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.. 19 February 2002 <br /> AGE-NC Project No. 95-0173 <br /> Page 7 of 7 <br /> HU6, HU7 and HU9 (Figure 4). <br /> 96. Generally, the most intense hydrocarbon-impact was reported from CPT-2A water samples <br /> collected at HU6 and HU7 hydrologic units (between 106 feet and 125 feet bsg); the <br /> laboratory reported the TPH-g sample chromatograms as having significant unmodified or <br /> weakly modified gasoline (Table 1). <br /> • Based on geologic cross section C-C, petroleum-impact at the site appears to be in excess <br /> of 140 feet bsg; generally, decreasing concentrations are observed with depth. <br /> .., The vertical extent of petroleum-impacted ground water has not been fully delineated on- or <br /> off-site. <br /> 4.0. RECOMMENDATIONS <br /> ' Based upon the CPT investigation results during the fourth quarter 2001, AGE recommends: <br /> 1. Continued quarterly ground water monitoring the site; the next quarterly ground water <br /> monitoring event is tentatively scheduled for March 2002. <br /> 2. Installation of at least one on-site and one off-site deep-screened ground water monitoring <br /> �. "✓ well; the screen intervals for the deep-screened monitoring wells will be placed to define and <br /> monitor the vertical extent of the ground water plume in selected informal hydrologic units. <br /> 3. Conduct ground water remediation feasibility studies at the site in shallow and deeper zones. <br /> Ground water pump testing should be performed at the site to evaluate a general radius of <br /> influence and capture zone during ground water extraction. The proposed aquifer pump tests <br /> will be designed to obtain general aquifer characteristics such as hydraulic conductivity, <br /> storativity, transmissivity and draw-down at a constant pumping rate. <br /> 5.0. LIMITATIONS <br /> �. Our professional services were performed using that degree of care and skill ordinarily exercised by <br /> environmental consultants practicing in this or similar localities. The findings were based mainly <br /> upon analytical results provided by an independent laboratory. Evaluations of the geologic/hydro- <br /> logic conditions at the site for the purpose of this investigation are made from a limited number of <br /> available data points (CPT data and ground water samples), and subsurface conditions may vary <br /> away from these data points.No other warranty, expressed or implied, is made as to the professional <br /> interpretations, opinions and recommendations contained in this report. <br /> Advanced GeoEnvironmental,Inc. <br /> i.r <br />