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t t t ' 05 September 2003 • AGE-NC Project No 97-0333 ' Page 9of10 The results from the ground water monitoring and sampling events performed in March 2003 are as ' follows • Generally,depth to ground water at the site varied between 17 and 19 feet bsg,ground water ' elevations range between 13 39 feet (MW-11 C) and 14 79 feet(MW-10A) above mean sea level The ground water elevation Increased approximately 2 48 feet between November 2002 and March 2003 ground water monitoring events, the average Increase in may be due to seasonal fluctuation • First Zone ground water flow was inferred to be towards a ground water depression in the ' area of wells MW-2,MW-6,MW-7 and EW-1 at gradients between 0 004 ft/ft and 0 33 ft/ft, off-site in the area of wells MW-11, MW-12 and MW-13, ground water appeared to flow towards the northwest and northeast (Figure 4) • Second Zone, Third Zone and the Primary Aquifer Zone ground water flows were inferred to be towards the northwest at approximate gradients of 0 001 ft/ft or less (Figures 5, 6 and 7) • 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 • The highest on-site concentrations of dissolved MTBE were detected in the samples ' collected in the area of First Zone monitoring wells MW-2, MW-3, MW-6, MW-7A and extraction well EW-1 at concentrations as high as 26,000µg/l Lower concentrations of on- site MTBE were detected in water samples from First and Second Zone monitoring wells t MW-1,MW-4,MW-7(B-C)and MW-8(B-C),generally,significant MTBE decreases were reported this quarter in wells MW-2, MW-6 and MW-7A (Table 3) ' Off-site MTBE was reported only in the water sample from Second Zone monitoring well MW-11C, at a low concentration of 7 4 µg/l • Concentrations of PCE and/or TCE have been detected in water samples collected from all ' well locations associated with the Rainwater Car Wash investigation Minor to significant PCE and/or TCE concentrations were detected in 42 of 47 ground water monitoring wells ' located in First Zone,Second Zone,Third Zone and Primary Aquifer Zone Aquifers(Figures 10 and 11, Table 4) The highest concentration of dissolved PCE were detected in the samples collected in the area of on-site wells MW-4(First Zone)and MW-8 (B,C)(Second ' Zone) and offsite well MW-12A (First Zone) at concentrations as high as 1,500 µg/1, • PCE and TCE are chlorinated solvents often associated with dry cleaning operations Based on Figures 10 and 11 depicting PCE isoconcentrations in First Zone and Second Zone ' Aquifers, 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 � 1