual uranium mass remaining in the vadose zone and the gradual leaching rate due to the site's semiarid climate create a long-lived source that can sustain a dissolved plume for thousands of years despite an estimated 99% mass removal achieved during mill tailings disposal. Residual uranium in vadose zone sediments beneath former tailings impoundments could present comparable uranium plume persistence and remediation challenges at other legacy uranium mill sites in semiarid climates. Other remaining uranium-impacted sites are similarly complex, and forecasted remedial time frames are needed to effectively achieve compliance, manage risk, assess the benefits of additional treatment, manage and project costs, and support beneficial site reuse.
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Affiliation(s)
- Ronald D Kent
- RSI EnTech, LLC, U.S. Department of Energy Office of Legacy Management Support, Grand Junction, CO, USA.
| | - Raymond H Johnson
- RSI EnTech, LLC, U.S. Department of Energy Office of Legacy Management Support, Grand Junction, CO, USA
| | - Alan D Laase
- RSI EnTech, LLC, U.S. Department of Energy Office of Legacy Management Support, Grand Junction, CO, USA
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3
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Shen C, Pan J, Chen M, Su M, Chen D, Song G. Statistically and visually analyzing the latest advancements and future trends of uranium removal. ENVIRONMENTAL RESEARCH 2023; 239:117280. [PMID: 37793586 DOI: 10.1016/j.envres.2023.117280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 09/09/2023] [Accepted: 09/26/2023] [Indexed: 10/06/2023]
Abstract
Uranium contamination and remediation is a very important environmental research area. Removing radioactive and toxic uranium from contaminated media requires fundamental knowledge of targets and materials. To explore the-State-of-the-Art in uranium contamination control, we employed a statistical tool called CiteSpace to visualize and statistically analyze 4203 peer-reviewed papers on uranium treatment published between 2008 and 2022. The primary content presentations of visual analysis were co-authorships, co-citations, keyword co-occurrence analysis with cluster analysis, which could offer purposeful information of research hots and trends in the field of uranium removal. The statistical analysis results indicated that studies on uranium removal have focused on adsorption of uranium from aqueous solution. From 2008 to 2022, biochar and biological treatment were firstly used to sequester uranium, then adsorption for uranium removal dominates with adsorbents of graphene oxide, primary nanofiber magnetic polymers and metal-organic frameworks (MOFs). In recent years, photocatalysts and metal-organic frameworks are expected to be two of the most popular research topics. In addition, we further highlighted the characteristics and applications of MOFs and GOs in uranium removal. Overall, a statistical review was proposed to visualize and summarize the knowledge and research trends regarding uranium treatment.
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Affiliation(s)
- Congjie Shen
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, China
| | - Jiaqi Pan
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, China
| | - Miaoling Chen
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, China
| | - Minhua Su
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, China.
| | - Diyun Chen
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, China
| | - Gang Song
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, China
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4
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Westrop JP, Yadav P, Nolan PJ, Campbell KM, Singh R, Bone SE, Chan AH, Kohtz AJ, Pan D, Healy O, Bargar JR, Snow DD, Weber KA. Nitrate-Stimulated Release of Naturally Occurring Sedimentary Uranium. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:4354-4366. [PMID: 36848522 DOI: 10.1021/acs.est.2c07683] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Groundwater uranium (U) concentrations have been measured above the U.S. EPA maximum contaminant level (30 μg/L) in many U.S. aquifers, including in areas not associated with anthropogenic contamination by milling or mining. In addition to carbonate, nitrate has been correlated to uranium groundwater concentrations in two major U.S. aquifers. However, to date, direct evidence that nitrate mobilizes naturally occurring U from aquifer sediments has not been presented. Here, we demonstrate that the influx of high-nitrate porewater through High Plains alluvial aquifer silt sediments bearing naturally occurring U(IV) can stimulate a nitrate-reducing microbial community capable of catalyzing the oxidation and mobilization of U into the porewater. Microbial reduction of nitrate yielded nitrite, a reactive intermediate, which was further demonstrated to abiotically mobilize U from the reduced alluvial aquifer sediments. These results indicate that microbial activity, specifically nitrate reduction to nitrite, is one mechanism driving U mobilization from aquifer sediments in addition to previously described bicarbonate-driven desorption from mineral surfaces, such as Fe(III) oxides.
