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1 <br /> QUARTERLY GROUNDWATER MONITORING REPORT <br /> ' THIRD QUARTER 2002 <br /> QUIK STOP MARKET NO. 132 <br /> 355 WEST HAMMER LANE <br /> ' STOCKTON CALIFORNIA <br /> 1 <br /> 1.0 INTRODUCTION <br /> ' ATC Associates Inc. (ATC) is pleased to present this report of the results of the Third Quarter 2002 <br /> groundwater monitoring conducted at the subject site in Stockton, San Joaquin County, California <br /> ' (Figure 1). The site plan (Figure 2) shows the location of the station building, adjacent streets, <br /> monitoring wells, and other site-specific features. <br /> ' The monitoring wells have been sampled quarterly to monitor two shallow groundwater aquifers <br /> underlying the site. The program objectives are listed below: <br /> • Measure depth of groundwater; <br /> ' • Analyze groundwater samples for select petroleum hydrocarbon constituents; <br /> • Construct groundwater elevation contour maps within the study area boundaries; and <br /> • Compare current and past data. <br /> The existence and degree of petroleum hydrocarbons in the groundwater underlying the site is evaluated <br /> ' by (1) the presence of the free-floating product and (2) laboratory analyses of groundwater samples to <br /> evaluate concentrations of total petroleum hydrocarbons as gasoline (TPH-G), and for benzene, toluene, <br /> ethylbenzene, and total xylenes (BTEX). Included with this report, in compliance with the July 18, 1997 <br /> ' request of the RWQCB-Central Valley Region, are results of analysis for the fuel oxygenates methyl-tert- <br /> butyl ether(MTBE) (a non-metallic antiknock and oxygenating compound used in gasoline), di-isopropyl <br /> ether (DIPS), ethyl-tert-butyl ether (ETBE), tert-amyl methyl ether (TAME), tert-butanol (TBA), <br /> ethylene dibromide (EDB), and 1,2-dichloroethane (1,2-DCA) by United States Environmental <br /> Protection Agency (USEPA) Method 8260 for samples collected from ten groundwater monitoring wells. <br /> As indicated in the RWQCB letter, the purpose of analyzing for these fuel oxygenates is to determine <br /> which oxygenated compounds are present, if any, in groundwater. <br /> In a letter to Quik Stop Markets Inc. dated April 27, 1998, the San Joaquin County Public Health <br /> Services, Environmental Health Division (PHS-EHD) required sampling of all site wells and analyzing <br /> for TPH-G, BTEX, and fuel oxygenates. Previously the PHS-EHD had recommended sampling of <br /> monitoring well MW-5 only. <br /> 2.0 GROUNDWATER SAMPLING <br /> ' On August 30, 2002 in accordance with ATC's Field Protocol (Appendix A), groundwater samples were <br /> collected from on-site groundwater monitoring wells MW-1R, MW-2, MW-3, MW-4, MW-5, and off- <br /> site groundwater monitoring wells MW-6, MW-7, MW-8, MW-9 and MW-10. Groundwater purged <br /> Quarterly GW Monitoring Report-3rd Qtr 2002 <br /> Quik Stop No. 132 <br /> NATCQuik Stop Markets,Inc. <br /> J:5P90.J£CTS=1K STOP MKTSQS 13ZROPUft12002%3rd0t2002Rp1 ATC Project No.75.62503.3203 <br /> November 11,2002 <br /> Page 1 of 3 <br />