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Groundwater Monitoring Well and Extraction Well Installations Results Report and Fourth Quarter 1005 Groundwater Monitoring Report Flag City New West#1003,6437 West Banner Street,Lodi,California Page 5 CONCLUSIONS Soil All soil samples were below detection limits except for MTBE for the extraction well samples collected at the 25 and 25 5-foot intervals, which were collected below the groundwater level The sample collected at well EW-4 at the 15 5-foot interval also had a detection of MTBE, also collected below the groundwater level A soil cross section location map and soil cross section map is included as Figures 3 and 4, respectively An MTBE in soil isoconcentration cross- section map is included as Figure 5 Groundwater Quarterly groundwater samples showed MTBE detected at all first zone wells except wells MW- 1 and MW-5A MTBE was detected at second zone wells MW-3B and MW-4B but was non- detect at wells MW-5B and MW-6B A combination of benzene, toluene and total xylenes constituents were detected at wells MW-1, MW-4B, MW-513 and MW-6B The detections were just above reporting limits TAME was detected at wells MW-3A, EW-3, MW-3B, and MW-4B at low concentrations Well EW-3 had a detection of TPHg for the first time and appears to be . due to laboratory interpretation because TBA had been elevated in the past and was below detection limits this quarter It should be noted that the December 29, 2005 samples were submitted to a different lab (Analytical Sciences) than was previously used (CLS), which could make the interpretation of the results different than past results Groundwater contour maps for the first and second zones using the New West site and FIag City Chevron site are included as Figures 6 and 7, respectively MTBE isoconcentration maps for the first and second zones using both sites are included as Figures 8 and 9, respectively These figures show that the two sites appear to have an elevated MTBE plume An MTBE groundwater cross-section isoconcentration map is included as Figure 10 RECOMMENDATIONS Apex recommends continued coordinated quarterly sampling of all wells The next sampling event is scheduled for March 2006 Apex currently has the bioremediation system installed to control the downgradient migration of the oxygenate plume Apex was in contact with the CVRWQCB as to the sampling requirements for the NPDES permit in October 2004 On November 10, 2005, Apex analyzed samples for the constituents as directed by the CVRWQCB Nitrates were above discharge limits and the CVRWQCB stated . they would issue a letter by the first week in December denying discharge to the storm drain unless nitrates could be treated Apex delayed submitting the permit for two weeks waiting for