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r 3 <br /> 06 May 2004 <br /> ' AGE-NC Project 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 /> z4 <br /> • Ground water elevations at the site averaged approximately 2-1~-5-5 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 18 feet above the screened intervals of the drowned wells - <br /> • The ground water was inferred to flow generally southwest across much of the site at a <br />' gradient of approximately 0 005 foot/foot This ground water now direction is inconsistent <br /> with the last 22 monitoring events (Table 4) <br /> • Detectable concentrations of TPH-g were found in all of the ground water wells sampled, <br />' concentrations were relatively stable as compared to the previous quarter One or more <br /> BTEX compounds were found in all ground water samples collected These samples <br /> contained one or more analytes at concentrations above California's Maximum Contaminant <br />' Levels (MCLs), except for the sample from MW-7 <br /> • Free product was encountered this quarter in well VW-5B Four gallons of water were bailed <br /> off to remove the free product from the ground water surface A ground water sample was , <br /> then collected from the bottom of a disposable plastic bailer The free product was not , <br /> measured this quarter ' <br />' • MTBE was detected in samples from wells MW-4, VW-2B, VW-3 and VW-4 at <br /> concentrations ranging from 50 gg/l(MW-4)to 510 µg/1(VW-4) 1,2-DCA was detected in <br />' MW-1,MW-2,MW-4 and VW-2B through VW-5C at a maximum concentration of 970 gg/l <br /> (VW-4), EDB was detected in MW-4 and VW-2B at a maximum concentration of 100 µg/l <br /> (VW-2B) The concentrations of MTBE, 1,2-DCA and EDB in the ground water samples <br /> Iexceed the MCLS for drinking water <br /> • Naththalene, 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 /> I <br /> 5.0. RECOMMENDATIONS <br /> Based upon data collected from the site, AGE recommends continued quarterly ground water <br /> monitoring The first quarter 2004 monitoring event was performed during March 2004 AGE is <br /> currently preparing awork plan to further delineate the vertical and lateral extent of impacted ground <br /> water on- and off-site, as requested in a meeting with the EHD on 12 June 2003 <br /> Advanced GeoEnvironmental,[n¢ <br />