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1. Biogeochemistry of upland to wetland soils, sediments, and surface waters across Mid-Atlantic and Great Lakes coastal interfaces

Author

Allison N. Myers-Pigg, Stephanie C. Pennington, Khadijah K. Homolka, Allison M. Lewis, Opal Otenburg, Kaizad F. Patel, Peter Regier, Madison Bowe, Maxim I. Boyanov, Nathan A. Conroy, Donnie J. Day, Cooper G. Norris, Edward J. O’Loughlin, Jesse Alan Roebuck, Lucie Stetten, Vanessa L. Bailey, Kenneth M. Kemner, Nicholas D. Ward, and EXCHANGE Consortium

Subjects
Science
Abstract

Abstract Transferable and mechanistic understanding of cross-scale interactions is necessary to predict how coastal systems respond to global change. Cohesive datasets across geographically distributed sites can be used to examine how transferable a mechanistic understanding of coastal ecosystem control points is. To address the above research objectives, data were collected by the EXploration of Coastal Hydrobiogeochemistry Across a Network of Gradients and Experiments (EXCHANGE) Consortium – a regionally distributed network of researchers that collaborated on experimental design, methodology, collection, analysis, and publication. The EXCHANGE Consortium collected samples from 52 coastal terrestrial-aquatic interfaces (TAIs) during Fall of 2021. At each TAI, samples collected include soils from across a transverse elevation gradient (i.e., coastal upland forest, transitional forest, and wetland soils), surface waters, and nearshore sediments across research sites in the Great Lakes and Mid-Atlantic regions (Chesapeake and Delaware Bays) of the continental USA. The first campaign measures surface water quality parameters, bulk geochemical parameters on water, soil, and sediment samples, and physicochemical parameters of sediment and soil.

Published
2023
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2. Coastal inundation regime moderates the short-term effects of sediment and soil additions on seawater oxygen and greenhouse gas dynamics: a microcosm experiment

Author

Peter Regier, Nicholas D. Ward, Alex Izquierdo, Andrew H. Baldwin, Donnie Day, Julia McElhinny, Kaizad Patel, Rodrigo Vargas, Jianqiu Zheng, Exchange Consortium, Allison Myers-Pigg, Silver Alford, Michael P. Back, Vanessa Bailey, Jade Bolinger, Madison Bowe, Maxim I. Boyanov, Jacob A. Cianci-Gaskill, Nathan A. Conroy, Matthew J. Cooper, Alex Demeo, Kyle Derby, Derek Detweiler, Suzanne Devres-Zimmerman, Erin Eberhard, Keryn Gedan, LeeAnn Haaf, Khadijah K. Homolka, Erin Johnson, Kenneth M. Kemner, Aliya Khan, Matthew Kirwan, Payton Kittaka, Erika Koontz, Adam Langley, Riley Leff, Scott Lerberg, Allison M. Lewis, Sairah Malkin, Amy M. Marcarelli, Steven E. McMurray, Tyler Messerschmidt, Taylor C. Michael, Holly A. Michael, Elizabeth C. Minor, Brian Moye, Thomas J. Mozdzer, Allison N. Myers-Pigg, Neubauer Scott, Cooper G. Norris, Edward J. O'Loughlin, Opal Otenburg, Andrea Pain, Kaizad F. Patel, Stephanie C. Pennington, Michael Philben, Evan Phillips, Dannielle Pratt, J. Alan Roebuck Jr., Lauren Sage, Daniel Sandborn, Stacy Smith, Alex Smith, Samina Soin-Voshell, Bongkeun Song, Amanda Sprague-Getsy, Kari St Laurent, Lorie Staver, Alice Stearns, Lucie Stetten, Rebecca Swerida, Ethan J. Theuerkauf, Katherine Tully, Elizabeth Watson, and Coreen Weilminster

Subjects
greenhouse gases, dissolved oxygen, aquatic carbon cycle, terrestrial-aquatic interface, coastal inundation, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract

The frequency and persistence of tidal inundation varies along the coastal terrestrial-aquatic interface, from frequently inundated wetlands to rarely inundated upland forests. This inundation gradient controls soil and sediment biogeochemistry and influence the exchange of soils and sediments from terrestrial to aquatic domains. Although a rich literature exist on studies of the influence of tidal waters on the biogeochemistry of coastal ecosystem soils, few studies have experimentally addressed the reverse question: How do soils (or sediments) from different coastal ecosystems influence the biogeochemistry of the tidal waters that inundate them? To better understand initial responses of coastal waters that flood coastal wetlands and uplands, we conducted short-term laboratory experiments where seawater was amended with sediments and soils collected across regional gradients of inundation exposure (i.e., frequently to rarely inundated) for 14 sites across the Mid-Atlantic, USA. Measured changes in dissolved oxygen and greenhouse gas concentrations were used to calculate gas consumption or production rates occurring during seawater exposure to terrestrial materials. We also measured soil and water physical and chemical properties to explore potential drivers. We observed higher oxygen consumption rates for seawater incubated with soils/sediments from frequently inundated locations and higher carbon dioxide production for seawater incubated with soils from rarely inundated transect locations. Incubations with soil from rarely inundated sites produced the highest global warming potential, primarily driven by carbon dioxide and secondarily by nitrous oxide. We also found environmental drivers of gas rates varied notably between transect locations. Our findings indicate that seawater responses to soil and sediment inputs across coastal terrestrial-aquatic interfaces exhibit some consistent patterns and high intra- and inter-site variability, suggesting potential biogeochemical feedback loops as inundation regimes shift inland.

