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r. <br /> 275 Grantline Rd, Page 5 of 7 <br /> This strata is underlain by approximately 4 feet of <br /> light to dark tan and brown, damp, slightly plastic clay; <br /> below this interval lies a moist gray-tan and tan-brown very <br /> fine-grained clayey sand. <br /> 2 . Groundwater was encountered at a depth of 10.5 feet below <br /> surface grade in a tan-brown, very fine-grained clayey sand. <br /> This zone is assumed to be the top of the water shallow water <br /> table. The water level stabilized to a depth of 8.5 feet 5 <br /> hours after it was first encountered. <br /> 3. Petroleum hydrocarbons as oil and grease were detected in the <br /> excavated soils in the area of the removed waste oil tank. <br /> This contamination was observed as dark grayish-green <br /> staining: <br /> 4. Petroleum hydrocarbons as gasoline were detected in one soil <br /> sample (SS-12) taken from the product line portion of the <br /> site. These analytical results indicate concentrations of TPH <br /> (as gasoline) below Corrective Action Levels (CAL) established <br /> by the dater Quality Control Board. <br /> �. 5. BTEX was detected in one shallow soil sample (SS--12) and is <br /> also below the CAL for BTEX. <br /> b. Oil and Grease was not detected in soil samples taken from <br /> the excavation area. <br /> 7. Analytical results of the pit water sample indicate <br /> concentrations of TPH (as gasoline), BTEX, 1,2-Dichloroethane, <br /> and oil and grease above CAL' for groundwater.. <br /> CONCLUSIONS <br /> I. ` Based on the geological field data and analytical results it <br /> appears that the vadose zone (saturated zone) has been <br /> impacted by hydrocarbon contamination as oil and grease. <br /> i .. This _hydrocarbon- contamination--is-most-likely-dui to leakage :- <br /> from the removed waste .oil tank. <br /> 3 The extent- of the groundwater contamination outward from the <br /> tank area is unknown at the present time. <br /> 4. Further sampling of.the groundwater and a detailed groundwater <br /> gradient map is needed to define .che limits and direction of <br /> the contaminant plume. This will also aid in the design of <br /> future groundwater remediation, if' it. is required. <br /> ~-� 5. There does appear to be. any hydrocarbon contamination in the <br /> product dispenser (pump island) area or below the product . <br />