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I 25 March 2002 AGE-NC Project No 97-0326 ' Page 5 of 9 ' Hydrological Unit 6 (HU6) extends from approximately 135 feet to and possibly beyond 150 feet bsg near the total depth penetrated by CPT-4, at the CPT-5 location, the cone penetrometer encountered refusal at 140 feet This interval consists dominantly of sand and gravelly sand and is ' characterized by very low to low pore pressure Geologic cross sections A-,4 ' and B-B' were generated from the CPT data and depict general lithology beneath the site in cross sectional view (Figures 3 and 4, respectively) Copies of the computer-generated CPT boring logs are included in Appendix A 3 2 LABORATORY RESULTS OF GRAB GROUND WATER SAMPLES ' water le were collected from CPT-4 and CPT-5 and submitted A total of seven grab ground a er samp s ' for laboratory analysis for the constituents listed in Section 2 2, the analytical results are provided in Table 2, along with the analytical results from the ground water samples collected from CPT-01 to CPT-03 on 14 and 15 February 2001 Based on the analytical results, each 14U was characterized below HLr I TPH-g and BTEX compounds were assessed in all ground water samples collected from HU 1,which ' had the highest concentrations of TPH-g and BTEC compounds detected in the water samples collected Analysis of a ground water sample collected at the top of HU1 (near the water table, 30 to 40 feet bsg)from off-site CPT-03 detected 110 µg/l TPH-g,2 1 µg/1 benzene, 3 8 p.g/l toluene and ' 0 53 p,g/l xylenes,respectively The maximum concentrations ofpetroleum hydrocarbon compounds (14,000 4g/1 TPH-g, 4,000 ug/l benzene, 79 Rg/1 toluene, 690 lig/l ethylbenzene and 710 µg/1 xylenes) were detected in off-site CPT-4, in a sample collected between 52 and 56 feet bsg A map ' showing lateral TPH-g and benzene distributions is provided as Figure 5 In addition to TPH-g and the BTEX compounds, low concentrations of di-isopropyl ether (RIPE), ' isopropylbenzene, n-propyl benzene, 1,1,2-trichloroethane, 1,2-dichloroethane, 1,2,4- tnmethylbenzene and 1,3,5-trimethylbenzene were also detected in HUI Isopropylbenzene was ' detected at the three CPT locations advanced in February 2001, n-propyl benzene and 1,1,2- trichloroethane were detected in samples from CPT-01 and CPT-03, 1,2,4- and 1,3,5- tnmethylbenzene were detected only in the sample from CPT-01,and DIPE and 1,2-dichloro ethane ' were only detected in the sample from CPT-02 The Higher concentrations of isopropylbenzene (22 Advanced GeoEnviran:nental,Inc