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11 March 2002 • AGE-NC Project No 95-0130 Page 3 of 13 were detected in initial ground water samples from all three wells at concentrations up to 11,000 micrograms per liter(µg/1) Analytical results of soil and ground water samples are summarized In Tables 2 and 3 Results of the December 1994 Investigation were reported I In Preliminary Investigation and Evaluation Report (PIER) dated 10 April 1995,prepared by Geological Audit Services, Inc • December 1995 - Three soil vapor extraction (SVE) wells (VW-1, VW-2 and VW-3)were Iadvanced to depths of 63 feet bsg near the former UST areas, one ground water monitoring well (MW-4) was advanced to a depth of 75 feet bsg and located approximately 60 feet southeast (crossgradient) of the former UST area TPH-g and BTEX-Impacted soil was encountered in all three SVE wells at depths of 15 feet to 60 feet at concentrations as high as 7,400 mg/kg, petroleum hydrocarbons were not detected in soil samples collected from MW-4 Dissolved TPH-g was not detected in initial ground water samples collected from MW-4 However, TPH-g and benzene were detected from MW-4 subsequent sampling events at concentrations as high as 78 µg/1 and 10 µg/1,respectively(Table 3) Results of the December 1995 investigation were reported in Corrective Action Plan (CAP), dated 20 March 1996, prepared by AGE • January 1996-One ground water monitoring well(MW-5)was advanced approximately 50 • feet northwest (crossgradient) of the former UST area to a depth of 70 feet TPH-g and BTEX-Impacted soil was encountered at depths of 45 and 50 feet at concentrations as high I as 940 mg/kg TPH-g and BTEX-Impacted ground water was detected in the initial sample from MW-5 at a concentration of 23,000 µg/1 (Tables 1 and 2) Results of the January 1996 investigation were reported in the CAP • January 1996-An 8-hour soil vapor extraction(SVE)pilot test was conducted at the site by inducing a vacuum from well VW-1B (screened 28 to 43 feet bsg), ground water was measured approximately 55 feet bsg The pilot test was performed to provide vapor ' extraction data for proper system design of a remediation system TPH-g and BTEX compounds were detected from Influent SVE air flow samples at concentrations as high as ' 95,000 micrograms per liter (µg/l) Significant vacuum was measured from monitoring points VW-1A, VW-1C, VW-2A,VW-2B, VW-3A, no measurable vacuum was observed at MW-3, located 35 feet east of VW-1 Based on the observed results, a theoretical radius ' of Influence for SVE at VW-lB was projected at approximately 30 feet Results of the January 1996 Investigation were reported in the CAP • April 2000-Five soil borings(CPT-1,CPT-1 A,CPT-2,CPT-2A and CPT-3)were advanced ' on- and off- site to approximately 105 feet bsg utilizing cone penetrometer testing (CPT) technology to characterize the geological and hydro-geological framework and to assess preferential migration pathways Laboratory analysis of grab water samples detected ' substantial petroleum-impact from CPT-lA and CPT-2A to depths of 105 feet bsg (Table • 4) Results of the April 2000 CPT investigation were reported in Quarterly Report-Second ' Quarter 2000, dated 31 July 2000, prepared by AGE Advanced GeoEnvironmental,Inc