ARCHIVED REPORTS_XR0007980 - Laserfiche WebLink

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' QUARTERLY GROUND WATER MONITORING Site Code 2163 Montgomery Ward Auto Service Center 5400 Pacific Avenue, Stockton CA 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 s The Equipment was flushed with tap water ' 24 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, a state certified hazardous waste testing laboratory (Certificate No 1353) The samples were tested for halogenated volatile organic compounds (HVOCs) using EPA Method 8010, benzene, toluene, xylenes and ethylbenzene (BTEX) 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 C I 4.0 DISCUSSION The current gauging data indicate that the ground water elevations in the wells have dropped on average approximately 2 5 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 west-southwesterly (i e , approximately S60°E) at a hydraulic gradient of approximately 0 006 I feet/foot (see Figure 2) This represents a change from the previous quarterly monitoring periods where the direction of ground water flow was reported to be southeasterly The data also show that the general direction of ground water flow at the former Unocal branded station, at the time of measurement, was predominantly southwesterly (see Figure 2) I 5.0 FUTURE SITE ACTIVITIES ■ IThe fourth quarter (October through December) ground water monitoring for the Site will be conducted in December 1995 Project No 1232 2 ENVIRONMENTAL AUDIT, INC