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2.1.2 Geoprobe Groundwater Survey <br /> IT will collect soil and groundwater grab samples from 14 locations using a Geoprobe 5400 <br /> ' Direct Penetration Technology (DPT) rig to further define the lateral and vertical extent of <br /> impacted soil and groundwater. The proposed 14 Geoprobe sampling locations are shown on <br /> ' Figure 3. Prior to the geoprobe survey,the five existing wells at the site will be monitored for <br /> groundwater depth, flow direction and gradient. <br /> tThirteen borings will be advanced to approximately 12 feet below ground surface (bgs). One <br /> ' boring (SB-5) will be advanced to the next lower water bearing zone,approximately 35 feet bgs. <br /> The one deeper boring is to be located downgradient of the site and in close proximity to the <br /> ' proposed monitoring well MW-8. From each of the borings, a soil sample will be collected at a <br /> depth of five feet using a pneumatically driven stainless steel sampling tool. The sampler will <br /> ' be driven to the target depth and up to 2 feet of soil will be collected in a sample tube. The <br /> sample will then be retrieved from the borehole using the DPT rig. A soil sample and discrete <br /> zone groundwater sample will be collected from the bottom of the deeper boring to evaluate <br /> ' vertical extent of impact and provide stratigraphic data. The borings will be logged for <br /> hydrogeologic and lithologic characteristics by a geologist and screened using an organic vapor <br /> ' meter equipped with a photoionization detector(PID). <br /> Groundwater grab samples will be collected from each of the 14 soil borings to test for the <br /> presence of pesticides, herbicides, nitrate, ammonia, and petroleum hydrocarbons in the <br /> ' groundwater. Groundwater will be collected from each borehole by creating a temporary well <br /> using PVC well casing. Groundwater samples will be collected using a disposable bailer. All <br /> ' soil and groundwater samples will be collected in appropriate containers, capped, sealed, labeled <br /> and placed in a zip-lock plastic bags. The packaged samples will be placed in an iced cooler and <br /> ' transported under chain-of-custody manifest to a state of California-certified laboratory. <br /> ' After the sampling is completed, the boreholes will be filled to the surface with cement grout. <br /> All drilling equipment will be cleaned prior to arrival on-site. To avoid cross-contamination of <br /> borings, all appropriate downhole sampling equipment will be cleaned between sampling events. <br /> 1 <br /> ' 5 <br />