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Site Background Information: Ernie's General Store Page 3 of 4 concentration of 1.3 mg/kg and in all four stockpile soil samples at concentrations as high as 0.67 mg/kg.A summary of soil analytical results from the UST tank removal is presented in Table 1 of this appendix. SITE ASSESSMENT ACTIVITIES • On 04 and 05 September 2001,five soil borings(B-1 through B-5)were advanced at the site. Boring B-1 was advanced to 40 feet bsg,boring B-2 was advanced to 90 feet bsg,boring B-3 was advanced to 70 feet bsg, and borings B-4 and B-5 were advanced to 25 feet bsg. Soil boring B-1 was advanced in the western portion of the former and existing UST area through a 12-inch diameter conductor casing. During drilling,the soil cuttings began to disrupt the position of the casing and boring B-1 was abandoned at 40 feet bsg, 50 feet short of the proposed 90-foot total depth.Boring B-2 was advanced fifteen feet west ofboring B-I to 90 feet bsg as a continuation of boring B-1. • Four ground water monitoring wells (MW-1 through MW-4)were installed on 28, 29, and 30 July 2003, and one angled soil boring [135 (7-3-03)] was advanced on 30 July 2003. A total of twenty-six soil samples from wells MW-1 through MW-4 were collected and analyzed for petroleum hydrocarbon compounds. MTBE was detected in soil samples collected from MW2-20 through MW2-50,MW3-30,MW3-40,MW4-30,and MW4-40 at concentrations ranging from 1.9 mg/1 (MW2-30) to 0.050 mg/1 (MW4-30). TPH-g and BTEX compounds were detected in soil samples collected from MW2-30 to MW2-50 at maximum concentrations of 13 milligrams per liter(mg/l;TPH-g,MW2-30) and 0.68 mg/1 (xylenes, MW2-30). There do not appear to be significant concentrations of adsorbed petroleum hydrocarbons in the investigated areas. • On 22 November 2006,two paired CPT soil borings(CPT-1 and CPT-2) were advanced to further delineate the lateral and vertical extents of hydrocarbon-impacted soil and ground water at the site. • On 14 December 2006, one additional shallow ground water monitoring well (MW-5)was installed on the property located at 4318 East Pepsi Place, Stockton, California, approximately 250 feet west of the site, to verify and monitor the eastern boundary of the dissolved MTBE plume. • On 12, 13,and 15 December 2006,three shallow-screened SVE wells screened from 15 feet to 30 feet bsg (VW-2, VW-4, and VW-5) and three deeper-screened SVE wells screened from 45 feet to 60 feet bsg(VW-1,VW-3,and VW-6)were installed on-site for use in SVE pilot tests. • On 26 and 27 December 2006,two 8-hour SVE pilot tests were conducted to provide vapor extraction data for the proper design of a soil remediation system. The pilot test conducted on 27 December 2006 utilizing the deeper-screened vapor wells was terminated after Advanced GeoEnvironmental,Inc.