1) the prevalence of Proctoeces maculatus in the four 

 mussel monitoring populations was not significantly- 

 different (Table 16, G=1.967, d.f.=6, p = 0.975), 



2) the prevalence of Chytridiopsis mytilovum in the WLISc 

 population was significantly higher than the other 

 three populations (Table 17, G H =3.837, d.f.=3, p<0.05,° 

 WLISc: G=5.217, d.f.=l, p<0.025), and 



3) the prevalence of Pinnotheres maculatus differed 

 significantly between the Rlr population and the ones 

 deployed at WLISrN, WLISc and 500MW (Table 18, 

 G H =11.170, d.f.=3, p<0.025). 



There was an overall 12% reduction of P_j. maculatus infection in 

 the transplanted populations as compared to the Rlr population. 



Based upon the study of 310 slides, no significant 

 differences in leukocytic infiltration were noted in all four 

 mussel populations (Table 19, G=8.389, d.f.=9, p=0.50). 



Discussion 



Trace Metal and PCB Concentrations. In the present 

 investigation, it was found that a suite of three trace metals, 

 Cd, Cu, and Zn, showed no discernible difference among the three 

 mussel populations, WLISc, 500MW and WLISrN. These observations 

 support the interpretation that any changes in the trace metal 

 concentrations of these elements in the monitoring populations 

 could not be attibuted to dredged material disposal. It is 

 significant to note that similar inferences were made in the 

 experimental populations during 1983 and 1984 disposal operations 

 in central and western Long Island Sound, respectively (Feng, 

 1984, 1985). This indicates that much more pervasive factors 

 than the episodic disposal of dredged materials are operating in 

 Long Island Sound. 



Factors contributing to the general uniformity of trace 

 metal concentration in the mussel populations held at reference 

 and experimental stations in both central and western Long Island 

 Sound could be the result of physical, chemical and biological 

 processes and/or of disposal management processes. The capping 

 procedure implemented during the 1983 operation at CLIS could 

 effectively reduce the release of toxic metals into the water 

 column, thus reducing the available trace metals to the mussels 

 and consequently mitigating the environmental impact of disposing 

 large quantities of relatively contaminated dredged material, 

 e.g., the Black Rock Harbor material. A second factor is the 

 amount of contaminant input by natural process which could be 

 orders of magnitude larger than the amount of dredged materials 



12 



