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• January 27, 1999 SECOR E F I� F lrrfct uctlrurtul itrcur�x,tulcc! 3 Ms Anastasia Duarte-Wilkinson Time Oil Company 2737 West Commodore Way Seattle, WA 98199 SUBJECT: Quarterly Monitoring Report, October- December 1998 Jackpot Food Mart 14000 East Highway 88 Lockeford, California ' k Ms Duarte-Wtlkmson t This report presents the results of quarterly groundwater monitonng and sampling conducted at the Jackpot Food Mart at 14000 East Highway, Lockeford, California (the site, see Figure 1) GROUNDWA'T'ER MONI'T'ORING AND SAMPLING , Ten groundwater monitor wells were sampled on October 26 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 Prior to purging each groundwater monitor well, a water sample was taken and subjective r ;r ianalyses 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-atr ' 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 � A or purged dry, the water level in the monitor well was allowed to recover to at least 80 percent of its static s; 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 j 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- f ` 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 afield duplicate for monitor well MW-1 hF � 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 Groundwater at the site was i ✓ E' h measured at depths between 64 14 to 76 39 feet bgs The groundwater potentiometric surface elevation averaged approximately 69 99 feet below ground surface (bgs) during this monitoring event The • groundwater potentiometric surface elevation has decreased approximately 0 18 feet since the last sampling event in August 1998 The groundwater flow direction during this reporting period is toward the south with a hydraulic gradient of approximately 0 03 ft /ft A summary of data regarding groundwater levels MIME" Y�r y D MT OJAI OCKFORDgm 496 SECOR a 1 7CO0"01 01/40004 Janenry 27 1999 wi 9912 Bnvnen Park l)m e Sinte iof) 5a(rainenro C',4 95827 (9161 364-1880(916) 364-1889/A1 a wn recorconr �`�a r