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from the last monitoring event The depth to groundwater, groundwater elevation data and monitoring well construction data, compiled in Table 1, indicates that the screened intervals for all wells were "submerged" during this sampling event Water table elevations and a groundwater contour map for September 14, 1996, are depicted on Figure 1 The data indicates a groundwater depression around MW-2 causing the groundwater to flow laterally inward from the north, east, and south The average hydraulic gradient is approximately 0 017 foot per foot The flow direction and gradient is different from the second quarter monitoring event where groundwater flow was generally to the southwest BRE personnel collected groundwater samples from 8 monitoring wells during this field event Groundwater samples were transported to a California certified laboratory, Centrum Analytical Laboratories, Inc , in Redlands California, and analyzed for Total Petroleum Hydrocarbons - Gasoline Range Organics (TPHg) by EPA Method 8015 (modified) and Total Volatile Organic Aromatics (TVOA), including Methyl Tertiary Butyl Ether (MTBE), by EPA Method 8020 Laboratory analysis of the groundwater samples indicates the presence of dissolved phase petroleum hydrocarbons above laboratory method detection limits (MDLs) in all monitoring wells TPHg concentrations ranged from 230 pg/L (MW-2) to 2,600 µg/L (MW-3), and TVOA concentrations ranged from 26 4 gg/L (MW-4) to 598 µg/L (MW-1) MTBE concentrations ranged from below the detection limits (MW-8) to i 1 gg/L (MW-4) Table 1 presents the analytical testing data The analytical data is depicted on a site plan as Figure 2 The analytical laboratory reports with the chain of custody is included as Appendix C Quality assurance and quality control (QA/QC) samples were also obtained dunng this quarterly sampling event The QA/QC samples consisted of one duplicate sample (obtained from well MW-1), one trip blank, and one equipment blank Except for MTBE (which was detected at 0 8 pg/L in the equipment blank), hydrocarbon constituents were not detected in either the trip blank or the equipment blank CONCLUSIONS AND RECOMMENDATIONS BRE recommends not sampling wells during the time period that the screen intervals are submerged Results may not be representative of groundwater conditions The San Joaquin County Public Health Services - Environmental Health Division has requested that the approved Corrective Action Plan (CAP) be implemented However, the implementation of the CAP must be pre-approved by the State UST Trust Fund if costs are to be reimbursed by the Fund Currently, the Justification for remediation at the Site has not been reviewed by the , State UST Trust Fund