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3.0 INVESTIGATION ACTIVITIES <br /> The objective of this investigation was to determine if TCE is present in <br /> groundwater near the former condensate-outlet pipe. Soil samples were not collected during this <br /> event because the presence of TCE in the soil was identified in previous investigations. Sample <br /> locations are shown on Figure 2-1. The rationale for selection of these locations is as follows: <br /> • CPT-1 - Adjacent to the former location of the condensate outlet pipe, <br /> and groundwater monitoring well MW-1. <br /> • CPT-2 - A location approximately 25 feet southeast of CPT-1 to <br /> determine if TCE has migrated laterally from the potential source area. <br /> CPT-3 - A location approximately 25 feet northwest of CPT-1 to <br /> determine if TCE has migrated laterally from the potential source area, <br /> A Cone Penetrometer Testing/HydroPunch® (CPTW) rig was used to collect <br /> lithologic information and groundwater samples. CPT lithologic information was collected at all <br /> three locations. Static water pressure measured during dissipation tests at each location allowed <br /> calculation of the water head at a particular depth. Next, two HP groundwater samples were <br /> collected at each location. A three foot HP screen was used and six 40 ml vials were collected for <br /> each sample. The shallower set of samples was collected from a sandy layer approximately 3 to 5 <br /> feet below the estimated water table. This depth was chosen to reduce the collection of separate <br /> phase petroleum hydrocarbons while still giving an indication of any TCE migrating from the <br /> vadose zone to the water table. The second and deeper groundwater sample at each location was <br /> collected from the next sand unit, approximately 50 feet bgs. The purpose of the deep sample at <br /> each location was to determine the vertical distribution of WE in groundwater, if present. All <br /> CPT/HP holes were abandoned by pumping a bentonite/neat-cement mixture through a tremie <br /> pipe from the bottom of the boring to the surface. <br /> Analysis for TCE and BTEX was performed using U.S. EPA Methods 8260A (low <br /> level) and 801018020. Both methods were used on all samples to achieve the lowest possible <br /> ® detection limit for TCE if the presence of petroleum hydrocarbons required sample dilution. Field <br /> 35275 Welty Road,Vemalis 7 March 1997 <br />