Published
2023
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3. Platinum Nanoparticle Extraction, Quantification, and Characterization in Sediments by Single-Particle Inductively Coupled Plasma Time-of-Flight Mass Spectrometry

Author

Sara Taskula, Lucie Stetten, Frank von der Kammer, and Thilo Hofmann

Subjects
multi-element single-particle inductively coupled plasma time-of-flight mass spectrometry, nanoparticle extraction, platinum nanoparticles, elemental composition, Chemistry, QD1-999
Abstract

Particulate emissions from vehicle exhaust catalysts are the primary contributors to platinum group elements (PGEs) being released into roadside environments, especially platinum (Pt) particles. With increasing traffic density, it is essential to quantify the emission, accumulation, and potential health effects of traffic-emitted Pt particles. In this study, three procedures were investigated to extract Pt nanoparticles (NPs) from sediments and characterize them by single-particle inductively coupled plasma time-of-flight mass spectrometry (spICP-TOF-MS). For this purpose, a reference sediment sample was spiked with manufactured Pt NPs. Pt NPs’ extraction recoveries reached from 50% up to 102%, depending on the extraction procedure and whether the particle mass or number was used as the metric. Between 17% and 35% of the Pt NPs were found as unassociated Pt NPs and between 31% and 78% as Pt NPs hetero-aggregated with other sediment particles. Multi-elemental analysis of Pt-containing NPs in the pristine sediment revealed frequently co-occurring elements such as Au, Bi, and Ir, which can be used to determine a natural background baseline. Our results demonstrated that spICP-TOF-MS elemental characterization allows for distinguishing anthropogenic Pt NPs from the natural background. In the future, this could enable the sensitive monitoring of PGE release from anthropogenic sources such as vehicle exhausts.

Published
2022
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4. Towards Standardization for Determining Dissolution Kinetics of Nanomaterials in Natural Aquatic Environments: Continuous Flow Dissolution of Ag Nanoparticles

Author

Lucie Stetten, Aiga Mackevica, Nathalie Tepe, Thilo Hofmann, and Frank von der Kammer

Subjects
engineered nanomaterials, flow-through dissolution testing, aquatic environments, OECD guidelines, environmental risk assessment, Chemistry, QD1-999
Abstract

The dissolution of metal-based engineered nanomaterials (ENMs) in aquatic environments is an important mechanism governing the release of toxic dissolved metals. For the registration of ENMs at regulatory bodies such as REACH, their dissolution behavior must therefore be assessed using standardized experimental approaches. To date, there are no standardized procedures for dissolution testing of ENMs in environmentally relevant aquatic media, and the Organisation for Economic Co-operation and Development (OECD) strongly encourages their development into test guidelines. According to a survey of surface water hydrochemistry, we propose to use media with low concentrations of Ca2+ and Mg2+ for a better simulation of the ionic background of surface waters, at pH values representing acidic (5 < pH < 6) and near-neutral/alkaline (7 < pH < 8) waters. We evaluated a continuous flow setup adapted to expose small amounts of ENMs to aqueous media, to mimic ENMs in surface waters. For this purpose, silver nanoparticles (Ag NPs) were used as model for soluble metal-bearing ENMs. Ag NPs were deposited onto a 10 kg.mol−1 membrane through the injection of 500 µL of a 5 mg.L−1 or 20 mg.L−1 Ag NP dispersion, in order to expose only a few micrograms of Ag NPs to the aqueous media. The dissolution rate of Ag NPs in 10 mM NaNO3 was more than two times higher for ~2 µg compared with ~8 µg of Ag NPs deposited onto the membrane, emphasizing the importance of evaluating the dissolution of ENMs at low concentrations in order to keep a realistic scenario. Dissolution rates of Ag NPs in artificial waters (2 mM Ca(NO3)2, 0.5 mM MgSO4, 0–5 mM NaHCO3) were also determined, proving the feasibility of the test using environmentally relevant media. In view of the current lack of harmonized methods, this work encourages the standardization of continuous flow dissolution methods toward OECD guidelines focused on natural aquatic environments, for systematic comparisons of nanomaterials and adapted risk assessments.

