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i IQ y p� Quarterly Report - First Quarter 2002 CALIFORNIA FUELS CARDLOCK STATION 2402 Pacific Avenue, Stockton, California 1.0 INTRODUCTION At the request of Mr David Atwater, Advanced GeoEnvzronmental, Inc (AGE) has prepared this quarterly report of ground water monitoring and soil remediation activities for 2402 Pacific Avenue, Stockton, California The objectives of the site activities were to monitor dissolved petroleum hydrocarbon concentrations in ground water, to assess ground water flow direction and gradient and to monitor the progress and effectiveness of soil vapor extraction (SVE) and in-situ air sparging (IAS) remediation at the site The site setting is illustrated on Figure I Site structures and Imonitoring well locations are depicted on Figure 2 This report has been prepared in accordance with guidelines issued by the California Regional Water Quality Control Board (RWQCB) - Central Valley Region for investigation of underground storage tank(UST) sites A summary of previous investigations at the site was included in the AGE-prepared Corrective Action Plan-May 1998, dated 05 May 1998 Analytical data acquired to date is included Iin this report 2.0 GROUND WATER MONITORING AND SAMPLING PROCEDURES On 08 March 2002, ground water monitoring and sampling were performed at the site on wells IMW-1 through MW-13 and air sparge wells AW-1A, AW-1B, AW-2A and AW-2B (AW-lA through AW-2B), as built construction details are sununanzed in Table 1 Ground water monitoring procedures for the site were outlined in Work Plan Addendum, dated 16 May 2000 and conform to ground water monitoring guidelines issued by the San Joaquin County Environmental Health Department (EHD) I 2 1 WELL MONITORING AND EVACUATION PROCEDURES ' The depth to ground water was measured at each well from the tops of the well casings to the nearest 0 01-foot, utilizing a Solinst water level meter Ground water elevation at the site was calculated by subtracting the measured depth to ground water from the surveyed well casing elevations (Table 1) Ground water elevations were plotted and contoured on a scaled site map (Figure 3) ' After water levels were measured, approximately 6 to 21 gallons of ground water (a minimum of three casing-water volumes per well) were evacuated (purged) from sixteen of the seventeen wells utilizing either a polyethylene disposable bailer or a submersible pump, approximately 1'/Z gallons of ground water were removed from well MW-1 I and I I gallons removed from well MW-13 before these wells were pumped"dry' Temperature, pH and conductivity of purged water were measured from each well for stabilization at regular purge-volume intervals using an Oakton water analyzer