Publications des scientifiques de l'IRD

Cossa D., Fanget A. S., Chiffoleau J. F., Bassetti M. A., Buscail R., Dennielou B., Briggs K., Arnaud M., Guédron Stéphane, Berne S. (2018). Chronology and sources of trace elements accumulation in the Rhone pro-delta sediments (Northwestern Mediterranean) during the last 400 years. In : Sempéré R. (ed.), Durrieu de Madron X. (ed.), Guieu C. (ed.), Pairaud I. (ed.). Special issue of MERMEX project : recent advances in the oceanography of the Mediterranean Sea. Progress in Oceanography, 163 (Special issue), p. 161-171. ISSN 0079-6611.

Titre du document
Chronology and sources of trace elements accumulation in the Rhone pro-delta sediments (Northwestern Mediterranean) during the last 400 years
Année de publication
2018
Type de document
Article référencé dans le Web of Science WOS:000434004400014
Auteurs
Cossa D., Fanget A. S., Chiffoleau J. F., Bassetti M. A., Buscail R., Dennielou B., Briggs K., Arnaud M., Guédron Stéphane, Berne S.
In
Sempéré R. (ed.), Durrieu de Madron X. (ed.), Guieu C. (ed.), Pairaud I. (ed.), Special issue of MERMEX project : recent advances in the oceanography of the Mediterranean Sea
Source
Progress in Oceanography, 2018, 163 (Special issue), p. 161-171 ISSN 0079-6611
The Rhone pro-delta sediments receive the particulate inputs from the Rhone River, the largest freshwater discharge of the Western Mediterranean Sea. Trace element (TEs: Ag, Cd, Co, Cr, Cu, Ni, Pb, and Zn) concentrations and stable Pb isotope ratios were determined along a 7.7-m-long sediment core collected from the Rhone prodeltaic lobe, archiving the deposits of the last 400 years. Trace element mean concentrations during the pre-industrialized era (before 1850 CE) were no different from the average composition of Earth's upper crust, except for Cr. Principal component analysis, performed on TEs and tracers, suggests three origins for TEs that we identified as (i) marine biogenic material (Ag, Cd), (ii) ultramafic rocks (Li, Cr, Ni), and (iii) other clay minerals (Co, Cu, Pb and Zn). During the pre-industrial period, several changes in the TE/AI ratios coincided with flood events or/and modifications in the channelization of the Rhone River mouth. Some frequencies in the TEs temporal variations allow us to hypothesize some influence of climate variation. Sediments deposited after 1850 CE exhibited concentrations of certain TEs exceeding 1.3-3.5 times the concentrations of the pre-industrial era (Ag > Cd-Pb > Cu-Zn). Principal component analysis, performed on post-1850 CE data, allows to distinguish pristine and "anthropogenically impacted" TEs. Pristine TEs, such as Co, Cr, and Ni, are linked with clay markers (Al, Li and Fe), Co and Ni are associated with Mn-enrichment, whereas Cr is correlated with Fe. "Anthropogenically impacted" elements consist of Ag, Cd, Cu, Pb, and Zn. Vertical profiles show that TE contamination has increased dramatically after the IInd World War and reached a maximum between 1970 and 1980, consistently with anthropogenic atmospheric emissions changes. Sediment deposited on the Rhone prodelta at the beginning of XVIIth Century have Pb-206/207 ratios close to values of natural Pb (1.200), whereas sediments deposited after 1850 CE are clearly contaminated by European gasoline and industrial Pb pools (<1.180). In addition, peak-events can be related to flooding periods, natural and man-induced channelization of the Rhone River mouth, or diagenetic processes.
Plan de classement
Limnologie physique / Océanographie physique [032]
Description Géographique
MEDITERRANEE ; FRANCE
Localisation
Fonds IRD [F B010073066]
Identifiant IRD
fdi:010073066
Contact