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Potential off-site sources have not been identified. <br /> 5.4. Project Samples <br /> Soil vapor samples will be collected and analyzed for VOCs and 1,4-dioxane, and soil <br /> samples will be collected and analyzed for either soil physical properties or VOCs, SVOCs, <br /> Title 22 metals,hexavalent chromium, and in select samples, dioxintfurans and pH. Sample <br /> locations, sampling depth and step-out and step-down procedures are discussed in the <br /> following subsections. <br /> 5.4.1. Proposed Sampling Locations <br /> Proposed sample locations are shown on Figure 2. The soil gas sample locations are <br /> based on the following: <br /> • Sampling near existing buildings and former potential source areas <br /> • Sampling near the areas of elevated soil gas concentrations during the 1989 soil <br /> gas sampling event <br /> • Sampling near the area of the highest shallow groundwater concentrations <br /> Soil gas samples will be collected from approximately 30 locations. Of the 30 locations, <br /> 11 will be sampled from multiple depths and 19 will be sampled from two depths. The <br /> 11 multi-depth sites will be located in former potential source areas. The 19 two-depth <br /> sites will be located near building perimeters and at locations which are anticipated to <br /> establish a100-ft.buffer zone encircling any vapor contamination. In the event that these <br /> sample results are above detection limits, a follow up sampling event will expand <br /> sampling to step out locations. <br /> Soil samples will be collected from the soil cores retrieved during installation of each of <br /> the 11 multi-depth soil gas points. These soil samples will be analyzed for VOCs, <br /> SVOCs,Title 22 metals, and hexavalent chromium. The soil samples from Pond 1 will <br /> also be analyzed for pH, as acids were reportedly disposed of there. <br /> In addition, six soil samples will be collected for dioxin and furan analyses from three <br /> locations. The three locations were chosen to characterize the former trash burning area <br /> and proximate downwind (east and southeast) areas. The sample location for the former <br /> trash burning area is the multi-depth vapor boring shown in Figure 2 at this location <br /> (labeled "D"). The downwind locations correspond to two-depth vapor borings, one <br /> immediately south of the warehouse and the second immediately west of the office <br /> trailer. If dioxins and furans are detected above analytical reporting limits in any of <br /> these six samples, additional sampling of downwind areas will be proposed. <br /> Eight soil samples will be collected for geotechnical analyses to enhance the site specific <br /> data input for modeling vapor intrusion risk. As shown in Figure 2, the geotechnical <br /> Soil Gas and Soil Sampling Work Plan—Rev.4 7693-05 <br /> Former Kearney-KPF Facility Dudek <br /> Stockton,CA 11 September 2013 <br />