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l� 3.0 LABORATORY ANALYSIS The groundwater samples were transported to Entech Analytical Laboratory (Entech), a state-certified laboratory, located in Santa Clara, California. The groundwater samples were analyzed as follows: Wells MW-1R, MW-2, MW4, and MW-5 were analyzed for the presence of TPH-g, BTEX, and the five fuel oxygenates (TAME,MTBE,DIPS,TBA, and ETBE)by EPA Method 9260B Copies of the laboratory analytical report and chain of custody record are provided in Appendix C. 4.0 SUMMARY OF RESULTS Based on groundwater elevation data for February, the groundwater flow direction in wells in both the upper and lower screened intervals was towards the southeast at gradients of approximately 0.002 feet per foot (ft/ft) and 0.001 ft/ft, respectively (Figures 3 and 4). The groundwater flow directions and gradients noted during this sampling event are consistent with historical trends. TPH-g concentration levels were less than the laboratory detection limit (25 gg[L) in wells MW-1R, MW-2,MW-4, MW-9,and MW-10; in MW-5 the reported concentration was 51 µg/L. BTEX compounds were sampled in MW-1R, MW-2, MW-4,.MW-5, MW-9, and MW-10; only toluene was reported above the laboratory detection limit in MW-4 (concentration of 1.3 gg/L). r- Oxygenates: The highest concentration of MtBE was reported in groundwater samples collected from upper zone well MW-5 at a concentration of 78 gg/L. MtBE was also reported in lower zone wells MW- 1R and MW-2 at concentrations of 1.2 p.g/L, 22 gglL, respectively. TBA was present in MW-5 at a concentration of 26 gg/L.No MtBE or fuel oxygenates were reported in wells MW-9 and MW-10. Cumulative analytical results of groundwater samples collected from current and past sampling events are presented in Tables 1 and 2. Well construction details and status of screened intervals relative to current groundwater elevation are provided in Table 3. The two shallow zone wells are the only ones sampling the top of the water column;all other wells have submerged screens. 5.0 CONCLUSIONS AND RECOMMENDATIONS During this sampling episode, ATC employed low flow sampling techniques. In general TPH-G, BTEX and fuel oxygenates have continued to decrease this quarter compared to previous quarters. The only increase in concentration noted this quarter is in MW-5 with a TPH-g concentration of 51 gg/L, compared to non-detect less than 50 gg/1.,,last quarter. MW-5 also saw an increase in TBA concentrations from 12 gg/L last quarter to 26 gg/L in this last sampling event. • Quarterly GW Monitoring ReporE—I st Qtr 2006 MMATC Quik Stop No. 132 Quik Stop Markets,Inc. ATC Project No,75.62503.3206 June 1,2006 Page 2 of 4