Chronologie et evolution de la contamination par les metaux lourds des sediments de la baie des anges (Mediterranee, France)

Abstract

This study deals with both the chronology and the evolution of the heavy metal pollution of the marine sediments from the bays of Nice and of Villefranche. Geochemical analyses were restricted to the grain fractions < 63 μm. The rates of sedimentation and the chronology are based on isotopic measurements (Cs‐137, Pb‐210). On the continental shelf, the rate of sedimentation shows figures between 0.6 to 2.2 mm per year. In the deeper zones of the bay of Nice (∼800 m), the sedimentation rate is approximately 1 mm per year. The level of contamination is sensitive in our cores from 1900 and it raises significantly since the decage 1950–60. In the sediments of both bays, the growing concentrations of Hg, Cd, Pb, Cu, Zn in surface sediments are due to the increase in pollution, and not to an upward migration of these metals in the sedimentary column.