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1 y ' 08 September 2005 . AGE-NC Project No 97-0333 ' Page 9of11 1 monitoring event, the overall trend of decreasing MTBE concentrations is evident t The results from the ground water monitoring and sampling event performed between 31 March and ' 01 April 2005 are as follows Generally,depth to ground water at the site varied between 17 and 19 feet bsg,ground water televations ranged between 13 59 feet(MW-12F)and 14 5 5 feet(MW-l OA)above MSL The ground water elevation increased approximately 3 23 feet between the December 2004 and 1 the March 2005 ground water monitoring events, the increase in elevation may be due to seasonal fluctuation First Zone ground water flow was inferred to be toward a ground water depression in the area ' of wells EW-1,MW-6,and MW-7A under a hydraulic gradient of approximately 0 012 ft/ft On the south-half of the site, ground water was inferred to be oriented toward'the ground water depression under a gradient of approximately 0 003 ft/ft,off site towards the north near well MW-12,ground water was inferred to be oriented towards the ground water depression at a gradient of approximately 0 001 ft/ft (Figure 4) �. - Second Zone,Third Zone,and Primary Aquifer ground water flow was inferred to be toward the northwest at approximate gradients of 0 002 ft/ft or less, (Figures 5, 6, and 7, respectively) - Due to the low ground water gradient at the site, small variations in ground water measurements or changes of recharge/discharge of the local ground water could greatly modify the inferred ground water flow direction Historically,the highest on-site concentrations of dissolved MTBE have been detected in the samples collected in the area of First Zone monitoring wells MW-2, MW-3, MW-6 and MW-7A, during the first quarter 2005,the highest MTBE concentration was detected from well MW-2 at 5,600 µg/1 Minor to significant PCE and/or TCE concentrations were detected in ground water monitoring wells located in First Zone,Second Zone,Third Zone,and Primary Aquifer Zone aquifers(Figure 10,Table 4) The highest concentrations of dissolved PCE were detected in the samples collected from First Zone well MW-3 at a concentration of 1,200 µg/l , from Second Zone wells MW-7(B-C),MW-10(B-C)at concentrations as high as 2,600 µg/l,and from Third Zone wells MW-7D at a concentration of 1,500 gg/l - PCE and TCE are chlorinated solvents often associated with dry cleaning operations Based on the December 2004 PCE iso-concentration map in First Zone water (Figure 10), AGE interprets the PCE/TCE plume to have originated from the dry cleaner's facility located immediately east of the Rainwater Car Wash Advanced GeoEnvironmental,Inc I 1