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i II) M UNDERGROUND STORAGE TANK ACTIVITY AND REMOVAL On 24 March 1999 three USTs and their associated dispensers and piping were removed from the site, the tanks had been active for over twenty years, from the early 1970s to the late 1990s The approximate locations of the former USTs, product piping and dispensers are shown on Figure 2 The UST removals were witnessed by a representative of the PHS-EHD Tracking records for waste removed from the UST should have been supplied to the PHS-EHD in the UST removal report History of the UST use, tank tests, product inventory and repairs are not known to AGE After being removed, the tanks were visually inspected and appeared to be intact, with no holes or extensive corrosion noted Pea gravel was used to backfill the base portion of the UST excavation equal the volume of the removed USTs Plastic sheeting was then placed into the excavation and the stockpiled soil was replaced and compacted back into the UST excavation The UST excavation was then capped with road base and leveled Following removal of the tanks,an excavator was used to collect six soil samples from 2 feet below the ends of the former USTs Since ground water was encountered in the bottom of the excavation, three separate ground water samples were also collected, in accordance with PHS-EHD requirements In addition,the PHS-EHD requested that ten soil samples be collected from two soil stockpiles Laboratory analytical results detected total petroleum hydrocarbons as gasoline(TPH-g)in the UST floor soil samples at concentrations up to 350 milligram per kilogram(mg/kg) Purgeable aromatic hydrocarbons(benzene,toluene,ethylbenzene and xylenes,BTE&X)were detected at concentrations up to 8 mg/kg(benzene) In addition,MTBE and total lead were detected at concentrations up to 13 mg/kg and 8 02 mg/kg, respectively, in the former UST excavation Stockpile soil samples contained TPH-g at concentrations up to 19 mg/kg while BTE&X compounds were detected at concentrations as high as 0 14 mg/kg MTBE was also detected in the stockpiled soil at concentrations up to 0 08 mg/kg Total lead was detected in the same samples at concentrations up to 8 46 mg/kg TPH-g was detected in the UST `grab' water samples at concentrations up to 950 milligram per liter (mg/1)while BTE&X compounds were detected at concentrations up to 62,900 microgram per liter (gg/l) MTBE was also detected at concentrations up to 32,650 pg/l in the water samples Total lead was detected in the same samples at concentrations up to 0 86 mg/l SITE ASSESSMENT AND REMEDIATION ACTIVITIES A summary of site assessment activities to date include • 13 April 2000, ten soil probe borings (B 1 through B 10) were advanced at the site TPH-g, BTEX, MTBE and/or tertiary butanol (TBA) were detected in each of eight grab bround water samples Low concentrations of TPH-g and BTEX were detected in soil samples