Published
2022
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5. Biogeochemistry of soils, sediments, and surface waters across the upland to wetland gradient of coastal interfaces

Author

Allison Myers-Pigg, Stephanie Pennington, Khadijah Homolka, Allison Lewis, Opal Otenburg, Kaizad Patel, Peter Regier, Madison Bowe, Maxium Boyanov, Nathan Conroy, Donnie Day, Cooper Norris, Edward O'Loughlin, Jesse Roebuck Jr., Lucie Stetten, Vanessa Bailey, Kenneth Kemner, Nicholas Ward, and EXCHANGE Consortium

Abstract

Transferable and mechanistic understanding of cross-scale interactions is necessary to predict how coastal systems respond to global change. Cohesive datasets across geographically distributed sites can enable a mechanistic understanding of coastal ecosystem control points and examine how geographically transferable this knowledge is. To address the above research objectives, data were collected by the EXploration of Coastal Hydrobiogeochemistry Across a Network of Gradients and Experiments (EXCHANGE) Consortium– a regionally distributed network of researchers that collaborated on experimental design, methodology, collection, analysis, and publication. The EXCHANGE Consortium collected samples from 52 coastal terrestrial-aquatic interfaces (TAIs) during Fall of 2021. At each site, samples collected include soils from across a transverse elevation gradient (i.e., coastal upland forest, transitional forest, and wetland soils), surface waters, and nearshore sediments. The data described herein aims to characterize the baseline distribution and chemical forms of carbon, nutrients, iron redox and mineralogy across research sites in the Great Lakes and Mid-Atlantic regions (Chesapeake and Delaware Bays) of the continental USA. This first campaign measures surface water quality parameters (e.g., conductivity, pH, ORP, alkalinity, and total suspended solids); bulk geochemical parameters on water, soil, and sediment samples (e.g., carbon, nutrient, and ionic concentration and composition); physicochemical parameters of sediment and soil (soil pH, conductivity, bulk density, water retention); and the rate of O2 consumption in inundated sediment and soil samples. Future campaigns will focus on building off these baseline datasets to enable a mechanistic understanding of coastal ecosystem biogeochemical control points.

Published
2023
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6. Influence of microorganisms on uranium release from mining-impacted lake sediments under various oxygenation conditions

Author

Marina Seder-Colomina, Arnaud Mangeret, Pascale Bauda, Jessica Brest, Lucie Stetten, Pauline Merrot, Anthony Julien, Olivier Diez, Evelyne Barker, Elise Billoir, Pascal Poupin, Antoine Thouvenot, Charlotte Cazala, Guillaume Morin, Laboratoire de recherche sur le devenir des pollutions de sites radioactifs (IRSN/PSE-ENV/SEDRE/LELI), Service des déchets radioactifs et des transferts dans la géosphère (IRSN/PSE-ENV/SEDRE), Institut de Radioprotection et de Sûreté Nucléaire (IRSN)-Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Terre et Environnement de Lorraine (OTELo), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Minéralogie Environnementale [IMPMC] (IMPMC_MINENV), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Service d'intervention radiologique et de surveillance de l'environnement (IRSN/PSE-ENV/SIRSE), Institut de Radioprotection et de Sûreté Nucléaire (IRSN), and Athos Environnement

Subjects
Lakes, Geologic Sediments, Water Pollutants, Radioactive, [SDE]Environmental Sciences, Public Health, Environmental and Occupational Health, Environmental Chemistry, Uranium, General Medicine, Management, Monitoring, Policy and Law, Oxidation-Reduction
Abstract

International audience; Microbial processes can be involved in the remobilization of uranium (U) from reduced sediments under O2 reoxidation events such as water table fluctuations. Such reactions could be typically encountered after U-bearing sediment dredging operations. Solid U(IV) species may thus reoxidize into U(VI) that can be released in pore waters in the form of aqueous complexes with organic and inorganic ligands. Non-uraninite U(IV) species may be especially sensitive to reoxidation and remobilization processes. Nevertheless, little is known regarding the effect of microbially mediated processes on the behaviour of U under these conditions.

Published
2022
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9. HERFD-XANES spectroscopy at the U M-edge applied to the analysis of U oxidation state in a heavily contaminated wetland soil

Author

Arnaud Mangeret, Guillaume Morin, Jessica Brest, Myrtille O.J.Y. Hunault, Jean-Claude Boulliard, Lucie Stetten, Pierre Le Pape, Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Centre National de la Recherche Scientifique (CNRS), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)

Subjects
geography, Radionuclide, geography.geographical_feature_category, Soil test, chemistry.chemical_element, Context (language use), Wetland, 010501 environmental sciences, Contamination, Uranium, 010502 geochemistry & geophysics, 01 natural sciences, Pollution, chemistry, 13. Climate action, Geochemistry and Petrology, Oxidation state, Environmental chemistry, Soil water, [SDE]Environmental Sciences, Environmental Chemistry, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

