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09 July 2002 AGE-NC Project No 00-0769 Page 3 of 5 ' 3 1 GROUND WATER GRADIENT AND FLOW DIRECTION The relative elevation of ground water In each well was calculated by subtracting the depth to ground ' water from the surveyed well head elevations (Table 1) Depths to ground water dunng the second ' quarter 2002 monitoring event ranged from 24 22 feet to 25 23 feet below the tops of the well casings Ground water elevations at the site ranged from -13 97 feet In MW-3B to -14 47 feet In ' MW-3A relative to mean sea level(MSL) Ground water was within the screened interval of shallow monitoring wells MW-2B and MW-313,but was approximately 5 0 feet above the screened interval of shallow monitoring well MW-1 ' Monitoring data from MW-1 through MW-3B was combined with monitoring well data collected from the adjacent Arc Pump and Welding(1211 Turnpike Road) on 22 May 2002 to determine the ' approximate ground water flow direction The shape of the water table during the May 2002 monitoring event was in the form of a southeast-plunging trough(Figure 3), ground water flow near the former UST No 1 and No 2 location was toward the south-southwest, ground water flow near ' the former UST No 3 location was toward the southeast The average gradient at the site was 0 002 feet/feet 3 2 ANALYTICAL RESULTS OF GROUND WATER SAMPLES TPH-g and BTEX compounds were detected in ground water samples collected from all monitoring wells except MW-2A at concentrations ranging between 8,100 pg/I (MW-3A) to 140,000 gg/l (MW-1) The maximum concentrations ofBTEX compounds were detected In the sample collected from MW-1, at concentrations of 36,000 pg/l (benzene), 48,000 pg/1 (toluene), 2,400 pg/1 (ethylbenzene) and 12,000 pg/l (total xylenes) I TBA was detected in sample MW-2B at a concentration of 280 pg/l,no other fuel oxygenates were detected in the samples analyzed 1,2-DCA was detected In ground water samples collected from MW-1, MW-2A, MW-2B and MW-3B at concentrations of 2,500 pg/l, 1 8 pg/l, 630 pgh and 9'7 µg11, respectively EDB was not ' detected in any of the ground water samples collected during the May 2002 monitoring event Laboratory results of water samples analyzed for petroleum hydrocarbons are summarized In ' Tables 2 and 3 The laboratory reports for the quarterly monitoring event (MAI Lab IDs 0205329- 001 through 0205329-005)QA/QC reports and chain-of-custody form are Included in Appendix B Advanced GeoEpvironmental,Inc