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Conestoga-Rovers & Associates <br /> STANDARD FIELD PROCEDURES FOR SOIL VAPOR PROBE <br /> INSTALLATION AND SAMPLING <br /> DIRECT PUSH AND VAPOR POINT METHODS <br /> This document describes Conestoga-Rovers & Associates' standard field methods for soil vapor <br /> sampling. These procedures are designed to comply with Federal, State and local regulatory <br /> guidelines. Specific field procedures are summarized below. <br /> Objectives <br /> Soil vapor samples are collected and analyzed to assess whether vapor-phase subsurface contaminants <br /> pose a threat to human health or the environment. <br /> Direct Push Method for Soil Vapor Sampling <br /> The direct push method for soil vapor sampling uses a hollow vapor probe, which is pushed into the <br /> ground, rather than augured, and the stratigraphy forms a vapor seal between the surface and <br /> subsurface environments ensuring that the surface and subsurface gases do not mix. Once the desired <br /> soil vapor sampling depth has been reached, the field technician installs disposable polyethylene <br /> tubing with a threaded adapter that screw into the bottom of the rods. The screw adapter ensures that <br /> the vapor sample comes directly from the bottom of the drill rods and does not mix with other vapor <br /> from-inside-the-rod-orfrom-the-ground-surfac�.--]n addition, Illydtafed-bentonite is`place aroun t e - <br /> sampling rod and the annulus of the boring to prevent ambient air from entering the boring. The <br /> operator then pulls up on the rods and exposes the desired stratigraphy by leaving an expendable drive <br /> point at the maximum depth. The required volume of soil vapor is then purged through the <br /> polyethylene tubing using a standard vacuum pump. The soil vapor can be sampled for direct <br /> injection into a field gas chromatograph, pumped into inert tedlar bags using a "bell jar" sampling <br /> device, or allowed to enter a Summa vacuum canister. Once collected, the vapor sample is transported <br /> under chain-of-custody to a state-certified laboratory. The ground surface immediately adjacent to the <br /> boring is used as a datum to measure sample depth. The horizontal location of each boring. is <br /> measured in the field relative to a permanent on-site reference using a measuring wheel or tape <br /> measure. Drilling and sampling equipment is washed between samples with trisodium phosphate or <br /> I <br /> R:IROCKLIMPUBUCPROCEDURES & SOPS\SOIL VAPOR SOP UPDATED 01-07.DOC <br />