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July 27, 1998 �i \ International IncuiPr,ielh' l Ms Anastasia Duarte-Wilkinson 4a Time Oil Company 2737 West Commodore Way w Seattle, WA 98199 SUBJECT; Quarterly Monitoring Report, April - June 1998 Jackpot Food Mart 14000 East Highway 88 Lockeford, Califorrua Ms Duarte-Wilkinson This 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 s Ten groundwater monitor wells were sampled on April 28, 1998 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 s 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 Excelchem Environmental Labs located in Roseville, California Groundwater samples were analyzed for TPHg,BTEX, and MTBE using modified EPA Method 8015, and EPA Method 602 respectively Sample DUP was submitted as a field duplicate for monitor well MW-2 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 potentiometnc surface map (Figure 2), and calculate the local groundwater flow direction and hydraulic gradient The groundwater potentrometnc surface elevation averaged approximately 72 62 feet below ground surface (bgs) during this monitoring event The groundwater flow direction during this reporting period is toward the southwest A summary of data regarding groundwater levels measured through April 28, 1998, is presented in Table 1 Copies of field observations documenting work performed at the site is presented in Attachment I SECOR LC1CFRDqul298 July 27 1998 } 7G005-001 01 9912 Business Park Drive, Suite 100 Sacramento, C'ri 95827 (916) 364-1880(916)364-1889 Fflh www secor com