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I <br /> _ <br /> A minor amount of additional over-excavation was conducted on January 7 and 11 , <br /> 1993 to remove soil determined to contain elevated levels of TPH-G from the west <br /> and southwest sides of,the UST excavation Additional confirmation soil samples <br /> were obtained from the excavation and submitted to Chromalab, Inc , a state of <br /> California-certified laboratory in San Ramon, California The maximum depth of the <br /> excavation was approximately 12 feet below the ground surface (bgs) in the <br /> immediate area around the former US_Ts and the southeast quarter of the excavation <br /> The-depth to groundwater during the excavation activities was approximately 9'5 feet w" <br /> bgs <br /> Figure 3, Soil Sample Location Map, illustrates the final extent of the excavation <br /> around the former USTs Field observations and PID measurements of the soils as <br /> they were being removed from the excavation were used to identify areas containing <br /> residual hydrocarbons Confirmation soil samples were then obtained from these <br /> areas with a hand operated core sampler for laboratory analysis The analytical results <br /> of the confirmation sampies obtained from the excavation are presented in Table 2 <br /> (samples SW-2, SW-4, SW-5, SW-9 through SW-11 , PS-1 , and PS-2) The final <br /> confirmation soil samples listed in Table 2 are presented in the shaded rows and in <br /> - - -� - bold-type�The-other=sampies=were=from=areas=that=were=removed-during=further=- <br /> -- ----- —excavation�Based�on-the-field-obser-vations=and-the results=of--the-confirmation-soil.--._ <br /> -sample results;-the=majority of-the-hydrocarbon-affected-soil-above-the water-table- <br /> was <br /> ater table was removed In addition, the heavily affected soil to approximately 2 to 3 feet below <br /> the water table was also removed during the excavation ' <br /> The groundwater present in the UST excavation contained a partial hydrocarbon sheen <br /> on its surface Therefore, immediately prior to the backfilling of the excavation <br /> approximately 1 ,320 gallons of groundwater were pumped out of the pit While <br /> pumping water out of the excavation, a device was used which allowed the sheen to <br /> be skimmed off the surface of the water The water was pumped directly into two <br /> f' <br /> /! i te#hauser <br /> C O A P O a s f i U <br /> P2168RO06 wP{63794) 4 <br />