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05 March 2015 • • AGE Project No. 14-3214 Page 3 of 4 drive rods. The assembly will then be advanced to the specified depth and retracted approximately six to twelve inches in order to disengage the expendable point and expose a column of strata from which soil-vapor can be extracted. Single use, '/<-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. For collection of soil-vapor samples at ten feet bsg, a temporary soil-vapor well will be installed in the borings after advancing to ten feet bsg. A disposable vapor implant and thirteen feet of %-inch Teflon tubing will be lowered to the base of the borehole; three feet of tubing will be left outside the borehole for vapor sample collection. Once the tubing and vapor implant are in place, a filter pack of#2/12 sand will be placed from the bottom of the borehole to 9.5 feet bsg. Following placement of the filter pack, dry bentonite crumbles will be placed atop the filter pack to eight feet bsg. Thereafter, bentonite will be placed and hydrated from eight feet bsg to surface grade to seal the vapor well from 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 and 3 minutes) to remove at a minimum three purge-volumes of air prior to collecting a soil-vapor sample in a one-liter Tedlar bag. 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, tubing, and sample bag in a plastic shroud, which will be weighted at the surface. Isopropyl alcohol (IPA) as a liquid will be placed in a stainless steel bowl within the plastic structure and allowed to volatilize into the air enclosed within the plastic structure surrounding the borehole, tubing and sample bag. After sample collection, Tedlar bags 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 TPH-g by EPA method 8015 modified and VOC's by EPA method 8260B. EQUIPMENT DECONTAMINATION Prior to 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. Advanced GeoEnvironmental,Inc.