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Discussion <br /> In addition to the quarterly sampling investigation at 'this site, <br /> ground water of the recently installed MW8 is sampled for the <br /> first time. MW8 was installed on February 8, 1993 to a depth of <br /> 60 feet . This 2" PVC well (see Appendix C, Limited Drilling <br /> Report) was placed 8' of the tank field. The drilling of this <br /> well occurred because of a need to comply with the September 30, <br /> 1992 San Joaquin County PHS/EHD letter which stated that a need <br /> exists for a monitoring point in the area of the underground <br /> storage tanks; monitoring wells, S1 and S2 are dry and are <br /> currently not able to monitor the quality of the ground water in <br /> this area. <br /> The added monitor well (MW8) gives further ground water quality <br /> control to this site . S1 and S2 may indicate ground water in <br /> their wells at a later date due to the present recharge to the <br /> aquifer,. currently these wells are dry. MW8 confirms the ground <br /> water flow direction of previous sampling intervals, but shows a <br /> local deflection to the ground water near this well,. see Figure <br /> 4B. This may reflect lithologies not expressed or recognized in <br /> soil samples from drilling of this well . For instance, clay or <br /> silt lenses within the aquifer or a highly permeable aquifer sand <br /> recognized in other wells on site but lacking in MW8 at the <br /> current ground water depth; this may explain why the recharge in <br /> this particular well is a lot slower than other wells at this <br /> site, see Field Notes in Appendix D. <br /> On March 16, 1993 USA Petroleum requested semi-annual ground <br /> water sampling at this site, Appendix A contains the April 16, <br /> 1993 response from San Joaquin County PHS/EHD. This letter <br /> indicated that ground water gauging should occur for all wells on <br /> a quarterly basis, Monitoring wells #1, #2 , #5 and #7 can be <br /> sampled semi-annually. The remaining wells, MW3 , MW4 , MW6 and <br /> MW8 will be sampled quarterly; these wells will be sampled on the <br /> next scheduled quarterly monitoring round. <br /> CONCLUSIONS <br /> 1 . 7 wells sampled, MW1, MW2 , MW3 , MW4, MW5, MW6 and MW7, <br /> showed no detectable levels of, contamination. <br /> 2 . MW8 indicated low levels of Total Fuel Hydrocarbons a <br /> gasoline of .21 ppm and Benzene of 450 ppb. <br /> 3 . The ground water flow direction is presently in a south, <br /> southeasterly direction. <br /> 4 . S1 and S2 were not sampled, these wells were dry. <br /> 6 <br /> 3 <br />