Determining U oxidation state in contaminated (sub)surface soils and sediments is essential to depict the geochemical processes affecting U in natural media. This information is also mandatory to infer the mechanisms governing the mobilization and transfer of this toxic radionuclide to the environment. Here, in attempt to detect U(IV), U(V) and U(VI) in wetland soil samples contaminated by past mining activities, we have performed high-resolution fluorescence detected X-ray absorption near edge structure (HERFD-XANES) measurements at the U M4-edge. Linear combination fitting (LCF) analysis of the spectra have been conducted using reference samples representative of the wetland geochemistry, in which U occurs as U-phosphate minerals and mononuclear U complexes. Our experimental constraints for HERFD measurements at low energy (3.7 keV) implied to limit the thickness of the Kapton® foil used to protect the samples, which lead to slow oxidation by air during the measurements. In this context, U(IV) appeared to partly oxidize into U(VI) and/or U(V) within a few tens of hours. Nano-crystalline reference samples showed contrasted oxidation pathways for U(IV), transforming into U(V)/U(VI)-uranate in biogenic nano-uraninite, and into U(VI)-uranyl in nano-U(IV)-rhabdophane. In the wetland soils samples, uranium was mainly present as U(IV) and U(VI) with detection of minor U(V) (

Published
2020
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10. Early diagenesis of radium 226 and radium 228 in lacustrine sediments influenced by former mining sites

Author

Marina Seder-Colomina, Lucie Stetten, Jean-Louis Reyss, Pieter van Beek, Arnaud Mangeret, Antoine Thouvenot, Guillaume Morin, Marc Souhaut, Laboratoire de recherche sur le devenir des pollutions de sites radioactifs (IRSN/PSE-ENV/SEDRE/LELI), Service des déchets radioactifs et des transferts dans la géosphère (IRSN/PSE-ENV/SEDRE), Institut de Radioprotection et de Sûreté Nucléaire (IRSN)-Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Océan et Interfaces (OCEANIS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS), PSE-ENV/SEDRE/LELI, Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Geologic Sediments, 010504 meteorology & atmospheric sciences, Health, Toxicology and Mutagenesis, chemistry.chemical_element, 010501 environmental sciences, 01 natural sciences, Mining, Radium, Pore water pressure, Radiation Monitoring, Environmental Chemistry, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Waste Management and Disposal, Dissolution, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, General Medicine, Uranium, Pollution, Tailings, Diagenesis, chemistry, 13. Climate action, Wetlands, Environmental chemistry, [SDE]Environmental Sciences, Sulfate minerals, Environmental science
Abstract

International audience; Radium is a naturally occurring radioactive element commonly found at low levels in natural systems such as lacustrine or marine sediments. Anthropogenic activities including former uranium mining activities can lead to the dissemination of radium isotopes having high radiological toxicities, which potentially threaten the safety of impacted nearby environments. Although radium mobility in oxidized environments is known to be largely governed by sorption/desorption onto Fe and Mn oxyhydroxides and coprecipitation with sulfate minerals (e.g. barite), little is known regarding its behavior under reducing conditions, which are the conditions typically encountered in organic-rich systems such as wetlands and sediments.The present study aims at understanding the behavior of long-lived radium isotopes (226Ra and 228Ra), during early diagenetis of lake sediments contaminated by former uranium mining activities. Solid and pore water concentrations of 226Ra and 228Ra were determined using ultra low background gamma spectrometry, which allowed us to improve detection limits and measurement accuracy.This study shows that the downcore distribution of radium isotopes is closely related to the reductive dissolution of iron and manganese oxyhydroxides below the sediment-water interface. The resulting diffusive fluxes of 226Ra and 228Ra (4.1 10-25 and 4.7 10-28 mol.cm-2.s-1) are however significantly lower than other radium-impacted environments, such as uranium mill tailings pond and phosphate industry-impacted sediments, and are similar to those reported for natural marine environments. Hence, in the reduced lacustrine sediments of Saint-Clement, the major fraction of radium trapped by the solid phase, while early diagenesis only induces a slight mobility of this radioelement.

Published
2020
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11. Experimental redox transformations of uranium phosphate minerals and mononuclear species in a contaminated wetland

Author

Anthony Julien, John R. Bargar, Lucie Stetten, Pierre Le Pape, Jessica Brest, Pierre Lefebvre, Guillaume Morin, Charlotte Cazala, Arnaud Mangeret, Pauline Merrot, Pascale Blanchart, Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Stanford Synchrotron Radiation Lightsource (SSRL SLAC), SLAC National Accelerator Laboratory (SLAC), Stanford University-Stanford University, Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS), Departamento de Ingeniería Electrónica and ISOM (ETSI Telecomunicacion), Universidad Politécnica de Madrid (UPM)-Ciudad Universitaria, Environnement, Géo-ingénierie et Développement (EGID), Stanford University, Institut de minéralogie et de physique des milieux condensés (IMPMC), Université Pierre et Marie Curie - Paris 6 (UPMC)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de recherche sur le devenir des pollutions de sites radioactifs (IRSN/PSE-ENV/SEDRE/LELI), Service des déchets radioactifs et des transferts dans la géosphère (IRSN/PSE-ENV/SEDRE), Institut de Radioprotection et de Sûreté Nucléaire (IRSN)-Institut de Radioprotection et de Sûreté Nucléaire (IRSN), and Unité d'expertise des sites et des déchets radioactifs (IRSN/PSE-ENV/SEDRE/USDR)

