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I r17 April 2002 AGE-NC Project No. 97-0343 Page 4 of 6 I Vadose Zone-Extending from surface grade to 54 feet bsg,the depth to the water table. The vadose zone is predominantly fine grained material from surface grade to 54 feet bsg, with a coarse grain sand unit occurring between 20 feet and 25 feet bsg across a portion of the site. The zone is characterized by low pore pressure. Hydrological Unit 1 (HU1), at the top of the current saturated zone, extends from 54 feet to 80 feet bsg and is comprised of silty sand to sandy silt and characterized by predominantly high pore pressure. Hydrological Unit 2 (HU2)extends from 80 to 96 feet bsg; it is composed of an upper 10-foot layer of fine-grained soil underlain by an approximately 5-foot sand and gravelly sand interval. HU2 is characterized by low pore pressure. Hydrological Unit 3 (HU3) extends from 96 feet bsg to and possibly beyond 134 feet bsg. Silt and clay are the dominant soil type in the interval. The interval is characterized by pore pressure variations from moderate to high pressures. • Hydrological units are depicted in cross sectional views A-A' and B-B' (Figures 5 and 6). 3.3. LABORATORY RESULTS OF GRAB GROUND WATER SAMPLES A total of five grab ground water samples were collected from CPT-1, CPT-2 and CPT-3 and submitted for laboratory analysis for the above mentioned constituents (Table 1). Ground water samples were collected from: CPT-1 at between 92 feet and 96 feet bsg (CPT1-92-96); CPT-2 at between 76 feet and 80 feet bsg(CPT2-76-80)and between 92 feet to 96 feet bsg(CPT2-92-96);and CPT-3 at between 74 feet and 78 feet bsg(CPT3-74-78)and between 92 feet and 96 feet bsg(CPT3- 92-96). Ground water samples CPT2-76-80 and CPT3-74-78 were collected from HU1.TPH-d was detected in sample CPT3-74-78 at a concentration of 64 micrograms per liter (µg/1). Total xylenes were detected in sample CPT2-76-80 at a concentration of 0.97 gg/l. No other target analytes were detected in samples CPT2-76-80 and CPT3-74-78. Ground water samples CPT 1-92-96 and CPT2-92•-96 were collected from HU2;sample CPT3-92-96 I was collected at the boundary between HU2 and HU3. TPH-g and TPH-d were detected in sample CPT1-92-96 at concentrations of 530 gg/1 and 98 gg/l,respectively.Toluene,ethylbenzene and total xylenes were detected in sample CPT 1-92-96 at concentrations of 9.9 µg11, 20 µg/1 and 140 gg/l, respectively. No other target analytes were detected in the samples from HU2. i Advanced GeoEnvironmental,Inc. 1