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Soil Vapor Sampling SOP Page 6 of 11 Stantec Rev. 1.0 Apr 2019 Note: for nested multi-depth soil vapor wells, will follow the same procedure for each selected depth. Drive-Point Method The drive-point method of soil vapor collection generally includes use of a Geoprobe direct- push, drill rig equipped with a drive point method and post-run tubing system (PRT). Proposed sampling locations should be based strictly on the absence of subsurface utilities documented as part of pre-field activities and the absence of strata or lithologies containing cobbles or boulders which can create gaps between the outer wall of the drive rod and the subsurface. The downhole components of the PRT system include: • Sample delivery tubing • Probe rods • PRT Adapter • Expendable point holder • Expendable point • O-ring seals are used on the PRT Adapter, the expendable point holder and at all rod joints. The 0-rings prevent soil ingress which can prevent air-tight docking of the PRT adapter. PRT Installation Installation procedures for PRT are generally as follows: 1. Place O-ring on PRT expendable point holder and attach to initial section of probe rod. 2. Place O-ring on expendable point and press into expendable point holder. 3. Add drive cap to probe rod and push PRT system into ground the distance of the intended open interval. Take special care to assure that the rods are in line with the push axis of the probe machine. 4. At the desired sampling depth, attach a point popper to an extension rod and insert extension rod string into rods so that the point popper rests on the expendable point. Using the rod puller and taking special care to maintain probe alignment with the rods, begin pulling the rods while maintaining pressure on the extension rods. The extension rods should drop when the pull is started, indicating that the expendable point has been ejected. The rods can then be pulled to expose the desired open sampling interval. 5. Secure the PRT adapter to a length of tubing sufficient to reach from the sampling interval to the surface, with several feet of excess tubing extending beyond the top of the probe rod to facilitate sampling. The adapter is secured tightly to the tubing using electrical tape. This will not compromise the integrity of the sample to be collected, as the sample is pulled directly through the adapter and is never exposed to the tape. 6. Run the tubing and adapter into the probe rod and, using steady downward pressure, turn the tubing counterclockwise to dock the adapter into the top of the expendable point holder. Tug gently on the tubing to ensure that the adapter engaged with the expendable point holder. Continue rotating tubing until the adapter is firmly seated. Failure to dock THIS INFORMATION FOR AUTHORIZED COMPANY USE ONLY STANTEC CONSULTING