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Affiliation(s)
- Jeffrey P Westrop
- Department of Earth and Atmospheric Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Pooja Yadav
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - P J Nolan
- Department of Earth and Atmospheric Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Kate M Campbell
- Geology, Geophysics, and Geochemistry Science Center, Denver Federal Center, U.S. Geological Survey, Denver, Colorado 80225, United States
| | - Rajesh Singh
- Environmental Hydrology Division, National Institute of Hydrology, Roorkee 247667, India
| | - Sharon E Bone
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Alicia H Chan
- Department of Earth and Atmospheric Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Anthony J Kohtz
- Department of Earth and Atmospheric Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Donald Pan
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Olivia Healy
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - John R Bargar
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Daniel D Snow
- School of Natural Resources and Nebraska Water Center, Part of the Daugherty Water for Food Global Institute, Water Sciences Laboratory, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Karrie A Weber
- Department of Earth and Atmospheric Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
- Daugherty Water for Food Global Institute, University of Nebraska, Lincoln, Nebraska 68588, United States
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5
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He Z, Dong L, Zhu P, Zhang Z, Xu T, Zhang D, Pan X. Nano-scale analysis of uranium release behavior from river sediment in the Ili basin. WATER RESEARCH 2022; 227:119321. [PMID: 36368086 DOI: 10.1016/j.watres.2022.119321] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 10/30/2022] [Accepted: 11/03/2022] [Indexed: 06/16/2023]
Abstract
Due to the limitations of the conventional water sample pretreatment methods, some of the colloidal uranium (U) has long been misidentified as "dissolved" phase. In this work, the U species in river water in the Ili Basin was classified into submicron-colloidal (0.1-1 μm), nano-colloidal (0.1 μm-3 kDa) and dissolved phases (< 3 kDa) by using high-speed centrifugation and ultrafiltration. The U concentration in the river water was 5.39-8.75 μg/L, which was dominated by nano-colloidal phase (55-70%). The nano-colloidal particles were mainly composed of particulate organic matter (POM) and had a very high adsorption capacity for U (accounting for 70 ± 23% of colloidal U). Sediment disturbance, low temperature, and high inorganic carbon greatly improved the release of nano-colloidal U, but high levels of Ca2+ inhibited it. The simulated river experiments indicated that the flow regime determined the release of nano-colloidal U, and large amounts of nano-colloidal U might be released during spring floods in the Ili basin. Moreover, global warming increases river flow and inorganic carbon content, which may greatly promote the release and migration of nano-colloidal U.
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Affiliation(s)
- Zhanfei He
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, China
| | - Lingfeng Dong
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, China
| | - Pengfeng Zhu
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, China
| | - Zhibing Zhang
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, China
| | - Tao Xu
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, China
| | - Daoyong Zhang
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, China; Xinjiang Key Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China.
