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' 30 May 2005 <br /> AGE-NC Protect No 95-0184 <br />' Page 4 of 5 <br />' 4.0. SUMMARY AND CONCLUSIONS <br /> Based upon data collected from the site, AGE concludes the following <br />' • Ground water elevations at the site averaged approximately 25 15 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 17 feet above the screened intervals of the drowned wells (MW-1) <br /> • The ground water was inferred to flow generally northeast across much of the site at a <br /> gradient of approximately 0 004 ft/ft This ground water flow direction is consistent with the <br />' last 24 of 25 monitoring events (Table 2) y <br /> • Detectable concentrations of TPH-g were found in all of the ground water wells sampled <br /> Generally,concentrations remained stable as compared to the previous quarter One or more <br /> BTEX compounds were found in all(except MW-7)ground water samples collected These <br /> samples contained one or more analytes at concentrations above the DHS' Maximum <br /> 1 Contaminant Levels (MCL) for drinking water - <br /> • MTBE was detected in samples from wells MW-4, VW-2B, and VW-4 at concentrations <br /> ranging from 65 pg/1 (MW-4)to 460 pg/1(VW-4) 1,2-DCA was detected in MW-2,MW-4, <br /> VW-2B, VW-3, VW-4, VW-5B, and VW-5C at concentrations ranging from 9 7 µg/1 <br /> (MW-2)to 480 µg/l (VW-2B) EDB was detected in MW-4,VW-2B,VW-5B,and VW-5C <br /> at concentrations ranging from 22 µg/l (VW-5C)to 220 µg/1 (VW-2B) The concentrations <br /> of MTBE, 1,2-DCA, and EDB in the ground water samples exceed their respective MCLs <br /> for drinking water <br />' • Naphthalene, 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 <br /> • The vertical and lateral extent of impacted soil and ground water has not yet been defined <br /> The concentration of dissolved constituents collected in samples from deeper monitoring <br /> wells have been documented to be lower than the shallow, vapor well samples Therefore, <br /> the maximum concentration of the release appears to reside in the upper 50 feet of the `7 <br />' subsurface <br />' 5.0. RECOMAMNDATIONS <br /> Based upon data collected from the site <br />' AGE recommends continued quarterly round water monitoring <br /> q Y g <br />' Advanced GeoEnhronmcatal,Inc <br />