Major and trace element partition and fluxes in the Rhone River

Patrick Ollivier , Olivier Radakovitch (1) , Bruno Hamelin (1)

1 CEREGE - Centre européen de recherche et d'enseignement des géosciences de l'environnement

Dissolved and particulate major and trace element concentrations and suspended particulate contents were determined during three years on the lower Rhone River (France) from subsurface water samples collected about twice a month and more regularly during flood events. Dissolved elements can be grouped into two sets showing similar relationship between concentration and water discharge related to dilution process and to local and diffuse inputs of dissolved elements in the Rhone basin. The variation of NO(3)/Na and Cl/Na ratios and the absence of correlation between NO(3) and the enrichment in Cl show that Rhone River is not highly affected by fertilizer applications compared to other large French rivers (Seine and Loire rivers). In particulate phase, Ca, Sr, U, Pb, Bi, Cd, Sb and Zn displayed high enrichment factors over shale composition. Lead, Bi, Cd and Zn enrichment could be related to the anthropogenic inputs, while Ca, Sr and U enrichment was explained by lithological composition of the Rhone basin dominated by carbonate rocks. Distribution coefficients of elements (Kd) are relatively stable with however some variations with increasing SPM concentrations. These variations were attributed to local and diffuse inputs and to a higher contribution of carbonate bedrock in the RhOne basin during flood events. Dissolved and particulate major and trace elements, and suspended particulate matter (SPM) fluxes of the Rhone River to the Mediterranean Sea were estimated for the period 2001-2003. SPM and particulate element fluxes were highly dependent on flood events: 69 to 91% of the annual fluxes were exported in less than 12% of the time. Rhone River inputs were the principal source of particulate elements (except for Cd and Zn) in the northwestern Mediterranean Sea, while the major part of dissolved elements were carried out by atmospheric inputs except dissolved As, for which Rhone River contributed to more than 50% of the input to the marine system

Mots clés: Rhone River; Major and trace elements; Metal elements; Suspended particulate matter; Fluxes; Distribution coefficient

Domaines: Milieux et Changements globaux

Patrick Ollivier, Olivier Radakovitch, Bruno Hamelin. Major and trace element partition and fluxes in the Rhone River. Chemical Geology, 2011, 285 (1-4), pp.15-31. ⟨10.1016/j.chemgeo.2011.02.011⟩. ⟨hal-01061560⟩