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Appendix A-Sampling and Analysis Plan BSK Project E19-016-01F Stockton Metropolitan Airport(SCK) March 1, 2023 Stockton, California Page 9 4.3.4.Groundwater Sampling for Vertical Definition of Groundwater Groundwater samples will be obtained from groundwater monitoring wells during the first and second phases of the investigation. Additionally, during the second phase of investigation, while advancing borings for vertical definition of groundwater using BESST INC's, SimulProbe sampler (SimulProbe), or similar sampling device. The SimulProbe sampler obtains a grab groundwater sample once the desired sample depth is reached by: 1. Pressurizing the SimulProbe sampler using Nitrogen gas or a compressed air source. 2. Next,the sampler is deployed through the center of the HSA where the SimulProbe is driven into the formation.The screen of the SimulProbe is exposed by pulling back on the sampler. 3. After the screen is exposed,the pressure is slowly released,creating a vacuum which draws water from the formation, into the SimulProbe sampler. 4. Once groundwater is collected into the sampling device, the SimulProbe is pressurized again to hold groundwater in the sample chamber and is retrieved to the surface. The bottom half of the sampler is disassembled, and groundwater is collected by inserting a small piece of tubing into the bottom of the SimulProbe, allowing the water to drain into the appropriate sample container(s). Materials used inside the sampler to collect groundwater and seal the sampler from the formation will be constructed of a material that is considered acceptable (i.e., high-density polyethylene, vinyl, acetate, etc.,) according to the California State Water Quality Control Board, Division of Water Quality document titled "Per- and Polyfluoroalkyl Substances (PFAS) Sampling Guidelines for Non-Drinking Water" dated September 2020. If it cannot be determined that the SimulProbe is appropriate for sampling constituents, such as PFAS, an equipment blank sample evaluating the SimulProbe and associated materials will be submitted prior to groundwater sampling, or alternate sampling devices will be considered. Groundwater samples will be collected once first groundwater is encountered and in 10 ft intervals thereafter, for 40 ft passed first encountered groundwater (i.e., groundwater encountered at 40 ft bgs, sampled to 90 ft bgs). A total of (6) groundwater samples will be collected per boring including one (1) duplicate groundwater sample per boring.Additionally,a field blank would be collected at boring location and/or each day of sampling. For in depth Quality Assurance/Quality Control (QA/QC) procedures please refer to Section S of this SAP. Please note that parameters such as pH, EC, DO,Turbidity, etc., may not be obtained while sampling with the SimulProbe.The SimulProbe collects a fixed volume of groundwater and the purpose of sampling with the SimulProbe is to collect a "representative"grab sample of groundwater and should not be subject to mixing, dilution, etc., which may occur while drilling to obtaining grab groundwater samples. EE�� , ,v