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• Sfemental Site Investigation Scoping Document Pittman Elementary School,Stockton,California January 23,2004 Page 7 from each of the 11 PEA sample locations in three directions (two along the dripline and one away from the building), a total of 33 new soil sample locations, for determination of the lateral extent of lead contamination. Soil samples will be collected from 0 to 6 inches and 2.0 to 2.5 feet bgs. Also, the sample locations around P1, P8, P9, and P20/P21 will have an additional sample collected at 3.5 to 4.0 feet bgs for vertical extent definition, as elevated concentrations of lead were detected in the sample collected from 2.0 to 2.5 feet bgs. The samples will be analyzed for lead by EPA Method 6010B. The proposed sample locations are indicated on Figures 9 and 10,Appendix A. Samples will be collected at the surface by loosening the soil with a stainless steel shovel. A stainless steel spoon will be used to place the loose soil into laboratory-supplied glass jars. The deeper subsurface samples will be collected at each sample location by using a stainless steel hand auger and transferring the soil directly from the hand auger into laboratory-supplied glass jars. The deeper subsurface samples shall be archived frozen by the laboratory for potential analyses pending the results of the surface samples. Each jar will be labeled for sample identification and placed in a cooler chilled with ice. Prior to use at each soil sample location, all sampling equipment will be decontaminated in the field by washing with a solution of laboratory-grade, non-phosphate detergent and deionized water and then rinsed. Following soil sample collection, an equipment blank sample will be collected by running deionized water through the sampling equipment and collecting the water in appropriate sample containers. The equipment blank sample will be analyzed for the same constituent as the samples collected with the field equipment. The general sample locations, sample types, and associated analyses are listed in Table 4, below. The laboratory analytical methods, detection limits, and associated USEPA Region IX PRG values are presented in Appendix C. Table 4—Proposed SSI S mpline Prollram Structure Dri lines Sample Locations De Ihs Numberof Sam les I Matrix I Analyses I Method 33 locations 11 PEA locations 3 locations per PEA location 0-0.5 and 2-2.5 33 surface, ( ) 2 feet awa feet bgs 33 intermediate(hold) soil Lead 60108 12 locations(4 PEA locations) 3 locations per PEA location 3.5-4 feet bgs 12 deep soil Lead 6010B 2 feet away) Second sample locations 2 locations 0-0.5 and 2-2.5 2 shallow, soil Lead 6010B feet bgs 2 intermediate hold Equipment blank 1 water Lead 6010E 3.3 SOIL GAS ANOMALY AT NORTHERN SITE BOUNDARY Soil gas sampling will be conducted to further investigate and define the presence of 1,3-butadiene in soil gas identified during the PEA fieldwork. One soil boring with continuous core will be installed to 25 feet bgs at least 20 feet away from PEA boring VB1 for the purpose of characterizing lithology (Figure 11, Appendix A). The lithology of that boring will be evaluated to determine from what depths soil gas samples should be collected. Two additional soil borings will be installed to 25 feet bgs at least 25 feet away from the previous borings. Soil gas samples will be collected at three depths where lithologies of highest permeablility are present. One duplicate sample will be collected immediately following the collection of one of the primary samples. This sample will not be identifiable as a duplicate sample to the laboratories. The duplicate sample sy; will be prepared in an identical manner and analyzed for the same analytes as its primary counterparts. Soil gas samples will be collected in laboratory 100%certified clean, six-liter Summa canisters. Soil gas sampling will be conducted in accordance with the DTSC Advisory—Active Soil Gas Investigations dated January 28, 2003. In addition, a trip blank sample will be collected by filling a summa canister with ambient air that has been filtered. The general sample locations, sample types, and associated analyses are listed in Table 5, on the next page. CONDOR