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SECOND QUARTER 1996 GROUND WATER MONITORING REPORT San Joaquin County Montgomery Ward Auto Service Center Public Health Services Department 5400 Pacific Avenue, Stockton, CA Site Code 2163 ' chilled until delivered to the laboratory for analytical testing All samples were logged on a chain of custody record form (see Appendix B) ' Ground water samples for analytical testing were collected by Unocal's consultant from Unocal wells MW-10 through MW-17 (see Figure 2) MPDS Services, Inc will submit a separate report documenting its work at the Unocal site during this quarter ' 2 3 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 tap water ' 2 4 EFFLUENT HANDLING All effluent generated during purging, sampling and equipment decontamination activities was ' sealed in labeled 55-gallon drums The drums were stored in a secured area on the Montgomery Ward site pending proper disposal 3.0 ANALYTICAL TESTING The samples were delivered for analytical testing to BC Analytical (BCA), a state certified hazardous waste testing laboratory (Certificate No 1353) BCA is certified for all tests completed as part of this investigation The samples were tested for halogenated volatile I organic compounds using EPA Method 8010, benzene, toluene, ethylbenzene, xylenes (BTEX) and methyl tertiary butyl ether (MTBE) using EPA Method 8020, and total petroleum hydrocarbons as gasoline (TPH-G) using modified EPA Method 8015 The results of the ' testing are shown on Table 2 and in Figure 3 The laboratory reports are contained in Appendix B I Figure 3 also contains analytical data provided to EAI by MPDS Services, Inc for the testing results associated with samples collected from Unocal site wells on June 19, 1996 4.0 DISCUSSION The current gauging dais i aicate that the ground water elevations in th ce wells have dropped on average approximately 1 feet as compared to the previous quarter's measurements (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 southwester) at a hydraulic gradient of approximately 0008�,foot/foot (see Figure 2) The grown water flow direction for previous quarters for which data are available is as follows I Project No 1232 - 2 - ENVIRONMENTAL.AUDIT, INC