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I i fi 23 October 2000 AGE-NC Project No 98-0448 Page 3 of 5 I3 2 LABORATORY RESULTS OF GROUND WATER SAMPLES TPH-g was detected in water samples collected from wells MW-2, MW-4A, MW-4B &MW-6 at ' concentrations ranging from 110 micrograms per liter(µg/1) to 8 1,000µgll The approximate extent of dissolved TPH-g is depicted in plan view in Figure 4 Various BTEX compounds were detected in water samples collected from MW-2,MW-4A,MW-4B and MW-6 at concentrations ranging from 2 1 µg/1 and 12,000 µg/1, the greatest benzene concentrations were detected in samples collected from MW-4B at a concentration of 5,900 µg/1 ' Fuel oxygenated compounds were not detected by laboratory analysis Analytical results of the ground water samples are summarized in Table 2 The laboratory reports (McCampbell Analytical ' Inc I D 44426 through 44430) and chain-of-custody forms are presented in Appendix B 4.0. DISCUSSION AND CONCLUSIONS The implications from the August 2000 ground water monitoring event are as follows • Ground water flow direction at the site appeared to be oriented generally towards the south- southwest at a gradient of 0 009, due to the low gradient at the site, slight variations in ' ground water measurements or changes of recharge/discharge of the local ground water could greatly modify ground water flow direction ' • Well MW-4B is"drowned" and yields a sample more representative of deeper ground water conditions I • Comparing the April 2000 monitoring event to the August 2000 monitoring event, decreases In concentrations of dissolved petroleum hydrocarbons were quantified in ground water samples collected from wells MW-2, MW-3, MW-4A and MW-6 (Table 2) Conversely, a ' slight concentration increase was recorded In well MW-4B Based on increased petroleum hydrocarbon concentrations quantified from well MW-4B (screened 45 to 50 feet bsg)during the June 1999, September 1999, April 2000 and August 2000 monitoring events, AGE suspects that well EW-1 (screened between 15 and 45 feet bsg) may be a vertical conduit between shallow depth ground water (approximately 15 to 30 feet bsg) and deeper depth ground water (approximately 45 to 50 feet bsg) • A trend of increasing ground water elevations was observed at the site between October 1994 and June 1998 Since June 1998, ground water elevations have fluctuated between 7 and 10 feet below mean sea level Advanced GeoEnvironmental,Inc