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• 13 September 1999 AGE-NC Project No 96-0232 - Page 3 of 5 groundwater samples and MTBE in all seven samples, laboratory analysis of one domestic drinking ' water well sample detected MTBE , 3 1 RELATIVE GROUND WATER ELEVATION AND GRADIENT During the June 1999 monitoring event, depths to ground water in wells MWA, MW-2, MW-4, MW-5, MW-6A, MW-6B and MW-7 were measured to be between 10 03 and 11 25 feet below the _ top of well casings, ground water elevations were calculated to be between 1 51 and'] 81 feet below mean sea level Ground water elevation at the site decreased an average 3 51 feet between the February 1999 and June 1999 ground water monitoring events The ground water elevation data for z MW-I, MW-2, MW-4, MW-5. MW-6A and MW-7 during the June 1999 ground -wafer monitoring event is depicted in Figure 3 Due to the deep screened interval, data collected fi om MW-613 was not utilized to determine ground water elevations Ground water monitoring data collected in the area of wells MWA, MW-5 and MW-7 indicated a ground water flow direction generally toward the northwest at a gradient of 0 002 ft/ft, or approximately 11 feet per mile (Figure 3), ground water monitoring data collected in the area of wells MW-1, MW-2, MW-4 and MW-6 suggested a ground water flow direction 91;nerally toward the east-northeast at a gradient of 0 002 ft/ft Ground water was approximately 32 feet above the screened intervals in monitoring wells MW6-13 Therefore this well is "drowned and yields a sample representative of deeper screened ground water 3 2 LABORATORY RESULTS OF GROUND WATER SAMPLES TPH-g was detected in the water sample collected from MW-1 during the June 1999 Sampling event at a concentration of 440 micrograms per liter (u.g/1), however the laboratory reported that the gasoline chromatogram for this sample did not have typical gasoline characteristics TPH-d was detected in a water sample collected from MW-2 at a concentration of 150 ,ug/l and in the deeper screened water from MW-6B at'a concentration of 110 Mcg/l The laboratory reported that the diesel chiomatograms for the MW-2 and MW-6B samples did not have typical diesel characteristics MTBE was detected in ground water samples collected from all seven ground water samples utilizing EPA Method 8020 at concentrations as high as 1,,600,ug/l, MTBE was confirmed in MW-1, MW-2, MW-4, MW-6A, MW-6B and MW-7 samples utilizing EPA Method 8260, no other fuel oxygenates were detected above Iaboratory reporting limits MTBE was detected in the domestic drinking water well sample (Rocky's Restaurant) utilizing EPA Method 8020 and confirmed utilizing EPA Method 8260 at concentrations as high as 11 pgll V � Advanced t.eor'nm rronmen[ai,inc f • i ) t '