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' 10 February 2006 i AGE-NC Project No 02-0977 ' Page 7 of 12 ' 3 3 GROUND WATER ELEVATION AND GRADIENT During the 22 December 2005 ground water monitoring event, measured depths to ground water in ' wells MW-1 through MW-8 ranged between 53 81 and 54 94 feet below the tops of the well casings - (Table 2) Ground water elevations were calculated to be between 15 51 feet(MW-4)and 15 76 feet (MW-2 and MW-5)below mean sea level(MSL) The ground water surface elevation at the site was ' within the screened intervals of wells MW-1 through MW-6 and MW-8, however,the ground water elevation determined from MW-7(screened 80 to 90 feet bsg)was approximately 26 feet submerged, and more representative of deeper ground water conditions IThe ground water elevation data for MW-1 through MW-8 during the December 2005 ground water -.monitoring event is depicted and contoured in Figure 9, the general ground water gradient at the site ' was calculated to be approximately 0 002 ft/ft or less,or approximately 11 feet per mile,and inferred to be flowing towards the south-southeast ' 34 LABORATORY RESULTS OF SOIL SAMPLES . A total of thirty-two soil samples were submitted to CTEL, a DHS-certified laboratory for analysis of TPH-g, BTEX, MTBE, TAME, DIPE, ETBE, TBA, 1,2-DCA and EDB ITPH-g was detected from B6(VW-2)-30/45/55 foot soil samples at concentrations as high as 22 milligrams per kilogram(mg/kg), from B7(VW-1)-30/40150 foot soil samples at concentrations ' as high as 10 mg/kg, and from B9(VW-4)-40/50/60 foot soil samples at concentrations as high as 9 mg/kg ' The only BTEX compound detected was from soil sample 136-55 at a concentration of 0 11 mg/kg of ethylbenzene ' MTBE was widely detected from 135-40/55/70 foot soil samples at concentrations as high as 0 71 mg/kg,from B6(V W-2)-20130/45/55/65 foot soil samples at concentrations as high as 21 mg/kg,from B7(VW-1)-20/30/40150165/70 foot soil samples at concentrations as high as 10 mg/kg, and from ' B9(V W-4)-25/40/50/60 foot soil samples at concentrations as high as 8 9 mg/kg The estimated extent of MTBE-impacted soil is illustrated on cross section C-C' m Figure 11 I TAME was detected from the B6(VW-2)-55 foot soil samples at a concentration of 0 80 mg/kg, and from B7(VW-1)-30/50 foot soil samples at concentrations of 0 062 mg/kg and 0 33 mg/kg, respectively INo other constituents of concern were detected from the laboratory analysis The analytical results • IAdvanced GeoEnvironmental,Inc