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' 02 June 1999 • AGE-NC Project No 97-0326 Page 5 of 7 41 STRATIGRAPHY ' Claywas encountered at depths of 10 and 30 feet bsg in borings MW2 and MW3 and at depths of p g g 20 and 40 feet in boring MW3 Sand was encountered at depths of 20 and 25 feet bsg in boring MWI Silty sand was encountered at a depth of 35 feet bsg in all borings Silt was encountered in the remaining samples collected at the site to the maximum depth explored (55 feet bsg) The boring Iogs are included as Appendix A 42 ANALYTICAL RESULTS OF SOIL SAMPLES Organic vapor was detected in 23 of the 27 soil samples collected at the site at concentrations as high as 1,507 ppm (MWI at 15 feet bsg) Organic vapor was not detected in soil samples collected at depths of 10 and 15 feet bsg in boring MW2 and at depths of 5 and 10 feet bsg in boring MW2 OVM data is included on the boring logs (Appendix A) TPH-g was detected at depths of 20 and 35 feet in boring MWI at concentrations of 4,200 parts per million (ppm, reported as milligrams per kilogram) and 11,000 ppm, respectively Low concentrations of hydrocarbons were detected at depths of 45 and 55 feet bsg in this boring TPH-g was detected in samples collected at depths of 20, 35 and 45 feet bsg in boring MW3 at concentrations of 1,400 ppm, 370 ppm and 1,800 ppm, respectively Low concentrations of hydrocarbons were detected in boring MW2 at depths of 20 and 35 feet bsg Hydrocarbons were not detected at a depth of 45 feet bsg in boring MW2 Benzene was detected only in sample MW2-35 ' at a concentration of 0 0058 ppm MTBE was detected in sample MW2-35 at a concentration of 0 011 ppm Oxygenates were not detected in the remaining samples analyzed by EPA Method 8260 Analytical results of soil samples are summarized on Table 1 The laboratory reports (AAL Batch No 98-1204-004) and chain-of- custody forms are included in Appendix B ' 43 GROUND WATER GRADIENT AND FLOW DIRECTION Ground water was encountered at a depth of approximately 40 feet bsg during the Installation of the monitoring wells During the December 1998 monitoring, ground water was measured at a depth of approximately 32 feet below the tops of the well casings, within the screened interval of MW2 and MW3, but approximately three feet above the screened interval in MW1 The elevation of ground ' water in each well was calculated by subtracting the depth to ground water from the surveyed casing . elevations Ground water elevations ranged from 17 27 to 17 42 feet below mean sea level (MSL) ' Ground water data Is summarized on Table 2 Advanced GeoEnrsronmental,Inc