Vertical distribution and fate of trace metals and persistent organic pollutants in sediments of the Seine and Marne rivers (France)

Trace metals: Cd, Cu, Cr, Ni, Pb and Zn and persistent organic pollutants: polycyclic aromatic hydrocarbons (PAHs) and polychlorobiphenyls (PCBs) were investigated in a fraction of sediments characterized by a granulometry < 200 mum. Cores from 17 to 54 cm depth, were collected at two sites of the Seine river upstream (Port a l'Anglais) and downstream (Saint-Cloud) from Paris and at one site of the Marne river (Saint-Maurice). Marne river sediments displayed higher Cu and Pb levels than those of the Seine river. Except for Cd and Cr, contents did not vary notably in the Seine river sediments. Metal contents, except Pb, were significantly correlated with the sediment fraction which granulometry is < 50 mum, particularly at Port a l'Anglais (p < 0.001). Correlation coefficients between Cr, Cu, Ni and Zn contents and clay fractions of the cores ranged from 0.85 to 0.99 at both sites of the Seine river. PCB levels varied widely, ranging from 27 to 689 mug kg(-1) and were highly correlated with both sediment fraction < 50mum and particulate organic carbon (POC) ratio. PAH levels ranged from 2.30 to 41.3 mug g(-1) and displayed the highest values close to dams; they showed no correlations with sediment fraction < 50 mum and POC.