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�I L/ UNDERGROUND STORAGE TANK REMOVAL ,. It is our understanding that six USTs were removed from the site in August 1989.The USTs ranged in volume up to 10,000 gallons. During tank removal activities, three grab ground water samples L were collected from the tank pit excavation. Laboratory analysis of the grab ground water samples detected volatile aromatics(benzene,toluene,ethylbenzene and xylenes:BTEX)at concentrations ranging as high as 120,000 parts per billion (reported as micrograms per liter:ppb); benzene was L detected at concentrations as high as 7,700 ppb.The highest BTEX concentrations were detected in the water sample collected from the north portion of the excavation. L Soil samples were collected from the base of the piping trench as well as the sidewalls and base of the UST removal excavation. The laboratory analysis detected tetraethyl lead (TEL) at a concentration of 1,200 parts per billion(reported as micrograms per kilogram:ppb)in a soil sample L collected from the eastern portion of the UST removal excavation. The laboratory detected total petroleum hydrocarbons quantified as gasoline (TPH-g) at concentrations ranging as high as 1,700,000 ppb.The laboratory detected BTEX at concentrations ranging as high as 370,000 ppb;the L greatest benzene concentration was 12,000 ppb.The highest TPH-g and BTEX concentrations were detected in the samples collected from the east portion of the UST removal excavation. LPREVIOUS SUBSURFACE INVESTIGATION On 08, 09 and 10 July 1998, six soil borings (B1 through B6) and four ground water monitoring wells (MW-1 through MW-4) were installed at the site to assess the lateral and vertical extent of impacted soil and ground water.A total of 23 soil samples and four ground water monitoring well samples were collected during the investigation and were submitted for laboratory analysis. Total petroleum hydrocarbons quantified as gasoline and diesel (TPH-g and TPH-d, respectively)were detected in analyzed soil samples at concentrations as high as 580 milligrams per kilogram(mg/kg); i dissolved TPH-g and TPH-d were detected from ground water monitoring well samples at L concentrations ranging as high as 2,400 micrograms per liter(ttg/l). Volatile aromatic compounds: benzene,toluene,ethylbenzene and xylenes(BTEX)were detected in selected soil samples and grab ground water samples at concentrations as high as 32 mg/kg and 36 µg/1,respectively. In May 2000,three soil borings(B7,MW5 and MW6)were advanced at the site;two of the borings L were completed as monitoring wells MW-5 and MW-6. TPH-g was detected in the 15-foot soil sample analyzed from boring MW6 at a concentration of 330 milligrams per kilogram(mg/kg).TPH- d was detected in MWS,MW6, and B7 at concentrations as high as 140 mg/kg(MW6-15).BTEX L compounds were detected in the 15-foot soil sample from MW6 at concentrations of 0.094 mg/kg, 2.6 mg/kg, 8.7 mg/kg and 2.8 mg/kg, respectively. LVERTICAL SUBSURFACE INVESTIGATION On 11 January2002,soil probe borings B8 and B 9 were advanced utilizing a van-mounted Geoprobe 5400 equipped with 1.125-inch diameter probe rods with an attached 2.15-inch diameter soil Rdywwed GeoEmvironmental,Inc.