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3.4 Installation of Groundwater Monitoring Well Groundwater monitoring well MW-12 was constructed using 2-mch ID flush-threaded, Schedule 40 PVC blank and slotted casing A threaded end-cap was placed at the bottom of the PVC slotted casing which was then set through the auger The screened portion of the well utilized 5 feet of ' 0 01-inch machine-cut slotted casing Number 2 sand was poured down the auger while removing approximately 3 feet of auger at a time The filter pack was placed to a height of 4 feet above the screened interval, 3 feet of bentonite pellets were added, and bentonite cement was poured through ' the auger to form an annular seal to a depth of 1-foot bgs The well was set inside a previously installed traffic-rated well cover box The well box was set in concrete, approximately 1/z-inch above grade, to prevent entry of surface runoff waters ' 3.5 Soil Analyses ' Selected soil samples were analyzed by a California State-certified laboratory (American Analytics, Inc , of Chatsworth, California) in accordance with the methods outlined in "Test Methods for Evaluating Solid Waste-Physical/Chemical Methods, SW-846, Third Edition," Environmental ' Protection Agency (EPA), July 1992 Selected soil samples were analyzed for TPH, BTEX, and MTBE using EPA Methods 8015M (modified for gasoline) and 8020, respectively Soil samples containing detectable concentrations of MTBE were additionally analyzed for MTBE and other fuel oxygenates using EPA Method 8260 3.6 Groundwater Sampling Each monitoring well was purged with a downhole electric pump (Grundfos) until values of temperature, conductivity, and pH stabilized, and a minimum of three (3) well casing volumes of groundwater were removed The wells were allowed to stand for a sufficient period of time to equilibrate to within 80%of static groundwater level, prior to sample collection Well purge data is ' included as Appendix F Groundwater samples were collected using a new, unused, disposable bailer, and placed in the appropriate laboratory-supplied containers The samples were labeled with the date, time, identifying well number, sample name, and project name The groundwater samples ' were placed in an ice-chilled cooler and transported to a laboratory under proper chain-of-custody documentation ' 3.7 Groundwater Analyses Analysis of the groundwater samples was performed by American Analytics in accordance with State guidelines and EPA protocol The groundwater samples were analyzed for TPH, BTEX, and MTBE using EPA Methods 8015M(modified for gasoline) and 8020, respectively MTBE concentrations were confirmed by EPA Method 8260 1 A.11528Ji ASA 8 1