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02 January 2015 AGE Project No. 14-3298 Page 3 of 4 FIELD PROCEDURES All field procedures will be overseen by an AGE representative working under the supervision of a California Professional Geologist. Procedures for sample collection and analysis, equipment decontamination and sample handling are presented below. SOIL VAPOR SAMPLING Soil-vapor samples will be collected at depths of approximately five feet and ten feet bsg in the borings advanced for collection of soil-vapor samples. Samples will be collected using a Geoprobe soil-vapor assembly. An expendable vapor point will be placed into a point holder at the bottom of an assembly of 1.25-inch diameter hollow 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, '/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 collecting a 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, and tubing in a plastic shroud, which will be weighted at the surface. 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 GcoEnvironmental,Inc.