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I r t II r s ,l , 1 i 30 August 1999 H ,f AGE-NC Project No ,97-0312 Page 5 of 8 During drilling of B 14,ground water was not present in the boring immediately prior to collection of the soil sample at 65 feet bsg Ground water was present after drilling to a depth of 70"feet bsg ' After drilling to a depth of 65 feet bsg in boring B 15, ground water was measured at a depth of 60 feet'bsg A continuous core sampler was'used during the drilling of 1316 Free water was`not observed prior to collection of a sample at 80 feet bsg, although thin sand lenses, encountered at s „ shallower'depths, may have contained free water Although static ground water in wells at the site is currently approximately 50 feet bsg, ground water , was not encountered during drilling until a depth of at least 60 feet bsg Ground water beneath the I site appears to be confined, rising to approximately 50 feet bsg after penetrating the confining layer Therefore, monitoring well UST-6 was installed with the screened interval belovj this confining layer I 32 ANALYTICAL RESULTS OF SOIL SAMPLES Organic vapor was detected in 20 of the 76 samples collected from borings B14 through 1:317 a: concentrations as high as 817 ppm (1314 at 15 feet bsg) Organic vapor was not detected in so;] • samples collected from boring B 16, from boring B 15 below a depth of 30 feet bsg or from boring' B 17 below a depth of 45 feet bsg PID readings are summarized on Table I TPH-g was detected in samples B 14-20,and B 15-15 at concentrations of 570 parts per million (ppm, reported as milligrams per kilogram),and 540 ppm, respectively TPH-d was detected in six of the 24 samples analyzed (B 14-20, B 14-30, B 15-15, B 15-20, B 17-25 and B 17-40) at concentration:, as high as 13,000.ppm (1314-20) Benzene was detected in sample,13114-20 at a concentration of 4 1 . ^ ppm Toluene, ethylbenzene ,and xylenes were detected in samples f B14-20 and B15-15 at concentrations as high as 9 8 ppm Other petroleum hydrocarbons were not detected in the 24 soil i ! samples analyzed , A , ; i MTBEwas detected by EPA Method 8260 in samples B 14-20,B 17-25 and B 17-40 at eoncentrati6ns of 0 41 ppm, 12`ppm'and 8 1 ppm, respectively Tert-butanol was detected,in sample B 14-20 at a concentration of 0 3 ppm Other oxygenates were'not detected in these three samples or in sample " B15-15 ' MTBE was detected by 'EPA Method 8015m in samples 1314-30 and B17-50 at concentration's of 0 051 ppm and 0 54 ppm, respectively Analytical results of soil samples are I summarized on Tables 2oand 3 The laboratory report (MAI Sample Nos 1317843201) and chain- of-custody forms are included in�Appendix B Petroleum hydrocarbons'were not detected in soil samples collected from B 16, limiting the northern , • extent of impacted soil Petroleum hydrocarbons were not detected below a depth of 40 feet bsg in; ,f 'the remaining borings, defining the vertical extent'of impacted soil at these locations ' r s Advanced CeoEnviroamental,Inc I I