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07 December 2020 Project No. 20-6249 Page 5 of 6 assembly will be attached to the 0.25-inch Teflon® tubing from the soil-vapor well. The purge canister will be attached to the end of the stainless-steel sampling manifold while the sample canisters will be attached to the tee-fitting between the 0.25-inch Teflon® tubing and purge container. Teflon® tape will be placed on the threads of each open fitting of the manifold assembly prior to attaching the 0.25-inch Teflon® tubing and sampling and purge canisters. Each canister’s initial vacuum will be measured and recorded between -26 and -30 inches of mercury (in hg). Shut-in tests will be performed on each assembly by attaching and securing the sample and purge canisters to the manifold and opening the valves on the purge canister and the manifold. Each soil-vapor well location will be isolated from ambient air by enclosing the borehole, tubing and manifold/canister assembly in a 100- liter shroud. Isopropyl alcohol (IPA) will be emitted into the shroud surrounding the well borehole, tubing and manifold/canister assembly and acts as a tracer gas to evaluate if leaks in the sampling apparatus have allowed infiltration of ambient air. Upon achieving a successful leak test, the purge canister valve will be opened for a period to allow the three calculated volumes of air to be purged. The purge vacuum gauge will be monitored to ensure a proper decrease of vacuum purged. Upon achieving the targeted purge volume, the purge canister valve will be closed, and the sample canister valve opened. The initial pressure and time is recorded. Upon reaching at least -5 in Hg or less, the sample canister valve will be closed, and final pressure and time recorded. The sampling port on the sampling canister will be capped with a brass end-cap. The soil-vapor samples will be transported under chain-of-custody procedures to an ELAP-certified laboratory and analyzed for VOCs and IPA (tracer gas) in accordance with EPA Method TO-15. 2.5. BORING ABANDONMENT All soil borings will be permanently sealed to prevent vertical migration of potential contaminants. Soil borings shall be abandoned by backfilling with cement grout from the total depth to surface grade. Borings advanced below the groundwater table will be abandoned with grout utilizing tremie procedures. The top three to six inches of the boring abandonments will be completed flush to surface grade with concrete or native material. The EHD will be notified for grout inspection at least 48 hours prior to conducting grouting procedures 2.6. EQUIPMENT DECONTAMINATION/WASTE MANAGEMENT All sampling tools used for sample collection will be thoroughly rinsed with clean water after being washed with a solution of Alconox. All probing rods will be cleaned prior to advancement at each probe boring location. Any soil or water waste generated during