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1 I r I I h 06 December 2002 E I ` AGE-NC Project No 97-0333 , I Page 7 of 9 ' ' y I No other analytes were detected above the respected laboratory reporting limits Previous and current ' analytical results of ground water monitoring well samples are summarized in Tables 5 and 6 The laboratory reports (Castle Analytical Laboratory Reference No 4987) and chain-of-custody forms are presented in Appendix F ' 4.0. SUMMARY AND CONCLUSIONS ti The implications from the August 2002 ground water monitoring event are as follows Ground water flow direction at the site was inferred to be radially inward towards wells MW-2, MW-6 and EW-1 at an approximate gradient of 0 017 ft/ft or less (Figure 3), however,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 ' The ground water elevation at the site was within the screened intervals of wells MW-1 , through MW-5, which should yield samples fully representative of shallow ground water conditions The ground water elevation at MW-6 is approximately 2 25 feet above the screen ' . interval,but should still be representative of shallow ground water conditions 'I Ground water elevation decreased at the site an average 3 93 feet between the Mj ay 2002 and ' the August 2002 ground water monitoring events, the decrease of ground water elevation may be due to seasonal fluctuation ' • I ' Previous analytical results indicate that the core of the dissolved petroleum hydrocarbon plume appears to be located in the area of MW-2 (screened between 12 and 32 feet bsg), MW-6 (screened 20 to 45 feet bsg) and EW-1 (screened 20'to 45 feet bsg)'and is primarily ' impacted by TPH-g, BTEX, and MTBE • Substantial concentrations of dissolved TAME have been detected in water samples collected I from wells MW-1,MW-2,MW-3 and MW-6 and a grab ground water sample collected from P-3, indicating that there is a limited area impacted with TAME in the area assessed • Substantial concentrations of PCE have been detected in water samples'collected from wells ' MW73 and MW-4, low concentrations,of TCE have been detected at wells MW-4 and MW-5 PCE and TCE are chlorinated solvents often associated with dry cleaning operations • Concentrations of chloroform,napthalene, 1,3,5-tnmethylbenzene, 1,2,4-tnmethylbenzene, 1 1,2-dichlorobenzene,,1,3-dichlorobenzene, l,4-dichlorobenzene, 1,2,4-dichlorobenzene were previously detected in water samples collected from wells MW-4 and MW-5' • With the exception of the western boundary, the lateral and vertical extent'of dissolved petroleum,hydrocarbons is not known in any direction at the site (Figures 4 and 5) r I F I Advanced GeoEnvironmental,inc