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Work Plan, PFAS Site Inspection Naval Computer and Telecommunications Station Stockton, California Technical Approach 3-4 DCN: TRBW-0202-5183-0010 After the field and laboratory data reports are reviewed and validated, the data will be entered into the project database for NCTS Stockton. The database contains data for (1) summarizing observations on contamination and geologic conditions, (2) preparing reports and graphics, (3) using with geographic information systems, and (4) transmitting in an electronic format compatible with Naval Installation Restoration Information Solution (NIRIS) Electronic Data Deliverable and NIRIS. 3.3.5 Equipment Decontamination Disposable sampling equipment will be used and, when not possible, all sampling equipment (including the drill rig components) will be decontaminated according to the procedures described in SOP-002 (Attachment 1 of Appendix A). All sampling tools will be decontaminated before sampling begins and between sample locations. Soil sampling tools will be decontaminated by scrubbing in a solution of potable water and non-phosphate detergent (Liquinox). The tools will then be double-rinsed with distilled water. Sampling tools that are not used immediately after decontamination will be allowed to air-dry and wrapped in plastic. 3.3.6 Investigation-Derived Waste Management IDW for this project consists of soil cuttings, purge and decontamination water, and general solid wastes generated from packaging, disposable sampling equipment and personal protective equipment (PPE) and other miscellaneous trash. All IDW will be managed as described by the Waste Management Plan (Section 4) and Section 14.2.12 of the SAP (Appendix A). 3.4 Drilling, Lithologic Logging, and Sampling 3.4.1 Soil Borings and Subsurface Soil Sample Collection Subsurface soil borings will be collected with direct push technology in accordance with SOP-016 (Attachment 1 in Appendix A). Select boreholes will be converted into temporary groundwater monitoring wells, as described in Worksheet #17 of the SAP. Soil cores (4-5-foot sections) will be collected for soil classification and recorded on the Drilling Log Form (Attachment 1 in Appendix A). Depth to groundwater varies at the site; therefore, the subsurface soil sample depths may vary. Groundwater monitoring conducted in 2019 recorded water table elevations ranging from 0 to 15 feet bgs across former NCTS Stockton. Each boring location will first be hand-augered to 5 feet bgs to confirm the absence of utilities or other shallow obstructions. Surface soil samples will be collected from the 0- to 0.5-foot bgs interval and the 0- to 2-foot bgs interval. Following collection of surface soil samples, the boring will be advanced to 25 feet bgs. Subsurface soil samples will be collected from 2-foot intervals between 2-foot bgs and the interval above the water table (i.e. 2-4 feet bgs and 4-6 feet bgs). The subsurface soil samples will be collected using a stainless-steel sampling trowel and will be performed in accordance with SOP-016 (Attachment 1 in Appendix A). Soil samples will be logged on the Soil Sample Collection Field Sheet (Attachment 1 in