28 



resulting in long-term accumulation of these materials outside the site boundaries. The 

 concentration ranges of metals found at WLIS were comparable to levels found in DAMOS 

 surveys conducted in August 1985 and 1986 and similar to others reported for the site and 

 for Central Long Island Sound (SAIC 1988b, 1987a). Together these facts strongly suggest 

 that contaminants associated with dredged sediments disposed over several years (i.e., since 

 1982) at the WLIS site were not accumulating in detectable concentrations outside the site. 



The results from the 1986 body burden study showed higher levels of Pb and lower 

 levels of Zn and Cd in Nephtys collected at the "A" mound than those collected at the 

 reference area (Figure 6-18). Concentrations of the metals were similar to those for Nephtys 

 collected at the CLIS reference station (Field Verification Program site; SAIC 1987c). PCB 

 levels were higher in Nephtys collected at the reference area than at the "A" mound. The 

 measured level of PCBs in the reference organisms was not expected due to the higher PCB 

 sediment concentration at the "A" mound. The measured wet weight concentrations for 

 PCBs were well below the FDA Alert Level (2 ppm). Reflecting the general pattern of 

 sediment contamination in 1987, body burden results showed no real trends and were 

 consistent with levels found in previous studies (Figure 6-18; SAIC 1990d). 



6.2.2 WLIS: 1990 Monitoring Results 



In July 1990, SAIC conducted field operations at WLIS to monitor the effects and 

 areal distribution of dredged material deposited during the 1989-1990 disposal season and to 

 assess the status of benthic recolonization and mound stability at the inactive disposal points. 

 Field operations included an 800 x 800 m bathymetric survey, REMOTS® sediment-profile 

 photography, sediment chemistry and grain size sampling, and near-bottom DO 

 determination. A second bathymetric survey (2500 x 3000 m) provided detail of the entire 

 WLIS site. 



The disposal of dredged material during the 1989-1990 season resulted in the 

 formation of the "D" mound with a minimum water depth of 28.0 m, a maximum thickness 

 of 5.3 m, and radius of approximately 225 m. The minimum water depth at the "A" and 

 "C" mounds increased slightly since the July 1988 survey; however, the minimum water 

 depth at the "B" mound increased 1.0 m, due partly to compaction of sediments on the 

 mound and partly to an artifact from the bathymetric data analysis. According to the 

 tabulation of disposal logs, barges disposed 185,000 m 3 of material at the site. 



Several REMOTS® stations on and around the "D" mound exhibited rapid infaunal 

 recolonization of the recently deposited dredged material. Benthic conditions within the three 

 reference areas (2000W, 2000S, and WLIS-REF) remained similar to the 1988 results; the 

 presence of Stage III taxa and high organism-sediment index (OSI) values ( + 11) indicated 

 that a relatively healthy and stable environment existed in these areas. 



DAMOS Summary Report, 1985-1990 



