the resources provided for the present investigation did not 

 allow for examining all sources of PCB in the environment, i.e., 

 dry fallout, riverine contribution, PCB associated with seston, 

 etc. (dredged material was not the only source) , even in cases 

 where correlations were established, e.g. before-during disposal 

 difference in PCBs, causation could not be assumed. 



The general conclusion that disposal of dredged material 

 played a minor role in elevating the tissue trace metal and PCB 

 concentrations, was further augmented by the results obtained 

 from employing the procedures of stepwise multiple regression 

 analysis. It was shown that intrinsic variables, i.e., wet/dry 

 ratios and shell length, not disposal volume, could account for a 

 major proportion of variance observed in the tissue trace metals. 

 The disposal volume as an independent variable entered only ca. 

 28% of the cases, and it ranked third or fourth when it entered 

 the regression model. For the tissue PCB concentrations obtained 

 at WLISc and 500MW, 50-80% of the variance could be explained by 

 the intrinsic variables. The only exception was the Aroclor 1242 

 concentration at WLISc where the volume of dredged material 

 disposed accounted for 74% of its variance. 



Mortalities . The patterns of cumulative mortalities of the 

 four mussel monitoring populations were similar to those of the 

 trace metals levels. Generally there was no spatial difference 

 that could be attributed to the disposal operation between the 

 reference population, WLISrN and the two populations closest to 

 the disposal site, WLISc and 500MW. The sharp increase of 

 cumulative mortalities from January to March 1985 at WLISc 

 appeared to be associated with the accelerated disposal activity 

 at the site. Because this was the only population to exhibit 

 such a trend, it is surmised that the effect of disposal on 

 mortality, if any, was limited to the immediate disposal area. 



Histopathology . Among the seven criteria examined, there 

 was evidence to suggest that retardation of gonadal development, 

 Leydig tissue staining characteristics, and the absence of 

 crystalline style and changes in kidney tubules could be 

 associated with the placement of mussels at WLISc and 500MW and 

 by inference with disposal activities. However, these results 

 should be considered only as a presumptive and the interpretation 

 tempered with caution for the following reasons: 



1. Field experimental results are by nature correlational, 

 therefore, no causation can be assumed; and 



2. The histopathology results presented herein were derived 

 from mussels which survived mortalities of undetermined causes 

 and hence, represented the "fittest" particularly at the three 

 transplanted stations in the western Sound (WLISc, 500MW and 

 WLISrN) , where the average cumulative mortality was more than 

 70%. 



in 



