65 



in western Long Island Sound, but the measured concentrations were within the NERBC 

 moderately contaminated category. 



More unusually, the normalized major element concentrations were quite different 

 from the NS&T data: Al was lower at both EAST and SOUTH than NS&T stations, and Fe 

 was higher. The statistical range of normalized Al concentrations at the NS&T sites (mean 

 ± one standard deviation) was 601-1044 ppm; both EAST and SOUTH Al concentrations 

 were below this range, and above the calculated statistical range of normalized Fe 

 concentrations (380-524 ppm). Assuming that these major elements (especially Al) are 

 reflective of regional background metals concentrations, the comparison of NS&T metals 

 data with the WLIS NED samples is suspect. Different digestion methods may explain part 

 of the difference, since incomplete dissolution of clay minerals (which release the Al and Fe) 

 is a common sample preparation problem. 



In summary, trace metal and PAH data indicated that the newly proposed reference 

 stations contained similar or lower concentrations of these analytes relative to the reference 

 stations sampled in 1991. Grain size distribution and TOC content were similar between the 

 two sets of data. PAH concentrations at the two proposed reference stations appeared to 

 represent western Long Island Sound ambient concentrations, as compared to several sites 

 measured by the NS&T program. Metals concentrations of samples from the two proposed 

 stations were also similar, with the exception of As and Zn. These elements were higher 

 than those measured in the same area by NS&T. However, the metals comparison may not 

 have been adequate since the reference elements (Al and Fe) demonstrated a potential 

 difference in laboratory results between the WLIS and NS&T samples. 



4.3.2 REMOTS® and Bathymetry 



The rough bathymetry done at both of the potential reference sites (EAST and 

 SOUTH) indicated that both areas were free of any distinct topographical features or steep 

 slope. Across both regions, the maximum depth change observed was 5 m depth over 800 m 

 in the horizontal. This was considered acceptable relief for a reference area. 



REMOTS® sampling showed that grain size distribution at SOUTH was more 

 comparable to ambient sediments at the disposal site than was 2000S. In addition, the 

 photographs showed no evidence of previous dredged material disposal. However, the full 

 REMOTS® grid at EAST indicated distinct signs of dredged material and of sediment 

 winnowing. Overall, the appearance of EAST was similar to that of WLIS-REF, in that 

 some relic dredged material was present at both areas. 



It would seem that much of the area surrounding WLIS has received dredged material 

 input at some point in time. Historic (prior to 1977) disposal operations were not controlled 

 and monitored in the manner they are today, and this material was disposed across a wide 



Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992 



