To evaluate the vapor intrusion pathway for a building and to assess the associated human health risks, soil gas samples near the building site and under the building foundation may be collected. In order to meet risk assessment goals, the analytical laboratory is often required to report compounds of concern for these soil gas samples down to the part per billion ranges or lower. To insure data quality objectives are achieved, the appropriate sample tubing, collection media, and leak check compounds should be selected. Several types of tubing and collection media commonly used in the soil gas and sub-slab sample collection trains are evaluated for background contribution and adsorption of volatile organic compounds (VOCs). Additionally, quality considerations when applying a leak check compound are described.
Impact of Sampling Media on Soil Gas Measurements