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i01 March 2000 AGE-NC Project No 99-1828 Page 3 of 8 was collected from the floor of the southern most excavation (EXE1) at a depth of 8 feet bsg The analytical data Indicated that the highest concentrations of TPH-g were in excavations EXE 2 and EXE 3 TPH-g was detected in the eastern soil sample from excavation EXE 2 at a concentration of ' 17,000 milligram per kilogram (mg/kg) TPH-g was also detected in the soil sample from the southern edge of excavation EXE3 at a concentration of 11,000 mg/kg BTEX compounds were detected at concentrations as high as 2,300 mg/kg (xylene) The highest concentration of benzene, ' 15 mg/kg, was detected in the eastern sample from excavation EXE2 TPH-d was detected in the soil samples from EXE2 and EXE3 that were also impacted with TPH-g and BTEX compounds Low concentrations of only TPH-d were detected in two soil samples from EXE 1 ' The stockpile soil was impacted by low to moderate concentrations of petroleum hydrocarbons Tables I and 2 present the analytical results from the excavation soil samples The locations of the soil excavations are shown on Figure 3 On 12 October 1999, the stockpiled soil was transported to ' Forward Landfill for final disposal Tracking records of the soil disposal are in Appendix A '• 2 4 GROUND WATER DEPTH AND FLOW DIRECTION Based on the Sari Joaquin County Flood Control District and Water Conservation District Lines of ' Equal Depth of Water Wells Fall 1996 map, the estimated depth to ground water in the vicinity of the site is 10 feet below surface grade (bsg) However, significant ground water recharge has ' occurred during 1994 through 1998 and ground water depth at the site may be more shallow than estimated in 1996 ' The San Joaquin River is the nearest surface water feature to the property, located approximately 1,500 feet east of the site The San Joaquin River is primarily used for commercial and recreational boating,with agricultural applications as a secondary use The channel contains water year round and ' may exert a tidal effect upon ground water depth or flow direction in the area Based upon information obtained during the UST removal, ground water is currently at the base of ' the former USTs or near the depth at which the former UST soil samples were collected 3.0. PROCEDURES 1 Tasks and procedures for this investigation were completed by AGE personnel,or under the direction ' of AGE personnel, and were conducted under the supervision of a California Registered Geologist in accordance with the AGE-prepared Preliminary Site Assessment Work Plan, dated 15 September ' 1999, as approved by the PHS-EHD Advanced GcoEnvironmental,Inc