77_ 



3.1.4.1 September 1997 



1997 Visual Descriptions 



The lengths of the twelve short cores collected in 1997 ranged from 59 cm (2A) to 153 

 cm (12A), and the length of the three long cores ranged from 222 to 276 cm (Table 2-6). All 

 cores were comprised predominantly of olive gray silty clay, with common darker black olive 

 gray sediment (Appendix D). Shell hash, black mottling, and streaks were common 

 throughout many of the cores. Discrete gravel and sand layers were present deeper (generally 

 >100 cm) in several short cores (1A, 5 A, 7 A) and in the deepest intervals of long cores 4 A 

 (>160 cm) and 10A (178-276 cm). The deep unit in 10A (178-276 cm) described as black 

 and "oily," was the only apparent indication of recovery of UDM. The olive gray silty sand 

 layers found deep in the other cores (1 A, 4 A, 5 A, and 7 A) were similar to the sediment 

 recovered in the reference core (13A) from WEST REF. 



There were strong odors emitted from the sediment in several of the cores. Core 5A 

 had an odor best described as a "sewer" or "septic-system" smell in the middle to lower 

 section. Core 9A also had a sewer odor and "rotten egg" (hydrogen sulfide) odor in the upper 

 section. Below 73 cm, Core 9A had an unidentifiable industrial (petroleum or chemical 

 solvent) odor, as did Cores 2 A and 2B throughout and Core 1 A below 100 cm. Core 3 A and 

 8 A emitted a hydrogen sulfide odor. The lowest section of Core 10A had a distinct petroleum 

 odor. Such observations are obviously limited by subjectivity and the dulling of the sense of 

 smell that occurs with prolonged exposure during core processing. In general, strong sulfide 

 odors are associated with high organic content sediments typically found in embayments, salt 

 marshes and harbors, they are not necessarily associated with sewage. Industrial and 

 petroleum odors are associated with sediments that have been deposited in association with 

 anthropogenic discharges from point and non-point sources. Both sets of smells are indicative 

 of dredged material in the context of the NLDS (ambient sediments at NLDS are not highly 

 sulfidic or enriched in petroleum or industrial compounds). 



1997 Physical Parameters 



Moisture Content. The moisture content was nearly uniform throughout the core 

 samples, ranging from 48 to 56% (Table 3-4). The average moisture content of samples 

 collected from the upper sediment (0-50 cm; short cores) in all three zones was uniformly 

 52- 54%, while the average of samples collected below this interface (>50 cm) in the long 

 cores was slightly lower (49.6%). All of the values of moisture content from the Seawolf 

 cores were significantly higher than measured in the core from the WEST REF reference area 

 (28.6%), primarily due to the difference in sediment grain size (see below). 



Monitoring Cruise at the New London Disposal Site, Seawolf Mound 1995 - 1998 



