Remobilization of trace metals from contaminated marine sediment in a simulated dynamic environment

In this study, release and redistribution of sediment bound trace metals due to resuspension were investigated by a lid-driven elongated annular flume (LEAF). The total suspended particulate matters (SPMs) increased significantly in quantity with the raised resuspension energies and varied distinctively in particle size and mineral composition. Except for Cu, Ni, Cd, Pb, and Zn showed an increase in dissolved phase as the resuspension energy increased. Relatively low Cu was observed in dissolved phase whereas it owned the highest original concentration in the sediment. This is primarily due to the very low solubility of Cu sulfide. In comparison to sediment, all metals were evidently enriched in SPMs which primarily contributed to the much more fine particles (silt/clay fraction) contained in the SPMs. Metals enrichment followed the Irving-Williams order of complex stability. However, metals content varied indistinctively in the SPMs among the three selected resuspension levels. The distribution coefficients (Kd) exhibited opposite trend with the increasing resuspension level with the exception of Cu. It indicated that physical and chemical characters of sediment such as grain composition, Fe/Mn, and organic matter content may also act as major factors in the release of metals and control their phase distribution in the water column.