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31 January 2013 AGE-NC Project No. 02-0926 Page 2 of 21 2.2. SUBSURFACE INVESTIGATIONS The following is a summary of previous site investigations of the unauthorized release of fuel products to the subsurface: November 1998 - One (1) soil boring (ED1-15) was advanced at the site by Upgradient Environmental Consultants. Total petroleum hydrocarbons quantified as gasoline (TPH-g) were detected at a concentration of 4,890 milligrams per kilogram (mg/kg). Benzene, toluene, ethylbenzene and xylenes compounds (BTEX) were detected at concentrations of 236 mg/kg toluene, 110 mg/kg ethylbenzene and 433 mg/kg total xylenes, respectively; benzene was not detected above laboratory reporting limits of 1.25 mg/kg. Total lead was detected at a concentration of 0.512 mg/kg. October 2002 - Four soil probe borings (B1 through B4) were advanced at the site as part of site assessment activities. A total of six (6) soil samples were submitted for laboratory analysis. TPH-g were detected in one of the six samples (B4-35) at a concentration of 2.2 mg/kg. BTEX compounds were reported at concentrations of 0.08 mg/kg benzene, 0.10 mg/kg toluene, 0.02 mg/kg ethylbenzene and 0.2 mg/kg total xylenes (B4-35). Total lead was detected in three of the six samples at a maximum concentration of 6.7 ring/kg (B1-10). During the investigation, one (1) grab groundwater sample was collected from boring B4. TPH-g were detected in the groundwater sample at a concentration of 1,200 micrograms per liter (pg/I). Total petroleum hydrocarbons quantified as diesel (TPH-d) were detected at a concentration of 160 pg/I. BTEX constituents were detected at concentrations of 81 mg/kg benzene, 130 mg/kg toluene, 35 mg/kg ethylbenzene and 200 mg/kg total xylenes. Methyl tertiary butyl ether (MTBE) was detected at a concentration 4.6 pg/I. February 2004 - Two borings (B5 and B6) were advanced at the site as part of additional site assessment activities. A total of eighteen (18) soil samples were collected during the investigation. TPH-g were detected in twelve of the eighteen samples at concentrations ranging from 260 mg/kg (B5-13) and 16,000 mg/kg (B5- 33). BTEX compounds were detected in twelve of the eighteen samples at maximum concentrations of 50 mg/kg benzene (B5-33), 1,800 mg/kg (B5-18), 2,100 mg/kg ethylbenzene (B5-18) and 3,690 mg/kg total xylenes (B5-18). Ethylene dibromide (EDB) was detected in one of the eighteen samples (B5-13) at a concentration of 1.9 mg/kg. Total lead was detected in two of the eighteen samples at concentrations of 38 mg/kg (B5-13) and 90 mg/kg (B5-15). During the investigation a grab groundwater sample was collected from each advanced boring (B5 and B6). TPH-g were detected in groundwater samples collected from B5 and B6 at concentrations of 460,000,000 pg/I and 12,000 pg/I, respectively; TPH-d were detected in the groundwater sample collected from B5 at a concentrations of 14,000,000 pg/I. BTEX constituents were detected at maximum concentrations of Advanced GeoEnvironmental, Inc.