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Geospte& consultants indicated to be in good condition and were accessible in 2023 without significant vegetation removal are included as part of the upcoming 2024 monitoring program(Table 3). This will prevent disturbances and potential schedule delays to the soil remedy and Soda Bulk Export Terminal construction programs. The excluded wells in the Landfill Area will be assessed when soil remedy and construction activities are complete. In general, the wells excluded from the 2024 GMWP in the Landfill area exhibit either non-detect, stable, or decreasing trends for cis- 1,2-dichloroethene (cis-1,2-DCE) and vinyl chloride. In addition, the installation of the replacement monitoring wells proposed in the Rail Line Area Well Destruction Work Plan (Geosyntec, 2021b) will also be delayed due to the ongoing remediation and the Soda Bulk Export Terminal construction. The replacement wells in the Landfill Area will not be able to be installed and sampled in 2024. Wells included in the 2024 sampling plan(Table 3) found to be inaccessible or damaged to the extent they cannot be sampled during the 2024 sampling event, if any, will not be sampled in 2024. If a monitoring well included in the 2024 sampling plan, located outside of the Landfill Area, is found to be inaccessible or damaged during the 2024 sampling event, then the well will be added to the 2024 well maintenance activities and located, repaired, or destroyed in accordance with the procedures described in Section 2 of this work plan. The 2024 Groundwater Monitoring Report will include a description of the groundwater monitoring network at RRI following the completion of the 2024 well maintenance activities. If data gaps in the monitoring network outside of the Landfill Area are identified, then additional well installations will be proposed in the 2025 Groundwater Monitoring Work Plan. 4.3 Sampling and Analysis Wells sampled for VOCs will be analyzed by USEPA Method 8260B (Table 3). Wells sampled for TPH gasoline will be analyzed by USEPA Method 8260B and TPH diesel and motor oil will be analyzed by USEPA Method 8015B with silica gel cleanup (Table 3). Existing monitoring wells W-048, W-167, and W-227, within the Landfill area, that had gross alpha method calculation limits above the maximum contaminant levels (MCLs) in 2022 or 2023 will be sampled for radionuclides and potassium-40 (K-40)by USEPA methods 901.1, 903.0, 904.0, 900.0 and SM7110C (Table 3). Existing monitoring wells W-064, W-071, and W-230, within the Landfill area, which had an exceedance of the MCL or the DTSC tap water screening level for metals in 2018 through 2021, will be sampled for title 22 metals by USEPA method 6010B and 7470A. Additionally, wells W-020 (Site 4), W-336 (Site 49 Central Area), and 917-10 (UST 817B Central Area)will be analyzed for the below biogeochemical parameters. Biogeochemical data collected will be used to assess the feasibility of MNA and in-situ treatment technologies for each operable unit. • Field parameters: oxygen reduction potential (ORP),pH, dissolved oxygen(DO), and specific conductance; • Nitrate, nitrite, sulfate, and chloride by USEPA Method 300.0; • Sulfide, total by Standard Method(SM) 4500 RRI 2024 Groundwater Monitoring Work Plan 13 June 13,2024