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soil samples collected from borings MW-1 and MW-2 between approximately 36 feet and 61 feet bgs (SECOR, May 4, 1995) Groundwater monitoring and sampling of the site wells were initiated in January 1995 In July 1996, SECOR supervised the installation of six additional groundwater monitoring wells (MW-5 through MW-10) to further define the extent of subsurface petroleum hydrocarbons The highest concentrations of petroleum hydrocarbons in groundwater were found In wells MW-1, MW-3, and MW-6, with the maximum concentrations of TPHg and benzene reported in well MW-1 at 13,600 ug/L and 1,130 ug/L, respectively (SECOR, October 9, 1996) Based on the results of assessment activities, the lateral extent of petroleum hydrocarbons in soil had been defined based on generally non-detectable concentrations at or above laboratory method reporting limits (MRLs) The dissolved petroleum hydrocarbon plume had been defined in all 1 directions of the site, except to the northwest (cross-gradient) of well MW-6 (SECOR, October 9, 1996) 1 Soil boring and well construction details are presented in Table 1 Historical soil and groundwater analytical results are included in Tables 2 through 5 Historical soil gas survey data are presented in Appendix A Historical figures depicting the locations of previous excavations, soil gas probes, soil borings, groundwater monitoring wells, and remediation wells are included in Appendix B Soil boring and well construction details are presented on logs included in Appendix C 32 Summary of Remedial Action In 1992, a soil vapor extraction (SVE) feasibility test was performed by Canonie Environmental, utilizing wells W-1, W-2, and W-3 to determine whether this technology was a viable remedial alternative for implementation at the site The SVE test system consisted of a Reltschle VFT- 180 carbon vane vacuum pump, a 200-pound granular activated carbon (GAC) vessel, piping, control panels, a lighting system, and generator that were mounted on a portable single-axle trailer This system was capable of extracting air at a flow rate of 127 standard cubic feet per minute (scfm) at a vacuum of 28 inches of mercury The portable SVE system was tested on each of the wells for 25-minute (W-1) and 30-minute periods (W-2 and W-3) SVE was determined to be an effective remedial approach based on induced vacuum measured within surrounding wells during testing, high concentrations of TPHg and BTEX vapor concentrations withdrawn during the test, and the subsurface geologic conditions beneath the site (Canonie, April 1993) In March 1998, SVE feasibility testing was also conducted by SECOR to further evaluate induced flow rates and estimate the radius of influence Individual tests were performed using SVE wells W-1 through W-8 by connecting each well to the intake of a Vaclean 1000 Internal Combustion Engine (ICE) Each test lasted between approximately one to four hours Induced vacuum influence was not observed in surrounding monitoring wells during the performance of each test due to the system's inability to produce a vacuum greater than 4 inches of water within each test SVE well However, the SVE radius of influence was estimated to be approximately i 50 feet based on the flow rates achieved, site soil stratigraphy, and data collected during previous investigations TPHg removal rates ranged from 1 1 pounds per day (lbs/day) In W-6 to 1,425 lbs/day in W-3 Based on the results of SVE feasibility testing, SECOR recommended Woo 4 Time Oil Asmt&SCM doc 4 March 17,2005 770T 41658 00 0015