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Byrnes I, Rossbach LM, Jaroszewicz J, Grolimund D, Ferreira Sanchez D, Gomez-Gonzalez MA, Nuyts G, Reinoso-Maset E, Janssens K, Salbu B, Brede DA, Lind OC. Synchrotron XRF and Histological Analyses Identify Damage to Digestive Tract of Uranium NP-Exposed Daphnia magna. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:1071-1079. [PMID: 36598768 PMCID: PMC9850915 DOI: 10.1021/acs.est.2c07174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 12/15/2022] [Accepted: 12/15/2022] [Indexed: 06/17/2023]
Abstract
Micro- and nanoscopic X-ray techniques were used to investigate the relationship between uranium (U) tissue distributions and adverse effects to the digestive tract of aquatic model organism Daphnia magna following uranium nanoparticle (UNP) exposure. X-ray absorption computed tomography measurements of intact daphnids exposed to sublethal concentrations of UNPs or a U reference solution (URef) showed adverse morphological changes to the midgut and the hepatic ceca. Histological analyses of exposed organisms revealed a high proportion of abnormal and irregularly shaped intestinal epithelial cells. Disruption of the hepatic ceca and midgut epithelial tissues implied digestive functions and intestinal barriers were compromised. Synchrotron-based micro X-ray fluorescence (XRF) elemental mapping identified U co-localized with morphological changes, with substantial accumulation of U in the lumen as well as in the epithelial tissues. Utilizing high-resolution nano-XRF, 400-1000 nm sized U particulates could be identified throughout the midgut and within hepatic ceca cells, coinciding with tissue damages. The results highlight disruption of intestinal function as an important mode of action of acute U toxicity in D. magna and that midgut epithelial cells as well as the hepatic ceca are key target organs.
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Affiliation(s)
- Ian Byrnes
- Faculty
of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Center for
Environmental Radioactivity (CERAD), P.O. Box 5003, 1433 Ås, Norway
| | - Lisa Magdalena Rossbach
- Faculty
of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Center for
Environmental Radioactivity (CERAD), P.O. Box 5003, 1433 Ås, Norway
| | - Jakub Jaroszewicz
- Faculty
of Materials Science and Engineering, Warsaw
University of Technology, Woloska Street 141, 02-507 Warsaw, Poland
| | - Daniel Grolimund
- Swiss
Light Source, Paul Scherrer Institute (PSI), 5232 Villigen, Switzerland
| | | | - Miguel A. Gomez-Gonzalez
- Diamond
Light Source Ltd., Harwell
Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, United Kingdom
| | - Gert Nuyts
- AXIS
Group, NANOlab Center of Excellence, Department of Physics, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Estela Reinoso-Maset
- Faculty
of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Center for
Environmental Radioactivity (CERAD), P.O. Box 5003, 1433 Ås, Norway
| | - Koen Janssens
- AXIS
Group, NANOlab Center of Excellence, Department of Physics, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Brit Salbu
- Faculty
of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Center for
Environmental Radioactivity (CERAD), P.O. Box 5003, 1433 Ås, Norway
| | - Dag Anders Brede
- Faculty
of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Center for
Environmental Radioactivity (CERAD), P.O. Box 5003, 1433 Ås, Norway
| | - Ole Christian Lind
- Faculty
of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Center for
Environmental Radioactivity (CERAD), P.O. Box 5003, 1433 Ås, Norway
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Roebbert Y, Rosendahl CD, Brown A, Schippers A, Bernier-Latmani R, Weyer S. Uranium Isotope Fractionation during the Anoxic Mobilization of Noncrystalline U(IV) by Ligand Complexation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:7959-7969. [PMID: 34038128 DOI: 10.1021/acs.est.0c08623] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Uranium (U) isotopes are suggested as a tool to trace U reduction. However, noncrystalline U(IV), formed predominantly in near-surface environments, may be complexed and remobilized using ligands under anoxic conditions. This may cause additional U isotope fractionation and alter the signatures generated by U reduction. Here, we investigate the efficacy of noncrystalline U(IV) mobilization by ligand complexation and the associated U isotope fractionation. Noncrystalline U(IV) was produced via the reduction of U(VI) (400 μM) by Shewanella oneidensis MR-1 and was subsequently mobilized with EDTA (1 mM), citrate (1 mM), or bicarbonate (500 mM) in batch experiments. Complexation with all investigated ligands resulted in significant mobilization of U(IV) and led to an enrichment of 238U in the mobilized fraction (δ238U = 0.4-0.7 ‰ for EDTA; 0.3 ‰ for citrate; 0.2-0.3 ‰ for bicarbonate). For mobilization with bicarbonate, a Rayleigh approach was the most suitable isotope fractionation model, yielding a fractionation factor α of 1.00026-1.00036. Mobilization with EDTA could be modeled with equilibrium isotope fractionation (α: 1.00039-1.00049). The results show that U isotope fractionation associated with U(IV) mobilization under anoxic conditions is significant and needs to be considered when applying U isotopes in remediation monitoring or as a paleo-redox proxy.
