Effect of solid/liquid ratio on the remobilization of Cu, Pb, Cd and Zn from polluted river sediment

The incidence of the solid/liquid ratio on the solubilization of heavy metals from a polluted river sediment was assessed by batch experiments. The percentage of solubilized metal increases strongly when the concentration of the sediment-water suspension decreases from 50 to 0.1 g L-1. This solubilization behavior is described by a simple equilibrium desorption model on the association of the metals and sediment. The association constants calculated with this model indicate the affinity between the metals and the sediment (Pb > Cu > Zn > Cd). If polluted river sediments are in situ resuspended, the decrease of the solid/liquid ratio associated to this natural event could provoke the remobilization of metals trapped in sediments.