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approved 17H drums. The contents of the drums were transported by a Iicensed waste hauler for disposal at a licensed waste treatment facility. The volume of groundwater removed from the wells and .1 other measured sampling parameters are noted on the water sampling logs included in Appendix B. 3.0 LABORATORY ANALYSIS The groundwater samples were transported to STL Chromalab Analytical Labs, Inc., astate-certified laboratory, located in Pleasanton, California. The groundwater samples were analyzed for the presence ' of TPH-G, BTEX, the five fuel oxygenates, and 1,2 DCA and EDB in accordance with USEPA Method 8260B. Copies of the laboratory analytical report and chain of custody record are provided in Appendix C. I 4.0 SUMMARY OF RESULTS Based on the groundwater-level data for January 30, 2004 (Table 1),the groundwater flow direction in both the upper and lower aquifers was towards the southeast at a gradient of approximately 0.001 feet per foot (Figure 3 and Figure 4). The average depth to water in upper aquifer wells MW-5, MW-6, MW-7 and MW-10 increased approximately 0.49 feet since September 2003, and the average depth to water in the lower aquifer wells MW-IR, MW-2,MW-3, MW-4,MW-8 and MW-9 increased 0.42 feet during the same time period. The groundwater flow directions and gradients noted during this sampling event are ' consistent with historical trends. Analytical results of groundwater samples collected from current and past sampling events are presented in Table 1 and Table 2. Analytical laboratory results of groundwater samples collected on January 30, !� 2004 indicate that TPH-G was present at a concentration of 610 micrograms per liter(µg/l) in monitoring well MW-5 (the reported concentration was flagged by the laboratory for not matching the TPH-G standard). BTEX compounds were reported below method detection limit concentrations in the sampled I� wells except MW-4, where toluene was reported at a concentration of 12 µg/I. MTBE was reported in lower aquifer wells MW-1R,MW-2, MW-4 and MW-9 at concentrations ranging from 0.58 µg/1 in MW- { 4 to 420 µg/l in MW-2. MTBE was also reported in groundwater samples collected from upper aquifer !� wells MW-5 and MW-10 at concentrations of 730µg/1 and 3.1 µg/l, respectively. Fuel oxygenates DIPE and ETBE, and 1,2-DCA and EDB were not detected in the groundwater samples collected from wells sampled this quarter. However, TBA was reported in groundwater samples collected from wells MW-IR (11 µg/1), MW-2 (320 µg/1), and MW-5 (430 µg/1) and TAME was detected at concentrations of 8.1 µg/1 and 9.5 µg/1 in wells MW-2 and MW-5, respectively. The next quarterly I� groundwater sampling is scheduled for the end of March 2004. t r 4.1 Conclusions 1I� The compounds 1,2-DCA and EDB have never been detected in groundwater samples collected at this site for the past two years. Based on the results, ATC recommended that future laboratory analysis for these analytes be discontinued. The removal of 1,2-DCA and EDB from the analytical list of compounds ti for all monitoring wells at the site was approved by Ms. Vicki McCarthey with San Joaquin County ? Environmental Health Department (EHD) in a letter dated March 24, 2004. In addition, EHD had r requested to remove other compounds from the analytical list. Starting next quarter the wells at the site will be sampled on a quarterly basis and analyzed for constituents listed in the letter from the EHD. A ' copy of the letter is provided in Appendix D. ' Quarterly GW Monitoring Report-4th Qtr 2003 (MATC Quik Stop No. 132 Quik Stop Markets, Inc. J:IPROJECTSIOUIK STOP MKTMS t32%RepoRs%2003Wth OIf2MRpt ATC Project No.75.62503.3204 March 29,2003 Page 2 of 4