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4W. direct-push rods. When the sampling probe reached the specified sampling depth, ECA retracted an outer sleeve and exposed a 3-inch screen section for soil vapor extraction. At least w. 20 minutes after probe installation, after subsurface equilibrium, ECA collected the soil vapor samples at each location. t•+ ECA collected the soil vapor samples through the tubing and into Summa Canisters using a '/a- horsepower air sampling pump with purge rates of between 10 and 200 milliliters per minute. Prior to sampling, the pump was run for approximately five minutes to evacuate the casing and to draw soil vapors from the surrounding formation. During sampling at each location, ECA used 1,1-difluoroethene (1,1-DFE) as a leak check gas to confirm that the sample train and probe LO were tight and free of any leaks. ECA properly decontaminated the soil vapor sampling equipment and used dedicated and disposable tubing for each soil vapor probe boring. Excelchem Environmental Labs (Excelchem), a state of California certified hazardous waste testing laboratory (Certification #2119) analyzed each of the soil vapor samples for TPH-as- �-+ gasoline by Method TO-3, and BTEX, MTBE, D1PE, ETBE, TAME, TBA, 1,2-DCA and 1,1-DFE by Method TO-15, and analyzed the samples from SV-1, SV-2 and SV-3 for TPH-as-diesel by NIOSH Method 1550. None of the analyzed compounds were detected above laboratory reporting limits in all five soil .+ vapor samples. The soil vapor sample analytical results are summarized in Table 4, and the laboratory report is included in Appendix B. 3.3 Sensitive Receptor Survey La For input into the human health risk assessment models, WRM completed a sensitive receptor survey for the site vicinity, within 2,000-feet of the site, according to Section 2654(b)(2), Article 5, Chapter 16, Division 3, Title 23 of the California Code of Regulations. The survey included a review of water well completion reports at the California Department of Water Resources (DWR), contact with local water purveyors, and a tour of the site vicinity. La DWR records included 188 well completion reports of which 137 were either not water supply wells or were destroyed wells, 23 reports were for wells outside of the 2,000-foot site vicinity I.,r radius, eight reports included incomplete or illegible well log data and could not be located, and 16 reports were for city of Tracy municipal wells. According to Den Wengrin, Water Production +� Supervisor, City of Tracy Public Works, Utilities Division, no public water supply wells are located within a 2,000-foot radius of the site. Of the four remaining well completion reports, only two wells were located during a tour of the site vicinity. Appendix D includes a map showing the locations of the two wells and a table summarizing the well details. �• 9