Subjects
Environmental Engineering, Health, Toxicology and Mutagenesis, 0211 other engineering and technologies, chemistry.chemical_element, 02 engineering and technology, 010501 environmental sciences, 01 natural sciences, Redox, chemistry.chemical_compound, Adsorption, Autunite, Dissolved organic carbon, Environmental Chemistry, Waste Management and Disposal, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Total organic carbon, 021110 strategic, defence & security studies, Chemistry, Uranium phosphate, 15. Life on land, Uranium, Pollution, Anoxic waters, 6. Clean water, 13. Climate action, [SDU]Sciences of the Universe [physics], Environmental chemistry, [SDE]Environmental Sciences
Abstract

International audience; Reducing conditions and high organic carbon content make wetlands favorable to uranium (U) sequestration. However, such environments are subjected to water-table fluctuations that could impact the redox behavior of U and its mobility. Our previous study on U speciation in a contaminated wetland has suggested a major role of water-table redox fluctuations in the redistribution of U from U(IV)-phosphate minerals to organic U(VI) and U(IV) mononuclear species. Here, we investigate the mechanisms of these putative processes by mimicking drying or flooding periods via laboratory incubations of wetland samples. LCF-XANES and EXAFS analyses show the total oxidation/reduction of U(IV)/U(VI)-mononuclear species after 20 days of oxic/anoxic incubation, whereas U-phosphate minerals are partly oxidized/reduced. SEM-EDXS combined with μ-XRF and μ-XANES analyses suggest that autunite Ca(UO2)2(PO4)2⋅11H2O is reduced into lermontovite U(PO4)(OH)⋅H2O, whereas oxidized ningyoite CaU(PO4)2⋅2H2O is locally dissolved. The release of U from this latter process is observed to be limited by U(VI) adsorption to the soil matrix and further re-reduction into mononuclear U(IV) upon anoxic cycling. Analysis of incubation waters show, however, that dissolved organic carbon enhances U solubilization even under anoxic conditions. This study brings important information that help to assess the long-term stability of U in seasonally saturated organic-rich contaminated environments.

Published
2020
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12. Redox Fluctuations and Organic Complexation Govern Uranium Redistribution from U(IV)-Phosphate Minerals in a Mining-Polluted Wetland Soil, Brittany, France

Author

John R. Bargar, Jessica Brest, Olivier Proux, Lucie Stetten, Guillaume Morin, Arnaud Mangeret, Pascale Blanchart, Anthony Julien, Pierre Lefebvre, Charlotte Cazala, Samuel M. Webb, Pauline Merrot, Pierre Le Pape, Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Institut de recherche pour le développement [IRD] : UR206-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC), Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Environnement, Géo-ingénierie et Développement (EGID), Departamento de Ingeniería Electrónica and ISOM (ETSI Telecomunicacion), Universidad Politécnica de Madrid (UPM)-Ciudad Universitaria, Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Stanford Linear Accelerator Center (SLAC), Stanford University [Stanford], Institut de minéralogie et de physique des milieux condensés (IMPMC), Université Pierre et Marie Curie - Paris 6 (UPMC)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS), Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), SLAC National Accelerator Laboratory (SLAC), and Stanford University

Subjects
Water table, chemistry.chemical_element, Wetland, 010501 environmental sciences, 010502 geochemistry & geophysics, 01 natural sciences, Redox, Phosphates, Soil, Environmental Chemistry, Organic matter, Redistribution (chemistry), ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, chemistry.chemical_classification, Minerals, geography, geography.geographical_feature_category, General Chemistry, Particulates, Uranium, chemistry, Wetlands, Environmental chemistry, [SDE]Environmental Sciences, Phosphate minerals, France, Oxidation-Reduction
Abstract

Wetlands have been proposed to naturally attenuate U transfers in the environment via U complexation by organic matter and potential U reduction. However, U mobility may depend on the identity of particulate/dissolved uranium source materials and their redox sensitivity. Here, we examined the fate of uranium in a highly contaminated wetland (up to 4500 mg·kg–1 U) impacted by former mine water discharges. Bulk U LIII-EXAFS and (micro-)XANES combined with SEM-EDXS analyses of undisturbed soil cores show a sharp U redox boundary at the water table, together with a major U redistribution from U(IV)-minerals to U(VI)-organic matter complexes. Above the water table, U is fully oxidized into mono- and bidentate U(VI)-carboxyl and monodentate U(VI)-phosphoryl complexes. Minute amounts of U(VI)-phosphate minerals are also observed. Below the water table, U is fully reduced and is partitioned between U(IV)-phosphate minerals (i.e., ningyoite and a lermontovite-like phase), and bidentate U(IV)-phosphoryl and monoden...