| | - Xiangliang Pan
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, China; Xinjiang Key Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China
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6
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Hanson A, Schwerdt IJ, Nizinski CA, Lee RN, Mecham NJ, Abbott EC, Heffernan S, Olsen A, Klosterman MR, Martinson S, Brenkmann A, McDonald LW. Impact of Controlled Storage Conditions on the Hydrolysis and Surface Morphology of Amorphous-UO 3. ACS OMEGA 2021; 6:8605-8615. [PMID: 33817521 PMCID: PMC8015116 DOI: 10.1021/acsomega.1c00435] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 03/02/2021] [Indexed: 06/12/2023]
Abstract
The hydration and morphological effects of amorphous (A)-UO3 following storage under varying temperature and relative humidity have been investigated. This study provides valuable insight into U-oxide speciation following aging, the U-oxide quantitative morphological data set, and, overall, the characterization of nuclear material provenance. A-UO3 was synthesized via the washed uranyl peroxide synthetic route and aged based on a 3-factor circumscribed central composite design of experiment. Target aging times include 2.57, 7.00, 14.0, 21.0, and 25.4 days, temperatures of 5.51, 15.0, 30.0, 45.0, and 54.5 °C, and relative humidities of 14.2, 30.0, 55.0, 80.0, and 95.8% were examined. Following aging, crystallographic changes were quantified via powder X-ray diffraction and an internal standard Rietveld refinement method was used to confirm the hydration of A-UO3 to crystalline schoepite phases. The particle morphology from scanning electron microscopy images was quantified using both the Morphological Analysis of MAterials software and machine learning. Results from the machine learning were processed via agglomerative hierarchical clustering analysis to distinguish trends in morphological attributes from the aging study. Significantly hydrated samples were found to have a much larger, plate-like morphology in comparison to the unaged controls. Predictive modeling via a response surface methodology determined that while aging time, temperature, and relative humidity all have a quantifiable effect on A-UO3 crystallographic and morphological changes, relative humidity has the most significant impact.
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7
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Byrne P, Fuller CC, Naftz DL, Runkel RL, Lehto NJ, Dam WL. Transport and speciation of uranium in groundwater-surface water systems impacted by legacy milling operations. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 761:143314. [PMID: 33187709 DOI: 10.1016/j.scitotenv.2020.143314] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 10/16/2020] [Accepted: 10/16/2020] [Indexed: 06/11/2023]
Abstract
Growing worldwide concern over uranium contamination of groundwater resources has placed an emphasis on understanding uranium transport dynamics and potential toxicity in groundwater-surface water systems. In this study, we utilized novel in-situ sampling methods to establish the location and magnitude of contaminated groundwater entry into a receiving surface water environment, and to investigate the speciation and potential bioavailability of uranium in groundwater and surface water. Streambed temperature mapping successfully identified the location of groundwater entry to the Little Wind River, downgradient from the former Riverton uranium mill site, Wyoming, USA. Diffusive equilibrium in thin-film (DET) samplers further constrained the groundwater plume and established sediment pore water solute concentrations and patterns. In this system, evidence is presented for attenuation of uranium-rich groundwater in the shallow sediments where surface water and groundwater interaction occurs. Surface water grab and DET sampling successfully detected an increase in river uranium concentrations where the groundwater plume enters the Little Wind River; however, concentrations remained below environmental guideline levels. Uranium speciation was investigated using diffusive gradients in thin-film (DGT) samplers and geochemical speciation modelling. Together, these investigations indicate uranium may have limited bioavailability to organisms in the Little Wind River and, possibly, in other similar sites in the western U.S.A. This could be due to ion competition effects or the presence of non- or partially labile uranium complexes. Development of methods to establish the location of contaminated (uranium) groundwater entry to surface water environments, and the potential effects on ecosystems, is crucial to develop both site-specific and general conceptual models of uranium behavior and potential toxicity in affected ground and surface water environments.
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Affiliation(s)
- Patrick Byrne
- School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool L3 3AF, United Kingdom.
