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First Quarter 2004 Monitoring Report • Quik Stop Market No 121 Page 3 Monitoring well MW-8, located on the south side of the Quik Stop Market was also reported to be free of detectable TPHg/BTEX and was reported to contain 48 ug/L Tert-Butyl alcohol (TBA) No other fuel oxygenate compounds were detected Two of the three deep wells, MW-9 and MW-10, screened from 65 to 75 feet within the B- aquifer, were reported to be free of detectable TPHg/BTEX and fuel oxygenate compounds Monitoring well MW-6 was reported by the laboratory to be free of detectable TPHg/BTEX, and was reported to contain 0 74ug/L MTBE No other fuel oxygenates were detected in any of three deep wells The results of the groundwater analysis are summarized in Table 2 A graph for well RW-1, summarizing MTBE concentrations overtime, is also presented herein The analytical reports from STL, chain-of-custody documents and field notes are attached in Appendix B Discussion Groundwater measurements taken in the ten shallow A-aquifer wells this quarter indicated the depth-to-groundwater ranged from approximately 19 90 to 2120 feet below the top of the well casings The water level in monitoring well MW-4 was measured at 20 04 feet below the top of the well casing The water table in the A-aquifer has risen approximately 2 5 feet during the last three months The groundwater table at the site is essentially flat,with slight flow directions to the northeast, northwest and southeast(Figure 4) Groundwater measurements taken in the three B-aquifer wells indicated the depth-to-groundwater ranged from approximately 28 85 to 29 84 feet below the top of the well casings The water table in the B-aquifer has risen approximately 6 feet during the last three months A groundwater gradient map for the B-aquifer was created and indicates a gradient of 0 002 feet per foot to the northeast (Figure 5) Dissolved oxygen (D O ) readings were also collected this quarter, which ranged from 4 87ug/L in well MW-5 to 8 54ug/L in MW-10 The D O readings for all of the wells are summarized in Table 3 showing D O readings from previous sample rounds Based on the groundwater data obtained during the quarter, it appears the MTBE and TPHg are "non-detect" in a majority of the site wells and continue to decrease in virtually all of the site wells with detectable concentrations The TPHg and MTBE plume has been reduced to the immediate area around the fuel tanks The MTBE concentrations reported in well RW-1 have dropped from 160,000ug/L on August 16, 2002 to a current concentration of 560ug/L The TPHg concentration in well RW-1 has also decreased significantly since the System began operation The MTBE concentration in MW-4 has dropped from 15,000 ug/L on August 16, 2002 to "non detect" No MTBE was detected in two of the three B-aquifer wells Monitoring well MW-6 was reported to have very minor (0 74 ug/L)MTBE this quarter, and MW-8 was reported to have 48ug/L TBA A summary of the data collected during the operation of the