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3.2 Sampling Aerated Soil <br /> To mitigate any physical hazards associated with the open tank pit and to prevent damage to the <br /> adjacent building, soils excavated in 1989 were backfilled into the open tank pit The excavated <br /> ' soils had been stockpiled on site and subsequently aerated <br /> Prior to backfilling, one 4 to 1 composite sample was collected for approximately every 50 yards <br /> of soil (as shown on Figure 3) A total of 4 composite samples were collected by driving 6' <br /> brass cylinders into undisturbed soil Collected samples were labelled, preserved, and <br /> transported under chain-of-custody to RESNA Environmental Laboratory Samples were <br /> composited in the laboratory and analyzed for benzene, toluene, ethylbenzene, xylenes (BTEX) <br /> and total petroleum hydrocarbons as gasoline (TPHG) utilizing EPA methods 8020 and modified <br /> 8015, respectively Stockpiled soil analyses are summanzed in Table 6 Laboratory data sheets <br /> and chain-of-custody documentation are exhibited in Appendix IX <br /> Dnll cuttings generated during the field investigation were inadvertently backfilled into the <br /> former pit along with aerated soil In light of the levels of contaminants in soil and groundwater <br /> beneath the former tank, the backfilling of the drill cuttings do not significantly add to the threat <br /> of groundwater contamination <br /> t4.0 SUBSURFACE CONDITIONS <br /> Soils encountered beneath the project site consist of interbedded silts, sands, and clays as <br /> exhibited by the boring/well logs contained in Appendix IV <br /> ' Strong to moderate product odors were noted on field observations in soil borings MW 1 and <br /> MW2 (Appendix IV) Moderate to slight product odors were noted in MW3 <br /> Groundwater was first encountered at a depth of 45 feet in MW 1 and subsequently rose to <br /> ' approximately 36 feet below grade In soil borings MW2 and MW3, first groundwater was <br /> encountered at an approximate depth of 40 feet below grade and subsequently stabilized at <br /> approximately 36 feet below grade Groundwater has been calculated to flow generally in a <br />' TPAR0492 TJL 7 <br />