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i <br /> t <br />' 12 November 2004 <br /> . AGE-NC Project No 95-0184 <br />' Page 4 of 5 <br /> 4.0. SUMMARY AND CONCLUSIONS <br /> t ' <br /> Based upon data collected from the site, AGE concludes the following <br />' • Ground water elevations at the site averaged approximately 22 90 feet below MSL All <br /> ground water wells except VW-3,VW-4,and VW-5B were"drowned",with water levels as <br />' high as 19 feet above the screened intervals of the drowned wells (MW-1) <br /> • The ground water was inferred to flow generally east-northeast across much of the site at a <br />' gradient of approximately 0 003 foot/foot This ground water flow direction is consistent <br /> with the last 22 of 23 monitoring events (Table 4) <br /> • Detectable concentrations of TPH-g were found in all of the ground water.wells sampled <br />' Generally,concentrations decreased as compared to the previous quarter One or more BTEX <br /> compounds were found in all ground water samples collected These samples contained one <br /> or more analytes at concentrations above the DHS' Maximum Contaminant Levels (MCL) <br />' for drinking water <br /> • MTBE was detected in samples from wells MW-4, VW-2B, VW-3, and VW-4 at <br /> concentrations ranging from 71 gg/l(MW-4)to 860 pg/1(VW-4) 1,2-DCA was detected in <br /> MW-2, MW-4, and in VW-2B through VW-5C at concentrations ranging from 8 3 gg/l <br /> (MW-2) to 540 gg/l (VW-4) EDB was detected in MW-4, VW-2B, VW-4, and VW-5B at <br />' concentrations ranging from 13 gg/l (VW-4) to 400 gg/l (VW-2B) The concentrations of <br /> MTBE, 1,2-DCA, and EDB in the ground water samples exceed their respective MCL for <br /> drinking water <br />' • Napththalene, 1,2,4-tnmethylbenzene, 1,3,5-tnmethylbenzene, and n-propylbenzene were <br /> detected in ground water samples at concentrations above the DHS-recommended drinking <br />' water Action Levels r <br /> • The vertical and lateral extent of impacted soil and ground water has not yet been defined <br /> r <br /> 5.0. RECOMMENDATIONS <br /> 1 Based upon data collected from the site AGE recommends continued quarterly ground water <br /> monitoring AGE is currently preparing a work plan to further delineate the vertical and lateral extent <br />' of impacted ground water on- and off-site, as requested in the EHD letter dated 31'August 2004 <br /> 1 J <br /> • <br />' Advanced GeoEnvironmental,Inc <br />