Soil Vapor Sampling Standard Operating Procedure

Soil vapor samples are collected at discrete depths using an expendable point, an expendable point holder, a PRT adapter and tubing. The expendable point is placed in the expendable point holder, which in turn is attached to our drive rod, and driven to depth. The drive rod and expendable point holder are retracted, separating the expendable point from the point holder, and creating the desired void in the soil. A PRT adapter and tubing are advanced down the inner rods and secured to the expendable point holder. The tubing at the surface is attached to the Vacuum/Volume System on the Geoprobe rig to purge the line and draw a sample. Vironex typically uses polyethylene tubing to draw samples, although other tubing is available as circumstances warrant. The used tubing is discarded after each sample. A regulator is placed in-line to maintain a 200 cc (ml) per min flow rate while purging or collecting soil gas samples. Once the line has been purged, samples can be extracted from the line using a syringe, glass bulb, summa canister or captured and stored in a tedlar bag with the use of a vacuum box.