total carbon and PCBs were within the range measured in the present 

 study (Table 4-2). At the FVP mound, Munns et al. reported 

 concentration ranges in 1985 samples which overlapped with those 

 in the present study for all parameters tested except PCBs, which 

 appeared to be higher in July 1986 (Table 4-2) . However, the PCB 

 concentrations at the FVP Center station actually were guite 

 variable in the Munns study and ranged as high as 1.8 ppm, above 

 the mean value reported in the present study. For many of the 

 other parameters measured in both studies, larger sample sizes in 

 the Munns study could account in part for the wider range of 

 concentrations reported. 



The FVP mound had the highest concentrations of Cu and 

 Cr compared to all the other CLIS mounds sampled in the present 

 study (Table 4-2) . The highest contaminant concentrations measured 

 in individual samples occurred at the CLIS-86 mound for Pb, Zn, Cu, 

 and Ni. A comparison of the present results at this mound with 

 those from August 1985 indicated that the levels of Pb, Zn, As, Cu 

 and PCBs were higher in the 1986 samples. These results are most 

 readily attributed to the ongoing disposal at this mound, involving 

 sediment from a number of different sources. 



The former CLIS reference station was sampled during 

 August 1985, September 1984, December 1983 and July 1983. 

 Comparisons of these data with the July 1986 results from the new 

 CLIS reference station did not reveal any large differences or 

 temporal trends in the concentrations of any of the parameters 

 measured. The FVP Center station was sampled during July and 

 August 1983. Data for samples collected at this station were 

 somewhat variable; however, for several parameters a trend of 

 decreasing concentrations with time was evident. This was 

 particularly true for Zn, As, Cd, Cr, Cu, % total carbon, chemical 

 oxygen demand and oil and grease. This might reflect the increased 

 oxidation of the disposed material with time, as well as some 

 "dilution" of the material both from deposition and mixing with 

 underlying sediments as a result of bioturbation. None of the 

 parameters measured showed higher concentrations in the 1986 

 samples compared to the earlier results. 



Sampling was previously performed at the MQR mound during 

 October 1985 and September 1984. Chemical concentrations measured 

 during all three sampling periods were relatively high at this 

 mound. However, there were no major concentration changes noted 

 in the samples collected between 1984 and 1986. Comparisons of 

 results from the STNH-N Center station from October 1985, September 

 1984 and August 1983 showed Hg concentrations were higher in the 

 samples collected during August 1983. The samples collected on the 

 other two dates and in the present study showed lower and 

 relatively consistent Hg levels. None of the other parameters 

 showed major changes in concentration over the period sampled. 



38 



