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. 15 February 2002 AGE-NC Project No 96-0229 Page 2 of 12 2 2 UNDERGROUND STORAGE TANK REMOVAL One 6,000-gallon gasoline UST and two 12,000-gallon gasoline USTs,dispensers and product piping were removed from the site on 18 February 1999 and replaced with one 20,000-gallon gasoline UST Soil samples were collected beneath the former USTs and product piping areas Total petroleum hydrocarbons quantified as gasoline (TPH-g) was detected in soil samples collected beneath the dispenser and product piping area at concentrations as high as 260 milligrams per kilogram (mg/kg) Benzene, toluene, ethylbenzene and xylene (BTEX) constituents were detected in samples collected beneath the dispenser and product piping areas and beneath the east end of the UST area at concentrations as high as 7 8 mg/kg The greatest benzene concentration was detected beneath the product pipe area at a concentration of 0 44 mg/kg Methyl tert butyl ether(MTBE)was detected in samples collected beneath the dispenser and product piping areas and beneath the east and west ends of the UST area at concentrations as high as 5 mg/kg, tert-amyl methyl ether(TAME)was detected in samples collected beneath the dispenser and product piping areas at concentrations as high as 0 47 mg/kg, tert butanol (TBA) was detected in . samples collected beneath the east and west ends of the UST area and beneath the dispenser and product piping areas at concentrations as high as 5 1 mg/kg No other analytes were detected above laboratory reporting limits from the analyzed samples Analytical results of soil samples collected during UST removal activities are summarized in Table 1 22 PREVIOUS SUBSURFACE INVESTIGATION The following is a brief summary of site assessment activities • Between July and October 1996,nine soil borings(P-1 through P-9)were advanced to depths of approximately 40 feet at the site Soil samples collected from borings P-2, P-3, P-4, P-5, P-7 and P-8 detected TPH-g at concentrations as high as 7,800 mg/kg, BTEX compounds were detected in soil samples from all bonngs at concentrations as high as 530 mg/kg, MTBE was detected in soil samples collected from P-1, P-3, P-4 and P-7 at concentrations as high as 0 012 mg/kg Grab ground water samples were collected from P-1, P-2, P-3, P-4, P-7, P-8 and P-9 contained TPH-g at concentrations as high as 210,000 micrograms per liter (1,tg/1) and BTEX compounds as high as 27,000µg/1, MTBE was detected in water samples from P-1, P-2, P-3,P-4 and P-9 at concentrations as high as 1,000µg/1 Analytical results of soil and grab ground water samples collected during the July through October 1996 investigation are summarized in Tables 2 and 3 • In November 1997, six ground water monitoring wells (MW-1 through MW-6) were installed on and off-site as part of site assessment TPH-g was detected in soil samples Advanced GeoEnvironmental,Inc