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SECOR www secor corn INTERNATIONAL 3017 Mgorc Road Suite 100 S E C O R INCORPORATED Rancho Cordova CA 95670 916 861-0400 TEL 916 861-0430 rAx January 30, 2003 Ms Anastasia Duarte-Wilkinson Time Oil Company 2737 West Commodore Way Seattle, WA 98199 RE Quarterly Monitoring Report, October--December 2002 Jackpot Food Mart 14000 East Highway 88 Lockeford, California SECOR Project No 770T 41737 00 Ms Duarte-Wilkinson This report presents the results of quarterly groundwater monitoring and sampling conducted at the Jackpot Food Mart at 14000 East Highway 88,Lockeford, California(the site,see Figure 1) In addition,the operation of the soil vapor extraction and air sparging remediation system is described GROUNDWATER MONITORING AND SAMPLING Nine groundwater monitor wells were sampled on November 12, 2002 at the site Monitor wells MW-1 through MW-4 were installed as part of an environmental investigation conducted in December 1994 In July 1996, monitor wells MW-5 through MW-10 were installed as part of an additional environmental site assessment Prior to purging each groundwater monitor well, a water sample was taken and subjective analyses performed The subjective analyses consisted of checking for liquid-phase hydrocarbons(LPH)ora hydrocarbon sheen by lowering a clean Teflon® bailer dawn the well and collecting a sample at the groundwater-air interface Wells not containing LPH were purged of approximately 2 to 4 casing volumes of water or until groundwater parameters of pH, temperature, and conductivity stabilized as measured by portable meters calibrated to a standard buffer and conductivity standard If the well was slow to recover or purged dry,the water level in the monitor well was allowed to recover to at least 80 percent of its static level before sampling The groundwater samples were then collected by lowering a clean disposable bailer into the well and collecting a representative sample The groundwater samples were slowly transferred to laboratory- cleaned sample containers,sealed with Teflon®-lined caps,labeled with the sample number,sample time and date, and immediately placed on ice in an insulated container Each sample was logged onto a chain-of- custody record for subsequent delivery to Excelchem Environmental Labs located in Roseville, California Groundwater samples were analyzed for TPHg and BTEX using modified EPA Method 602/8015,and by EPA Method 8260 for fuel oxygenates methyl tertiary butyl ether(MTBE),di-isopropyl ether(DIPE), ethyl tertiary butyl ether (ETBE), tertiary amyl methyl ether(TAME), and tertiary butanol (TBA) GROUNDWATER ELEVATION DATA Depth to groundwater was obtained from the existing groundwater monitor wells at the site using a water level indicator graduated to 0 01 foot The depth to groundwater measurement was converted to a groundwater elevation for each well and used to construct a groundwater elevation contour map (Figure 2), and calculate the local groundwater flow direction and hydraulic gradient Groundwater at the site was measured at depths between 71 68 to 85 55 feet below ground surface(bgs) The groundwater potentiometric surface elevation averaged approximately 24 82 feet bgs during this monitoring event \Time Od\LockefordQ402 doc