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} <br /> �1 <br /> AHR <br /> Working to Restore Nature <br /> June 1993 Quarterly Groundwater Sampling & Analysis August 16, 1993 <br /> Quik Stop Market No. 132, Stockton, California F7132.93 <br /> Quarterly Well Pumping <br /> As agreed upon`with' the`�Sari Jbaguin_"County- _ublic-Health.-Services-(SJCP-HS} (see Site <br /> `BackgroundmAppendix A} monitoring--'e'll-NTW"�S i9_0umped out..onra.quarteriy-basis,as_an <br /> i-eerimjt­'medial`"measure. `This quarter pumping was conducted on Ma 93. Prior <br /> to pumping a groundwater sample was obtained from the well and labeleMW- The well <br /> was then pumped for about three hours and approximately G515=galto s-.o . water was <br /> removed from the wel pumping was complete, another groundwater sample was <br /> collected and labele �-IB. f _Saa <br /> P'11'f <br /> fPll <br /> Groundwater.Sampling /Y)it) lot W <br /> le <br /> Wler <br /> Groundwater samples were collected on June 18, 1993 from five of the seven monitoring <br /> wells in accordance with RESNA's groundwater sampling protocol (Appendix B). In <br /> November 1992, the SJCPHS approved semi-annual of sampling for monitoring wells MW-3 <br /> and MW-4 (SJCPHS, November 17, 1992) and in February 1993 they approved <br /> discontinuation of sampling for these wells (Personal Communications, February 2, 1993). <br /> Groundwater purged from the wells and equipment deco i in <br /> a licen r-mounted container and disposed of a Gibson tvironmen7tal,,alicensed <br /> recycling facility, a volume of groundwater removed from each we an oeasure <br /> same ing parameters are noted on the groundwater sampling field log included in <br /> Appendix C. <br /> Laboratory Analyses <br /> The groundwater samples were transported to Sequoia Analytical, a state-certified <br /> laboratory, located in Redwood City, California. Samples were analyzed for the presence <br /> of TPHG following modified Environmental Protection Agency (EPA) Method 8015 and <br /> for BTEX following EPA Method 8020/602. The laboratory analytical report and chain-of- <br /> custody record are attached in Appendix D. <br /> Summary of Results and Discussion <br /> A summary of the analytical results from current and past well samplings is presented in <br /> Table 1. Plates 2 and 3 show the groundwater elevation contour maps for the upper and <br /> lower aquifers, respectively, based on the water level data in Table 1. In the local upper <br /> aquifer, the groundwater levels in wells MW-5 and MW-7 rose an average of 0.56 feet while <br /> in MW-6 it rose 0.80 feet. In the local lower aquifer, the groundwater levels in wells MW-2, <br /> MW-3 and MW-4 rose an average of 0.77 feet and in MW-1R it rose 3.01 feet. The <br /> apparent groundwater flow direction in the local upper aquifer is southerly at a gradient of <br /> 2 <br />