Published
2018
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13. New insights into Pb isotope fingerprinting of U-mine material dissemination in the environment: Pb isotopes as a memory dissemination tracer

Author

Alkiviadis Gourgiotis, Mathieu Le Coz, Lucie Stetten, Pierre Lefebvre, Guillaume Morin, Pierre Le Pape, Gérard Manhès, Arnaud Mangeret, Pascale Blanchart, Charlotte Cazala, PSE-ENV/SEDRE/LELI, Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Institut de Physique du Globe de Paris (IPGP), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), PSE-ENV/SEDRE/USDR, Equipe de Minéralogie Environnementale, Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Minéralogie Environnementale (MinEnv), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de recherche sur le devenir des pollutions de sites radioactifs (IRSN/PSE-ENV/SEDRE/LELI), Service des déchets radioactifs et des transferts dans la géosphère (IRSN/PSE-ENV/SEDRE), Institut de Radioprotection et de Sûreté Nucléaire (IRSN)-Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), and Unité d'expertise des sites et des déchets radioactifs (IRSN/PSE-ENV/SEDRE/USDR)

Subjects
Soil test, Wetland, 010501 environmental sciences, 01 natural sciences, Soil, Isotopes, TRACER, Soil Pollutants, Environmental Chemistry, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Water discharge, geography, geography.geographical_feature_category, Radiogenic nuclide, Isotope, General Chemistry, Soil core, Lead, 13. Climate action, [SDU]Sciences of the Universe [physics], Wetlands, Environmental chemistry, [SDE]Environmental Sciences, Environmental science, Redox cycling, Environmental Monitoring
Abstract

International audience; Stable Pb isotope ratios were measured and compared to U distributions in three soil cores located in a wetland highly impacted by water discharge of a former U-mine. Pb isotope ratios showed notable alignments in binary mixing plots demonstrating the dissemination of radioactive-enriched material from the U-mine. Thanks to theses alignments and to the measurement of 204Pb isotope, a precise characterization of the Pb isotope composition of the U-ore was performed without the use of U-ore samples. The well-defined end-members with the help of a reevaluated isotope mixing model allowed the accurate determination of the radiogenic Pb percentages in the cores that were overall found to be >50%. Non-correlated distributions of radiogenic 206Pb and U are observed in several of the wetland soil samples studied. They reveal post-depositional U redistribution explained by major U speciation changes due to redox cycling in the wetland. On the contrary, the radiogenic 206Pb showed no or small post-depositional mobility and thus can be considered to be a memory tracer of the dissemination of U-rich radioactive material: even after an important U loss, the radiogenic 206Pb is able to reveal past contamination by U-rich materials.

Published
2019
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14. Carbonate Facilitated Mobilization of Uranium from Lacustrine Sediments under Anoxic Conditions

Author

Evelyne Barker, Pauline Merrot, John R. Bargar, Antoine Thouvenot, Charlotte Cazala, Anthony Julien, Marina Seder-Colomina, Olivier Diez, Lucie Stetten, Arnaud Mangeret, Guillaume Morin, Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Centre National de la Recherche Scientifique (CNRS), Laboratoire Microorganismes : Génome et Environnement (LMGE), Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Stanford Synchrotron Radiation Lightsource (SSRL SLAC), SLAC National Accelerator Laboratory (SLAC), and Stanford University-Stanford University

Subjects
Geologic Sediments, media_common.quotation_subject, Bicarbonate, Carbonates, chemistry.chemical_element, 010501 environmental sciences, 010403 inorganic & nuclear chemistry, 01 natural sciences, Redox, chemistry.chemical_compound, Soil, Environmental Chemistry, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Incubation, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, media_common, Chemistry, General Chemistry, Uranium, Anoxic waters, 0104 chemical sciences, Speciation, Bicarbonates, [SDU]Sciences of the Universe [physics], Environmental chemistry, Carbonate, Oxidation-Reduction
Abstract

Sorbed U(IV) species can be major products of U(VI) reduction in natural reducing environments as sediments and waterlogged soils. These species are considered more labile than crystalline U(IV) minerals, which could potentially influence uranium migration in natural systems subjected to redox oscillations. In this study, we examined the role of oxygen and carbonate on the remobilization of uranium from lake sediments, in which ∼70% of the 150–300 ppm U is under the form of mononuclear U(IV) sorbed species. Our results show that both drying and oxic incubation only slightly increase the amount of remobilized U after 8 days, compared to anoxic drying and anoxic incubation. In contrast, the amount of remobilized U increases with the quantity of added bicarbonate even under anoxic conditions. Moreover, U LIII-edge XANES data show that a significant amount of the solid U(IV) is mobilized in such conditions. Thermodynamic speciation calculations based on the supernatant composition indicates the predominance o...