| | | | - David L Naftz
- U.S. Geological Survey, 3162 Bozeman, Helena, MT 59601, USA
| | - Robert L Runkel
- U.S. Geological Survey, 3215 Marine St, Boulder, CO 80303, USA
| | - Niklas J Lehto
- Faculty of Agriculture and Life Sciences, Lincoln University, Lincoln 7647, New Zealand
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Cardarelli EL, Bargar JR, Francis CA. Diverse Thaumarchaeota Dominate Subsurface Ammonia-oxidizing Communities in Semi-arid Floodplains in the Western United States. MICROBIAL ECOLOGY 2020; 80:778-792. [PMID: 32535638 DOI: 10.1007/s00248-020-01534-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 05/29/2020] [Indexed: 06/11/2023]
Abstract
Subsurface microbial communities mediate biogeochemical transformations that drive both local and ecosystem-level cycling of essential elements, including nitrogen. However, their study has been largely limited to the deep ocean, terrestrial mines, caves, and topsoils (< 30 cm). Here, we present regional insights into the microbial ecology of aerobic ammonia oxidation within the terrestrial subsurface of five semi-arid riparian sites spanning a 900-km N-S transect. We sampled sediments, profiled communities to depths of ≤ 10 m, and compared them to reveal trends regionally within and surrounding the Upper Colorado River Basin (CRB). The diversity and abundance of ammonia-oxidizing microbial communities were evaluated in the context of subsurface geochemistry by applying a combination of amoA (encoding ammonia monooxygenase subunit A) gene sequencing, quantitative PCR, and geochemical techniques. Analysis of 898 amoA sequences from ammonia-oxidizing archaea (AOA) and bacteria (AOB) revealed extensive ecosystem-scale diversity, including archaeal amoA sequences from four of the five major AOA lineages currently found worldwide as well as distinct AOA ecotypes associated with naturally reduced zones (NRZs) and hydrogeochemical zones (unsaturated, capillary fringe, and saturated). Overall, AOA outnumber AOB by 2- to 5000-fold over this regional scale, suggesting that AOA may play a prominent biogeochemical role in nitrification within terrestrial subsurface sediments.
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Affiliation(s)
- Emily L Cardarelli
- Department of Earth System Science, Stanford University, Stanford, CA, 94305-4216, USA
| | - John R Bargar
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - Christopher A Francis
- Department of Earth System Science, Stanford University, Stanford, CA, 94305-4216, USA.
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9
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Dong H, Wei L, Tarpeh WA. Electro-assisted regeneration of pH-sensitive ion exchangers for sustainable phosphate removal and recovery. WATER RESEARCH 2020; 184:116167. [PMID: 32682079 DOI: 10.1016/j.watres.2020.116167] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 07/07/2020] [Accepted: 07/09/2020] [Indexed: 05/03/2023]
Abstract
Removal and recovery of phosphate from wastewater can minimize deleterious environmental impacts and supplement fertilizer supply. Hybrid anion exchangers (HAIX, with doped ferric oxide nanoparticles (FeOnp)) can remove phosphate from complex wastewaters and recover concentrated phosphate solutions. In this study, we integrate HAIX with a weak acid cation exchanger (WAC) to enrich phosphate and calcium in mild regenerants and precipitate both elements for recovery. We demonstrated an electro-assisted regeneration approach to avoid strong acid and base input. Based on demonstrated pH sensitivities of both materials, electrochemically produced mild electrolytes (pH 3 and pH 11), which are 100-1000 times less concentrated than typical regenerants, preserved 80% WAC and 50% HAIX capacities over five batch adsorption-regeneration cycles. FeOnp in HAIX facilitated regeneration due to pH sensitivity and their likely distribution on the resin particle surface, which reduced intraparticle diffusion path length. In column tests, repeatable phosphate removal (> 95%) from synthetic wastewater (3 mg P/L) was achieved with 20 kWh/kg P specific energy consumption. After removal, a similar 50% HAIX regeneration efficiency as batch experiments was achieved. In spent regenerant, more than 95% phosphorus was recovered as hydroxyapatite. This novel approach enhances ion exchange by minimizing chemical inputs.
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Affiliation(s)
- Hang Dong
- Department of Chemical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Lingze Wei
- Department of Chemical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - William A Tarpeh
- Department of Chemical Engineering, Stanford University, Stanford, CA, 94305, USA; Engineering Research Center for Re-inventing the Nation's Urban Water Infrastructure (ReNUWIt), Stanford, CA, 94305, USA.
