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1 ' Quarterly Report - Third Quarter 2005 PACIFIC MINI-MART I4511 Pacific Avenue, Stockton, California ' 1.0. INTRODUCTION At the request of Mr Art Wyatt, Advanced GeoEnvironmentai, Inc (AGE) has prepared this ' quarterly report for 4511 Pacific Avenue, Stockton, California (site) This report documents the procedures for collection and analysis of ground water samples frond the well network and the results of the monitoring event in August 2005 The location of the site is illustrated on Figure 1 Structures, ' monitoring well and soil boring locations are illustrated on Figure 2 The site history and a description of previous work performed at the site are detailed in Appendix A Data from previous Iground water monitoring events are included in the tables of this report I2.0. PROCEDURES Field work was performed in accordance with guidelines issued by the Central Valley Regional Water Quality Control Board(CVRWQCB)for the investigation of underground storage tank(UST) sites This report was prepared under the supervision of a registered geologist • 2 1 WELL MONITORING AND EVACUATION On 11 August 2005, a Solinst water level meter was used to measure the depth to ground water in monitoring wells MW-1 through MW-18,except MW-9 and MW-10 which were inaccessible this quarter The ground water elevation in each well was calculated by subtracting the measured depth Ito ground water from the surveyed casing elevation (Table 2) On 11 August 2005,a minimum of three casing-water volumes were purged from vapor well VW-1 Iand monitoring wells MW-4, MW-6, MW-8, MW-11A/13, MW-15, MW-16, MW-17 using a disposable bailer and well MW-18 was purged using a Watera Hydrolift pump with dedicated tubing Temperature, pH and conductivity of purged ground water was measured at various intervals, depending on the volume of water in each well, using an Oakton water analyzer The field data and field sheets are included in Appendix B Purged water was discharged into the active ground water treatment system for treatment and disposal 2 2 COLLECTION AND ANALYSIS OF GROUND WATER SAMPLES A water sample was collected from each monitoring well using a new disposable bailer or the Watera Hydrohft pump with dedicated tubing after allowing the wells to achieve a minimum 80%recovery of the pre-purge water volume Immediately upon retrieval,the samples were transferred into three . 40-milliliter (ml) EPA-approved volatile organic analysis (VOA) vials containing 0 5-ml 18% Advanced GeoEnvironmental,Inc