Published
2018
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15. Geochemical control on the reduction of U(VI) to mononuclear U(IV) species in lacustrine sediments

Author

B. Bombled, Marina Seder-Colomina, Lucie Stetten, Luca Olivi, Nina Zeyen, Jean-Louis Reyss, Jessica Brest, A. Thouvenot, Charlotte Cazala, Christophe Rabouille, Maya Ikogou, Arnaud Mangeret, Anthony Julien, Gilles Alcalde, Olivier Proux, Guillaume Morin, P. Le Pape, Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS), Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Océan et Interfaces (OCEANIS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), ELETTRA (ELETTRA), ELETTRA, Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut de minéralogie, de physique des matériaux et de cosmochimie ( IMPMC ), Institut de recherche pour le développement [IRD] : UR206-Centre National de la Recherche Scientifique ( CNRS ) -Muséum National d'Histoire Naturelle ( MNHN ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ), Géosciences Paris Sud ( GEOPS ), Université Paris-Sud - Paris 11 ( UP11 ) -Centre National de la Recherche Scientifique ( CNRS ), Institut National de Recherche sur les Transports et leur Sécurité ( INRETS ), Institut de Radioprotection et de Sûreté Nucléaire ( IRSN ), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] ( LSCE ), Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay-Centre National de la Recherche Scientifique ( CNRS ), ELETTRA ( ELETTRA ), Institut Néel ( NEEL ), Université Grenoble Alpes [Saint Martin d'Hères]-Centre National de la Recherche Scientifique ( CNRS ), Institut de minéralogie et de physique des milieux condensés ( IMPMC ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -IPG PARIS-Université Paris Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ), Institut de recherche pour le développement [IRD] : UR206-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Institut de minéralogie et de physique des milieux condensés (IMPMC), Université Pierre et Marie Curie - Paris 6 (UPMC)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire des Sciences de l'Univers de Grenoble [2016-2019] (OSUG [2016-2019]), Institut polytechnique de Grenoble - Grenoble Institute of Technology [2007-2019] (Grenoble INP [2007-2019])-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Géosciences Paris Sud (GEOPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), and Institut National de Recherche sur les Transports et leur Sécurité (INRETS)

Subjects
[ SDU.OCEAN ] Sciences of the Universe [physics]/Ocean, Atmosphere, Iron, Speciation, Mononuclear, chemistry.chemical_element, 010501 environmental sciences, 010502 geochemistry & geophysics, 01 natural sciences, Redox, Lake, Pore water pressure, Geochemistry and Petrology, [ SDU.ENVI ] Sciences of the Universe [physics]/Continental interfaces, environment, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Total organic carbon, Chemistry, Sediment, Uranium, Anoxic waters, XANES, Diagenesis, EXAFS, 13. Climate action, [SDU]Sciences of the Universe [physics], Environmental chemistry, [SDE]Environmental Sciences
Abstract

Contaminated systems in which uranium (U) concentrations slightly exceed the geochemical background are of particular interest to identify natural processes governing U trapping and accumulation in Earth’s surface environments. For this purpose, we examined the role of early diagenesis on the evolution of U speciation and mobility in sediments from an artificial lake located downstream from a former mining site. Sediment and pore water chemistry together with U and Fe solid state speciation were analyzed in sediment cores sampled down to 50 cm depth at four locations in the lake. These organic-rich sediments (∼12% organic C) exhibited U concentrations in the 40–80 mg kg−1 range. The sediment columns were anoxic 2–3 mm below the sediment-water interface and pore waters pH was circumneutral. Pore water chemistry profiles showed that organic carbon mineralization was associated with Fe and Mn reduction and was correlated with a decrease in dissolved U concentration with depth. Immobilization of U in the sediment was correlated with the reduction of U(VI) to U(IV) at depth, as shown by U LIII-edge XANES spectroscopic analysis. XANES and EXAFS spectroscopy at the Fe K-edge showed the reduction of structural Fe(III) to Fe(II) in phyllosilicate minerals with depth, coincident with U(VI) to U(IV) reduction. Thermodynamic modeling suggests that Fe(II) could act as a major reducing agent for U(VI) during early diagenesis of these sediments, leading to complete U reduction below ∼30 cm depth. Shell-by-shell and Cauchy-Wavelet analysis of U LIII-EXAFS spectra indicates that U(VI) and U(IV) are mainly present as mononuclear species bound to C, P or Si ligands. Chemical extractions confirmed that ∼60–80% of U was present as non-crystalline species, which emphasizes that such species should be considered when evaluating the fate of U in lacustrine environments and the efficiency of sediment remediation strategies.

Published
2018
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16. Arsenic Incorporation in Pyrite at Ambient Temperature at Both Tetrahedral S

Author

Pierre, Le Pape, Marc, Blanchard, Jessica, Brest, Jean-Claude, Boulliard, Maya, Ikogou, Lucie, Stetten, Shuaitao, Wang, Gautier, Landrot, and Guillaume, Morin

Subjects
X-Ray Absorption Spectroscopy, Iron, Temperature, Ferrous Compounds, Oxidation-Reduction, Arsenic
Abstract

Pyrite is a ubiquitous mineral in reducing environments and is well-known to incorporate trace elements such as Co, Ni, Se, Au, and commonly As. Indeed, As-bearing pyrite is observed in a wide variety of sedimentary environments, making it a major sink for this toxic metalloid. Based on the observation of natural hydrothermal pyrites, As

Published
2016

17. Arsenic incorporation in pyrite at ambient temperature at both tetrahedral S-I and octahedral Fe+II sites: evidence from EXAFS-DFT analysis

