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Quik Stop Market No 121 CCI Project No 12118-3 Page 2 for chemical analysis The laboratory employed methods approved by the California Regional Water Quality Control Board (CRWQCB) and the EPA The groundwater samples were analyzed for total petroleum hydrocarbons as gasoline (TPHg) and benzene, toluene, ethyl benzene and total xylenes (BTEX), using EPA Test Method 8015 and 8020 The samples were also analyzed for fuel oxygenates following EPA 8260 Test Method Summary of Laboratory Results Groundwater samples collected from the monitoring wells indicated two of the three wells (MW-1 and MW-2) to be free of detectable TPHg and BTEX contamination The laboratory reported monitoring well MW-3 to contain TPHg at 230 micrograms per liter(ug/1) and toluene at 3 ug/l No other TPHg or BTEX compounds were detected in any of the three monitoring wells The laboratory also reported two of the three monitoring wells to have detectable concentrations of methyl-t-butyl ether (MTBE) Monitoring well MW-3 was reported to contain the highest concentration of MTBE at 12,000 ug/1 MTBE was also detected in monitoring well MW-1 at 87 ug/l No other fuel oxygenates were reported in any of the three wells The results of the groundwater analysis are summarized in Table 2 The analytical reports from North State and chain- of-custody documents are attached in Appendix B Discussion Groundwater measurements taken in the three onsite monitoring wells on July 21, 1999 indicated the depth-to-groundwater ranged from approximately 16 42 to 16 98 feet below the top of the well casings The water table has fallen approximately 2 feet since the April 1999 sample round Groundwater contours in the vicinity of the three monitoring wells indicate a groundwater flow direction to be toward the southeast, at a relatively flat gradient of approximately 0 003 feet per foot (Figure 2) The groundwater flow direction determined during this sample round has shifted approximately 90 degrees from the northeast flow direction reported in CCI's May 1999 Monitoring Well Installation report Groundwater samples collected during this quarterly sample round indicated the three onsite wells to be virtually free of detectable TPHg and BTEX compounds Monitoring well MW-3 was reported to contain 230 ug/l TPHg and 3 ug/l toluene No detectable benzene was reported in any of the three monitoring wells However, MTBE contamination has impacted monitoring well MW-2,A�S-+gp& + Monitoring well MW-3, at concentrations of 12,000 ug/l MTBE The current concentration of MTBE reported in MW-3 is significantly higher than was reported during the last sampling round, since all three site wells were reported to be free of detectable MTBE in April 1999