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I I28 October 2005 AGE-NC Project No 95-0130 ' Page 10 of 13 ' Laboratory I D Nos 0504062,0505033 and 0506040)are summarized in Table 8,laboratory reports are Included in Appendix 1, GeoTracker confirmation pages of the submitted laboratory electronic deliverable format (EDF) files are included in Appendix D I 4 6 MASS-VOLUME REMOVAL CALCULATIONS ' Between 08 March 2005 and 03 June 2005,an estimated 59 pounds of total petroleum hydrocarbons were extracted from ground water(Table 9), since the system was initiated on 17 November 2004, I a total mass of 117 pounds of petroleum hydrocarbons have been removed The March 2005 to June 2005 mass-volume calculations of gasoline-impacted ground water extracted from the ground water extraction and treatment system are presented in Appendix J Plots of cumulative groundwater pump and treat mass removal trends and influent ground water TPH-g concentrations versus time are included in Appendix K 5.0. SUMMARY AND CONCLUSIONS The implications from the June 2005 ground water monitoring event are as follows • Ground water flow direction within Hydrologic Units 1 and 2 (First Water Zone) was inferred to be towards the east-northeast at a gradient of 0 02 ft/ft(Figure 3), ground water flow direction within Hydrologic Units 2 and 3 (Second Water Zone) was inferred to be towards the east-northeast at a gradient of 0 003 ft/ft • 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 Iwater elevations have generally fluctuated between 24 feet and 29 feet below MSL(Table 2) • Ground water at the site was generally observed between 43 and 45 feet bsg and was above I the screened intervals of wells MW-1 through MW-5,MW-6(B-E),MW-7(B-E),VW-1C, VW-2A and VW-3A (I e screened below ground water table), and may not yield samples fully representative of shallowest ground water conditions I • The greatest concentrations of Top Filling Station dissolved TPH-g and BTEX were detected In samples collected from wells MW-713(50-55 ft),VW-1 C(48-63 ft)and VW-2A(43-63 ft) which is consistent with previous monitoring results (Table 3) TPH-g concentrations were detected as high as 160,000 pg/1 from wells VW-IC and MW-7B, and benzene as high as 48,000 µg/l from well MW-713 (Table 4) Additionally, the deepest detection of dissolved TPH-g and BTEX were In samples collected from well MW-6E (137-142 feet), the approximate extent of dissolved TPH-g is depicted in Figures 5 and 7 • Advanced CeoEnvii onmental,Inc