1. Uranium speciation and transport behavior in the wetland of the former extraction mine of Rophin (France)
- Author
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Nivesse, A.-L, Landesman, C, Martin, A, Arnold, T, Sachs, S, Bok, F, Scheinost, A, Stumpf, T, Coppin, F, Février, L, Gourgiotis, A, Michel, H, den Auwer, C, del Néro, M, Mallet, C, Chardon, P, Montavon, G, Laboratoire de physique subatomique et des technologies associées (SUBATECH), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Nantes université - UFR des Sciences et des Techniques (Nantes univ - UFR ST), Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ), Institut de Chimie de Nice (ICN), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Côte d'Azur (UCA), Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany, Laboratoire de recherche sur les transferts des radionucléides dans les écosystèmes terrestres (IRSN/PSE-ENV/SRTE/LR2T), Service de recherche sur les transferts et les effets des radionucléides sur les écosystèmes (IRSN/PSE-ENV/SRTE), Institut de Radioprotection et de Sûreté Nucléaire (IRSN)-Institut de Radioprotection et de Sûreté Nucléaire (IRSN), 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 Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Microorganismes : Génome et Environnement (LMGE), Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), Laboratoire de Physique de Clermont (LPC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), and LTSER 'Zone Atelier Territoires Uranifères', 63000, Clermont-Ferrand, France
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[SDE]Environmental Sciences - Abstract
International audience; IntroductionIn the vicinity ofold uranium mines, wetlands prove to be specific zones with significant amountsof accumulated U. At the center ofthe ancient mining district of Lachaux in France (45.994°N,3.596°E), the site of Rophin (within the ZATU: Uranium Working Zone = Long Term SocioEcological Research Tool ofCNRS) is characterized by awetland areawith high U concentrationsup to 3.6 g.kg-1. In this context, the main challenge is to describe the behavior ofU and relevantdecay products in the wetland using a predictive model that combines chemical speciation andtransport.MethodsThe overall adopted scientific approach is to propose a mechanistic description ofthe mobility ofthese elements, from the molecular scale (speciation) to in situ behavior (lability), by couplingfield and laboratory experiments with modelling. Batch desorption and column experiments werecarried out with in situ soil samples to assess the mobile fraction part of U and its distributioncoefficients (Kd). Labile behavior of U was examined directly on site by using the DGT/DETtechniques while U speciation was investigated by the combination ofseveral techniques (SEM,XAS). From laboratory data, predictive modelling (smart-Kd model) was implemented under sitespecific conditions.ResultsObservations by SEM, XANES and EXAFS confirmed the U transportin particulate form duringthe mining activities and the establishment of reducing conditions over time, implying thepresence of both U(IV) and U(VI). Labile quantity and Kd values of U were confirmed to behomogeneous at the scale of the Rophin wetland and consistent with in situ labile behaviordeduced from the DGT/DET approach, considering a kinetically controlled interaction.ConclusionsThanks to the combination of different techniques, a better understanding of what happened inthe wetland over 70 years can be achieved. All these data should now allow us to define the keyparameters to be integrated in the reactive part ofthe transport model ofthe Rophin site
- Published
- 2022