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RKSMA Working To Restore Nature Additional Subsurface Soil Characterization On November 16, 1993, RESNA advanced three hand augured borings in the northern vicinity of the underground gasoline product line as depicted on Figure 2. Two soil borings (SBI, SB2) were located within the existing concrete walkway and one boring (SB3) was located within the concrete floor of the prisoner bay entrance. Soil borings SBI and SB2 were advanced to approximate depths of 10 and 11 feet below grade, respectively. Boring SB3 was advanced to a depth of approximately 8.5 feet below rade where auger refusal was encountered. Groundwater was not encountered during drilling activities. Soil Sampling Six soil samples (two from each boring) were collected at various depths (Table 1) utilizing a drive sampler with a six-inch brass sleeve insert. Collected samples were sealed at each end with Teflon sheets and plastic end caps, and placed on ice. Soils were field screened with a photoionization detection meter (PID) and logged by an experienced geologist. The samples were submitted to Sequoia Analytical Laboratory and analyzed for benzene, toluene, ethylbenzene, and xylenes (BTEX), total petroleum hydrocarbons as gasoline (TPHg), and total petroleum hydrocarbons diesel (TPHd) using appropriate EPA methodologies. Analytical results for soils are summarized in Table 1. Drill cuttings produced during the recent site activities were stockpiled at the City Corporation Yard with previously excavated materials. SOIL CHARACTERIZATION Soils encountered beneath the site consist predominately of sand to depths of 2.5 - 3 feet below ground surface and clay from 2.5 - 3 feet to 11.5 feet below ground surface, the maximum depth explored during this investigation. No hydrocarbon impacted soils were obvious in soil borings SBI and SB3 during field activities. However, a petroleum odor in boring SB2 was observed from approximately 3 to S feet below grade exhibiting a maximum PID measurement of 1,250 parts per million (ppm). Soil boring logs are included in Attac ment Laboratory analytical results indicate "TPHd" was present in one or more soil samples collected from borings SB1 and SB2. However, TPHd chromatogram patterns for the samples collected from soil boring SBl (SP-SBI-6' and SP-SBI-10') were reported as displaying a non-diesel mix and discrete peaks indicating a longer chain hydrocarbon other than diesel with a semi-volatile compound. The TPHd chromatogram pattern for the sample collected at 5 feet below grade in soil boring SB2 (SP-SB2-5'), reported as a non-diesel mix, exhibited petroleum hydrocarbons in the gasoline range and the reported TPHd value can be attributed as such. 0W014MRepoM\LR-20294.FNL 3