61 



The discussion below details the interpretation of the analyses done to compare the existing 

 and potential replacement reference areas. 



4.3.1 Chemical and Grain Size Analyses 



Sediment samples were collected from the two sites proposed as WLIS reference 

 stations and analyzed for grain size, TOC, metals, PAHs, pesticides, and PCBs. The 

 analysis included a comparison of the sediment data with the WLIS reference station data 

 from 1991, and a comparison with ambient western Long Island Sound trace metal and 

 organic compound concentrations. Due to the similarity of grain size and TOC, and the lack 

 of comparable metals data, PAH data were considered the most useful indicators of reference 

 applicability. 



The 1992 EAST samples were slightly sandier than the 1991 WLIS-REF, although the 

 fine-grained fraction (which is commonly associated with anthropogenic contaminants) was 

 approximately the same for both sites (Table 3-1). Grain sizes between SOUTH and 2000S 

 were very similar in composition. TOC at EAST was slightly higher than at WLIS-REF, 

 and slightly higher at SOUTH than at 2000S (Table 3-1). Metals data for the two sets of 

 areas were similar, although the lack of several metal analyses for samples from the 1991 

 reference stations made this a tenuous comparison (Table 3-2). 



The most complete data set for comparison purposes was the PAH data from both 

 areas. Raw, non-normalized PAH data indicated that EAST and WLIS-REF (1991) had 

 similar concentrations of PAHs, with WLIS-REF slightly higher in several LMW and HMW 

 compounds. PAH concentrations at 2000S (1991) ranged from two to three times higher 

 than the same measured compounds at SOUTH. 



Natural variations in sedimentary parameters can influence the concentration of trace 

 metal and organic constituents measured in the laboratory. For example, an increase in bpth 

 the fme-grained fraction and in TOC can be positively correlated with metal and organic 

 concentrations. Normalizing to Al is increasingly being used for metals and can be 

 particularly useful for regional variations of sediment type (Schropp et al. 1990). 



For comparison purposes, PAH values were normalized to TOC for both EAST and 

 WLIS-REF data. Grain size was not used, as the variation between the locations was small. 

 After normalization to TOC, the sum of WLIS-REF PAH concentrations was less than twice 

 that of EAST. Normalized PAH concentrations of 2000S samples ranged from four to six 

 times greater than those of SOUTH. 



In order to place the potential WLIS reference stations in context, sediment data from 

 the area were compiled and compared with the 1992 sediment data. The NOAA National 

 Status and Trends (NS&T) Program has collected and analyzed coastal and estuarine 



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



