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Site Background Information Quick N Save#1 Page 3 of 3 and 1,420mg/kg of benzene, toluene, ethylbenzene, and xylenes, respectively in boring B 1-35' I MONITORING WELL INSTALLATION ' On 17 and 18 March 2004, four soil borings (MW 1 through MW4) were advanced at the site A CME-75HT truckmounted drill rig was utilizing to advance 8 25-mch diameter hollow-stem augers to the total depth of each boring The drill rig and three-man crew were supplied by Cascade Drilling Incorporated of Rancho Cordova,California Soil samples were collected ahead of the drill bit using a California modified split-spoon sampler loaded with three pre-cleaned 2-mch by 6-inch brass ' sleeves The samples were collected from the pilot borings at 5-foot intervals, beginning at 10 feet bsg,using a 140-pound hammer to advance the sampler ' Generally, an orange-brown, dry, clayey silt (fill matenal),was encountered from surface grade to approximately 6 feet bsg Orange brown to brown,dry, silts and clayey silts were encountered from approximately 6 feet bsg to 26 feet bsg Orange brown to blue grey hydrocarbon stained, slightly moist, clay was encountered from approximately 26 feet to 36 feet bsg in MW1, MW2 and MW3 and from 20 to 24 feet bsg in the area of MW4 Gray hydrocarbon stained,moist to saturated silty ' sand was encountered from approximately 36 feet bsg to 53 feet bsg Saturated soil was encountered at 40 feet bsg Blue, hydrocarbon-stained clay was encountered from approximately 53 feet bsg to 55 feet bsg Pilot borings MW1 and MW3 were completed as ground water monitoring wells using 2-inch diameter PVC casing,with 0 020-inch slotted screen installed from approximately 35 to 55 feet bsg, ' MW2 was completed in a similar manner with slotted screen installed from approximately 25 to 45 feet bsg, and MW4 was installed in a similar manner with slotted screen installed from approximately 30 to 50 feet bsg ' TPH-g was detected in soil samples collected from borings MW 1 through MW4 at maximum concentrations in each boring of 12 milligrams per kilogram (mg/kg) (MW 1-40), 2 9 mg/kg ' (MW2-45),5 7 mg/kg(MW3-45)and 2 7 mg/kg(MW4-40),respectively At least one of the BTEX constituents were detected in soil samples collected from borings MW 1 through MW4 at maximum concentrations of 0 44 mg/kg(benzene),0 072 mg/kg(toluene),0 12 mg/kg(ethylbenzene)and 0 20 ' mg/kg(xylenes),respectively MTBE was detected in soil samples collected from borings MW2 and MW4 at a maximum concentration of 0 31 mg/kg in sample MW2-35 by EPA Method 8260 No additional analytes were detected at or above laboratory detection limits in the samples analyzed t ' Advanced Geo&nvironmentnl,Inc