station, however the NL-85 station was dominated by crustaceans 
(Table 3-13). The Reference station had three times as many 
species and twice as many individuals as the NL-85 mound station 
(Table 3-14). The Reference station also had ten times as many 
non-Ampelisca individuals. Ampelisca vadorum was the most numerous 
species at both stations and was found in similar densities (Table 
3-15). There was a difference in biomass; only juveniles were 
found at the NL-85 station and both adults and juveniles were found 
at the Reference station. 
The abundant mussel Musculus niger at the Reference 
station were all juveniles about 3 mm _  _1long. The small 
tube-dwelling spionid polychaete Prionospio steenstrupi was 
important at both stations as were the burrow-inhabiting amphipods 
Leptocheirus pinguis and Unciola irrorata. Many of the remaining 
dominants at the Reference station were polychaetes (Tharyx spp., 
Mediomastus ambiseta, Clymenella zonalis, Ampharete arctica, 
Harmothoe extenuata, and Aricidea jeffreysii). Many of the 
individuals in these samples were small in size. These included 
small species such as Skeneopsis planorbis, Turbonilla interrupta, 
Protodorvillea kefersteini, syllids, and Corophium spp. as well as 
juveniles of larger species such as the molluscs’ Lunatia 
triseriata, Crepidula spp., Anadara transversa, Ensis directus, the 
polychaetes Clymenella spp., Aglaophamus circinata, Harmothoe 
extenuata, and sabellids. All Cancer irroratus (sand crab) were 
less than 10 mm in carapace width. An asteroid about 1 mm in 
diameter was too undifferentiated to identify. 
The dominants at the NL-85 mound station were all 
suspension feeders. At the Reference station, M. niger was also 
a suspension feeder. MTharyx spp., M. ambiseta, Oligochaeta, Cc. 
zonalis, H. arctica, and A. jeffreysii are all deposit feeders. 
H. extenuata is a scavenger/predator. There were many predators 
present among the subdominants at the Reference station. These 
included the gastropods Anachis, Lunatia, Mitrella, and Urosalpinx, 
all rhynchocoels, and the polychaete family Phyllodocidae. 
Most of the species recovered in this study were typical 
of larger estuaries and the nearshore shelf of southern New 
England. The bivalve Hiatella arctica is usually found in offshore 
or northern waters. Polydora ligni, Mulinia lateralis, Ensis 
directus, and Mysella planulata, usually found in shallower, more 
estuarine waters, occurred in very low numbers. 
3.6 Body Burden Analysis 
The concentrations of eight trace metals (arsenic, lead, 
zinc, chromium, copper, cadmium, mercury and iron) and PCBs were 
measured in samples of the bivalve Pitar morrhuana collected at the 
New London Disposal Site in July 1986 (Tables 3-16, 3-17, and 3- 
18). Statistical analyses (Mann-Whitney U-test) were conducted on 
30 
