disposed in the Sound. Moreover, it is assumed that releasing of 

 trace metals and other constituents from the sediment due to 

 bioturbation (sediment reworking by infauna) over a vast area of 

 the seafloor in the Sound is a continuous process. The nepheloid 

 layer which prevails at the sediment-water interface throughout 

 much of the area of the Sound with silt-clay bottom (including 

 the disposal sites) is presumably the result of bioturbational 

 activities of the resident infauna. It is believed that 

 bioturbation of shallow sea sediment is possibly the most 

 important factor in vertical transport of contaminants to the 

 water column, while physical factors such as storm events, 

 circulation patterns, residence time of water masses, etc., play 

 important roles in large scale mixing of contaminants in the 

 Sound. 



It is reasonable to assume that vertical and horizontal 

 mixing of water masses in western Long Island Sound (the 

 narrowest part of the estuary) are maintained most of the time 

 except during the warm months when large areas of hypoxia exist 

 due to temperature stratification of the water column (Rhoads, 

 1987; Welsh, personal communication). Bohlen (1980) reports that 

 dredging-induced sediment resuspension is generally small in 

 comparison to the transport resulting from natural storm events. 

 Additionally, sediment resuspension produced by commercial 

 fishing activities could also be a factor contributing to 

 particulate-bound contaminant transport; studies in the Gulf of 

 Mexico have shown that resuspension due to shrimp trawling 

 activities could be 10-100 times greater than that generated by 

 maintenance dredging of shipping channels in a year (Schubel et 

 al. , 1979) . 



In recent years, lobster and scup fisheries have become 

 major commercial activities in Long Island Sound; these 

 activities may play a role in sediment resuspension with the 

 subsequent release and transport of contaminants including trace 

 metals and particulate-associated PCBs. Thus, sediment 

 resuspension generated from bioturbation, mixing due to tidal 

 currents, storms and anthropogenic activity could serve as a 

 driving force that renders the environment more uniform, which in 

 turn is reflected in the homogeneous concentration of trace 

 metals and PCBs found in the three experimental mussel 

 populations located at WLISc, 500MW and WLISrN. In addition, the 

 lack of distinction between WLISrN and the two stations nearest 

 to the disposal site suggests that environmental conditions in 

 the general western Sound are unfavorable as compared to the 

 reference station in the eastern Sound. The results of this 

 portion of the study support the hypothesis that the intrinsic 

 and extrinsic factors played more of a role in changes in tissue 

 trace metal levels than did disposal activities. 



Temporal and spatial variations in PCB levels behave in the 

 same manner as the tissue trace metal concentrations. The lack 



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