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Communication dans un congrès

Pb-Zn-Cd-Hg multi isotopic characterization of the Loire River basin, France

Abstract : Introduction: The impact of human activities such as industries, agriculture and domestic inputs, becomes more and more significant on the chemical composition (major ions and pollutants including metals) of the dissolved load of rivers in addition with natural inputs. Furthermore, this influence can also be evidenced in the suspended solid matter known to play a major role in the transport of heavy metals through river systems. Human factors act as an additional key process. Therefore the mass-balance for the budget of catchments and river basins includes anthropogenic disturbances. Here we are reporting concentration and isotope data for heavy metals zinc (Zn), cadmium (Cd), lead (Pb) and mercury (Hg) in river waters and suspended sediments from the Loire River Basin. In addition, we also report concentration and isotope data for these metals for the different anthropogenic sources within the Loire Basin, as well as data for biota samples such as mussels and oysters from the Bay of Biscay and North Brittany, these organisms are known to be natural accumulators of metal pollutants. Results: The Loire River in Central France is approximately 1010 km long and drains an area of 117 800 km2. Upstream, the Loire River flows south to north from the Massif Central down to the city of Orléans, 650 km from its source. The Loire River is one of the main European riverine inputs to the Atlantic Ocean. Over time, its basin has been exposed to numerous sources of anthropogenic metal pollutions, such as metal mining, food industry, agriculture and domestic inputs. The Loire River basin is thus an excellent study site to develop new isotope systematics for tracking anthropogenic sources of metal pollutions. We have chosen to analyse the isotope composition of Cd, Zn, Hg and Pb. These heavy metals have been selected for their toxicity, even at low levels, to humans. The main goal of this study is to characterize 1) the sources and behaviour of these heavy metals in the aquatic environment, and 2) their spatial distribution using a multi-isotope approach. Sources responsible for the release of Pb-Zn-Cd-Hg in the Loire basin were sampled and analysed for their concentrations and corresponding isotope compositions. We also analysed river waters, suspended solids samples and biota samples (mussels, oysters). All trace elements were analysed in the BRGM laboratories using a Q-ICPMS. Pb-Zn-Cd isotope compositions were measured using a Neptune MC-ICPMS at the BRGM. Hg isotope compositions were measured at the University of Illinois using a Nu Plasma MC-ICPMS. To analyse Zn and Cd, we carried out a two-steps analytical development: 1) a chromatographic separation, followed by 2) analysis on the MC-ICPMS. Each of these isotope systematics on their own reveals important information about their geogenic or anthropogenic origin but, considered together, provide a more integrated understanding of the budgets of these pollutants within the Loire River Basin. Acknowledgments: We would like to thank the IFREMER (French Oceanographic Institute) for providing biota samples and we also cordially thank AMP (Analyses Mesures Pollution) for their help during the sample collection of suspended sediments.
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https://hal-brgm.archives-ouvertes.fr/hal-00835784
Contributeur : Romain Millot <>
Soumis le : mercredi 19 juin 2013 - 16:19:15
Dernière modification le : lundi 18 mai 2020 - 14:54:13

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  • HAL Id : hal-00835784, version 1

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Romain Millot, Anne-Marie Desaulty, David Widory, Catherine Guerrot, Christophe Innocent, et al.. Pb-Zn-Cd-Hg multi isotopic characterization of the Loire River basin, France. Applied Isotope Geochemistry Conference AIG-10, Sep 2013, Budapest, Hungary. pp.1. ⟨hal-00835784⟩

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