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19 December 2011 <br /> AGE-NC Project No. 11-2006 <br /> Page 4 of 5 <br /> push the attached soil vapor sampling tool to the specified depth. <br /> Thereafter, one (1) soil vapor sample will be obtained at depths of approximately 5 feet <br /> bsg. Samples will be collected using a 'direct-push' Geoprobe soil vapor sampling <br /> assembly. An expendable vapor point will be placed into a point holder at the bottom of an <br /> assembly of 1.25-inch diameter hollow drive rods. The assembly will then be advanced to <br /> the specified depth and retracted approximately six to twelve inches in order to disengage <br /> the expendable point and expose a column of strata from which soil vapor can be <br /> extracted. A single use, '/4 inch diameter disposable polyethylene tubing is then attached <br /> to a tubing adapter equipped with an O-ring to ensure a vacuum-tight seal. The adapter <br /> assembly is then lowered through the center of the Geoprobe hollow drive rods to the <br /> specified depth and secured by threading into the expendable vapor point holder. <br /> Above ground, the surface around the soil vapor sampler will be sealed with a bentonite <br /> sealant to prevent ambient air intrusion. The end of the polyethylene tubing is attached by <br /> a two-way inlet port to a Tedlar bag placed inside an SKC Vac-U-Chamber (lung box) <br /> vacuum chamber.A vacuum pump attached to a purge port of the vacuum chamber is then <br /> used to purge the exposed soil column, through the sampling tubing and inlet port, until <br /> approximately three volumes of soil vapororambient air is evacuated through the sampling <br /> system. The vacuum chamber is then sealed and the vacuum pump is attached to a <br /> vacuum outlet port of the chamber. When vacuum is applied to the chamber, a negative <br /> pressure is created around the Tedlar bag, which inflates, allowing the soil vapor sample <br /> to enter directly into the bag via the inlet port. When the sample is collected, the negative <br /> pressure in the chamber is reduced and the sample bag is sealed, labeled, log on a chain- <br /> of-custody form, and place into a dry cooler (cool temperature). Subsequently, all of the <br /> collected soil-vapor samples will be delivered to a State-certified laboratory for analysis of <br /> the TPH-all and VOC's by the methodology listed above. <br /> After collection of the sample, soil vapor from the polyethylene tubing will be monitored for <br /> the presence of volatile organics using a photo-ionization detector (PID) <br /> EQUIPMENT DECONTAMINATION <br /> Prior to use, all sampling tools used for sample collection will be thoroughly rinsed with <br /> clean water after being washed with a solution of Alconox. All probing rods will be cleaned <br /> prior to advancement at each probe boring location. <br /> BORING ABANDONMENT <br /> The probe borings will be permanently sealed to prevent vertical migration of potential <br /> Advanced GeoEnvieonmenfal,Inc. <br />