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07 February 2006 AGE-NC Project No. 97-0360 Page 3 of 7 (P4). BTEX compounds were detected in the ground water samples collected from 131 and P4 at concentrations as high as 5.5 pg/l; dissolved benzene was detected at concentrations as high as 3.7 pg/l (P 1). Dissolved MTBE was detected in the ground water sample from P4 at a concentration of 8.2 pg/l utilizing EPA Method 8020, and confirmed at a concentration of 7.6 pg/l utilizing EPA Method 8260. No other fuel oxygenated compounds were detected at or above laboratory reporting limits. On 31 January 2002, six soil borings were advanced at the site. Pilot borings MW I through MW5 were completed as ground water monitoring wells using 2-inch diameter polyvinylchloride (PVC) casing with 0.020-inch slotted screen installed from approximately 5 feet to 20 feet bsg in borings MW 1, MW3, MW4,and MW5 and from approximately 30 feet to 35 feet bsg in boring MW2, with blank casing extended to the surface in each well. Pilot boring EW 1 was completed as a ground water extraction well using 6-inch diameter PVC casing with 0.020-inch slotted screen installed from approximately 5 feet to 20 feet bsg. TPH-g was detected in the soil samples collected from MW I, MW3, MW4, MW5, and EW1 at 10 feet bsg at concentrations as high as 160 mg/kg. TPH-d was detected in the same samples,with the exception of EW 1, at concentrations as high as 3,800 mg/kg. No other analytes were detected at or above laboratory reporting limits in the soil samples analyzed. During the second quarter 2003,AGE recommended site closure and abandonment of the wells on- site. This request was denied by the San Joaquin Environmental Health Department (EHD), and quarterly monitoring events resumed in the third quarter 2004. 2.4. STRATIGRAPHY Generally, gray to brown, damp to saturated, silty clay was encountered from surface grade to approximately 15 feet to 20 feet bsg and 25 feet to 30 feet bsg. Discontinuous intervals of brown, saturated, sandy silt of varying thickness were encountered at 15 feet to 20 feet bsg and 30 feet to 35 feet bsg. Pea gravel was encountered in the former UST pit at 5 feet and 10 feet bsg. 3.0. SCOPE OF WORK The scope of the work includes the advancement of up to four soil probe borings for the collection of soil and ground water samples. The scope of work will include the following tasks: • Permitting and pre-field work activities; • Probe boring advancement; • Soil and ground water sample collection; Advanced GeoEnvironmental,Me.