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4-W-0 � Site Background Information: Cherokee Truck Stop AGE-NC Project No. 97-0312 Page 5 of 11 soil samples MW7A-25 and MW7A-45 were described as a brown silt and a brown clay with specific gravity of 2.76 and 2.75,permeability of 6.2 x 10'and 8.4 x 10',porosity of 49.96% and 43.99%,pH of 7.6 and 7.5, and total organic content of 1.8%and 2.2%, respectively. Tetrachloroethene was detected in the ground water sample collected from UST-7 at a concentration of 1.3 µg/1.No other analytes of concern were detected. • 07 September 2005 - Ground water monitoring wells UST-8 and UST-9 were completed using 2-inch diameter polyvinylchloride (PVC) casing; 0.020-inch slotted screen was installed from approximately 65 feet to 75 feet bsg in well UST-8,and from approximately 95 feet to 105 feet bsg in well UST-9, with blank casing extending to the surface in both borings.Generally,clayey silt was encountered to 70 feet bsg and silty and sandy soil(sandy silt, silty sand, and sand)were encountered in the borings to 105 feet bsg (total depth of UST-9).TPH-g and TPH-d were detected at concentrations ranging from 1.7 mg/kg(UST9- 100)to 320 mg/kg(UST9-25)and 14,000 mg/kg(UST8-10 and UST9-25)to 16,000 mg/kg (UST9-10), respectively in the soil samples collected from UST-8 and UST-9. BTEX constituents were also detected in the soil samples UST9-10,UST9-25,UST9-90 and UST9- 100 with maximum concentrations found in sample UST9-25 at 2.6 mg/kg benzene, 83 mg/kg toluene,41 mg/kg ethylbenzene and 247 mg/kg total xylenes. • December 2005-All monitoring wells were re-designated with a preceding MW instead of UST to normalize the well identifications. QUARTERLY GROUND WATER MONITORING EVENTS Between May 1995 and September 2006,AGE conducted forty-six ground water monitoring events at the Cherokee Truck Stop site. Petroleum hydrocarbons and/or fuel additives have been detected only in wells MW-5 and MW-6 since June 2004,although MTBE was detected for the first time in well MW-8 (installed October 2005)in Third Quarter 2006. CPT LITHOLOGIC INVESTIGATION On 24 April 2006,two groups of soil borings(CPT-I and CPT-2)were advanced at the site utilizing CPT technology;at each boring location,lithologic data was collected from an initial CPT boring; two immediately adjacent borings were then advanced to collect grab ground water samples from selected depths.The CPT investigation utilized a 25-ton truck-mounted CPT drill rig equipped with 1.50-inch diameter hollow-stem rods. A hydraulic ram was utilized to advance a piezocone(cone penetrometer with pore pressure measurement) attached to the hollow-stem rod assembly to total depth of each soil boring. Soil borings CPT-1 and CPT-2 were advanced to a total depth of 110 feet bsg.At each boring location,the soil parameters of piezocone rip resistance,sleeve friction and pore Advanced GeoEnvironmental,Inc.