ARCHIVED REPORTS_1ST QUARTER 2008 SITE STATUS REMEDIAL SUMMARY AND GROUNDWATER MONITORING REPORT

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S E C O R - -- • 6.0 SOIL VAPOR SAMPLING 6.1 Previous Soil Vapor Sampling Activities Baseline, startup, and monthly soil vapor sampling results were presented in the report entitled Soil Vapor Well Installation and Soil Vapor Extraction Start-Up Report for events prior to October 2005. Monthly soil vapor sampling results for the October 17 and November 18, 2005 sampling event were presented in the Fourth Quarter and Annual 2005 Site Status, Remedial Summary, and Groundwater Monitoring Report. The DPE system was shut down for retrofit on December 12, 2006, and restarted on May 31, 2007. 6.2 Soil Vapor Sampling First Quarter 2008 On February 15, 2008, soil vapor samples were collected from 11 of the 15 soil vapor monitoring points located in the adjacent Delta View Apartment complex (APSV locations) and on undeveloped portions of the Site (UPSV locations). Soil vapor point APSV-2 was not sampled due to water in the sampling tube during 1Q08 sampling event. Groundwater was encountered in soil vapor points UPSV-5, APSV-4 and APSV-5. Soil vapor point UPSV-4 was destroyed fourth quarter 2006 due to its location which interfered with the installation of an additional remediation system on Site, with CRWQCB-CVR concurrence. Samples were collected following guidance provided by the California DTSC and Los Angeles RWQCB Advisory—Active Soil Gas Investigations, dated January 28, 2003. Soil vapor analytical results from this monitoring event are presented in Table 26 and Figure 22 and are summarized below. • The sampling event is part of a quarterly sampling protocol that commenced on February 15, 2008. Laboratory analytical reports and SECOR laboratory validation forms for the first quarter 2008 sampling event are provided in Appendix F. 6.2.1 Soil Vapor Sampling A Transglobal Environmental Geochemistry-Northern California (TEG) mobile lab and a TEG technician were used to collect and analyze soil gas on site from 11 of 15 soil vapor points (UPSV-1, USPV-2, UPSV-3 and UPSV-6, and APSV-1, APSV-3, and APSV-6 through APSV-10) on February 15, 2008. In order to sample the soil vapor points, a syringe with a gas-tight fitting was attached to the Y< -inch Teflon® tubing inlet at each soil vapor point. The syringe was used to extract a purge volume of air based on the diameter and depth of inlet tubing. The syringe was then used to collect an air sample and taken to the on site mobile laboratory for immediate analysis. Samples were analyzed for the following: • TPHg using EPA Method 82606; • BTEX compounds, fuel oxygenates (MtBE, DIPE, EtBE, TBA, TAME), and naphthalene, using EPA Method 82606; and • Methane using EPA Method 8015M. Duplicate samples were collected from UPSV-2 and APSV-10 during the first quarter 2008 event. • 1 Q080SSRQRSRQMR.Final.doc 29 April 30,2008 77TW.26397.42.1307