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10
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Bone SE, Cliff J, Weaver K, Takacs CJ, Roycroft S, Fendorf S, Bargar JR. Complexation by Organic Matter Controls Uranium Mobility in Anoxic Sediments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:1493-1502. [PMID: 31886668 DOI: 10.1021/acs.est.9b04741] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Uranium contamination threatens the availability of safe and clean drinking water globally. This toxic element occurs both naturally and as a result of mining and ore-processing in alluvial sediments, where it accumulates as tetravalent U [U(IV)], a form once considered largely immobile. Changing hydrologic and geochemical conditions cause U to be released into groundwater. Knowledge of the chemical form(s) of U(IV) is essential to understand the release mechanism, yet the relevant U(IV) species are poorly characterized. There is growing belief that natural organic matter (OM) binds U(IV) and mediates its fate in the subsurface. In this work, we combined nanoscale imaging (nano secondary ion mass spectrometry and scanning transmission X-ray microscopy) with a density-based fractionation approach to physically and microscopically isolate organic and mineral matter from alluvial sediments contaminated with uranium. We identified two populations of U (dominantly +IV) in anoxic sediments. Uranium was retained on OM and adsorbed to particulate organic carbon, comprising both microbial and plant material. Surprisingly, U was also adsorbed to clay minerals and OM-coated clay minerals. The dominance of OM-associated U provides a framework to understand U mobility in the shallow subsurface, and, in particular, emphasizes roles for desorption and colloid formation in its mobilization.
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Affiliation(s)
- Sharon E Bone
- Stanford Synchrotron Radiation Lightsource , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , United States
| | - John Cliff
- Environmental Molecular Sciences Laboratory , Pacific Northwest National Laboratory , Richland , Washington 99354 , United States
| | - Karrie Weaver
- Earth System Science Department , Stanford University , Stanford , California 94305 , United States
| | - Christopher J Takacs
- Stanford Synchrotron Radiation Lightsource , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , United States
| | - Scott Roycroft
- Earth System Science Department , Stanford University , Stanford , California 94305 , United States
| | - Scott Fendorf
- Earth System Science Department , Stanford University , Stanford , California 94305 , United States
| | - John R Bargar
- Stanford Synchrotron Radiation Lightsource , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , United States
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11
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Briggs MA, Wang C, Day-Lewis FD, Williams KH, Dong W, Lane JW. Return flows from beaver ponds enhance floodplain-to-river metals exchange in alluvial mountain catchments. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 685:357-369. [PMID: 31176222 DOI: 10.1016/j.scitotenv.2019.05.371] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 05/23/2019] [Accepted: 05/24/2019] [Indexed: 06/09/2023]
Abstract
River to floodplain hydrologic connectivity is strongly enhanced by beaver- (Castor canadensis) engineered channel water diversions. The hydroecological impacts are wide ranging and generally positive, however, the hydrogeochemical characteristics of beaver-induced flowpaths have not been thoroughly examined. Using a suite of complementary ground- and drone-based heat tracing and remote sensing methodology we characterized the physical template of beaver-induced floodplain exchange for two alluvial mountain streams near Crested Butte, Colorado, USA. A flowpath-oriented perspective to water quality sampling allowed characterization of the chemical evolution of channel water diverted through floodplain beaver ponds and ultimately back to the channel in 'beaver pond return flows'. Subsurface return flow seepages were universally suboxic, while ponds and surface return flows showed a range of oxygen concentration due to in-situ photosynthesis and atmospheric mixing. Median concentrations of reduced metals: manganese (Mn), iron (Fe), aluminum (Al), and arsenic (As) were substantially higher along beaver-induced flowpaths than in geologically controlled seepages and upstream main channel locations. The areal footprint of reduced return seepage flowpaths were imaged with surface electromagnetic methods, indicating extensive zones of high-conductivity shallow groundwater flowing back toward the main channels and emerging at relatively warm bank seepage zones observed with infrared. Multiple-depth redox dynamics within one focused seepage zone showed coupled variation over time, likely driven by observed changes in seepage rate that may be controlled by pond stage. High-resolution times series of dissolved Mn and Fe collected downstream of the beaver-impacted reaches demonstrated seasonal dynamics in mixed river metal concentrations. Al time series concentrations showed proportional change to Fe at the smaller stream location, indicating chemically reduced flowpaths were sourcing Al to the channel. Overall our results indicated beaver-induced floodplain exchanges create important, and perhaps dominant, transport pathways for floodplain metals by expanding chemically-reduced zones paired with strong advective exchange.
