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

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S E C O R • through 2AMW-15) in suspected areas of contamination. A preliminary endangerment assessment was performed on the parcels to evaluate the environmental health risk associated with residual petroleum hydrocarbon concentrations in soil and groundwater. Details are presented in T&R's Site Characterization Report, South Shore Parcels, Stockton, California, dated December 13, 1999. In 2001, additional assessment activities were conducted by T&R in the vicinity of the Site within Parcel 3. Results are included in T&R's report entitled Subsurface Investigation for Area 3, dated August 17, 2001. In September 2001, a total of 11 Cone Penetrometer Test (CPT) borings (DP-1 through DPA 1) were drilled to investigate the following: (1) subsurface lithology; (2) the presence of separate phase hydrocarbons (SPH); (3) the lateral extent of petroleum hydrocarbon impacted groundwater east, south, and west of the Site; and (4) to investigate potential off-site sources upgradient (north-northwest) of the Site. Surficial soil samples were also collected from depths up to 5 feet below ground surface (bgs) to evaluate whether the presence of residual concentrations of metals present a threat to groundwater quality. Results are presented in the Clayton Group Associates (Clayton) report entitled Further Characterization at the West Weber Avenue and North Lincoln Street Site, Parcel 2A, dated December 18, 2001. In May 2002, Clayton initiated quarterly monitoring activities, installed eight additional CPT soil borings (DP-12 through DPA 9), and collected grab samples to delineate soil and groundwater impacts previously identified in the vicinity of borings DP-1 through DP-6. In addition, Clayton performed a soil gas survey in July 2002 involving the installation of 111 Gore-Sorber® modules • to investigate the areas of greater petroleum hydrocarbon impact. Results are summarized in Clayton's Site Delineation Report, dated August 6, 2002. In December 2002, a 5-day DPE feasibility test was performed by SECOR, following the installation of seven DPE wells (DPE-1 though DPE-7). SPH were reportedly present in wells DPE-1, DPE-3, DPE-4, DPE-6, and DPE-7 prior to the initiation of testing. DPE tests were performed utilizing well 2AMW-14 for approximately 45 hours; simultaneously on wells DPE-4 and DPE-6 for approximately 28 hours; and simultaneously on wells DPE-1, DPE-3, and DPE-7 for approximately 26 hours. Results of DPE feasibility testing indicated the following: (1) a calculated radius of influence of 31 feet west of well 2AMW-14, and lower estimated radii of influence to the south and east due to the presence of low permeability clays and lower induced vacuum readings in wells DPE-3, DPE-4, and DPE-7; and (2) the removal of an estimated 196.38 pounds of total petroleum hydrocarbons in gasoline range organics (TPHg)from soil and groundwater, 97.02 pounds of total petroleum hydrocarbons in diesel range-organics (TPHd) from groundwater, and 9.57 pounds of total petroleum hydrocarbons in motor oil range organics (TPHo) from groundwater. Results are summarized in SECOR's report entitled Well Installation and DPE Feasibility Report, dated January 24, 2003. An additional DPE test was performed at the Site from March 3 through 7, 2003, using a 25-horsepower (hp) liquid ring vacuum pump connected to a thermal oxidizer unit for abatement of the extracted soil vapor prior to discharge to the atmosphere. DPE tests were performed separately on wells DPE-4 and 2AMW-14 simultaneously for approximately 21.5 hours and wells DPE-4, DPE-6, and 2AMW-14 simultaneously for approximately 72.5 hours. The DPE unit ran for a total of approximately 97 hours during the test. Groundwater and soil vapor were removed simultaneously from the test wells by applying a high vacuum to a drop tube that was • lowered below the water table within each test well. Results of DPE feasibility testing indicated 1Q08QSSRQRSRQMR.Final.doc 3 April 30,2008 77TW.26397.42.1307