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I <br /> I <br /> 31 August 1999 <br />' AGE-NC Project No 97-0290 <br /> Page 5 of 6 <br /> I4.0. SUMMARY AND CONCLUSIONS <br />' Based on the data collected from the site, AGE finds <br /> • A pumping rate of 3 9 gpm produced a drawdown of only 14 feet during the 19 July 1999 <br />' pump test A maximum drawdown of approximately 19 feet was observed on 15 July 1999 <br /> after six hours of pumping with a maximum pumping rate of 4 3 gpm <br /> I • The aquifer transmissivity was calculated to be 13096 gal/day-ft at well VW1C Similar <br /> transmissivities were calculated at MW2 and SW2 A higher transmissivity of 22,383 <br /> gal/day-ft was calculated at SWI Variations in transmissivity may be due to inhomogeneity <br />' of the soil at the site <br /> • Greater vacuum potentials were observed at S W 1 and MWI during performance of the soil <br /> vapor extraction pilot test than in nearby wells Soil near SWI and MWI appear to have <br /> higher permeabilities than soil near V W 1 C <br /> • A radius of influence of up to 40 feet was calculated for an extraction rate of 3 9 gpm at the <br /> site Measurable influence was observed at wells MWI and MW4, located 60 and 75 feet <br /> from the extraction point, respectively <br /> • Due to the high transmissivity at the site, high pumping rates and a large radius of influence <br /> are possible at the site, however, drawdown in the extraction wells will be minimal <br /> I • Ground water extraction may be effective for water remediation, but would not acheive <br /> significant exposure of impacted soil beneath the current water table for soil vapor extraction <br /> without the extraction of large volumes of water <br /> I <br /> • Ground water was encountered in the monitoring wells at approximately 43 to 44 feet bsg <br /> and was inferred to have a southerly flow direction during the July 1999 monitoring event <br /> • The highest concentrations of petroleum hydrocarbons in ground water were detected in <br /> samples collected from MW2, MW4 and MWI Only TPH-d was detected in MW7 and <br /> I MW8, at concentrations of 64 ppb and 54 ppb, respectively Only benzene was detected in <br /> MW6, at a concentration of 0 79 ppb Petroleum hydrocarbons were not detected in the <br /> samples collected from MW3 and MW5 <br /> 5.0. RECOMMENDATIONS <br /> • Based on the findings of the environmental activities recounted in this report, AGE recommends <br /> IPreparation of a Remedial Action Work Plan for the site Based upon data presented in the <br /> Adianred GeoEnaronmental,Inc <br /> i <br />