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AZ��� <br /> Working To Restore Nature <br /> Additional Subsurface Soil Characterization <br /> On November 16, 1993, RESNA advanced three hand augured borings in the northern vicinity <br /> of the underground gasoline product line as depicted on Figure 2 Two soil borings (SBI, SB2) <br /> were located within the existing concrete walkway and one boring (SB3) was located within the <br /> concrete floor of the prisoner bay entrance Soil bonngs SBI and SB2 were advanced to <br /> approximate depths of 10 and II feet below grade, respectively Boring SB3 was advanced to <br /> a depth of approximately 8 5 feet below grade where auger refusal was encountered <br /> Groundwater was not encountered during drilling activities <br /> Soil Sampling <br /> Six soil samples (two from each boring) were collected at various depths (Table 1) utilizing a <br /> drive sampler with a six-inch brass sleeve insert Collected samples were sealed at each end <br /> with Teflon sheets and plastic end caps, and placed on ice Soils were field screened with a <br /> photoionization detection meter (PID) and logged by an experienced geologist <br /> The samples were submitted to Sequoia Analytical Laboratory and analyzed for benzene, <br /> toluene, ethylbenzene, and xylenes (BTEX), total petroleum hydrocarbons as gasoline (TPHg), <br /> and total petroleum hydrocarbons diesel (TPHd) using appropriate EPA methodologies <br /> Analytical results for soils are summarized in Table 1 <br /> Drill cuttings produced during the recent site activities were stockpiled at the City Corporation <br /> Yard with previously excavated materials <br /> SOIL CHARACTERIZATION <br /> Soils encountered beneath the site consist predominately of sand to depths of 2 5 - 3 feet below <br /> ground surface and clay from 2 5 - 3 feet to 11 5 feet below ground surface, the maximum depth <br /> explored during this investigation No hydrocarbon impacted soils were obvious in soil bonngs <br /> SBI and SB3 during field activities However, a petroleum odor in boring SB2 was observed <br /> from approximately 3 to 8 feet below grade exhibiting a maximum PID measurement of 1,250 <br /> parts per million (ppm) Soil boring logs are included in Attachment 1 <br /> Laboratory analytical results indicate "TPHd" was present in one or more soil samples collected <br /> from bonngs SBI and SB2 However, TPHd chromatogram patterns for the samples collected <br /> from soil boring SB1 (SP-SBI-6' and SP-SBI-10') were reported as displaying a non-diesel mix <br /> and discrete peaks indicating a longer chain hydrocarbon other than diesel with a semi-volatile <br /> compound The TPHd chromatogram pattern for the sample collected at 5 feet below grade in _ - - <br /> soil boring SB2 (SP-SB2-5'), reported as a non-diesel mix, exhibited petroleum hydrocarbons <br /> in the gasoline range and the reported TPHd value can be attributed as such <br /> 0W014Mepods\LR-20294 FNL 3 <br />