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M � 17 June 2008 AGE-NC Project No. 99-0637 Page 2 of 7 2.2. PREVIOUS SITE INVESTIGATIONS I On 20 March 2000, three soil borings (B1 through B3) were advanced at the site as part of site assessment activities. MTBE was detected in the soil sample collected from probe boring B2,at 20 feet below surface grade (bsg), at a concentration of 1 j6 mg/kg. No other analytes were detected above laboratory reporting limits in the soil samples collected and analyzed from B 1 through B3. TPH-g,benzene,and MTBE were detected in the grab ground water samples collected from borings B 1 through B3, at concentrations as high as 1,200 micrograms per liter (pg/1) TPH-g, 310 µg/l benzene,and 10,000µg11 MTBE.In addition,tertiary-butyl alcohol(TBA)was detected in the water sample collected from Bl,at a concentration of 400 µg/1�Analytical results of soil and groundwater samples collected from the March 2000 investigation are presented in Table 2. On 05 April 2001, four monitoring wells (MW1 through MW4) were installed at the site. Soil samples were collected and analyzed from each pilot boring. Toluene was detected at very low concentrations in one sample collected from MW 1, in two samples from MW3,and in two samples from MW4, at concentrations as high as 0.025 mg/kg MTBE was detected in the soil samples collected from pilot boring MW4,at concentrations as high as 1.2 mg/kg. Concentrations of toluene and MTBE were detected only in the soil samples collected from the vadose and saturated zones(15- 25 feet bsg). Analytical results of soil samples collected from the April 2001 investigation are presented in Table 3. On 08 and 09 January 2002,three cone penetrometer testing(CPT)borings(CPT1 through CPT3) were advanced at the site. MTBE was detected at a concentration of 0.006 mg/kg in the one soil sample collected from the CPT investigation(CPT 1-35). Grab ground water samples were collected at three selected intervals in each CPT boring.TPH-d was detected just above minimum reporting limits in CPT31, at depths between 41 to 45 feet bsg, at a concentration of 54 µg/l; MTBE was detected in CPT31, at depths between 81 to 85 feet bsg, at a concentration of 1.6 µg11. Analytical results of soil and grab ground water samples collected from the January 2002 investigation are presented in Table 4. On 28 January 2002, three monitoring wells (MWS, MW6, and MW7) were installed at the site. MTBE was detected,at a concentration of 0.0510 mg/kg;in one soil sample(MW5-20)of the seven collected from monitoring well pilot borings MW5, MW6, and MW7. Analytical results of soil samples collected from the January 2002 well installations are presented in Table 3. f In February 2003,three monitoring wells(MW8,MW9,and MW 10)were installed at the site.Two soil samples were collected from each pilot boring. MTBE was detected,at concentrations as high as 0.064 mg/kg, in two of the soil samples collected (MW9-25 and MW10-28). Analytical results Advanced GeoEnvironmental,Inc. 1