Laserfiche WebLink
Soil Vapor Sample Collection <br /> Manual (Hand) Driven-Rod Probes <br /> A hardened steel soil vapor probe of —1 inch OD equipped with a hardened <br /> steel tip is driven to the target depth with an electric rota-hammer. Inert 1/8" <br /> OD nylon tubing runs down the center of the probe rod and is connected to a <br /> sampling port just above the tip. This internal sample tubing design eliminates <br /> any contact between the soil vapor sample and the steel rod. Once at the <br /> target depth, the probe rod is slightly lifted exposing a sampling port at the tip. <br /> Surface Seals <br /> The probe rods are sealed at the ground surface with granular and hydrated <br /> bentonite. <br /> Use of Tracer Compound to Ensure Probe Seal Integrity <br /> Since such small sample volumes are being withdrawn, the chances of <br /> leakage from the surface is small despite the shallow sampling depths. <br /> Nevertheless, diflouroethane will be used as a tracer to determine if there is <br /> a leak from the surface. A towel with the compound on it will be placed at the <br /> base of the probe rod where it contacts the ground. This will be done at the <br /> 1-foot depth. If no leaks are seen at this depth, it will not be done at the <br /> deeper depths at that location. If a leak is detected at the 1-foot depth, it will <br /> be done at the 2-foot depth and so on for the rest of the vertical profile. <br /> Probe Purging <br /> 20cc to 50cc (3 to 8 dead volumes) are purged at each depth before <br /> collecting a sample for analysis. <br /> Sample Depths <br /> Samples will be collected every foot from 1-foot to 6-foot bgs <br /> ©Hartman Environmental Geoscience 2011 <br />