Pb-Zn-Cd-Hg multi isotopic characterization of the Loire River Basin, France - BRGM - Bureau de recherches géologiques et minières
Conference Papers Year : 2012

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

Abstract

The contribution of human activities such as industries, agriculture and domestic inputs, becomes more and more significant in the chemical composition (major ions and pollutants such as metals) of the dissolved load of rivers. Furthermore, this influence can also be evidenced in the suspended solid matter known to play an important role in the transport of heavy metals through river systems. Human factors act as a supplementary key process. Therefore the mass-balance for the budget of catchments and river basins include anthropogenic disturbances. The Loire River in central France is approximately 1010 km long and drains an area of 117,800 km2. Initially, the Loire upstream flows in a south to north direction originating in the Massif Central, and continues up to the city of Orléans, 650 km from the source. In the upper basin, the bedrock is old plutonic rock overlain by much younger volcanic rocks. The Loire River then follows a general east to west direction to the Atlantic Ocean. The intermediate basin includes three major tributaries flowing into the Loire River from the left bank: the Cher, the Indre and the Vienne rivers; the main stream flows westward and its valley stretches toward the Atlantic Ocean. Here, the Loire River drains the sedimentary series of the Paris Basin, mainly carbonate deposits. The lower Loire basin drains pre-Mesozoic basement of the Armorican Massif and its overlying Mesozoic to Cenozoic sedimentary deposits. The Loire River is one of the main European riverine inputs to the Atlantic ocean. Here we are reporting concentration and isotope data for heavy metals Zn-Cd-Pb-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 industrial 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. The main objective of this study is to characterize the sources and the behavior of these heavy metals in the aquatic environment, and their spatial distribution using a multi-isotope approach. 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.
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Dates and versions

hal-00726507 , version 1 (30-08-2012)

Identifiers

  • HAL Id : hal-00726507 , version 1

Cite

Romain Millot, David Widory, Christophe Innocent, Catherine Guerrot, Xavier Bourrain, et al.. Pb-Zn-Cd-Hg multi isotopic characterization of the Loire River Basin, France. AGU Fall Meeting, Dec 2012, San Francisco, United States. pp.1. ⟨hal-00726507⟩

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