Effects of Suspended Dredged Material on Aquatic Animals.
CALIFORNIA UNIV BODEGA BAY BODEGA MARINE LAB
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This report describes laboratory research designed to evaluate the impact of suspensions of relatively uncontaminated and contaminated harbor sediments on juvenile and adult marine, estuarine and freshwater fish and invertebrates. Studies of survival and tissue accumulation of contaminants were conducted for 21 days exposure to suspended sediments in a flow-through aquarium system. Even the most sensitive fish survived days of continuous exposure to suspensions of relatively uncontaminated sediment on the order of grams per litre, and the invertebrates generally survived similar exposures to tens of grams per litre of relatively uncontaminated sediment. Exposure to suspensions of contaminated sediment decreased survival substantially, but, even so, mortality occurred only after exposure to higher concentrations for longer time periods than are created in the water column by the typical dredging operation. Only fingerling striped bass Morone saxatilis showed a sensitivity great enough to indicate a potential cause for concern from continuous pipeline discharge of highly contaminated dredged material. Tissue uptake of contaminants from suspensions of highly contaminated sediment was limited. Of 100 species-salinity-contaminant combinations where uptake might have been measured, it actually occurred in less than one fourth of the cases.
- Civil Engineering