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August IG, 1945 Page-2- approximately bapproximately 6 to 11 feet bgs and approximately 6 feet wide was present on the north sidewall. • The stained soil was not removed due to the likelihood of structural damage to the building canopy located immediately north of the over-excavation. Laboratory analyses of the soil sample collected from the north sidewall of Pit 1 at a depth of 10 feet bgs detected toluene, ethyl benzene and xylene in concentrations ranging from 3,200,ug/kg to 65,000µg/kg. Gasoline was detected at a concentration of 1,400 mg/kg and ethylene dibromide was detected at a concentration of 5 3µg/kg No evidence of hydrocarbon contamination was detected at or Iabove the reported laboratory detection limits in the sample collected from the floor of the over-excavation at 17 feet bgs. No evidence of hydrocarbon contamination was detected in the sample collected from the south sidewall at 14.5 bgs or samples collected from the east and west sidewalls at 11 feet bgs. Field observations indicated a light brown, indurated silt with gray mottling was present from 6 feet to 11 feet bgs along the north sidewall of Pit 1. The total depth of the over-excavation was approximately 17 feet bgs. 3.0 SOIL INVESTIGATION IFive angle soil borings were drilled at the site to assess the lateral and vertical extent of petroleum contamination to the north of Pit 1. The soil boring locations are shown on Figure 3, Appendix A. Prior to drilling, the Underground Service Alert (USA) was notified to locate known underground utilities at the site. The soil bonngs were drilled by B and F Drilling of Rancho Cordova, California (C57 License #519428). The boreholes were drilled using 6-loch O.D., hollow-stem, continuous-fhght augers. Prior to use, the augers were steamed cleaned and all sampling equipment was washed in a solution of non-phosphate detergent and laboratory grade, hydrocarbon-free water and triple rinsed in hydrocarbon-free water. SB1 was oriented N60E and drilled at an angle of approximately 40 from horizontal. SB2 was oriented N90W and drilled at an angle of approximately 60 from horizontal. SB3 through SB5 were oriented N90W and drilled at an angle of approximately 80 from horizontal. SB1 was terminated at a total vertical depth of approximately 13.5 feet bgs. SB2 through SB5 were terminated at a total vertical depth of approximately 15.5 feet bgs. 4.0 SAMPLE COLLECTION & FIELD OBSERVATIONS Soil samples were collected from SB1 at vertical depths of 10 feet and 13 feet bgs. Soil samples were collected from SB2 through SB5 at vertical intervals of approximately five feet The soil samples were collected using a California-modified, split-spoon sampler fitted with three clean brass tubes. Due to the angle at wluch the borings were drilled, the split-spoon was hydraulically pushed, rather than pounded, ahead of the augers during sample collection. The ' upper-most tube was discarded and the middle sample tube was retained for geologic logging Ntip� ' �� CONDOR