Tracking land-to-sea transfer of sediments and associated heavy metals in the Gulf of Lions (NW Mediterranean), based on 133Cs normalization
Congress title :ASLO Summer Meeting
Congress town :Saint-Jacques-de-Compostelle
Congress date :19/06/2005
Détermination of heavy métal concentrations in surficial sédiments is often used to assess the environmental state in coastal areas. Total concentrations in bulle sédiments, however, are not always meaningful in this respect because of the strong association of metals with the finest sédiment fraction, and normalization procédures based on clay minerai indicator éléments are commonly used to correct for the grain-size effect. This work présents an attempt to distinguish between natural background levels and enhancement due to pollution on the platform sédiments of the Gulf of Lions. Although only rarely used in the literature, 133Cs was found to be the most suitable normalization élément. Enhanced heavy métal concentrations exist in the direct vicinity of ail river mouths, pointing out the potential use of thèse éléments for the tracking of riverine sédiments. This is important for the évaluation of the ultimate fate of land-derived pollutants in the marine realm, but also more fundamental studies on the gênerai understanding of the sedimentological processes controlling the sédiment distribution on the platform may benefit from our findings.