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1 <br /> QUARTERLY GROUND WATER MONITORING Site Code 2163 <br /> Montgomery Ward Auto Service Center <br /> 5400 Pacific Avenue, Stockton CA <br />' 1.0 INTRODUCTION <br />' This document constitutes the third quarter (July through September) 1995 ground «ater <br /> monitoring report for the Montgomery Ward Auto Service Center property located at 5400 <br /> Pacific Avenue, Stockton, California (Site) (see Figure 1) The quarterly ground xNater <br />' monitoring and sampling is being conducted in accordance with a request from the San Joaquin <br /> County Public Health Services Department (County) <br />' As requested by the County, the gauging and sampling activities at the Montgomery Ward site <br /> occurred on the same day that wells were gauged and sampled at the former Unocal branded <br /> service station located at 5606 Pacific Avenue, Stockton, California <br /> 2.0 FIELD INVESTIGATION <br /> 21 GROUND WATER ELEVATION SURVEY <br /> On September 19, 1995, prior to purging or sampling activities, depth measurements to fluid <br /> levels were obtained using an interface probe accurate to 0 01 foot from the six wells (MW-1 <br /> through MW-6) located on the Montgomery Ward site (see Figure 2 and Table 1) Table 1 also <br /> contains well gauging information from wells MW-10 through MW-15 located at the former <br /> Unocal site (see Figure 2) No free-product was detected in the Montgomery Ward wells and <br /> no free-product was reported in wells associated with the former Unocal site (see Table 1) The <br /> water level measurement for each well was converted to mean sea level (MSL) datum by <br /> subtracting the measured water level for each well from its respective "top of well casing <br /> elevation" datum (see Table 1) The data in Table 1 were used to construct a ground Xrater <br /> elevation map (see Figure 2) <br /> I22 GROUND WATER SAMPLING <br /> On September 19, 1995, an Environmental Audit, Inc (EAI) geologist collected ground water <br /> samples for analytical testing from the six Montgomery Ward wells Prior to sampling, the wells <br /> were purged using a Grundfos MP-1 submersible pump <br /> Temperature, conductivity, pH, and turbidity were recorded to evaluate the effectiveness of <br /> purging activities (see Appendix A) The wells were sampled in the order that purging activities <br /> were completed Water samples were collected from each well from just below the water <br /> surface using Voss Technologies disposable bottom bailers equipped with volatile organic <br /> compound samplers The use of these bailers precludes the potential for cross-contamination <br /> Mr Michael Infurna of the County was on-site during the onset of purging and sampling <br /> activities <br /> Each water sample was sealed in four 40-milliliter volatile organic analysis (VOA) vials with <br /> Teflon septa lined lids The VOA vials were completely filled so that no head space existed <br /> between the sample and the lids The samples were labeled with the sample point identification, <br /> preservative added, if any, date, time and EAI project number, and immediately placed into an <br /> ice chest chilled using frozen blue and crushed ice The samples were kept chilled until <br /> delivered to the laboratory for analytical testing All samples were logged on a chain of custody <br /> record form (see Appendix B) <br /> IProject No 1232 1 ENVIRONMENTAL AUDIT, INC <br />