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Active Groundwater Sampling Standard Operating Procedure <br /> SWE-FSOP-401;Revision 1 Ahtna Southwest Environmental Operations <br /> [PFAS Project]: Use PFAS-free tape <br /> • Paper towels <br /> • Purge water storage (drums, tanks, etc.) <br /> • Sample bottles <br /> [PFAS Project]: Do not use glass, LDPE, or Teflon®-lined caps. <br /> • Sample Labels <br /> • Sample tubing (inert material) <br /> [PFAS Project]: Do not use Teflon°-lined tubing. <br /> • Timing device <br /> • Tools to open wells <br /> • Vehicle battery(or external power supply)to power pump with pump controller <br /> 4.0 Procedures <br /> Procedures are provided for: <br /> • Pre-sampling tasks (Section 4.1) <br /> • Preparing a well for collecting representative samples (Section 4.2) <br /> • Sampling using four different devices (Section 4.3 to 4.6) <br /> • Filling sampling containers (Section 4.7) <br /> • Document control (Section 4.8) <br /> 4.1 Pre-Sampling Tasks <br /> The PL or FTL should rank sampling locations based on the concentrations of target analytes.The highest <br /> concentrations should be sampled last to minimize potential cross-contamination.The PL should provide <br /> instruction for the order of sampling or whether contaminant-level ranking is necessary. <br /> The most recent groundwater levels and water quality data should be available to the Field Team. That <br /> information is used to evaluate the reasonableness of the water level and water quality measurements of <br /> the current event. Unusual measurements should be verified. <br /> Determine the intended pump intake placement in advance, considering the most recent water level <br /> measurement. Typically, the screen midpoint is used or a depth selected from the evaluation of multi- <br /> depth sampling.The PL shall ensure those depths are available to the Field Team. <br /> Decontaminate all equipment that could come into contact with sampling equipment and decontaminate <br /> and calibrate all instruments before obtaining field data according to SWE-FSOP-801 (Equipment <br /> Decontamination) and SWE-FSOP-107 (Equipment Calibrations). Equipment in contact with groundwater <br /> at one location must be decontaminated before reusing at another location. <br /> [PFAS Project]: Reusable non-dedicated equipment will be rinsed with certified PFAS-free water <br /> prior to and following the collection of each sample. If another source of water is used, collect a <br /> water sample and run laboratory tests for PFAS before using that source. <br /> Page 7 of 14 <br />