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DATA GAP ASSESSMENT WORK PLAN AND PATH TO CLOSURE REVIEW Chase Chevrolet, 424 N. Van Buren Street LTCP Closure Evaluation January 2, 2018 during SVE operation was not available on GeoTracker, or in the SCJEHD and City files. An ozone sparging system with 17 wells was operated at the site between June 2003 and sometime before the destruction of all site wells in March 2004 (T&R, 2004). A report detailing the calculated petroleum hydrocarbon mass removed during SVE operation was not available on GeoTracker, or in the SCJEHD and City files. Between April and May 2004, approximately 1,180 tons of impacted soil was excavated from a 28-foot by 30-foot by 22-foot-deep area that included the former UST pit and well MW-3. During the excavation, approximately 40,000 gallons of petroleum hydrocarbon-impacted groundwater was pumped from the pit and discharged to the sanitary sewer after carbon filter treatment. Prior to backfilling the excavation with clean imported fill material, approximately 500 pounds of oxygen release compound (ORC) was placed in the bottom of the excavation pit (T&R 2004). Soil and groundwater has been tested for MTBE and results reported in accordance with Health and Safety Code section 25296.15? Yes. Nuisance as defined by Water Code section 13050 does not exist at the site? Yes. There are no known nuisance conditions at the site. 3.2 MEDIA-SPECIFIC CRITERIA 3.2.1 Groundwater-Specific Criteria A groundwater monitoring and sampling program was performed at the site between September 1990 and October 2003 before all site wells were destroyed in March 2004 prior to site redevelopment. An analysis of the characteristics that define if the site meets the requirements for case closure under the groundwater-specific criteria of the LTCP is as follows: Plume Length: During the last groundwater monitoring and sampling event, the length of dissolved phase plume was estimated to be approximately 350 feet (October 2003 dissolved -phase isoconcentration map, Appendix D). It should be noted the dissolved gasoline range organics (GRO) and benzene plume length is controlled by the presence of 69 ug/L GRO and 0.87 ug/L benzene reported in the downgradient well MW-15. Referring to groundwater data for MW-15 included in Appendix C, the well was sampled 30 times and 26 of the water samples collected from well did not contain GRO or benzene at concentrations above the laboratory reporting limits. The plume was stable to shrinking in aerial extent based on the decreasing concentrations of petroleum hydrocarbon constituents in site wells over time (historical groundwater analytical tables, Appendix C). A very conservative estimate of the plume current plume length is >250 feet and <1,000 feet; however, the actual length of the dissolved phase plume is likely <250 feet given the historical groundwater data collected Stantec bm \ \ us1312- f02 \ workgroup \ 1857 \ active\ 185703766 \ 05_report_deliv \ deliverable \ work_plan \ 185703766_20180102_424_van_buren_work_plan_final.docx 3.2