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� 6.0 CONCLUSIONS t The following conclusions and recommendations are based on the observations and i. analytical data collected to date. Site, soil and ground water conditions not discovered or currently known may cause a change in the opinions presented in this report. La Laboratory analysis of ground water samples indicates the presence of significant levels of gasoline and gasoline constituents in water collected from monitoring wells MW-1 and L. MW-6. These data are consistent with previous sampling event data. Laboratory results indicate that the concentration of dissolved lead and chromium are 4.0 below the MCL's for all ground water samples analyzed. 7.0 RECOMMENDATIONS +� The lateral and vertical extent of gasoline contaminated soil and ground water have not been defined to date. Additional soil and ground water investigation is required at this site to fully define the limits of contamination. AGS recommends that a work plan be prepared to address the definition of the contaminant boundaries, and to investigate possible remediation alternatives. The San Joaquin Public Health Services has requested that this work plan be prepared and submitted to their office by September 15, 1995. Because total dissolved lead and chromium are below the MCL's, AGS recommends eliminating lead and chromium analyses from subsequent quarterly sampling events. Water samples were not collected from the two supply wells located on the site. Samples L. were previously collected from the supply well pressure tank and indicated non detectable levels of BTEX. Sample taps have not been installed near the well heads to allow for more representative sampling. AGS recommends that spigots be installed near each well �. head prior to the collection of new samples from these wells. In a letter to Remcor, dated April 4, 1995, the San Joaquin Public Health Services L• requested that slug test data collected from MW-6 be provided, and that the methodology employed be described in an addendum to their PIER. In discussions with AGS, Remcor disclosed that the slug test consisted of removing approximately one liter of water from the well and monitoring the rate of change of the water level within the well. It is the opinion of AGS that the data obtained by removing such a small volume of water yields unreliable aquifer characteristic information. Therefore, AGS recommends that Lo American Geological Services, Inc. CA95DE-029 Lo 11