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Water table elevations and a groundwater contour map for December 8, 1996, are depicted on Figure 1 Groundwater flow was generally to the southwest The average hydraulic gradient is approximately 0 0005 foot per foot (ft/ft ) The flow direction and gradient is different from the third quarter monitoring event The third quarter groundwater monitoring report indicated the groundwater flowed laterally inward from the north, east and south with an approximate gradient of0017ft/ft BRE personnel collected groundwater samples from 8 monitoring wells during this field event Groundwater samples were transported to a California certified laboratory, Centrum Analytical Laboratones, Inc , in Redlands California, and analyzed for Total Petroleum Hydrocarbons - Gasolrne 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 below laboratory detection limits (MW-2, MW-6, MW-7 and MW-8) to 1,500 pg/L (MW-1) TVOA concentrations ranged from 6 60 �ng/L (MW-2) to 595 µg/1. (MW-1) MTBE concentrations ranged from below the detection limits (MW-2, MW-3, MW-7 and MW-8) to 22 µg/L (MW-1) Table I 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 during this quarterly sampling event The QA/QC samples consisted of one duplicate sample (obtained from well MW-3) and one equipment blank Toluene and total xylenes were detected in the equipment blank at a concentration of 0 7 µg/L and 2 8 µg/L, respectively Although BRE cannot identify the cause of the contamination in the equipment blank sample, typical reasons include hydrocarbons present on the pre-cleaned disposable bailer or in the distilled water, field methods used to collect the sample, or laboratory methods used to analyze the sample Automobile traffic was very heavy during sample collection activities, which may account for the equipment blank contamination Duplicate sample results are within an acceptable range The original sample result for MW-3 is presented on Figure 2 CONCLUSIONS AND RECOMMENDATIONS The San Joaquin County Public Health Services - Environmental Health Division has requested 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 4pi UST Trust Fund