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21 October 2013 AGE Project No. 13-2675 Page 4 of 5 Single use, '/4-inch diameter disposable polyethylene post run tubing (PRT) is then attached to a tubing adapter (PRT adapter) equipped with a new disposable O-ring to ensure a vacuum-tight seal. The adapter assembly is then lowered through the center of the hollow drive rods to the specified depth and secured by threading into the expendable vapor point holder (PRT Point Holder). Hydrated bentonite will be placed around the drive rod at ground surface to prevent ambient air intrusion. A minimum of 30 minutes equilibrium time will be allowed at each soil-vapor boring location and depth prior to purging and sample collection. Each sampling point will be purged for a calculated time period (between 2.5 and 3 minutes) to remove three purge-volumes of air prior to obtaining a sample in 1 liter tedlar bags. Once the purging is complete a sample will be collected using a peristaltic pump and low-flow sampling techniques (200 milliliters per minute). Each soil-vapor boring location will be isolated from ambient air by enclosing the borehole, and tubing in a plastic shroud, which will be weighted at the surface. After sample collection the tedlar bag will be labeled and stored in a dry container. Soil vapor samples will be transported under chain-of-custody procedure to a CDPH-certified laboratory and analyzed for VOC's by EPA method 8260B. EQUIPMENT DECONTAMINATION Priorto use, all non-disposable sampling tools used for sample collection will be thoroughly rinsed with clean water after being washed with a solution of Alconox. BORING ABANDONMENT The soil borings will be permanently sealed to prevent vertical migration of potential contaminants. Each soil boring shall be backfilled to surface grade with neat portland cement and covered with concrete. Advanced Geo Environmental,Inc.