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I ' 24 March 2004 • AGE-NC Project No 97-0301 ' Page 4 of 5 I 4.0. SUMMARY AND CONCLUSIONS The implications from the September 2003 ground water monitoring event are as follows - Generally,depth to ground water at the site vaned between 33 and 35 feet bsg, ground water elevations ranged between 2139 feet(MW-8A)and 22 57 feet(MW-L1 D)below mean sea level 1 - Ground water flow cljerection for the area bound by First Water Zone wells MW-1 through MW- pwasl"Welrr0ed to be east-northeast at an approximate gradient of 0 003 ft/ft or less ' (Figure 3) Due to the low gradient at the site, slight vanations in ground water measurements or changes of recharge/discharge of the local ground water could greatly modify ground water flow direction - Ground water elevation generally decreased at the site an average 2 20 feet between the June 2003 and the September 2003 ground water monitoring events The decrease in ground water elevation is probably due to seasonal fluctuation - The core of the First Water Zone dissolved gasoline plume appears to be currently distributed near the location of wells MW-1 and MW-7, and contained within network of ' wells consisting of MW-2, MW-3, MW-4, MW-6, MW-9A, MW-10A, MW-11A and MW-12A(Figure 4) Analysis of groundwater samples collected from MW-1 and MW-J-2' suggest the core of the plume is impacted by TPH-g, BTEX and 1,2-DCAI u$ a' q 10-) I Is,e MV u» - Substantial concentrations of dissolved TPH-d and TPH-k have previously been detected in water samples collected from wells MW-1 and MW-7, indicating a limited distribution of ' TPH-d and TPH-k in the area assessed BTEX and 1,2-DCA concentrations in ground water samples MW-1 and MW-7 were ' substantially above their respective Maximum Contaminant Levels in drinking water DA Very low concentrations of MTBE, TAME, EDBand TBA have been detected at wells ' MW-1,MW-2,MW-3,MW-4,MW-band MW-7 indicating that there is only a minor impact of these components Based on one quarterly ground water monitoring event, the lateral and vertical extent of ' dissolved petroleum hydrocarbons appears to be limited to the First Water Zone on the site and approximately 50 feet north of the site, residual contaminants have been detected between the Second and Third Water Zones from well MW-5 Advanced GeoEnvironmental,Inc