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Affiliation(s)
- Martin A Briggs
- U.S. Geological Survey, Earth System Processes Division, Hydrogeophysics Branch, 11 Sherman Place, Unit 5015, Storrs, CT, USA.
| | - Chen Wang
- Department of Earth and Environmental Sciences, Rutgers University, Newark, NJ, USA
| | - Frederick D Day-Lewis
- U.S. Geological Survey, Earth System Processes Division, Hydrogeophysics Branch, 11 Sherman Place, Unit 5015, Storrs, CT, USA
| | - Ken H Williams
- Lawrence Berkeley National Laboratory, Earth & Environmental Sciences Area, 1 Cyclotron, Road, MS74R316C, Berkeley, CA, USA; Rocky Mountain Biological Lab, Gothic, CO, USA
| | - Wenming Dong
- Lawrence Berkeley National Laboratory, Earth & Environmental Sciences Area, 1 Cyclotron, Road, MS74R316C, Berkeley, CA, USA
| | - John W Lane
- U.S. Geological Survey, Earth System Processes Division, Hydrogeophysics Branch, 11 Sherman Place, Unit 5015, Storrs, CT, USA
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Velasco CA, Artyushkova K, Ali AMS, Osburn CL, Gonzalez-Estrella J, Lezama-Pacheco JS, Cabaniss SE, Cerrato JM. Organic Functional Group Chemistry in Mineralized Deposits Containing U(IV) and U(VI) from the Jackpile Mine in New Mexico. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:5758-5767. [PMID: 30998849 PMCID: PMC6557721 DOI: 10.1021/acs.est.9b00407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
We investigated the functional group chemistry of natural organic matter (NOM) associated with both U(IV) and U(VI) in solids from mineralized deposits exposed to oxidizing conditions from the Jackpile Mine, Laguna Pueblo, NM. The uranium (U) content in unreacted samples was 0.44-2.6% by weight determined by X-ray fluorescence. In spite of prolonged exposure to ambient oxidizing conditions, ≈49% of U(IV) and ≈51% of U(VI) were identified on U LIII edge extended X-ray absorption fine structure spectra. Loss on ignition and thermogravimetric analyses identified from 13% to 44% of NOM in the samples. Carbonyl, phenolic, and carboxylic functional groups in the unreacted samples were identified by fitting of high-resolution X-ray photoelectron spectroscopy (XPS) C 1s and O 1s spectra. Peaks corresponding to phenolic and carbonyl functional groups had intensities higher than those corresponding to carboxylic groups in samples from the supernatant from batch extractions conducted at pH 13, 7, and 2. U(IV) and U(VI) species were detected in the supernatant after batch extractions conducted under oxidizing conditions by fitting of high-resolution XPS U 4f spectra. The outcomes from this study highlight the importance of the influence of pH on the organic functional group chemistry and U speciation in mineralized deposits.
