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Limited Site Investigation Irerracon Vacant Property ■Tracy, California November 13, 2020 ■Terracon Project No. NA197074 provided by the laboratory, it is our opinion that the overall dataset is useable as qualified for the purposes of this LSI. 5.0 SCREENING LEVELS The tabulated results of analytical testing are provided in the attached Table 1 — Summary of Soil Sample Analytical Results. Terracon reviewed the laboratory reports and compared the results to the Department of Toxic Substances Control (DTSC) Human and Ecological Risk Office (HERO) Note 3—modified recommended Screening Levels(SLs)for Soil—April 2019, and United States Environmental Protection Agency (USEPA) Recommended Screening Levels (RSLs) for completeness when there is no DTSC-SL for a combination of receptor and endpoint, and DTSC Characteristics of Toxicity 22 CCR§ 66261.24 for waste characterization. Results of TPH, VOCs, OCPs, and CHs were reported in samples as follows: Total Petroleum Hydrocarbons as GRO were reported at a concentration of 100 milligrams per Kilogram (mg/Kg) to 2,300 mg/Kg in sample SB7-8 from a depth of 8 feet bgs. The TPH-GRO concentrations were reported above the applicable Commercial/Industrial Soil RSLs in samples from soil boring locations SB7 (near the pipeline), and SB9, SB11, S131 2, SB13, SB14, SB15, and SB16 (from the soil stockpile material). Total Petroleum Hydrocarbons as DRO were reported at a concentration of 130 milligrams per Kilogram (mg/Kg) to 5,000 mg/Kg in sample SB7-8 from a depth of 8 feet bgs. The TPH-DRO concentrations were reported above the applicable Commercial/Industrial Soil RSLs in samples from soil boring locations; SB4 and SB7 (near the pipeline), and S139, SB11, SB12, SB13, SB14, SB15, and S131 (from the soil stockpile material). Total Petroleum Hydrocarbons as MORO was reported at a concentration of 5,400 mg/Kg in sample SB14-8 from the stockpile material at a depth of 8 feet bgs. The TPH-MORO concentrations reported were below the applicable Commercial/Industrial Soil SLs. VOC 1,1,2-Trichloroethane was reported at a concentration above the Commercial/Industrial Soil SL at 26 mg/Kg in sample SB14-8 from the stockpile material at a depth of 8 feet bgs. OCPs were not reported above laboratory reporting levels, or their respective SLs and RSLs, in the four shallow soil samples analyzed. CHs were not reported above the Commercial/Industrial Soil SLs, in the four shallow soil samples analyzed. The analytical results of the soil samples indicate the soil exceeds the DTSC recommended screening levels for commercial/industrial use in sample SB7-8 near the pipeline and in samples from the stockpile material (SB9, SBI 1, S1312, SBI 3, S131 4, S1315, and S131 6), however, the soil samples collected during this investigation are not considered representative of a hazardous waste based on DTSC Characteristics of Toxicity 22 CCR§ 66261.24. Responsive ■ Resourceful ■ Reliable 5