Soil Vapor Implants & PRT Systems

PRT (Post Run Tubing) Active Sampling for Soil Gas

The Geoprobe system is used to collect soil-gas samples through disposable Post-Run Tubing (PTR), which runs from the tip of the probing unit to a purging pump located in the rear of the Geoprobe van.

The Post Run Tubing System (PRT) is an ideal tool for locating and delineating contaminated areas when used properly. It allows the user to collect soil vapor samples quickly and easily at the desired sampling depth WITHOUT the time-consuming complications associated with rod leakage and contamination. O-ring connections enable the PRT system to deliver a vacuum-tight seal that prevents sample contamination from UP hole, and assures that the sample is taken from the desired depth at the BOTTOM of the hole. The sample is drawn through the point holder, through the adapter, and into the sample tubing. The tubing can be replaced after each sample, thus eliminating sample carryover problems and the need to decontaminate the probe rods. The resulting time-savings translates into a higher productivity rate for you and your client.

The PRT is inserted AFTER the probe rods are driven to depth. Advantages include...

• Increases speed and accuracy of soil gas sampling.
• Eliminates problems associated with rod leakage and sample carryover.
• Utilizes simple design for ease of use and vacuum-tight probing.
• Sampling train and all connections can be checked to verify leak-free status.
• Requires no management of inner tubing during probing.

PRT Applications:

• Rapidly define the extent of VOC contamination in the subsurface, under appropriate conditions.
• Rapidly define potential source areas of VOC contamination over large or small areas.
• Determine the types of VOC contamination present in the subsurface at a facility.
• Rapidly define the potential extent of groundwater contamination and down gradient migration of VOC's under appropriate conditions.
• Determine presence, extent, concentration, and types of landfill gasses (methane, carbon dioxide, et.) present in the subsurface at active and abandoned landfills.
• Locate potential sources and delineate plumes of perchloroethylene (PCE) associated with active or abandoned dry cleaning facilities.
• Locate potential source and delineate plumes of carbon tetrachloride (CCI4) associated with active or abandoned grain storage facilities.
• Locate potential sources and delineate plumes of benzene, toluene, ethyl benzene, and xylenes (BTEX) associated with active or abandoned gasoline storage facilities [both underground storage tanks (UST) and above ground storage tanks (AST)].
• Locate potential sources and delineate plumes of chlorinated solvents, including compounds such as trichloroethane, trichloroethylene, dichloroethane, and dichloroethylene, associated with active or abandoned facilities where degreasing or metal plastic parts cleaning operations were conducted.

Installing Soil Gas Sampling Standard Operating Procedures:

• Connect expendable drive point to Post Run Tubing expendable point holder.
• Adapt PRT point holder to 1.5" steel rods.
• Advance rods to predetermined depth.
• Release expendable point and expose end of probe by retracting rods approximately 6".
• Connect PRT tubing adapter to client selected tubing.
• Connect tubing to PRT point holder.
• Seal drill rods at surface of borehole and top of the rod where tubing is inserted using hydrated bentonite to inhibit surface air infiltration into the system.
• Allow bentonite to hydrate and conduct leak test.
• Allow at least a 30 minute equilibrating period before purging and collecting soil gas sample.
• Grout boring upon completion.