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ASSOCIATESC- OLTC I NC . ANALYTICAL RESULTS The laboratory analytical results indicate TPHg and ethyl benzene were detected in the groundwater sample collected from monitoring well MW 1 at concentrations of 490 micrograms per liter ([Ig/L) and 3.1 gg/L, respectively. None of the gasoline oxygenates/additives were detected in the sample collected from MW TPHg was detected in the groundwater sample collected from monitoring well MW2 at a concentration of 160 p.g/L. BTEX constituents and gasoline oxygenates/additives were not detected in this sample. TPHg, toluene, ethyl benzene, and xylenes were detected in the groundwater sample collected from monitoring well MW3 at concentrations of 960 µg/L, 0.6 µg/L, 3.9 gg/L, and 4.0 µg/L, respectively. None of the gasoline oxygenates/additives were detected in the sample collected from MW3. The Maximum Contaminant Level (MCL) for benzene, 1 pg/L, was not exceeded in any of the groundwater samples. GROUNDWATER FLOW DIRECTION Water level measurements were collected from monitoring wells MW1, MW2, and MW3 on March 2, 2004. Water level elevations ranged from 37.42 to 37.47, representing an average increase in water table elevation of approximately 0.58 feet since December 2003. The water level data were used to develop the groundwater elevation contour map (Figure 3). Assuming that horizontal isotropic conditions prevail, groundwater in the uppermost aquifer beneath the site flowed toward the northwest. The average hydraulic gradient on March 2, 2004, was calculated to be 0.0006 or approximately 3.3 ft/mile. Summaries of groundwater monitoring data and analytical results are presented in Table 1 and Table 2, respectively. CONCLUSIONS Groundwater flow direction and gradient is generally consistent with previous sampling events. Water table elevations have generally decreased since monitoring was initiated at the site in 1999. Groundwater analytical results remained within historical parameters as set by previous groundwater analytical results. Benzene has not been detected in quarterly groundwater samples collected from MW1 since September 2003 and from MW2 and MW3 since March 2003 and September 2002, respectively. The laboratory analytical results of the groundwater sample collected from MW 1 on March 2, 2004 represent historical lows for quarterly samples collected from this well. The lack of benzene concentrations detected in groundwater samples collected from MW 1 during the last two quarterly groundwater monitoring events may be attributable to the effectiveness of the interim remedial action activities conducted at the site from July 8 to December 4, 2003. s:lenvironmenta1\149$11Reportsl l QR-04.doe 3