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08 September 1999 <br /> • AGE-NC Project No 95-0103 <br /> Page 5 of 9 <br /> 3 1 STRATIGRAPHY AND DEPTH TO GROUND WATER <br /> Silty clay was generally encountered from a depth of approximately 5 feet to 15 feet bsg A gray silty <br /> sand was distributed at depths between 15 and 25 feet bsg on site and the sand was generally <br /> distributed at depths between 20 and 30 feet bsg off site A blue green clay was encountered at a <br /> depth of 30 feet bsg in most locations Ground water was encountered at depths ranging mom 17 feet <br /> to 20 feet bsg Once ground water was encountered, the level increased to a depth of approximately <br /> 10 feet to 12 feet bsg Soil borings are depicted in Appendix A A stratigraphic cross section with <br />' the distribution of hydrocarbon impacted soil is depicted in Figure 3 <br /> 32 HYDROCARBON-IMPACTED SOIL <br /> Seventeen soil samples were analyzed for TPH-g BTEX and fuel additives including MTBE <br /> • TPH-g was detected in seven of the seventeen soil samples analyzed TPH-g was detected <br /> at concentrations as great as 880 milligram pre kilogram (mg/kg) in soil sample CB5-15' <br /> ' TPH-g was detected in soil above 25 feet bsg near the northen end of the building on the site <br /> at concentrations up to 531 mg/kg (CB5-30') TPH-g was detected in a soil boring at depths <br /> ' below 25 feet bsg at a maximum concentration of 350 mg/kg <br /> * TPH-g not detected below was detected below 20 feet bsg overall, except in the area of <br /> boring CB5 <br /> • Benzene was not detected in any of the soil samples analyzed <br /> • Various other BTEX compounds were detected in six of the seventeen soil samples analyzed <br /> The greatest concentrations of BTEX compounds detected were generally in soil samples <br /> collected at a depth of 20 feet bsg offsite and at a depth of 15 feet bsg in dhe area of soil <br /> ' boring C135 <br /> • MTBE was detected in one of the seN enteen soil samples analyzed MTBE was detected at <br /> a concentration of 0 007 mg/kg (CB 1-25') The other fuel additives were not detected in the <br /> soil samples analyzed <br /> ' Laboratory results of soil samples analyzed for petroleum hydrocarbons aiea summarized in Tables <br /> 2 and 3 The laboratory reports (Onsite Laboratory ID 1FO18-01 to 1FO18-22 and 1FO1901-02), <br /> ' quality assurance and quality control (QA/QC) reports and chains-of-custody are included in <br /> • Appendix C <br /> ' AdvancedceoLmironmenui, Inc - <br />