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Mr. Infurna <br /> San Joaquin County Environmental Health Department <br /> 31 January 2011 <br /> Page 2 <br /> Samolin2 Procedures <br /> All samples will be collected from boreholes advanced using direct push methods (i.e. <br /> GeoProbe® or equivalent). Gregg Drilling and Testing of Martinez, California will provide the <br /> drilling services with supervision by Geosyntec personnel. <br /> Temporary sub-slab and soil gas probes will be installed at locations 2 through 6 using the <br /> procedures described in Attachment 1 Suggested Operating Procedures. The sub-slab and soil <br /> gas probes are illustrated on Figures 2 and 3, respectively. Soil gas samples will be collected <br /> through dedicated Nylaflow tubing attached to each probe with airtight fittings and analyzed for <br /> the methods listed in Table 1. Sub-slab soil gas probe installation, sampling, and <br /> decommissioning will occur within the same day and the probes will not remain in place <br /> overnight. After the sub-slab soil gas samples are collected, the probes will be destroyed by <br /> removing the probe hardware, filling with grout, and finishing the surface to match the <br /> surrounding surface. The soil gas probes will be constructed with a filter pack and bentonite <br /> grout as shown on Figure 3 and will be completed with a closed ball valve to serve as the probe <br /> casing cap. Soil gas probe locations may be left in place over one night prior to sampling. <br /> Monitoring well boxes consisting of a waterproof surface seal and a secure surface cover will be <br /> installed at soil gas probe locations left in place overnight. After the soil gas samples are <br /> collected, the temporary probes will be destroyed by removing the monitoring well boxes and <br /> sampling tubing, filling with grout,and finishing the surface to match the surrounding surface. <br /> Groundwater samples will be collected at locations 1 through 6 from separate boreholes located <br /> adjacent to the soil gas probes. Three of the boreholes (locations 1, 3, and 4) will be <br /> continuously cored to identify the depth to fust groundwater. The soil cores will be field <br /> screened for the presence of methane and VOCs and logged according to the Unified Soil <br /> Classification System (USCS) by the field geologist or engineer under the supervision of a <br /> California Professional Engineer or Geologist. Groundwater samples will be collected through a <br /> temporary 1" polyvinyl chloride (PVC) well. After sampling, the boreholes will be sealed via <br /> tremmie pipe. The surface finish will be completed to match the surrounding surface. All soil <br /> boring/temporary well locations will be installed, sampled, and decommissioned within the same <br /> day and will not remain open overnight. ,1 OVI <br /> 1 <br /> Draft—San Joaquin County Investigation Plan JL-LVT-CK-1.31.1 I <br /> 2 <br /> engineers I scientists I innovators <br />