ARCHIVED REPORTS_FOURTH QUARTER AND ANNUAL 2010 SITE STATUS, REMEDIAL SUMMARY, AND GROUNDWATER MONITORING REPORT

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Stantec L & M OPERABLE UNIT- FOURTH QUARTER AND ANNUAL 2010 SITE STATUS, REMEDIAL SUMMARY, AND GROUNDWATER MONITORING REPORT Introduction January 31, 2011 at the Site at 14 locations. Results are summarized in SECOR's report entitled Revised Underground Utility Search Report, dated March 5, 2004. In January 2004, SECOR completed construction of the DPE system. Electrical power and natural gas service were established by Pacific Gas and Electric (PG&E) on March 4, 2004. Under the conditions of the initial air permit for the DPE system issued by the San Joaquin Valley Air Pollution Control District (SJVAPCD) in April 2003, which covered the first six months of system operation utilizing propane as a fuel source, startup of the DPE system was performed and initial groundwater and air influent and effluent samples were collected on March 18, 2004. SECOR submitted a request to the SJVAPCD for modifying the existing air permit, which included the operation of the DPE system using natural gas rather than propane, and extension of the life of the permit. SJVAPCD required that the revised permit be resubmitted for public review over a 30-day period, which ended on July 15, 2004. Throughout the duration of the review period, the SJVAPCD did not authorize the operation of the DPE system under the existing permit due to minor detections of polyaromatic hydrocarbons (PAHs) in the effluent sample collected on March 22, 2004. Since no public comments were received by July 15, 2004, the SJVAPCD issued the revised air permit on July 20, 2004. Initial start-up and shake-down of the DPE system was performed on August 2 and 3, 2004. Concurrently during the installation of the DPE system, SECOR submitted the report entitled Work Plan For Pipeline Abandonment, Removal, and Soil Vapor Extraction Well Installation, dated April 15, 2004. This report outlined a plan for abandoning or removing the steel pipelines that were discovered during the December 2003 underground utility search on the Parcel 2A property, and locating pipelines that were anticipated beneath West Weber Avenue and the Waterfront Towers parking lot and beneath former Edison Avenue near the eastern entrance to the Delta View Apartments. The work plan also proposed the installation of horizontal SVE wells to extract petroleum hydrocarbons from soil beneath five apartment buildings to the south, west and northwest of the DPE remedial well field, and connection of those wells to the DPE system. The RWQCB-CVR approved the April 15, 2004 work plan and the June 14, 2004 letter addressing RWQCB-CVR comments to the work plan (Response to RWQCB-CVR Letter Dated May 14, 2004) in electronic correspondence dated June 21, 2004. SECOR completed pipeline abandonment/removal activities during the fourth quarter 2004, and the installation and connection of horizontal SVE wells to the DPE system during the third quarter 2005. Pipelines discovered during the December 2003 investigation, as well as additional pipelines discovered during pipeline abandonment/removal activities, were removed from the undeveloped portion of the L&M OU, soil was excavated to approximately 10 ft bgs, a 500-gallon steel UST was removed, and old well was properly abandoned, and pipelines trending off the undeveloped portion of the L&M OU were rinsed and filled with cement. Approximately 300 gallons of product/water mixture were removed from three pipelines and approximately 350 gallons of product was pumped out of the UST. Horizontal SVE wells were installed beneath the bottom of the excavation and the bottom was lined with a high density polyethylene (HDPE) liner. Additionally, six horizontal SVE wells were installed beneath five I:\Tidewater\TW Stockton(Parcel2A-0415)\Reports\QMR\2010\4010-Annual\4Q10 and Annual OSSRQRSRQMR Stockton_FINAL.doc 1.6