ARCHIVED REPORTS_XR0012120 - Laserfiche WebLink

Home Browse Search

02 June 2005 AGE-NC Project No 95-0130 Page 10 of 13 Utilizing a Blue-White Industries F-2000 flow meter,total flow(totalizer)was recorded between 29 December 2004 and 08 March 2005 (Table 9) During this time,the extraction and treatment interim ground water remediation system was in operation for approximately 69 days Based on the total of approximately 81,280 gallons of water recorded during this time, AGE estimated that an average 1,178 gallons of water was discharged per day during this time 4 6 MASS-VOLUME REMOVAL CALCULATIONS ' Between 29 December 2004 and 08 March 2005, an estimated 43 94 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 58 pounds of petroleum hydrocarbons have been removed The December 2004 to March 2005 mass-volume calculations of gasoline-impacted ground water extracted from the ground water extraction and treatment system are presented in Appendix K Plots of cumulative ground water pump and treat mass removal trends and influent ground water TPH-g ' concentrations versus time are included in Appendix L 5.0. SUMMARY AND CONCLUSIONS ' The implications from the March 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 southeast at a gradient of 0 003 ft/ft(Figure 3), ground water flow direction within Hydrologic Units 2 and 3 (Second Water Zone)was inferred to be towards the 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 ' water elevations have generally fluctuated between 24 feet and 29 feet below MSL(Table 2) • Ground water at the site was generally observed between 44 and 46 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 ' • The greatest concentrations of Top Filling Station dissolved TPH-g and BTEX were detected in samples collected from wells MW-7B(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 I detected as high as 230,000 µg/l from well VW-2A and benzene as high as 87,000 gg/l from well MW-7B (Table 4) Additionally, the deepest detection of dissolved TPH-g and BTEX were detected in samples collected from well MW-6E(137-142 feet),the approximate extent Advanced GeoEnvironmental,Inc