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SECOR I1rtcr rrrrtrorrrrl Irrc.orr�orrrtcrl May 6, 1997 Ms Anastasia Duarte-Wilkinson Time Oil Company 2737 West Commodore Way Seattle,WA 98199 SUBJECT: Quarterly Monitor ing Report,January- March 1997 Jackpot Food Mart 14000 East Highway 88 Lockeford, California Ms Duarte-Wilkinson 1 Tlus report presents the results of quarterly groundwater monitoring and sampling conducted at the Jackpot Food Mart at 14000 East Highway, Lockeford, California(the site, see Figure 1) GROUNDWATER MONITORING AND SAMPLING Ten groundwater monitor wells were sampled on February 26, 1997 at the site Monitor wells MW-1 through MW-4 were wstalled as part of an environiuental 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 floating product or a hydrocarbon sheen by lowering a clean teflon bailer down the well and collecting a sample at the groundwater-air interface Wells not containing floating product 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 caps, labelled 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 Exeelchem Environmental Labs located in Roseville,California Groundwater samples were analyzed for TPHg, and BTEX,using modified EPA Method 8015, and EPA Method 602 respectively Additionally,two groundwater samples were analyzed for MTBE using EPA Method 602 Sample MW-11 was submitted as afield duplicate for monitor well MW-10 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 potentiometric surface map (Figure 2), and calculate the local groundwater flow direction and hydraulic gradient. The groundwater potentiometric surface elevation averaged approximately 74 23 feet below ground surface(bgs)during this monitoring event The groundwater flow direction at the site is directed toward the southwest with a hydraulic gradient of approximately 0 08 (ft/ft) A summary of data regarding groundwater levels measured through February 26, 1997, is presented in Table I Copies of field observations documenting work performed at the site is presented in Attachment I LCKFRp1-01 SECOR J0710.00 y4l May 6,3"7 5852 Bolsa Awnue Su tie 200 11+ wingfan Beach GA 92649-1715 (714) 379-3366 (714) 379-3375 FAX