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„r ATC Associates Inc. 1117 Lone Palm Avenue, Suite 201 Modesto, California 95351 209-579-2221 A SSOC IATES I N c . Fax. 209-579-2222 connection valves located at the surface of each soil gas sampling point. Results of the soil gas study activities will be submitted under separate cover. SCOPE OF WORK Planning and Permits ATC will obtain the necessary SJCEHD permits for the advancement of the proposed soil boring. ATC will schedule field personnel and equipment, notify Underground Services Alert to locate underground utilities as required, and perform other necessary field preparation and job start-up activities. Vertical Evaluation Activities To further evaluate the vertical extent of impacted groundwater beneath the site, one vertical soil boring employing cone penetrometer testing (CPT) methods will be advanced to approximately 125 feet bgs. The proposed CPT soil boring will be advanced between soil borings SB-3 and SB-5 as shown on Figure 3. Drilling will be conducted by a State-licensed C57 drilling company. A field geologist will be present to supervise drilling activities, evaluate sample depths, and collect groundwater samples. During the initial CPT soil boring, a cone mounted with sensors at the tip will be advanced into the soil using direct push rods. The sensors will test the response of the soil to the force of the penetrating cone and this will allow the subsurface stratigraphy to be characterized. The CPT data will be used to evaluate the presence of separate depth discrete water bearing zones within the aquifer. Based on the known construction detail associated with the former water supply well located on-site, the CPT boring will be advanced to approximately 125 feet bgs. After the subsurface materials have been characterized and evaluated, a field geologist will select sample depths for collecting discrete groundwater samples. For each discrete sample, a direct push Hydropunch® boring will be advanced adjacent to the initial CPT boring and a groundwater sample will be collected from the selected deeper water bearing zone. Following the collection of groundwater samples, the borings will be grouted to the surface with a neat cement slurry mixture using a tremmie pipe. ATC estimates a minimum of two groundwater samples will be collected after evaluating the CPT logs for potential water bearing zones separated by an overlying aquitard and/or significant clay layer. Groundwater samples will be collected using Hydropunch® type groundwater sampling system. The system includes an expendable drive point attached to poly vinyl chloride (PVC) or stainless steel filter screen threaded onto the leading end of the direct push rods. While the sampler is advanced, O-ring seals and the expendable drive point will provide a watertight system to ensure sample integrity. To minimize sample interference from drag down of contaminants, ATC will request that the Hydropunch sample locations are advanced with a dual core system. When the Hydropunch® type groundwater sampling system has been advanced to the desired depth, the expendable drive point is held in place by the surrounding soil while the direct push rods are retracted. Once retracted, up to 60-inches of PVC or stainless steel filter screen with s:\environmentan25803�Reports\CPT Workplan 4