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Ms Pamela Lopez December 1996 9647-0771 ` collected from drill hole SBA indicated that petroleum hydrocarbons were present at depths below the water table The analytical results are included in Attachment I Ground water samples were collected through the hollow-stem augers at the location of the drill holes and analyzed for the presence of TPH-g and BTEX The analytical results indicated the greatest concentrations were detected at the location of SBA On the basis of these results, RAH Environmental, Inc concluded that the source of the petroleum hydrocarbons identifed at the location of drill hole SBA most probably resulted from the former UST on the Lopez property The analytical results are included in Attachment 1 In February 1996, Fugro supervised the advancement of rive drill holes (MW-1, MW-2, MW-3, SB-Al, and SB-A2) at the locations illustrated on Figure 2 The drill holes were advanced to approximate depths ranging form 20 5 to 35 5 feet Selected soil samples collected from the drill holes were analyzed for the presence of TPH-g and BTEX by U S EPA Method 8015M/8020 The analytical results are included in Attachment 1 as Table 3 GROUND WATER MONITORING Ground Water Levels On November 26, 1996, Fugro collected depth to ground water measurements at the b • locations of monitoring wells MW-1 through MW-3 prior to purging and sampling P All depth to ground water measurements were recorded according to the Fugro standard operating procedures (SOPS) included as Attachment 2 Ground water level data are summarized in Table 1 Since the last sampling event conducted in August 1996, the ground water elevation in all monitoring wells has increased an average of 1 1 1 feet A ground water elevation hydrograph is included as Figure 3 - Ground Water Elevation Hydrograph On the basis of the November 26, 1996, measurements, ground water is estimated to flow to the southwest at an average hydrogeologic gradient of approximately 0 002 feet per foot (ft/ft) (Figure 4 - Potentiometric Surface Map, November 26, 1996) Ground Water Sampling and Analysis On November 26, 1996, Fugro collected ground water samples at the locations of monitoring wells MW-1 through MW-3 The ground water samples were collected according to the Fugro SOPS included in Attachment 1, and were delivered under chain-of-custody documentation to Excelchem Environmental Laboratory, a state-certified analytical laboratory The samples were analyzed for concentrations of • TPH identified as gasoline by modified U S EPA Method 8015, and . Benzene, toluene, ethylbenzene, and total xylenes by U S EPA Method 602 The analytical results are summarized in Table 2 The analytical report and chain-of- 96470771B hain-of-96470771B QNI R 2