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BOREHOLE DRILLING, WELL CONSTRUCTION, DEVELOPMENT AND SAMPLING PROCEDURES Borehole Drilling and Sampling Boreholes will be drilled by a California licensed water well driller, using a truck-mounted drilling rig equipped with nominal 8- or 10-inch outside-diameter hollow-stem augers. Prior to drilling, each borehole location will be hand augered to a depth of approximately 5 feet below ground surface to check for underground utilities. Soil samples will be collected for lithologic determination by continuous coring the boring or sampling at 5-foot intervals during the drilling process. Samples will be collected to the total depth of the boring. Borehole depths will be based on site conditions, including but not limited to depth to water, topography, and depth to bedrock. Soil cuttings generated during the drilling procedures will be placed on visqueen and covered with visqueen at the end of the day, or placed in steel 55-gallon drums. At the end of the drilling and sampling operations, each borehole will be completed as a groundwater monitoring well. Soil samples will be collected throughout the investigation for Gthologic classification and chemical analysis. One boring will be continuously cored to total depth and the remaining borings will be sampled at five foot intervals using a California modified split-spoon sampling device. The soil core and discrete samples will be examined in the field and classified according the Unified Soil Classification System. In addition, the soil core and samples will also be screened in the field with a photoionization detector (PID), or similar instrument, for the presence of volatile organic compounds (VOCs). The relative permeability of the soil will be qualitatively estimated, and the Ethology, PID reading, and estimated permeability of each sample interval will be recorded on the borehole log next to the depth interval from which the sample was obtained. Soil samples for potential laboratory chemical analysis will be collected from the capillary fringe zone near the bottom of each boring. The samples will be obtained using a 2-inch-diameter by 18-inch-long split-spoon sampler lined with three 6-inch-long thin-walled brass tubes. The sampler will be driven its entire length into undisturbed soil, using a 140-pound drop hammer. When the sampler is extracted from the borehole, the brass tubes will be removed and the ends of the tubes will immediately be screened for the presence of VOCs with a PID or equivalent instrument. The brass tube having the highest PID reading will be selected for possible chemical analysis. The ends of the selected brass tube will be: (1) covered with aluminum foil and plastic caps, which will then be taped with plastic tape to provide an air-tight seal; (2) labeled and placed into re-sealable plastic bags; and (3) stored in a ice chest containing crushed ice for delivery to the analytical laboratory. These procedures minimize the potential for cross contamination and volatilization of volatile organic compounds prior to chemical analysis. The remaining soil will be extracted from the tubes and logged as previously described. It is EA2092\pha ffiwoftl .dm