Sedimentary record of metal contamination in the Seine River during the last century

The time evolution of heavy metal contamination in the Seine River catchment is documented through the analysis of sediment cores sampled at three different sites: in upstream Seine River where agricultural activity is predominant, in the Oise River (a tributary of the Seine River) characterized by intensive industrial activity, and downstream Seine River where various kinds of activities (agricultural, industrial and urban activities) are mixed. The chronology of the cores is obtained through 137Cs and 210Pb dating. Only cores with a clear dating are selected for the study. Concentrations of Pb, Cd, Cu, Zn, Cr, As, Sb and Hg are analyzed by neutron activation, inductively coupled plasma-atomic emission spectrometry, inductively coupled plasma-mass spectrometry and atomic absorption spectroscopy after sediment dissolution.The maximum of pollution is registered during the 1960–1970 decade in the Oise River site, and 10 years later in the downstream Seine River. The sites are compared, showing some specific signatures. The different occurrence of every metal at each site is discussed. The present level of pollution is lower in the Oise River, compared to that of the downstream site. The decrease of the metallic pollution is discussed in each site considering its origins and history, as well as recent French and EU environmental policy implementation.