16 



(Appendix A, Table 3, Figure 2-5). Data from the CLIS-REF, 2500W, and 4500E 

 reference areas were used for comparison of ambient central Long Island Sound sediments 

 relative to the sediments deposited at CLIS through disposal operations. 



2.6 Sediment Sampling and Analysis 



2.6.1 Sediment Toxicity Testing 



The benthic conditions displayed at three REMOTS® sediment-profile photography 

 stations over NHAV 93 (CTR, 200N, and 400S) prompted a return to CLIS in late 

 September 1994 to acquire additional bottom grab samples for toxicity testing. The 

 surface sediments from two of the three stations over the NHAV 93 mound (CTR and 

 400S) were collected and exposed to a 10-day Ampelisca abdita bioassay (Figure 2-5). 

 Station 200N was not re-visited due to its relative position and strong probability of similar 

 chemical content in comparison with CTR sediments. 



Two bottom grabs were collected from each station using a 0.1 m^ Kynar-coated, 

 Young-modified, van Veen grab sampler. The top 6 cm of sediment in each grab was 

 collected, homogenized, and placed into one gallon polyvinylchloride (PVC) containers. 

 The PVC containers were held at 4° Celsius (C) and transported to SAIC's Environmental 

 Testing Center (ETC) in Narragansett, RI, for further processing. Upon arrival at the 

 ETC, the sample containers were held at 4° C in the dark until final preparations for 

 testing were complete. 



Several days later, the sediments were extracted from each sample container and 10- 

 day Ampelisca bioassays conducted using Green Book protocols (Appendix A, Table 9; 

 EPA/US ACE 1991). 



Reference sediments used for comparison of the NHAV 93 material were collected 

 from the historic South Reference Site (41°07.950' N, 72°52.700' W) approximately 

 700 m south of CLIS (Rogerson et al. 1985). Delineated at the inception of the DAMOS 

 Program, these reference area sediments have been used to compare the results of many 

 NED, WES, and EPA environmental monitoring programs. 



2.6.2 Sediment Chemistry 



Sediment samples for chemical analysis were also collected with the use of the 

 0.1 m^ Kynar-coated, Young-modified, van Veen grab sampler. Eleven stations were 

 randomly selected over the NHAV 93 and MQR disposal mounds (Appendix A, Table 4; 

 Figure 2-6). The current DAMOS reference areas 2500W and 4500E were sampled at 



Monitoring Cruise at the Central Long Island Sound Disposal Site, July 1994 



