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f 1%' Stantec PHASE 11 ENVIRONMENTAL SITE ASSESSMENT REPORT Field Activities March 31,2011 2.2.2.5 Duplicate Sample The soil vapor sampling event included one duplicate sample as part of the quality control/ quality assurance sampling protocol for the project. The duplicate sample was collected immediately after the primary sample and was analyzed for all of the constituents of concern. The duplicate sample was collected from soil vapor point SV-5. 2.3 ANALYTICAL LABORATORY 2.3.1 Analytical Laboratory Certification and Methodology BC Labs is a California State-certified laboratory. Based on the Site history, the soil vapor analytical data was used to delineate the extent of the volatile VOC contamination beneath the Site. Soil vapor samples were analyzed for VOCs using a gas chromatograph/mass spectrometer (GC/MS) by United States Environmental Protection Agency (USEPA) method TO-15. Detection limits for the targeted VOCs vary between constituents. The analytical results are included in Table 1 and the certified analytical results are included in Appendix B. Selected soil samples SS-1 (northern warehouse), SS-5 (parts washer area), and SS-6 (sewer lateral) were analyzed for TPH fuel fingerprint by the Leaking Underground Fuel Tank (LUFT) method, VOCs using USEPA method 8260, and CAM 17 metals. The soil sample analytical results are included in Tables 2 through 4, and the certified analytical results are included in Appendix B. Based on the soil vapor results, the soil sample from SS-2 (northern warehouse) was also analyzed for VOCs using USEPA method 8260. 2.3.2 Quality Assurance/Quality Control Sampling BC Labs complied with the project Quality Assurance Project Plan and adhered to the quality assurance/quality control (QA/QC) requirements in the most current Active Soil Gas Investigation Manual and EPA methodology. QC samples were collected and analyzed in the same manner as the primary samples. The QC samples consisted of the following: • Method Blank — Used to verify the effectiveness of the decontamination procedures and to identify possible interference with the ambient air and soils. • Duplicate Sample — One duplicate sample was collected during the soil vapor investigation. The duplicate sample was collected from soil vapor sample SV-5. The duplicate sample was collected immediately after the primary sample. The analytical results from the duplicate sample were similar to those of the primary sample. A few disputes were reported between sample pairs for the VOCs. Disputes are defined as detections that are found in either the duplicate sample or the associated primary sample, but not both samples. Most of the disputes were detections that were estimated values (J — flagged). i:\projects\r 1pine\lodi\report\lodi.svrpt.docx 2.5