Executive Summary 



Biological monitoring of Western Long Island Sound Disposal 

 Site (WLIS) was conducted from June 1984 to June 1985 using 

 mussels (Mytilus edulis ) suspended from underwater platforms., 

 The mussel monitoring platforms were deployed at four stations: 

 WLISc and 500MW, on and near the disposal site, WLISrN, the 

 reference station, and Rlr or LATr, the master reference station 

 at Eastern Long Island Sound. Monitoring criteria included the 

 tissue concentrations of nine trace metals and three PCB Aroclors 

 (1242, 1254 and 1260), the tissue wet and dry weight ratios, and 

 the mortalities and histopathology of the mussel populations. In 

 addition, extrinsic factors such as water temperatures, 

 quantities of dredged material disposed and period of disposal 

 activities were also recorded. The objectives of the mussel 

 watch project were to determine (1) whether or not increases in 

 tissue concentrations of trace metals and polychlorinated 

 biphenyls were associated with on-going open-water disposal of 

 dredged materials and (2) whether or not such increases were 

 correlated with changes in mortalities, in tissue wet/dry weight 

 ratios, in gonadal development, as well as in histology. 



Trace Metal Data . Trace metal results indicated similar 

 significant spatial and temporal variations as reported in our 

 previous 1983 and 1984 studies at the Central Long Island Sound 

 (CLIS) and WLIS disposal sites (Feng 1984, 1985). Spatial 

 variations in Cd, Cu and Zn tissue concentrations were noted 

 among the mussel populations held at the four stations; levels of 

 these three metals were significantly lower in the population at 

 the master reference station, Rlr, than in the other three 

 populations. The reference station, WLISrN, displayed the same 

 variations in tissue concentrations of Cu, Cd, and Zn, as the two 

 disposal site stations, WLISc and 500MW, indicating that the 

 concentrations were not associated with the disposal of dredged 

 materials at the WLIS disposal site. 



Temporal or before-during disposal differences in the tissue 

 concentrations of Co, Cu, and Fe were observed in the three 

 mussel populations deployed in western Long Island Sound. In 

 all cases the three tissue trace metal concentrations before 

 disposal were significantly lower than those during disposal. 

 Although no post-disposal data were available, based on our 

 previous experience, we could predict that the elevated levels of 

 the trace metals encountered in mussels during the disposal 

 period were transient and of short duration. 



PCB data . Similar conclusions as presented for the trace 

 metals could also be drawn from the PCB results. There was a 

 discernible increase of the tissue PCB concentrations in all four 

 of the mussel populations. Hence, no spatial difference could 

 be attributed to the disposal activity at WLIS. Heightened 

 levels of Aroclor 1242 and total PCBs associated with the 

 disposal operation were observed at WLISc and WLISrN. Because 



