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'7 iY EINZ z • Lopez Property May 1, 1997 Page 2 Environmental, Inc , concluded that the source of the petroleum hydrocarbons identified at the location of drill hole SBA was most likely the former UST on the Lopez property A summary of the analytical results is included in Attachment 1 In February 1996, Fugro supervised the advancement of five drill holes (MW-1, MW-2, MW-3, SB-A1, 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 March 14, 1997, ENSR collected depth to ground water measurements at the locations of monitoring wells MW-1 through MW-3 prior to purging and sampling All depth to ground water measurements were recorded according to the ENSR standard operating procedures (SOPs) included in Attachment 2 All field documentation is included in Attachment 3 Ground water level data are summarized to Table 1 Since the last sampling event conducted in November 1996, the ground water elevation in all monitoring wells has increased an average of 3 37 feet A ground water elevation hydrograph is included as Figure 3 - Ground Water Elevation Hydrograph On the basis of the March 14, 1997 measurements, ground water is estimated to flow to the northwest at an average hydrogeologtc gradient of approximately 0 004 feet per foot (ft/ft) (Figure 4 - Potentiometric Surface Map, March 14 1997) Ground Water Sampling and Analysts On March 14, 1997, 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 ENSR 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, • Benzene, toluene, ethylbenzene, and total xylenes by U S EPA Method 602, and • Methyl tert-butyl ether (MTBE) by U S EPA Method 602 9716002 AQR