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11 July 2007 AGE-NC Project No. 98-0533 Page 5 of 5 of six inches, placing the expendable tip in soil and creating a void open boring. Above ground,the polyethylene tubing is attached to a vacuum sampling chamber.A Tedlar bag will placed into the vacuum chamber.The sampling tube will be attached directly to the Tedlar sampling bag,through a collapsible,air tight port. The vacuum chamber is then sealed.The vacuum will then be used to purge the exposed soil column, through the sampling tubing, until approximately three volumes of soil vapor or ambient air is evacuated through the sampling system.The vacuum is then applied to the chamber,creating a negative pressure on the inside of the sample Tedlar bag. The bag then fills with vapor from the subsurface, allowing the sample to enter directly into the Tedlar bag. On completion of the collection of the gas sample,the negative pressure in the chamber is reduced and the sampling bag sealed. Upon collection, each sample will be labeled, logged on a chain of custody form and place into a dry cooler. Samples will be delivered to a State-certified laboratory for analysis of the constituents described in Section 2.2. �Vd After collection of the sample, soil vapor from the polyethylene tubing will be monitored for the presence of volatile organics using a photo-ionization detector pre-calibrated to isobutylene. _ 3.4. EQUIPMENT DECONTAMINATION Prior to use,all sampling tools used for sample collection will be thoroughly rinsed with clean water after being washed with a solution of Alconox. All probing rods will be cleaned prior to advancement at each soil boring location. _ 3.5. BORING ABANDONMENT All soil borings will be permanently sealed to prevent vertical migration of potential contaminants. Soil borings shall be abandoned by backfilling with portland cement from the total depth to within six inches surface grade and backfilled with native soil or concrete. Advanced GeoEnvironmental,Inc.