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Affiliation(s)
- Carmen A. Velasco
- Department of Civil, Construction & Environmental Engineering, MSC01 1070, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Kateryna Artyushkova
- Department of Chemical and Biological Engineering, MSC01 1120, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Abdul-Mehdi S. Ali
- Department of Earth and Planetary Sciences, MSC03 2040, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Christopher L. Osburn
- Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, North Carolina 27607, United States
| | - Jorge Gonzalez-Estrella
- Department of Civil, Construction & Environmental Engineering, MSC01 1070, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Juan S. Lezama-Pacheco
- Department of Environmental Earth System Science, Stanford University, Stanford, California 94305, United States
| | - Stephen E. Cabaniss
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - José M. Cerrato
- Department of Civil, Construction & Environmental Engineering, MSC01 1070, University of New Mexico, Albuquerque, New Mexico 87131, United States
- Corresponding Author. Telephone: (001) (505) 277-0870. Fax: (001) (505) 277-1918
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Lefebvre P, Noël V, Lau KV, Jemison NE, Weaver KL, Williams KH, Bargar JR, Maher K. Isotopic Fingerprint of Uranium Accumulation and Redox Cycling in Floodplains of the Upper Colorado River Basin. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:3399-3409. [PMID: 30807121 DOI: 10.1021/acs.est.8b05593] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Uranium (U) groundwater contamination is a major concern at numerous former mining and milling sites across the Upper Colorado River Basin (UCRB), USA, where U(IV)-bearing solids have accumulated within naturally reduced zones (NRZs). Understanding the processes governing U reduction and oxidation within NRZs is critical for assessing the persistence of U in groundwater. To evaluate the redox cycling of uranium, we measured the U concentrations and isotopic compositions (δ238U) of sediments and pore waters from four study sites across the UCRB that span a gradient in sediment texture and composition. We observe that U accumulation occurs primarily within fine-grained (low-permeability) NRZs that show active redox variations. Low-permeability NRZs display high accumulation and low export of U, with internal redox cycling of U. In contrast, within high-permeability NRZs, U is remobilized under oxidative conditions, possibly without any fractionation, and transported outside the NRZs. The low δ238U of sediments outside of defined NRZs suggests that these reduced zones act as additional U sources. Collectively, our results indicate that fine-grained NRZs have a greater potential to retain uranium, whereas NRZs with higher permeability may constitute a more-persistent but dilute U source.
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Affiliation(s)
- Pierre Lefebvre
- Department of Earth System Science , Stanford University , Stanford , California 94305 , United States
- Département de Géosciences , Ecole Normale Supérieure , Paris 75005 , France
| | - Vincent Noël
- Stanford Synchrotron Radiation Lightsource , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , United States
| | - Kimberly V Lau
- Department of Geological Sciences , Stanford University , Stanford , California 94305 , United States
| | - Noah E Jemison
- Department of Geology , University of Illinois at Urbana-Champaign , Champaign , Illinois 61820 , United States
| | - Karrie L Weaver
- Department of Earth System Science , Stanford University , Stanford , California 94305 , United States
| | - Kenneth H Williams
- Earth Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - John R Bargar
- Stanford Synchrotron Radiation Lightsource , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , United States
| | - Kate Maher
- Department of Earth System Science , Stanford University , Stanford , California 94305 , United States
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Noël V, Boye K, Kukkadapu RK, Li Q, Bargar JR. Uranium storage mechanisms in wet-dry redox cycled sediments. WATER RESEARCH 2019; 152:251-263. [PMID: 30682569 DOI: 10.1016/j.watres.2018.12.040] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 11/30/2018] [Accepted: 12/01/2018] [Indexed: 06/09/2023]
Abstract
