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OU 4 Work Plan <br />Spot <br />Check <br />Slide <br />Hammer <br />Passive Soil Gas <br />Survey <br />Soil Vapor Soil Hydropunch <br />Explorations <br />Samples 27 (100%) <br />Analyses <br />For each of the 27 Phase 11 results noted in the existing data sections, Kleinf elder will assess the <br />initial Phase 11 paper-copy laboratory reports and tabulate the associated laboratory <br />reporting/detection limits and screening levels. Kleinf elder will provide these data to the Board for <br />its review. <br />OPERABLE UNIT 5 <br />OU 5 Description <br />OU 5 Corresponds to Sub-Recommendation 12.3, which concerns a diesel fuel above-ground <br />storage tank (AST). The Phase I identified potential for soil contamination via leaks/spills of <br />petroleum-related compounds. Phase II samples were collected and analyzed for petroleum- <br />related compounds (Figure 0U5-1). <br />Petroleum: Existing Data <br />Eight soil samples were analyzed for TPHd, TPH1o, and TPHueh (EPA 3550, DHS Luft), BTEX <br />(EPA 5030/8020), MtBE (EPA 5030/8020M), and TPHg (EPA 5030/8020) (Table 0U5-P, soil <br />samples 12-39 through 12-42). These analyses yielded 72 results, of which all are ND except for <br />one sample collected from a 15-foot depth, from which concentrations of 2,800 mg/kg of TPHd, <br />40 mg/kg of TPHg, and 0.009 mg/kg of xylenes were reported. The TPHd concentration exceeds <br />both the Industrial Threshold of 440 mg/kg and the Protection of Groundwater SSL of 1.5 mg/kg. <br />Laboratory reporting limits are not tabulated. <br />In addition, one Hydropunch sample was collected due to petroleum odor noted during exploration <br />(Table 0U5-P, hydropunch sample 12-42-HP). The sample was analyzed for TPHd, TPHueh, and <br />TPHIo. TPHd was detected at a concentration of 4,900 ug/L. This concentration exceeds Tier 1 <br />and EPA Tap Water ESLs of 100 ug/L. <br />Monitoring Wells MW-15, MW-22, MW-23, and MW-24 were installed in 1997 to monitor OU 5 <br />conditions. MW-15 is located about 20 feet northwest of the AST, where soil staining was noted <br />during ongoing field investigations. MW-22 through MW-24 were installed about 150 feet cross- <br />and downgradient of the AST to define lateral extent of potential groundwater impacts. <br />20173951.001A/SAC17R68420 Page 9 of 26 November 2, 2017 <br />© 2017 Kleinfelder www.kleinfelder.com <br />KLEINFELDER 2882 Prospect Park Dr., Suite 200, Rancho Cordova, CA 95670 p I 916.366-1701 f I 916.366-7013