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5 • Third Quarter 2003 Monitoring Report Quik Stop Market No 121 Page 3 Monitoring well MW-4, screened from 33 to 43 feet in the A-aquifer, was also reported to be free of detectable TPHg/BTEX and MTBE compounds Monitoring well MW-5, located on the southwest side of the Quik Stop Market was reported to contain I ug/L MTBE No other compounds were detected in this well All three deep wells (B-aquifer), wells MW-6, MW-9 and MW-10, screened from 65 to 75 feet within the B-aquifer, were reported to be free of detectable TPHg/BTEX compounds this quarter Monitoring well MW-6 was reported to contain 0 68 ug/L MTBE No other fuel oxygenates were detected in any of the three deep wells The results of the groundwater analysis are summarized in Table 2 Graphs for wells MW-3, MW-4 and RW-1, summarizing MTBE concentrations over time, are 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 seven shallow A-aquifer wells this quarter, indicated the depth-to-groundwater ranged from approximately 21 19 to 22 88 feet below the top of the well casings The water level in monitoring well MW-4 was measured at 22 08 feet below the top of the well casing The water table in the A-aquifer has dropped approximately 3 to 4 feet during the last three months The groundwater table at the site is essentially flat, with a very slight gradient of 0 008 feet per foot to the north-northeast (Figure 4) Groundwater measurements taken in the three B-aquifer wells indicated the depth-to- groundwater ranged from approximately 28 92 to 29 95 feet below the top of the well casings The water table in the B-aquifer has fallen approximately 8 feet during the last three months A groundwater gradient map for the B-aquifer was created and indicates a gradient of 0 004 feet per foot to the northeast (Figure 5) CCI also collected background dissolved oxygen (D O ) readings, which ranged from 3 29 ug/L in MW-5 to 9 25 ug/L in MW-4 Since the System was reactivated in early August,the D O levels have increased significantly in almost all the wells The D O levels are summarized in Table 3 Based on the groundwater data obtained during the quarter, it appears the MTBE and TPHg concentrations have decrease significantly in many of the site wells The MTBE concentrations reported in well RW-1 have dropped from 160,000 ug/L on August 16, 2002 to 5,200 ug/L on July 14, 2003 The MTBE concentrations have also decreased in MW-3, from 130,000 ug/L on July 2, 2002 to non detect on July 14, 2003 The TPHg concentration in well . RW-1 has also decreased significantly since the System began operation The MTBE