Background levels of heavy metals in surficial sediments of the Gulf of Lions (NW Mediterranean): An approach based on 133Cs normalization and lead isotope measurements

Vincent Roussiez (1) , Wolfgang Ludwig (1) , Jean-Luc Probst (2) , André Monaco (1)

1 CEFREM - Centre de Formation et de Recherche sur les Environnements Méditérranéens
2 LMTG - Laboratoire des Mécanismes et Transfert en Géologie

This paper presents an attempt to reach natural background levels of heavy metals in surficial sediments of the Gulf of Lions(NW Mediterranean). To correct for the grain-size effect, normalization procedures based on a clay mineral indicator element are commonly used, after a first grain size separation by sieving. In our study, we tested the applicability of this method with respect to commonly used normalizer elements, and found that stable Cs shows the best ability to reflect the fine sediment fraction. Background levels were successfully reached for Co, Cr, Cu, Ni and Pb, compared to various literature references. Nevertheless, in the case of lead, the normalized data depicted a general enrichment in all samples, and the natural levels could only be reached when concentrations were corrected for the atmospheric contribution by analysing lead isotope ratios. Also for Zn, a general enrichment was found in our samples, although less important.

Mots clés: Heavy metals; Coastal sediments; Normalization; Cs; Background levels; Lead isotopes; Gulf of Lions

Domaines: Sciences de la Terre

Vincent Roussiez, Wolfgang Ludwig, Jean-Luc Probst, André Monaco. Background levels of heavy metals in surficial sediments of the Gulf of Lions (NW Mediterranean): An approach based on 133Cs normalization and lead isotope measurements. Environmental Pollution, 2005, 1 (1), pp.167-177. ⟨10.1016/j.envpol.2005.02.004⟩. ⟨hal-03600183⟩