transplanted populations in the western Sound (both on and off 

 the disposal site) , suggesting that disposal activities had no 

 effect on tissue concentrations of these elements. Significant 

 temporal differences were found in tissue Co, Cu, and Fe before 

 and during disposal; unfortunately, no post-disposal samples were 

 available. However, similar results were found during earlier 

 transplanted mussel investigations for disposal site monitoring 

 at central and western Long Island Sound; very limited and 

 transient changes could be associated with disposal activities 

 (i.e., metal levels elevated during disposal quickly returned to 

 background levels in post-disposal samples) . Therefore, one 

 could reasonably predict that the elevated levels of Co, Cu, and 

 Fe were of short duration and would return to background 

 following cessation of disposal activities. 



Variations in concentrations of tissue PCBs (both Aroclors 

 and total PCBs) exhibited a pattern similar to the trace metal 

 concentrations: no difference was found among the three 

 populations in the western Sound, while a significant difference 

 existed between the populations in the western Sound compared to 

 the eastern Sound. This again supports the conclusion that the 

 disposal operation was not a major factor for the uptake of PCBs 

 in the experimental populations. Significant temporal 

 differences in PCB uptake were also demonstrated, but because of 

 the lack of post-disposal samples, it could not shown that this 

 was a long-term change; however based on prior experience, one 

 could predict that these elevated levels were of a transient 

 nature. 



Concurrent with the previous disposal site mussel 

 investigations carried out in Long Island Sound, some of the 

 measured variables of physiological change (tissue wet/dry weight 

 ratios and overall length) generally could account for the major 

 proportion of variance observed in the tissue trace metal and PCB 

 concentration. Histopathological studies revealed that the only 

 effects which could be associated with disposal activities were a 

 fewer number of mussels with crystalline styles, a higher 

 incidence of parasitic infection by Chytridiopsis mvtilovum . and 

 a higher incidence of mussels with possible functional atrophy of 

 the plycate organ. Otherwise, there was no effect of dredged 

 material disposal on mussel gametogenesis, glycogen synthesis, 

 gut content (a measure of feeding) , parasitic infections by 

 Pinnotheres maculatus . or destruction of the gonadal tissue by 

 sporocysts of Proctoeces maculatus . The general lack of 

 distinctions among the three transplanted mussel populations has 

 been attributed to the uniform environmental condition in the 

 western Sound mediated by complex physical and biological 

 processes (e.g., water temperature, bioturbation, tidal currents, 

 storms, commercial fishing activities) . These considerations, 

 coupled with the correlational nature of field data, suggest that 

 causative effects cannot be assumed. Therefore, the observed 

 biological effects from the histopathological studies can only be 



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