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GROUNDWATER MONITORING REPORT USA PETROLEUM - STOCKTON#110 OCTOBER, 1995 ' 2.2 Monitoring Well Purging Each monitoring well was purged by pumping at least three well volumes of water from each well (MW-1-P, MW-2-P and MW-3-P) Temperature, pH and conductivity were monitored while the wells were being purged Data was recorded on field data sheets The wells were allowed to recharge to at-least 90% of their initial static water level prior to sampling Groundwater purged I from the wells was placed into appropriately labeled DOT approved 55-gallon drums The purge water will be disposed of appropriately after the analytical results are reviewed Disposal of the purge water is the responsibility of the client A summary of field data is presented in Table 2, and copies of the field data sheets are included in Appendix A 2.3 Groundwater Sampling Each groundwater sample was collected using a new Teflon disposable bailer The sampled water was placed into laboratory prepared sterile 40 milliliter glass,one liter plastic, and one quart amber containers The sample containers were filled to the top to eliminate air space and were sealed with Teflon-lined caps Water sample containers were labeled with the name of the sampler, the date, the job number, the preservative, and an identifying number The samples were then transported to Sierra Laboratories (Sierra), in Anaheim, California, a state certified laboratory Full chain-of-custody (COC)protocol was followed during sample handling and ' delivery 2.4 Groundwater Analyses Analyses of the groundwater samples were performed by Sierra in accordance with state guidelines and EPA protocol The samples were analyzed for TPH G,TPH D, BTEX, and total ' lead using EPA Methods 8015M, 8020 and 239 2 ,respectively 5 ' 3.0 SUMMARY AND CONCLUSIONS 3.1 Results of Groundwater Laboratory Analyses ' Detectable levels of TPH G were reported in monitoring wells MW-1-P, MW-2-P and MW-3-P at 81, 1,700 and 670 parts per billion (ppb),respectively TPH D was non-detect in all wells BTEX compounds were present at various concentrations ranging from non-detect to a high of 98 ppb for benzene in MW-2-P No detected levels total lead were reported in any of the wells Analytical results are summarized in Table 3 Groundwater laboratoryresults for September, 1992, September, 1993, March, August, and P December, 1994, and March, 1995 are also summarized in Table 3 Certified laboratory reports and COC documents for the most recent sampling event are included in Appendix B 2