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WN <br /> • 'fake water samples from the primary supply well and backup supply <br /> well. at the site. These water samples were analyzed for volatile <br /> organic compounds plus ethylene dibromide by EPA Methods 601 and <br /> 602, and total volatile hydrocarbons by Modified EPA Method 8015. <br /> A total of ten groundwater monitoring bells and five soil borings were <br /> completed during the Sebastiani Vineyards site assessment investigation. <br /> SOIL AND GROUNDWATER SAMPLING <br /> Soil and groundwater sampling procedures, analytical methods, monitor well <br /> construction details and analytical service providers are presented in <br /> this section. Soil boring and monitor well drilling logs are presented <br /> in Appendix II, The locations of the soil borings and monitor wells are <br /> shown in Figure 3, <br /> Soil SamRiint <br /> Monitor wells MW-1 through -8 and soil borings SB-1 through -5 were <br /> drilled from May 15 to 26, 1989. Monitor wells MW-9 and -10 were drilled <br /> on June 1 and 2, 1989. Drilling services were provided by Beylik Drilling <br /> Company, Inc. Monitor wells MW-1 through -8 and SB-1 through -5 were <br /> drilled with an Ingersol-Rand TH-10, hollow stem auger drill rig. Monitor <br /> wells M6'-9 and -10 were drilled with a Mobile Drill B-61, hollow stem <br /> auger drill rig. Monitor well MW-1 was initially drilled with 6 5/8-inch <br /> outside diameter (O.D.) hollow stem augers to a total depth of 41 feet <br /> - below ground surface. The bottom seven feet of this pilot hole were <br /> backfilled with pelletized sodium bentonite and the remaining 34 feet of <br /> mom borehole was enlarged by redrilling with 11 7/8-inch O.D. hollow stem <br /> augers to allow for construction of a four inch diameter well. Monitor <br /> i wells MW-2 through -10 and soil borings SB-1 through -5 were drilled with <br /> 6 5/8-inch O.D. hollow stem augers. Monitor wells MW-1, -2, and -3 were <br /> drilled to a total depth of 41 feet below ground surface. Monitor wells <br /> MW-5 through -8 were drilled to 40 feet below ground surface, and monitor <br /> wells MW-4, -9, and -10 were drilled to approximately 30 feet below ground <br /> surface. Soil borings SB-1 through -5 were drilled to 17.5 feet below <br /> - ground surface. Materials encountered in each well and soil boring were <br /> logged in accordance with the Unified Soil Classification System and <br /> inspected for indication of petro eum yrocarbon contamination. <br /> Undisturbed soil samples were collected at five-foot intervals and at the <br /> soil/groundwater interface from each boring using a 2-inch O.D. modified <br /> California split spoon sampler lined with clean, brass sample sleeves. <br /> The split spoon sampler was driven ahead of the lead auger with a standard <br /> 140-pound drive hammer, free falling 30 inches. Blow counts were taken <br /> for each 6-inch driving interval. The brass sample sleeves containing the <br /> Soil samples were each fitted with aluminum foil end pieces and plastic <br /> end caps secured with tape. All soil samples were immediately placed on <br /> ice in a thermally insulated chest. Selected soil samples were labeled <br /> and delivered under chain-of-custody to Weston Analytical Laboratory of <br /> Stockton, California for total petroleum hydrocarbon as gasoline (TPH-G) <br /> and aromatic volatile organics (VOA) analyses using EPA Methods 8015 <br />