Trace metal leaching from quarry by-product-stabilized marine sediments

Millions of cubic meter of sediments are dredged annually to open channels for navigation of ships in ports and harbors. Beneficial reuse of these dredgings is typically possible upon their stabilization with calcium-rich amendments. A series of long-term laboratory column leaching tests and contaminant transport models were employed to study metal leaching behavior of bottom-sea dredged material (DM) and their blends with quarry by-products in the natural environment. Column leach tests yielded generally low or non-detectable metal concentrations. The results of the transport modeling indicated that the analyzed metals leached from the DM and the blends were below the national water quality limits at the point of entry to surface water or upon reaching groundwater. Model results showed a significant reduction in leached porewater concentrations due to adsorption and natural attenuation onto a simulated natural formation located between the DM or treated DM and the body of surface water. The overall findings showed that dredged sediments can be considered for reuse following amendment with quarry by-products.