conditions exists, most near-bottom waters at the site were 

 aerobic (> 4 mg/1) and had higher DO concentrations than the 

 reference stations at the time of the survey. It had been 

 hypothesized that stressed benthic habitats at the site in 1986 

 were directly related to the Sound-wide phenomenon of near-bottom 

 hypoxia. There was no evidence in the REMOTS images from 1987 of 

 widespread hypoxic stress in the benthos at New London. 

 Significantly higher OSI values in 1987 compared to 1986 suggest 

 that successful infaunal recruitment and recolonization has 

 occurred at the site in the past year. Such recruitment success 

 indicates an absence of chronic near-bottom hypoxia in the weeks 

 and months preceding the survey. 



4.4 Sediment Characteristics 



The results of physical testing of sediments at New 

 London, which show that mixtures of silt-clay and very fine sand 

 predominate at the surface, generally were in good agreement with 

 the results obtained in the REMOTS survey. These results reflect 

 both the natural heterogeneity in sediment types characteristic of 

 the site, as well as the addition of dredged material which 

 consisted primarily of sand and silty-sand with lesser amounts of 

 clay. 



One objective of the sediment chemical analyses was to 

 determine the concentrations of sediment-associated contaminants 

 that were deposited at the site and to determine whether the 

 contaminants were subject to further resuspension and transport. 

 As indicated by the REMOTS dredged material mapping (Figure 3-3) , 

 station 400SE, the only station with significantly elevated levels 

 of several metals and % total carbon compared to NLON-Ref, is 

 located within the mound formed by recently disposed material. 

 While 400SE is elevated compared to NLON-Ref, the metals (for 

 which NERBC interim criteria exist) occur at this and other 

 stations exclusively at Class I levels. This is consistent with 

 their classification in the dredged material prior to disposal. 

 Likewise, significant contamination was not observed in and around 

 the disposal mound in terms of Fe, % total carbon, organochlorine 

 pesticides and PCB's. 



The lack of a significant contaminant signature in the 

 disposed material confounds attempts to assess contaminant 

 resuspension and transport. Although the sediment chemistry data 

 (Figure 3-21) indicate that the stations on the mound (CTR and 

 400SE) were higher in concentrations of trace metals and PCB's, a 

 consistent concentration gradient was not evident. The statistical 

 results (Table 3-3) show that contaminant levels at these outer 

 transect stations were not significantly different from the 

 reference station. If transport was occurring along the transect 



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