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20 March 2006 AGE-NC Protect No 95-0130 ' Page 11 of 13 ' files are included in Appendix C Utilizing a Blue-White Industries F-2000 flow meter,total flow(totalizer)was recorded between 07 September and 06 December 2005 (Table 9) During this time,the extraction and treatment interim ' ground water remediation system was in operation for approximately 90 days Based on the total of approximately 174,065 gallons of water recorded during this time,AGE estimated that an average ' 1,934 gallons of water was discharged per day during this time 1 4 6 MASS-VOLUME REMOVAL CALCULATIONS Between 07 September 2005 and 06 December 2005,an estimated 36 33 pounds of total petroleum hydrocarbons were extracted from ground water (Table 9), since the system was initiated on 17 November 2004,a total mass of 207 pounds of petroleum hydrocarbons have been removed The September to December 2005 mass-volume calculations of gasoline-impacted ground water ' extracted from the ground water extraction and treatment system are presented in Appendix I Plots of cumulative ground water pump and treat mass removal trends and influent ground water TPH-g concentrations versus time are included In Appendix J 5.0. SUMMARY AND CONCLUSIONS ' The implications from the December 2005 round water monitoring event are as follows p g ' • Ground water at the site was generally observed between 43 and 45 feet bsg and was above the screened intervals of wells MW-1 through MW-5,MW-6 (B-E),MW-7 (B-E), VW-1 C, VW-2A and VW-3A (i e screened below ground water table), and may not yield samples ' fully representative of shallowest ground water conditions • Ground water flow direction within HU1 (First Water Zone) was inferred to be towards the ' north-northeast at a gradient of 0 02 ft/ft(Figure 3), ground water flow direction within HU2 and HU3 (Second Water Zone) was inferred to be towards the northeast at a gradient of 0 002 ft/ft or less • Between January 1995 and August 2001, ground water elevations at the site generally increased from 44 feet to 23 feet below MSL, since August 2001 and present day, ground ' water elevations have generally fluctuated between 24 feet and 29 feet below MSL(Table 2) • The highest concentrations of dissolved TPH-g and BTEX were detected in samples ' collected from wells MW-7B(50-55 ft),VW-1C (48-63 ft),VW-2A(43-63 ft)and VW-3A (43-63 ft) which Is consistent with previous monitoring results (Table 3) TPH-g • concentrations were detected as high as 150,000 µg/1 from well MW-713 and benzene as high ' Advanced GeoEnv=ronwnental,Inc