Pb, Zn, Cd, Tl, Hg
1 Persisting impact of historical mining activity to metal (Pb, Zn, Cd, 2 Tl, Hg) and metalloid (As, Sb) enrichment in sediments of the Gardon 3 River, Southern France 4 5 Eléonore Resonglesa*, Corinne Casiota, Rémi Freydiera, Laurent Dezileaub, Jérôme Viersc and 6 Françoise Elbaz-Poulicheta 7 8 a HydroSciences UMR 5569, CNRS, Universités Montpellier I & II, IRD, Place Eugène 9 Bataillon, CC MSE, 34095 Montpellier Cedex 5, France 10 b Géosciences UMR 5243, CNRS, Universités Montpellier II, Place Eugène Bataillon, CC 60, 11 34095 Montpellier Cedex 5, France 12 c Géosciences Environnement Toulouse UMR 5563, Université Paul Sabatier, CNRS, IRD, 14 13 Avenue Edouard Belin, 31400 Toulouse, France 14 1 1 Abstract 2 In this study, we assessed past and present influence of ancient mining activity on metal(loid) 3 enrichment in sediments of a former mining watershed (Gardon River, SE France), that is 4 now industrialized and urbanized. A sedimentary archive and current sediments were 5 characterized combining geochemical analyses, zinc isotopic analyses and sequential 6 extractions. The archive was used to establish local geochemical background and recorded (i) 7 increasing enrichment factors (EF) for Pb, Zn, Cd, Tl, Hg, As and Sb throughout the industrial 8 era, (ii) a contamination peak in 1976 attributed to a tailings dam failure, and (iii) current 9 levels in 2002 and 2011 similar to those of 1969, except for Sb and Hg, reflecting a persisting 10 contamination pattern. Inter-element relationships and spatial distribution of EF values of 11 current sediments throughout the watershed suggested that both ancient and current 12 contamination had a common origin for Pb, Zn, Cd, Tl and As related to the exploitation of 13 Pb/Zn mineralization while old Sb mines and coal extraction area were the main sources for 14 Sb and Hg respectively.
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