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09 July 2001 <br /> AGE-NC Project No 97-0249 <br /> Page 3 of 6 <br /> I3.0. FINDINGS <br /> Ground water elevation, flow direction and gradient were determined from field data collected on <br /> 13 June 2001, the contaminant impact to ground water was assessed from the ground water <br /> laboratory data <br /> I3 1 GROUND WATER ELEVATION AND GRADIENT <br /> The depths to ground water in wells MW-1 through MW-6 varied from 11 77 to 14 35 feet below <br /> the tops of well casings, ground water elevations were calculated to be between 4 29 feet and 5 00 <br /> feet below mean sea level Ground water elevation at the site decreased an average 4 14 feet between <br /> the March 2001 and the June 2001 ground water momtonng events The ground water elevation data <br /> for MW-1 through MW-6 during the June 2001 ground water monitoring event is depicted in <br /> Figure 3 <br /> I Ground water flow direction in the area bound b Three B's Truck Plaza wells MW-1 through <br /> Y g <br /> lieMW-6 and Flag City Chevron wells MW-7, MW-12A and MW-13A was inferred to be towards the <br /> southwest at a gradient of 0 003 ft/ft or less, or approximately 16 feet per mile (Figure 3) <br /> 3 2 LABORATORY RESULTS OF MONITORING WELL GROUND WATER SAMPLES <br /> A total of six ground water samples were submitted to a DHS-certified laboratory in June 2001 <br /> TPH-g was detected in water samples collected from wells MW-1,MW-2,MW-3,MW-5 and MW-6 <br /> at concentrations ranging between 130 and 15,000 micrograms per liter (4g11), the laboratory <br /> I reported each TPH-g chromatogram as having unmodified or weakly modified gasoline patterns <br /> TPH-d was detected in water samples collected from MW-1, MW-2, MW-3 and MW-6 at <br /> concentrations ranging between 190 and 1,100 4g/l, however, the laboratory reported diesel in <br />' samples collected from MW-1,MW-2,MW-3 and MW-6 as having sigmficant lighter range gasoline <br /> compounds, the laboratory reported the sample collected from MW-1 as having unmodified or <br /> weakly modified diesel, and the laboratory reported the sample collected from MW-3 as having <br /> significant diesel-range compounds <br /> BTEX compounds were detected in water samples collected from MW-1,MW-2,MW-3,MW-5 and <br /> IMW-6 at concentrations as high as 3,400 ,ug/l (benzene, MW-6), MTBE was detected in a water <br /> sample collected from MW-4 at a concentration of 63 4g11 by the EPA 8020 analysis <br /> IMTBE was detected in water samples collected from MW-1, MW-2, MW-4 and MW-6 utilizing <br /> EPA Method 8260 Modified at concentrations as high as 60 µg/l TBA was detected in the water <br /> Advanced GeoEnvironmental,Inc <br />