were below the detection limits in many samples while chemical 
oxygen demand, oil and grease, and total carbon results showed no 
consistent changes between the three sampling dates. PCBs were not 
analyzed in the samples collected in 1982 and 1984. 
A comparison of sediment chemical concentrations from New 
London Disposal Site with existing data from other areas of Long 
Island Sound revealed that, in most cases, the range of 
concentrations were similar (Table 4-1). Munns et al. (in press) 
reported concentrations for sediment collected at the Reference 
station near the Central Long Island Sound Disposal Site. 
Benninger et al. (1979) measured concentrations of Pb, Zn, and Cu 
in sediments collected in central Long Island Sound. Grieg et al. 
(1977) measured the concentrations of several metals in surface 
sediments collected at stations in eastern Long Island Sound near 
the New London Disposal Site. Total carbon levels were measured 
in Block Island Sound by Boehm and Quinn (1978) and in Narragansett 
Bay by Wade and Quinn (1979) along with PCB's. At the disposal 
site, concentrations of all metals fell within the Class I (low) 
or lower Class II (moderate) categories set by the New England 
River Basins Commission (NERBC, 1980). The exception to this was 
one replicate sample for Zn at the NL-I mound, which was at the 
upper Class II level. 
Although the exact effect of elevated sediment 
contaminant concentrations in the sediment on the benthic community 
is not known, chemical concentrations in the tissue of the bivalve 
Pitar were measured to determine the potential for biological 
uptake of contaminants from the sediment. Contaminant 
concentrations in Pitar from the disposal mound did not differ 
significantly from those at the Reference station. Similar levels 
of contaminants were found in samples collected and analyzed by 
other investigators (Table 4-2). Eisler et al. (1978) reported the 
concentrations of several metals from Pitar collected at control 
(i.e., "Cclean") stations in Narragansett Bay. Feng (1975) reported 
four trace metals in Pitar collected from an unspecified, but 
presumably clean, area of the Thames River. In all cases, the 
measured wet weight concentrations of trace metals in Pitar samples 
collected at the disposal mound station were well below the FDA 
Alert Levels (see Table 3-17). The PCB data were compared to 
concentrations in caged mussels Mytilus edulis maintained at the 
New London Disposal Site (Arimoto and Feng, 1983) and at the 
Reference station near the Central Long Island Sound Disposal Site 
(Munns et al., in press). All of the measured concentrations of 
PCBs were at least 50 times below the FDA Alert Level of 2 ppm. 
The largest ecosystem stress affecting the New London 
Disposal Site apparently was not directly related to disposal 
activities but to a Sound-wide phenomenon of hypoxia in near-bottom 
waters. A low-oxygen, or hypoxic, event was inferred in 
July/August 1985 from low RPD values at REMOTS® stations along the 
northern boundary and in the southeast quadrant of the New London 
36 
