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' SEMI-ANNUAL GROUND WATER MONITORING REPORT San Joaquin County Public Health Services JANUARY THROUGH JUNE 2000 ' Montgomery Ward Auto Service Center Site Code 2163 . 5400 Pacific Avenue Stockton,CA EAl Pro3ect No 1232 ' Each water sample was sealed in three 40-milliliter volatile organic analysis (VOA) vials with Teflon septa lined lids The VOA vials were completely filled so that no head space existed ' between the sample and the lids The samples were labeled with the sample point identification, preservative added, if any, date, time, and EAI project number, and immediately placed into a chilled ice chest The samples were kept chilled until delivered to the laboratory for analytical testing A11 samples were logged on a chain of custody record form (see Appendix B) ' 23 Sampling Equipment Cleaning Protocol The submersible pump and hose system (Equipment), used only to purge the wells prior to sampling, was decontaminated between each event using the following procedure • The Equipment was flushed in a solution of Alconox detergent and tap water, and ' ■ The Equipment was flushed with top water 2.4 Effluent Handling All effluent generated during purging, sampling and equipment decontamination activities was sealed in labeled 55-gallon druids The drums were stored on the Montgomery Ward site pending proper disposal 2.5 Delta College Well In addition to the Unocal and Montgomery Ward site wells, a Delta College irrigation well located west of Pacific Avenue was also sampled by EAI (see Table 2) The Delta college well ' is operated, as needed, during late spring, summer, and early fall to meet landscaping irrigation needs of Delta College During months when the well is in operation ground water flow direction is generally westerly, toward the Delta College well During months when the well is not in operation around water flow direction is generally easterly and away from the well 3.0 ANALYTICAL TESTING The samples were delivered for analytical testing to American Scientific Laboratories (ASL), a state certified hazardous waste testing laboratory (Certificate No 2200) ASL is certified for all tests completed as part of this investigation The samples were tested using EPA Method 8260 ' for volatile organic compounds including benzene, toluene, ethylbenzene, xylenes, methyl tertiary butyl ether, tertiary butyl alcohol, di-isopropyl ether, ethyl tertiary butyl ether and tertiary amyl methyl ether The samples were also tested for total petroleum hydrocarbons as gasoline using modified EPA Method 8015 The results of this testing are shown in Table 2 and Figure 3 40 DISCUSSION ' The current gauging data indicate that the ground water elevations in the wells at the Montgomery Ward site have decreased on average approximately 2 86 feet as compared to the previous sampling event in December 1999 (see Table 1) Interpretation of the ground water elevation map indicates that the predominant direction of ground water flow below the Montgomery Ward site, at the time of measurement, was generally westerly at a hydraulic BHM 1232R0061 2 ENVIRONMENTAL AUDIT, INC