Severe and contrasted polymetallic contamination patterns (1900-2009) in the Loire River sediments (France)

Cécile Grosbois (1) , M. Meybeck (2) , L. Lestel (2) , I. Lefèvre (3, 4) , Florentina Moatar (1)

1 GéHCO EA6293 - GéoHydrosystèmes COntinentaux
2 SISYPHE - Structure et fonctionnement des systèmes hydriques continentaux
3 LSCE - Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]
4 GEDI - Géochimie Des Impacts

The Loire River basin (117,800km(2), France) has been exposed to multiple sources of metals during the last 150years, originating from major mining districts (coal and non-ferrous metals) and their associated industrial activities. Geochemical archives are established here from the analysis of a 4m sediment core in the downstream floodplain and then compared to stream bed sediments from pristine monolithological sub-basins and from bed and bank sediments in impacted tributaries. The contamination is assessed for 55 major and trace elements through their enrichment factors to Al (EF), normalized to the pre-anthropogenic background. Archives from 1900 to 2009 show enrichment (EF<1.3) not only for Ba, Be, Cs, Ga, Rb, REE, Sr, V. and Zr but also for U and Th, despite U mining activities until the 1990s. From 1900 to 1950, the level of contamination is severe for Hg, Au, Ag (10

Mots clés: Sedimentary archive; Polymetallic contamination; Loire basin; Contamination history; Sensitive element ranking

Domaines: Hydrologie; Sciences de l'environnement

Cécile Grosbois, M. Meybeck, L. Lestel, I. Lefèvre, Florentina Moatar. Severe and contrasted polymetallic contamination patterns (1900-2009) in the Loire River sediments (France). Science of the Total Environment, 2012, 435, pp.290-305. ⟨10.1016/j.scitotenv.2012.06.056⟩. ⟨hal-01195713⟩