79 



Each PAH sample was spiked with three system monitoring or surrogate compounds 

 (2-fluorobiphenyl, nitrobenzene-Ds, and terphenyl-Di4) as a measure of accuracy. 

 Surrogate samples are analyzed as a check on the laboratory's ability to extract known 

 concentrations of compounds not normally found in die sample. All PAH surrogate 

 recoveries for this data set were within acceptance limits and indicate no laboratory 

 extraction problem (USEPA 1988). 



2.7 Geotechnical Coring 



The coring operations completed on 18 July were part of the fourth phase in a five- 

 part geotechnical survey of the NHAV 93 mound. Seven sediment cores, oriented to 

 produce a cross-section of the NHAV 93 mound, were obtained through an SAIC and 

 University of Rhode Island (URI) joint effort. The sampling scheme was centered on the 

 NHAV 93 buoy position (41°09.122' N, 72°53.453' W) (Appendix A, Table 7; Figure 2- 

 7). Cores U through Y were taken in a northeast-southwest transect across the NHAV 93 

 mound. Cores Z and Zl were obtained on a northwest-southeast transect of NHAV 93 

 mound. 



The sediment cores were obtained with the use of the PVC core barrel version of 

 the University of Rhode Island/Marine Geomechanics Laboratory (URI/MGL) Large 

 Diameter Gravity Corer (LGC) (Figure 2-8) (Silva et al. 1994). The core barrels consist 

 of a 3 m (10 ft) section of Schedule 40 PVC piping (10. 2 cm or 4. OLD.) and includes a 

 nose cone and core catcher on the end. 



All cores were transported back to the URI laboratory facilities and refrigerated 

 during storage. The CLIS sediment cores were processed to obtain overall sediment 

 composition, bulk density, water content, grain size, Atterberg Limits, specific gravity, 

 and shear strength (Silva et al. 1994). A detailed description of the methods used for the 

 analysis of sediment Cores U through Zl is included in a report submitted by Armand J. 

 Silva of the Marine Geomechanics Laboratory, University of Rhode Island (Silva et al. 

 1994). 



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



