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1 GROUND WATER MONITORING REPORT THIRD QUARTER 1994 ' Montgomery Ward Auto Service Center 5400 Pacific Avenue Stockton, California 1.0 INTRODUCTION PAu15 AVA 4 t`{R This document constitutes the third quarter (July through September) 1994 ground water ' monitoring report for the Montgomery Ward Auto Service Center property located at 5400 Pacific Avenue, Stockton, California (see Figure 1) The quarterly ground water .monitoring and sampling is being conducted in accordance with a request from the San Joaquin County Public ' Health Services Department (County) As requested by the County, the gauging and sampling activities at the Montgomery / ' Ward site occurred on the same day that wells were gauged and sampled at the former Unocal J branded service station located at 5606 Pacific Avenue, Stockton, California ' 2.0 FIELD INVESTIGATION 21 GROUND WATER ELEVATION SURVEY On September 14, 1994, prior to purging or sampling activities, depth measurements to ' fluid levels were obtained using an interface probe accurate to 0 01 foot from the two wells (MW-1 and MW-2) located on the Montgomery Ward site and the six wells (MW-10, MW-11, MW-12, MW-13, MW-14 and MW-15) located at the former Unocal site (see Figure 2) No ' f free-product was detected in any of these six wells The water level measurement for each well was converted to mean sea level (MSL) datum by subtracting the measured water level for each well from the ground level datum (see Table 1) The data in Table 1 were used to construct a ground water elevation map (see Figure 2) The data show that, at the time of measurement, the predominant direction of ground water flow was southerly� d ? 2 2 GROUND WATER SAMPLING On September 14, 1994, an Environmental Audit, Inc (EAI) geologist collected ground water samples from the two Montgomery Ward wells for analytical testing Prior to sampling, the wells were purged using a Grundfos MP-1 submersible pump Temperature, conductivity, pH and turbidity were recorded to evaluate the effectiveness of purging activities (see Appendix A) The wells were sampled in the order that purging activities were completed Water samples were collected from each well from dust below the water surface using Voss Technologies disposable bottom bailers equipped with volatile organic compound samplers The use of these bailers precludes the potential for cross-contamination Mr MichaelIY"urna of the County was on-site during purging and sampling activities Each water sample was sealed in three 40-milliliter (ml) VOA vials with Teflon septa lined lids The vials were completely filled so that no head space existed between the sample Iand the lids The samples were labeled with the sample point identification, preservative added, Project No 1232 1 ENVIRONMENTAL AUDIT. INC,,