Field Verification Program (Aquatic Disposal). Effects of Black Rock Harbor Dredged Material on the Histopathology of The Blue Mussel Mytilus edulis and Polychaete Worm Nephtys incisa After Laboratory and Field Exposures

A study was conducted to field verify histopathological changes in two aquatic species, Mytilus edulis and Nephtys incisa, by comparing histological changes under both laboratory and field exposures to contaminated dredged material. A second objective of the study was to determine the degree of correlation between tissue residues resulting from bioaccumulation of dredged material contaminants with histopathological changes. A laboratory dosing system was designed to deliver a constant exposure concentration of suspended sediment (both reference and contaminated dredged material from Black Rock Harbor (BRH)) to the blue mussel Mytilus edulis and the polychaete worm Nephtys incisa. Residue concentrations in both mussels and worms, particularly stable compounds such as polychlorinated biphenyls (PcBa), were found to be closely related to exposure concentrations. Histopathological changes included the female reproductive tract, grills, and gastrointestinal tract for M. edulis and the parapodial epidermis for N. incisa. Histopathological changes observed for the specimens of both species following laboratory exposures were directly related to BRH exposure and subsequent tissue concentrations. There was a definite relationship between histopathological change and tissue residues in M. edulis in the laboratory for those BRH contaminants that were bioaccumulated. A residue-effect relationship was not evident for N. incisa in the laboratory, since a change in the parapodial epidermis was not considered to be a pathological condition and was the only response reported. Prepared in cooperation with Science Applications International Corp. Narragansett, RI.