title: Trace elements and Pb isotopes in soils and sediments impacted by uranium mining.
abstract: The purpose of this study is to evaluate the contamination in As, Ba, Co, Cu, Mn, Ni, Sr, V, Zn and REE, in a high uranium activity (up to 21,000Bq∙kg(-1)) area, downstream of a former uranium mine. Different geochemical proxies like enrichment factor and fractions from a sequential extraction procedure are used to evaluate the level of contamination, the mobility and the availability of the potential contaminants. Pb isotope ratios are determined in the total samples and in the sequential leachates to identify the sources of the contaminants and to determine the mobility of radiogenic Pb in the context of uranium mining. In spite of the large uranium contamination measured in the soils and the sediments (EF≫40), trace element contamination is low to moderate (2<EF<5), except for Ba (5<EF<15), due to the precipitation of barium sulfate resulting from mining activities. Most of the trace elements are associated with the most mobile fractions of the sediments/soils, implying an enhanced potential availability. Even if no Pb enrichment is highlighted, the Pb isotopic signature of the contaminated soils is strongly radiogenic. Measurements performed on the sequential leachates reveal inputs of radiogenic Pb in the most mobile fractions of the contaminated soil. Inputs of low-mobile radiogenic Pb from mining activities may also contribute to the Pb signature recorded in the residual phase of the contaminated samples. We demonstrate that Pb isotopes are efficient tools to trace the origin and the mobility of the contaminants in environments affected by uranium mining.
authors.affiliation: ECOLAB, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France; IRSN/PRP-ENV/SESURE/Laboratoire d'études radioécologiques en milieu continental et marin, BP 1, 13108 Saint Paul Lez Durance Cedex, France. Electronic address: alicia.cuvier@hotmail.fr.
authors.forename: A
authors.initials: A
authors.lastname: Cuvier
authors.affiliation: IRSN/PRP-ENV/SESURE/Laboratoire d'études radioécologiques en milieu continental et marin, BP 1, 13108 Saint Paul Lez Durance Cedex, France.
authors.forename: L
authors.initials: L
authors.lastname: Pourcelot
authors.affiliation: ECOLAB, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France.
authors.forename: A
authors.initials: A
authors.lastname: Probst
authors.affiliation: Observatoire Midi-Pyrénées, laboratoire Géosciences Environnement Toulouse, CNRS/IRD/Université Paul Sabatier, 14 avenue Edouard Belin, 31400 Toulouse, France.
authors.forename: J
authors.initials: J
authors.lastname: Prunier
authors.affiliation: ECOLAB, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France. Electronic address: gael.leroux@ensat.fr.
authors.forename: G
authors.initials: G
authors.lastname: Le Roux
mesh_terms: D004784:Environmental Monitoring; D005602:France; D019015:Geologic Sediments / Q000032:analysis*; D007856:Lead Radioisotopes / Q000032:analysis*; D008906:Mining; D012989:Soil Pollutants / Q000032:analysis*; D014131:Trace Elements / Q000032:analysis*; D014501:Uranium
chemical_list: D007856:Lead Radioisotopes; D012989:Soil Pollutants; D014131:Trace Elements; D014501:Uranium
keywords: Enrichment factor; Pb isotopes; Sequential extraction; Soils; Trace Elements; U-mining