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I'VerafflarINC SACRAMENTO Letter to Mr. Ulycess Williams May 16, 1989 Page 3 The three borehole locations were selected based on previously obtained information as well as a visual inspection of the site. The three boreholes were drilled with a truck -mounted CME -55 drilling rig, using eight -inch outside diameter hollow -stem augers. Soil samples were obtained using a California modified split -spoon sampler with all sampling equipment and containers decontaminated using EPA and California accepted protocols. Five soil samples from depths of five, 10, 15, 20, and 25 feet were taken in each borehole. The brass sample containers were covered with foil and plastic end caps and sealed with duct tape. The samples were stored on ice under Versar's chain of custody. Soil samples from each interval were tested by headspace analysis using an OVA. All headspace readings were zero. The soil profile at 2400 Airport Way was consistent at all borehole locations with only minor variations. The soil profile consists of light to dark brown clay which is locally silty or sandy. In boreholes BH -2 and BH -3 at approximately 24 feet below the surface is a thin Tense of light brown, fine to medium grained sand, underlain by clay similar to the clay encountered above it. At no time was any discolored soil observed, hydrocarbon odor noted, or instrument reading made which indicated possible hydrocarbon contamination The geologic interpretive logs are included in Attachment IV. A total of 15 soil samples were collected during the investigation. Three samples, BH1-20, BH2-20, and BH3-20 were selected for chemical analyses for total petroleum hydrocarbons (TPH) by EPA Method 5030, and benzene, toluene, ethylbenzene, and xylenes (BTEX) by EPA Method 8020. The preserved samples were transported under the chain of custody to Trace Analysis Laboratory, an EPA and State of California certified laboratory. Laboratory Analytical Results Results from the laboratory analyses of soil samples BH1-20 and BH3- 20 did not indicate any TPH or BTEX above the detection limits. In sample BH2-20 the analyses identified 350 micrograms per kilogram (ug/kg) of TPH as gasoline and 83 ug/kg of benzene while all other components were below the detection limit. Micrograms per kilogram are approximately equal to parts per billion (ppb). The analytical results are summarized in Table 1, and included with the chain of custody as Attachment V. Discussion IDPetroleum during field hydrocarbon contamination was not visibly identified investigation activities at 2400 Airport Way in Stockton.