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�&►f Wu` <br /> Working To Restore Nature <br /> photoionization detector (PID)was used as a screening device for petroleum hydrocarbon vapors <br /> in drill cuttings and cored samples. <br /> Samples were collected, preserved and transported under chain-of-custody protocol to Sequoia <br /> Analytical in Redwood City, California (cert. no. 1210). Two soil samples were selected from <br /> each boring, based upon field observation, for analysis of BTEX and TPHd by EPA methods <br /> 8020 and modified 8015, respectively. <br /> x_ 4.3 Monitoring Well Installation and Sampling <br /> Groundwater was encountered at a depth of approximately 15 feet below grade. Monitoring <br /> wells MW-5 and MW-6 were constructed of 4-inch diameter F480 threaded polyvinyl chloride <br /> (PVC) screen and casing and installed to approximately 30 feet below grade. No glues or <br /> solvents were used. The wells were screened between approximately 10 and 30 feet below grade <br /> with 0.010-inch slotted casing. A filter pack of RMC Lonestar #2/12 silica sand was used to <br /> fill the annulus of the borehole to approximately two feet above the screened interval. A <br /> minimum two foot thick bentonite annular seal was set directly above the sandpack prior to <br /> k1 grouting with neat cement. A water-tight, locking cap was placed on each casing and a water- <br /> __ tight wellbox was concreted over each well. Well logs showing construction details are <br /> =' presented in Appendix IV. <br /> Subsequent to completion, all wellheads were surveyed to a common arbitrary datum of three <br /> feet above mean sea level (MSL) as determined by the United States Geological Survey's <br /> Stockton West Quadrangle. Static groundwater levels were monitored. The wellhead survey <br /> and groundwater monitoring data are presented in Table 4. The elevation of groundwater in ; <br /> `-' well MW-4 was adjusted for the presence of free product (1.89 feet). <br /> Subsequent to the installation and development of monitoring wells MW-5 and MW-6, water <br /> samples were collected from all site monitoring wells after purging a minimum of five casing <br /> volumes of water from each well. The development/purge logs are presented in Appendix V. <br /> REPORTS/PAR1093.FNL 5 <br /> `I <br /> �r.i <br />