Sediment Properties as Tracers of Dredged Material Disposed in Open Ocean

In conjunction with dredging activities planned for San Diego Bay, a study was conducted to identify and investigate selected physical chemical, and biogenic parameters of sediment for use as potential tracers of material dredged from a polluted area of the bay and disposed in the EPA approved 100 fathom disposal site. Specific properties measured included grain size distribution, concentrations of cadmium, mercury, lead, oil and grease, and foraminifera species. Results of this study indicated that mercury, cadmium, and lead concentrations and foraminifera species composition can be used to distinguish dredged material from disposal site material. However, of these parameters foraminifera species composition appears to be the best indicator for monitoring the fate of dredged material disposed off San Diego, since foraminifera species abundant in the dredge site were practically nonexistent in the disposal site.