Author

Marc Blanchard, Jean-Claude Boulliard, Maya Ikogou, Guillaume Morin, Shuaitao Wang, Lucie Stetten, Pierre Le Pape, Jessica Brest, Gautier Landrot, Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Absorption spectroscopy, Inorganic chemistry, Mineralogy, chemistry.chemical_element, 010501 environmental sciences, engineering.material, 010502 geochemistry & geophysics, 01 natural sciences, law.invention, Oxidation state, law, Environmental Chemistry, [CHIM]Chemical Sciences, Crystallization, Arsenic, 0105 earth and related environmental sciences, Arsenopyrite, X-ray absorption spectroscopy, Extended X-ray absorption fine structure, Chemistry, General Chemistry, 13. Climate action, visual_art, engineering, visual_art.visual_art_medium, Pyrite
Abstract

International audience; Pyrite is an ubiquitous mineral in reducing environments, and is well-known to incorporate trace elements such as Co, Ni, Se, Au and commonly arsenic. Indeed, As-bearing pyrite is observed in a wide variety of sedimentary environments, making it a major sink for this toxic metalloid. Based on the observation of natural hydrothermal pyrites, As-I is usually assigned to the occupation of tetrahedral S sites, with the same oxidation state as in arsenopyrite (FeAsS), even if rare occurrences of AsIII or AsII are reported. However, the modes of As incorporation into pyrite during its crystallization in low-temperature diagenetic conditionsare not elucidated yet since arsenic acts as an inhibitor for pyrite nucleation at ambient temperature. Here, we bring evidence from X-ray absorption spectroscopy for AsII,III incorporation into pyrite at octahedral FeII sites and to As-I at tetrahedral S sites during crystallization at ambient temperature. Extended X-Ray absorption fine structure (EXAFS) spectra of these As-bearing pyrites are explained by local structure models obtained using density functional theory (DFT), assuming incorporation of As at the Fe and S sites as well as local clustering of arsenic. Such observation of As-I incorporation at ambient temperature may help understanding the early formation of authigenic arsenian pyrite in subsurface sediments. Moreover, evidence for AsII,III for Fe substitution in our synthetic samples questions both the possible occurrence and geochemical reactivity of such type of As-bearing pyrites in low-temperature subsurface environments.

Published
2016
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18. Mononuclear U(IV) complexes and ningyoite as major uranium species in lake sediments

Author

Jérôme Guillevic, Christelle Courbet, A. Thouvenot, G. Ona-Nguema, Marina Seder-Colomina, Olivier Proux, Sylvain Bassot, John R. Bargar, Jessica Brest, Lucie Stetten, O. Mathon, Guillaume Morin, Arnaud Mangeret, Guillaume Othmane, Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Université de Clermont-Ferrand, European Synchrotron Radiation Facility (ESRF), Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Stanford Synchrotron Radiation Lightsource (SSRL SLAC), SLAC National Accelerator Laboratory (SLAC), and Stanford University-Stanford University

Subjects
inorganic chemicals, media_common.quotation_subject, chemistry.chemical_element, Mineralogy, 010501 environmental sciences, 010502 geochemistry & geophysics, 01 natural sciences, complex mixtures, Uranium mine, uranium, chemistry.chemical_compound, Uraninite, contamination, Geochemistry and Petrology, Environmental Chemistry, non-uraninite, lake, 0105 earth and related environmental sciences, media_common, ningyoite, mononuclear U(IV) complexes, sediments, technology, industry, and agriculture, crystal-chemistry, Geology, Uranium, Phosphate, Silicate, XANES, Diagenesis, Speciation, EXAFS, immobilisation, chemistry, speciation, 13. Climate action, [SDU]Sciences of the Universe [physics], Environmental chemistry, early diagenesis, Alluvial aquifer, mineralogy
Abstract

International audience; Natural attenuation of uranium in subsurface environments is usually assigned to immobilisation processes due to microbially mediated reduction of U(VI). Recent laboratory studies have established that the end products of such a process include both low solubility biogenic uraninite and more labile non-crystalline U(IV) species. Indeed, biogenic uraninite formation may be inhibited in the presence of organic or inorganic phosphoryl ligands, leading to the formation of non-crystalline U(IV)-phosphate complexes or nanoscale U(IV)-phosphate solids. Such species have been observed in shallow contaminated alluvial aquifers and can thus be suspected to form in other important environments, among which lacustrine sediments have a global environmental significance since they may represent major uranium accumulation reservoirs in riverine watersheds. Here, on the basis of microscopic, spectroscopic and chemical extraction analyses, we report the occurrence of mononuclear U(IV)-phosphate/silicate complexes, accompanied by nano-crystalline ningyoite-like U(IV)-phosphate minerals, as major scavengers for uranium in lacustrine sediments downstream from a former uranium mine in France. This observation reveals that uranium trapping mechanisms during early diagenesis of lacustrine sediments can virtually exclude uraninite formation, which has important implications for better modelling uranium cycling in natural and contaminated freshwaters. Moreover, our results raise issues concerning the long term fate of mononuclear U(IV) complexes and U(IV) phosphate nano-minerals, especially with respect to re-oxidation events. © 2016 European Association of Geochemistry.

Published
2016
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