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Affiliation(s)
- Yvonne Roebbert
- Leibniz Universität Hannover, Institut für Mineralogie, Hannover D-30167, Germany
| | | | - Ashley Brown
- École polytechnique fédérale de Lausanne, Lausanne 1015, Switzerland
| | - Axel Schippers
- Federal Institute for Geosciences and Natural Resources, Hannover D-30655, Germany
| | | | - Stefan Weyer
- Leibniz Universität Hannover, Institut für Mineralogie, Hannover D-30167, Germany
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3
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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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Han YS, Jeong HY, Hyun SP, Hayes KF, Chon CM. Beam-induced redox transformation of arsenic during As K-edge XAS measurements: availability of reducing or oxidizing agents and As speciation. JOURNAL OF SYNCHROTRON RADIATION 2018; 25:763-770. [PMID: 29714186 DOI: 10.1107/s1600577518002576] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 02/12/2018] [Indexed: 06/08/2023]
Abstract
During X-ray absorption spectroscopy (XAS) measurements of arsenic (As), beam-induced redox transformation is often observed. In this study, the As species immobilized by poorly crystallized mackinawite (FeS) was assessed for the susceptibility to beam-induced redox reactions as a function of sample properties including the redox state of FeS and the solid-phase As speciation. The beam-induced oxidation of reduced As species was found to be mediated by the atmospheric O2 and the oxidation products of FeS [e.g. Fe(III) (oxyhydr)oxides and intermediate sulfurs]. Regardless of the redox state of FeS, both arsenic sulfide and surface-complexed As(III) readily underwent the photo-oxidation upon exposure to the atmospheric O2 during XAS measurements. With strict O2 exclusion, however, both As(0) and arsenic sulfide were less prone to the photo-oxidation by Fe(III) (oxyhydr)oxides than NaAsO2 and/or surface-complexed As(III). In case of unaerated As(V)-reacted FeS samples, surface-complexed As(V) was photocatalytically reduced during XAS measurements, but arsenic sulfide did not undergo the photo-reduction.
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Affiliation(s)
- Young Soo Han
- Geologic Environment Division, Korea Institute of Geoscience and Mineral Resources, Deajeon 34132, Republic of Korea
| | - Hoon Young Jeong
- Department of Geological Sciences, Pusan Natinal University, Busan 46241, Republic of Korea
| | - Sung Pil Hyun
- Geologic Environment Division, Korea Institute of Geoscience and Mineral Resources, Deajeon 34132, Republic of Korea
| | - Kim F Hayes
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, MI 48105, USA
| | - Chul Min Chon
- Geologic Environment Division, Korea Institute of Geoscience and Mineral Resources, Deajeon 34132, Republic of Korea
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Bone SE, Cahill MR, Jones ME, Fendorf S, Davis J, Williams KH, Bargar JR. Oxidative Uranium Release from Anoxic Sediments under Diffusion-Limited Conditions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:11039-11047. [PMID: 28876920 DOI: 10.1021/acs.est.7b02241] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Uranium (U) contamination occurs as a result of mining and ore processing; often in alluvial aquifers that contain organic-rich, reduced sediments that accumulate tetravalent U, U(IV). Uranium(IV) is sparingly soluble, but may be mobilized upon exposure to nitrate (NO3-) and oxygen (O2), which become elevated in groundwater due to seasonal fluctuations in the water table. The extent to which oxidative U mobilization can occur depends upon the transport properties of the sediments, the rate of U(IV) oxidation, and the availability of inorganic reductants and organic electron donors that consume oxidants. We investigated the processes governing U release upon exposure of reduced sediments to artificial groundwater containing O2 or NO3- under diffusion-limited conditions. Little U was mobilized during the 85-day reaction, despite rapid diffusion of groundwater within the sediments and the presence of nonuraninite U(IV) species. The production of ferrous iron and sulfide in conjunction with rapid oxidant consumption suggested that the sediments harbored large concentrations of bioavailable organic carbon that fueled anaerobic microbial respiration and stabilized U(IV). Our results suggest that seasonal influxes of O2 and NO3- may cause only localized mobilization of U without leading to export of U from the reducing sediments when ample organic carbon is present.
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Affiliation(s)
- Sharon E Bone
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
| | | | - Morris E Jones
- Stanford University , Stanford, California 94305, United States
| | - Scott Fendorf
- Stanford University , Stanford, California 94305, United States
| | - James Davis
- U.S. Geological Survey, Menlo Park, California 94025, United States
| | - Kenneth H Williams
- 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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Abstract
Uranium is an important carbon-free fuel source and environmental contaminant that accumulates in the tetravalent state, U(IV), in anoxic sediments, such as ore deposits, marine basins, and contaminated aquifers. However, little is known about the speciation of U(IV) in low-temperature geochemical environments, inhibiting the development of a conceptual model of U behavior. Until recently, U(IV) was assumed to exist predominantly as the sparingly soluble mineral uraninite (UO2+x) in anoxic sediments; however, studies now show that this is not often the case. Yet a model of U(IV) speciation in the absence of mineral formation under field-relevant conditions has not yet been developed. Uranium(IV) speciation controls its reactivity, particularly its susceptibility to oxidative mobilization, impacting its distribution and toxicity. Here we show adsorption to organic carbon and organic carbon-coated clays dominate U(IV) speciation in an organic-rich natural substrate under field-relevant conditions. Whereas previous research assumed that U(IV) speciation is dictated by the mode of reduction (i.e., whether reduction is mediated by microbes or by inorganic reductants), our results demonstrate that mineral formation can be diminished in favor of adsorption, regardless of reduction pathway. Projections of U transport and bioavailability, and thus its threat to human and ecosystem health, must consider U(IV) adsorption to organic matter within the sediment environment.
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