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I <br /> C A MB R I A Mr Ron Rowe <br /> I August 17, 1998 <br /> r CPT Pore Pressure Dissipation Test Results: Groundwater depth was calculated using Pore Pressure <br /> Dissipation Tests during pauses in cone penetration The pore pressure over time was plotted for each <br /> of the tests Based on the final pore pressure, ground water depth was calculated to range from <br /> I approximately 22 0 ft to 23 0 ft below grade These depth towater calculations are relatively consistent <br /> with field observations of depth to water in MW-1 (26 85 ft below grade), and in the Den Dulk well <br /> (26 65 ft below grade) Soil permeabihties were estimated based on the pore pressure dissipation data <br /> I (Robertson, et al), and ranged from 2 x 10 s cm/s to 5 x 10'cm/s The results of the pore pressure <br /> dissipation analyses are summarized in Table 4 <br /> Offsite Welllnvestigatton Results No contaminants were detected in any of the analyses performed <br /> on the ground water samples collected from the offsite wells <br /> bh <br /> Onsite Well Purging and Sampling Results The analytical results are summarized in Table 4 <br /> CONCLUSIONS <br /> The horizontal and vertical extent of TPPH, BTEX, and MTBE in soil are defined by the CPT boring <br /> installations during this phase of the investigation <br /> None of the contaminants,with the exception of MTBE,are present in ground water beyond the source <br /> area near the southeastern dispenser MTBE in ground water has been delineated vertically to the west <br /> I to the detection limit by borings CPT-6, CPT-7, CPT-8, and CPT-9, to the southwest by boring at <br /> CPT-10, and to the northeast by boring at CPT-3 In the source area,MTBE concentrations in ground <br /> water decrease rapidly with depth <br /> IBased on the data collected during this phase of the investigation,none of the offsite wells have been <br /> Iaffected by petroleum hydrocarbons <br /> I5 <br />