Biogeochemical redox processes that govern radionuclide mobility in sediments are highly sensitive to forcing by the water cycle. For example, episodic draining and intrusion of oxidants into reduced zones during dry seasons can create biogeochemical seasonal hotspots of enhanced and changed microbial activity, affect the redox status of minerals, initiate changes in sediment gas and water transport, and stimulate the release of organic carbon, iron, and sulfur by oxidation of solid reduced species to aqueous oxic species. In the Upper Colorado River Basin, water-saturation of organic-enriched sediments locally promotes reducing conditions, denoted 'Naturally Reduced Zones' (NRZs), that accumulate strongly U(IV)sol. Subsequently, fluctuating hydrological conditions introduce oxidants, which may reach internal portions of these sediments and reverse their role to become secondary sources of Uaq. Knowledge of the impact of hydrological variability on the alternating import and export of contaminants, including U, is required to predict contaminant mobility and short- and long-term impacts on water quality. In this study, we tracked U, Fe, and S oxidation states and speciation to characterize the variability in redox processes and related Usol solubility within shallow fine-grained NRZs at the legacy U ore processing site at Shiprock, NM. Previous studies have reported U speciation and behavior in permanently saturated fine-grained NRZ sediments. This is the first report of U behavior in fine-grained NRZ-like sediments that experience repeated redox cycling due to seasonal fluctuations in moisture content. Our results support previous observations that reducing conditions are needed to accumulate Usol in sediments, but they counter the expectation that Usol predominantly accumulates as U(IV)sol; our data reveal that Usol may accumulate as U(VI)sol in roughly equal proportion to U(IV)sol. Surprisingly high abundances of U(VI)sol confined in transiently saturated fine-grained NRZ-like sediments suggest that redox cycling is needed to promote its accumulation. We propose a new process model, where redox oscillations driven by annual water table fluctuations, accompanied by strong evapotranspiration in low-permeability sediments, promote conversion of U(IV)sol to relatively immobile U(VI)sol, which suggests that Usol is accumulating in a form that is resistant to redox perturbations. This observation contradicts the common idea that U(IV)sol accumulated in reducing conditions is systematically re-oxidized, solubilized and transported away in groundwater.
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Affiliation(s)
- Vincent Noël
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, United States
| | - Kristin Boye
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, United States
| | - Ravi K Kukkadapu
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, 99354, United States
| | - Qingyun Li
- Department of Environmental Earth System Science, Stanford University, Stanford, CA, 94305, United States
| | - John R Bargar
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, United States.
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Noël V, Boye K, Lezama Pacheco JS, Bone SE, Janot N, Cardarelli E, Williams KH, Bargar JR. Redox Controls over the Stability of U(IV) in Floodplains of the Upper Colorado River Basin. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:10954-10964. [PMID: 28873299 DOI: 10.1021/acs.est.7b02203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Aquifers in the Upper Colorado River Basin (UCRB) exhibit persistent uranium (U) groundwater contamination plumes originating from former ore processing operations. Previous observations at Rifle, Colorado, have shown that fine grained, sulfidic, organic-enriched sediments accumulate U in its reduced form, U(IV), which is less mobile than oxidized U(VI). These reduced sediment bodies can subsequently act as secondary sources, releasing U back to the aquifer. There is a need to understand if U(IV) accumulation in reduced sediments is a common process at contaminated sites basin-wide, to constrain accumulated U(IV) speciation, and to define the biogeochemical factors controlling its reactivity. We have investigated U(IV) accumulation in organic-enriched reduced sediments at three UCRB floodplains. Noncrystalline U(IV) is the dominant form of accumulated U, but crystalline U(IV) comprises up to ca. 30% of total U at some locations. Differing susceptibilities of these species to oxidative remobilization can explain this variability. Particle size, organic carbon content, and pore saturation, control the exposure of U(IV) to oxidants, moderating its oxidative release. Further, our data suggest that U(IV) can be mobilized under deeply reducing conditions, which may contribute to maintenance and seasonal variability of U in groundwater plumes in the UCRB.
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Affiliation(s)
- Vincent Noël
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
| | - Kristin Boye
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
- Department of Environmental Earth System Science, Stanford University , Stanford, California 94305, United States
| | - Juan S Lezama Pacheco
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
- Department of Environmental Earth System Science, Stanford University , Stanford, California 94305, United States
| | - Sharon E Bone
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
| | - Noémie Janot
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
| | - Emily Cardarelli
- Department of Environmental Earth System Science, Stanford University , Stanford, California 94305, United States
| | - Kenneth H Williams
- Earth Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - John R Bargar
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
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