All samples had >50% fines, with the total fine fraction (silt and clay) ranging 

 from 54 to 71 % . There was no particular spatial pattern of grain size in the potential 

 reference area that could be discerned from the grab sample data. The consistency of grain 

 size was best demonstrated by the coefficient of variation (CV) values (variability around 

 the mean) for the major components ( > 10%). The CVs were all within 20% except for 

 the clay fraction (37%; Table 3-5). 



3.5.3.2 Geochemistry Results 



Total Organic Carbon (TOC) and Percent Solids. TOC values were very 

 consistent among the WLIS SE-REF samples, ranging from 22,000 to 25,000 mg/kg (2.2 

 to 2.5%) with a CV of 4.5% (Table 3-6). The data suggest that there were no spatial 

 patterns of organic carbon among the reference station grab samples. Percent solids data 

 were slightly more variable (CV = 5.3%), with values ranging from 35 to 41 %. 



Polynuclear Aromatic Hydrocarbons (PAHs). The PAH composition of the 

 WLIS SE-REF sediments was relatively consistent in all of the sediment samples, showing 

 low concentrations of both high and low molecular weight PAHs (Table 3-7). In general, 

 the dominant PAHs were pyrogenic (high molecular weight [HMW]), with the highest 

 detected concentrations being fluoranthene, pyrene, and benzo(a)pyrene. The presence of 

 detectable low molecular weight (LMW) PAHs indicated the possible presence of 

 petroleum residues. The greatest variability of individual compounds (CV), ranging from 

 25 to 71 %, occurred in a few samples that had the highest detected values of the 

 compounds (Table 3-7). Stations GR-1, GR-5, GR-9, and GR-10 had the highest PAH 

 concentrations for both HMW and LMW PAHs. Overall, however, the concentrations 

 were lower than the mean reference value calculated from historical WLIS reference 

 station data (Figure 3-14; Murray 1995). Normalizing the data to TOC resulted in a 

 similar pattern between stations. These concentrations were also below the mean values 

 measured in historical sampling. The spatial distribution of these detected PAHs showed 

 no consistent pattern, and no direct relationship to the presence of dredged material as 

 noted in side-scan and REMOTS® data. 



Pesticides and Polychlorinated Biphenyls (PCBs). There were no pesticides or 

 PCB arochlors detected at the WLIS SE-REF potential reference area (Table 3-8). 

 Detection limits for pesticides ranged from < 10 jug/kg for most compounds to 

 23-91 /ig/kg for methoxychlor and toxaphene. Arochlor detection limits ranged from 46 to 

 91 /xg/kg. The laboratory checked for potential negative bias of the data, and the lack of 

 detected compounds was verified. 



Monitoring Cruise at the WLIS Disposal Site, September 1997 and March 1998 



