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J a <br /> y <br /> 07 May 2009 <br /> AGE-NC Project No. 97-0343 <br /> Page 3 of 7 <br /> Method 8260B; and, <br /> • Fuel additives methyl tertiary-butyl ether(MTBE),di-isopropyl ether(DIPE),ethyl tertiary- <br /> butyl ether (ETBE), tertiary-amyl methyl ether (TAME), tertiary butanol (TBA), ethylene <br /> dibromide (EDB) and 1,2-dichloroethane (1,2-DCA) in accordance with EPA Method <br /> 8260B. <br /> 2.4. EQUIPMENT DECONTAMINATION <br /> All probing rods used were cleaned prior to advancement in each probe boring location. Sampling <br /> equipment was washed in an Alconox solution and rinsed with water prior to each sampling run to <br /> avoid cross-contamination. <br /> 2.5. BOREHOLE ABANDONMENT <br /> At the conclusion of soil boring activities, borings were permanently sealed to prevent vertical <br /> migration of contaminants.Under EHD oversight,boreholes were backfilled with cement slurry from <br /> the total depth to surface grade. <br /> 3.0. FINDINGS <br /> Soil descriptions were determined from field data. Petroleum hydrocarbon impact to soil was <br /> inferred from laboratory analyses of soil samples.Analytical results from past and current subsurface <br /> investigations were utilized in calculating the mass volume of remaining absorbed TPH and in the <br /> evaluation of environmental screening levels. <br /> 3.1. STRATIGRAPHY <br /> Soil encountered in borings P1 and P2 was generally silt, sandy silt, or clay between surface grade <br /> and 15 feet bsg, and 25 feet and 50 feet bsg. Silty sand was encountered in both borings at a depth <br /> of 20 feet bsg.This sand layer appears to be consistent across the site,as shown in the geologic cross <br /> section D-D' (figure 3), which was generated from cone penetration testing borings CPT-1 and <br /> CPT-3. Ground water was not encountered in any of the borings; depth to water measured during <br /> the most recent ground water monitoring event, October 2008, was approximately 60 feet bsg. <br /> Historically, depth to ground water was measured between 32 feet bsg and 62 feet bsg. Soil boring <br /> logs are included in Appendix B. Boring logs were uploaded to the State GeoTracker online <br /> Advanced GeoEnvironmental,Inc. <br />