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Morita Brothers Service Station 13 November 6, 1992 <br /> 1 i k <br /> ' Drilling for all hormgs was accomplished using a truck mounted CMETm 55 drill rig <br /> utilizing 10-inch outside diameter hollow-stem augers The borings were drilled to a <br /> maximum depth of approximately 10 feet below the first encountered groundwater, <br /> ' or 65 feet below surface grade The regional unconfined aquifer had been <br /> anticipated to be encountered at a depth greater than 60 feet below surface grade <br /> However, a perched groundwater zone was encountered at a depth of 57 feet below <br /> surface grade The underlying aquitard was encountered at 61 feet below surface <br />' grade Therefore, the wells were terminated at a depth of 65 feet below surtace grade <br /> without penetrating the underlying regional aquifer <br /> Soil sampling was performed, while drilling the borings, at a five foot interval <br /> beginning at 5 feet below grade to the designed termination depth Soil sampling was <br />' accomplished using a split-spoon sampler (ASTM D 3550 with shoe similar to ASTM D <br /> 1586) equipped with three 6-inch by 2 5-inch diameter brass sleeves for soil <br /> retention The soil samples were obtained by driving the sampler with a one <br /> hundred and forty pound hammer dropping thirty inches in accordance with ASTM D <br />' 1586 <br /> The lowermost sleeve at each sample interval (corresponding to approximately 6 <br /> inches below the actual sample interval) was screened for total organic vapors with a <br /> portable photo-ionization detector (PID) Headspace vapor analysis was performed by <br /> first discarding a portion of the soil retained at one end of the sleeve to produce a <br /> headspace The sleeve was then capped and the probe of the PID inserted through a <br /> hole in the cap and into the headspace tot analysis The PID readings were recorded <br /> on the boring logs The uppermost sleeve was observed for lithology <br /> 1 The middle sample sleeve of the sampler was immediately sealed with Teflon T`y` film, <br /> capped, labeled, and placed on ic,e at 40C for transport to a California Department of <br /> Health Services (DHS) certified laboratory Strict chain-of-custody procedures were <br /> utilized for all samples collected to ensure sample integrity and to document sample <br /> possession from the time of collection to the final destination Based on field <br /> EB-8101-3 9210-E055 RPT <br />■ <br />