SITE INFORMATION AND CORRESPONDENCE

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29 November 2005 Flag City Chevron Fact Sheet Page 2 of 5 through MW-20 to monitor petroleum hydrocarbon concentrations in ground water. Based on the results of the quarterly ground water samples,(1)methyl tertiary butyl ether(MTBE) was established as the contaminant of concern at the site; (2) ground water levels were generally recorded between 7 and 15 feet bsg; (3) prior to pump-and-treat ground water remediation activities at the site(November 2000),ground water flow direction was typically inferred to be towards the north-northeast-northwest;(4)during pump-and-treat ground water remediation(November 2000 to August 2004), ground water flow direction at the site was typically inferred inward towards a ground water depression near the UST and fuel dispenser area;and(5)following termination of pump-and-treat operations(August 2004),the ground water flow direction was typically inferred east and southeast. • Forty-three (43) soil borings (P-1 through P-43) were drilled on and off-site to maximum depths of 130 feet bsg to characterize the geological and hydro-geological framework and to assess potential contaminant migration pathways. Based on the subsurface soil distribution, a subsurface model of the stratigraphy/hydrostratigraphy was developed and consisted of a vadose zone (surface-10 feet) and five informal hydrogeologic zones: First Zone (10-35 feet),Second Zone (40-60 feet),Rocky's Upper Zone (70-75 feet),Secondary Zone (90-110 feet) and Primary Zone (greater than 120 feet). • The domestic water well located at Rocky's Restaurant(14659 North Thornton Road)was properly abandoned due to MTBE-impact. Well abandonment activities were performed under the direct supervision of the SJCEHD and documented by representatives of AGE and the RWQCB. • A sensitive receptor survey was performed to locate potential vertical conduits within a 2,500-foot radius of the site.The sensitive receptor survey located two San Joaquin County operational municipal water wells(CSA Nos. 1 &2)approximately 1,600 feet and 700 feet, respectively,southeast of the site.Domestic water wells serving Rocky's Restaurant(14659 North Thornton Road),Three B's Truck Plaza(14749 North Thornton Road)and Flying J's Travel Plaza(15100 North Thornton)were located approximately 150 feet southwest,450 feet west-southwest and 600 feet north of the of the site,respectively. 3.0. CORRECTIVE ACTION Between November 2000 and August 2004, ground water pump-and-treat remediation was performed at the site by extracting MTBE-impacted ground water from onsite wells. All extracted MTBE-impacted ground water was routed through a ground water treatment system consisting of media vessels containing coconut shell, liquid phase granular activated carbon. During the above referenced pump-and-treat operational period, a grand total of approximately 27,086,201 gallons of MTBE-impacted water was treated and discharged to a conveyance ditch