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4.2 Post-Excavation Soil Sampling <br /> Following the completion of excavation, confirmation soil samples were collected from the floor <br /> of the excavation. At the request of DTSC, additional delineation samples were also collected <br /> east of the excavated area and one additional delineation sample was collected from the face of <br /> the levee. Sampling locations are shown on Figure 3. In keeping with the previous work, the <br /> samples were identified by X & Y coordinates: X = distance in feet east or west (E or W) of the <br /> zero point marked on the ground, and Y = distance in feet south (S) of the asphalt pavement. <br /> Confirmation samples are indicated by the letter "C" in the first part of the identification and by <br /> 1 "SURF" at the end. These were collected from the floor of the excavated area, or approximately <br /> 3 inches beneath the original ground surface. The additional delineation samples were collected <br /> from the current ground surface. <br /> ' The soil samples were collected in clean brass tubes sealed with teflon sheets and plastic end <br /> P � - <br /> caps. Each sample was identified with the sample ID, date and time collected, collector's initials <br /> and requested analysis. The sample tubes were placed in individual sealed plastic bags and stored <br /> on ice in an insulated container for transport to the laboratory. Sampling equipment was cleaned <br /> between samples in order to minimize the possibility of cross contamination. <br /> All soil samples were submitted under chain of custody protocol to State-certified GeoAnalytical <br /> Laboratories, Inc. in Modesto, California. Per the DTSC workplan approval memorandum, the <br /> analysis consisted of total copper by EPA Method 6010B for all samples with the addition of total <br /> lead and total chromium by EPA Method 6010B and hexavalent chromium by EPA Method <br /> 7196A for three selected samples. After reviewing the results and consulting with DTSC, <br /> additional analysis was performed. Samples 0/3S, 151E/3S and 166E/3S were analyzed for <br /> soluble copper by DI-WET extraction and EPA 6010B analysis. Sample 0/3S was also analyzed <br /> ' for soluble copper and soluble lead by citric acid-WET (STLC) extraction and EPA 6010B <br /> analysis. <br /> ' 4.3 Analytical Results <br /> The analytical results for all post-excavation soil samples are summarized in Table 2. Laboratory <br /> reports and chain of custody documention are included in Appendix D. <br /> Total Metal Concentrations <br /> The minimum, maximum and 95% upper confidence level (UCL) metal concentrations in ppm <br /> are presented below. Non-detect values (hexavalent chromium only) were treated as positive <br /> results at the detection limit concentration but statistics were not calculated. Note that due to the <br /> ' small number of samples, the UCL concentrations for lead and chromium are higher than the <br /> maximum values detected. <br /> 5 <br />