ARCHIVED REPORTS_2019 SOIL MGMT PLAN (MAY)

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ekienvironment & water • TPH-d and -mo with silica gel cleanup by EPA Method 8015m; and • Benzene, toluene, ethylbenzene, and xylenes ("BTEX") by EPA Method 8260B or 8021. If the applicable soil screening levels listed in Section 1.4 are exceeded for the area where the soils are present, then the RWQCB will be notified and the extent of the impacted soil will be evaluated. If the evaluation indicates that the extent of the impacts can be fully excavated, the process in the next paragraph will be followed. If the evaluation indicates that the extent of impacts is limited and if the area of impacts extends under an existing slab, building, or other structure, then the RWQCB will be consulted about the potential for leaving the soil in place. Such soils left in place will be noted on a map and the map will be retained to guide how to the deal with the impacts if some future construction occurs in the area If it is determined that the material must be excavated, remedial excavation will proceed until: • analysis of confirmation soil samples for relevant COCs indicates that applicable soil screening levels are met, or • the excavation reaches the top of the groundwater table, approximately 12 ft bgs. Confirmation samples will be collected from in-place soils at the limits of a remediation excavation as follows: • Discrete sidewall samples will be collected from freshly exposed soil approximately one- half of the excavation depth at an interval of approximately one sample per 50 linear feet of sidewall excavation face. • Bottom confirmation samples will be collected from excavation bottoms at discrete locations on approximately 50 -foot centers for areas greater than approximately 2,500 square feet. • A minimum of one bottom sample and one sidewall sample per excavation face will be collected from each excavation. Soil samples will be collected in brass or stainless steel liners capped with Teflon tape and plastic end caps. The samples will be immediately placed on ice to maintain the samples at a temperature of 4 (±2) °C. They will then be transported to a State -certified analytical laboratory under chain -of -custody for analysis. All sampling and sample handling will be performed in accordance with standard environmental protocols and will be documented. Soil sampling locations and the extent of excavations will be surveyed by the contractor or field located based on existing aboveground structures. Excavated soils that are visibly stained, shiny, or oily or have a noticeable solvent -like, or hydrocarbon odor will be segregated and stockpiled on-site for characterization prior to off-site disposal. Stockpiles shall be managed in accordance with the procedures described in Section 2.4.