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22 May 2007 AGE-NC Project No. 97-0360 Page 5 of 6 Each ground water sample will be extracted by lowering a polyethylene bailer through the hollow center of the push rods into the screen section. Samples for BTEX will be collected into laboratory supplied, 40-m1 volatile organic analysis (VOA) vials without sample preservative. Samples for TPH-d analysis will be collected into laboratory-supplied, 1 liter amber bottles without sample preservative. Appropriately sealed and labeled samples will be placed in a chilled container under ice and transported under chain of custody procedure to a DHS-certified laboratory. Each sample container will be labeled with the boring designation, time. date and sampler's initials. 3.1.3. Soil-Vapor Sampling Procedures Soil vapor samples will be obtained at a depth of approximately 5 feet bsg in each soil vapor boring. 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 a string of 1-inch diameter hollow drive rods. The assembly will then be advanced to the specified depth and retracted between six inches in order to engage the expendable point and expose a column ofstrata from which soil gas can be extracted. A post run tubing adapter equipped with an O-ring to ensure a vacuum-tight seal is then attached to a %4-inch diameter. single use, disposable polyethylene tubing. The sampling tube is then lowered through the center of the hollow drive rods and secured by threading into the expendable point holder. The probe rod is retracted a minimum of two feet, 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 complete 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 volatile organic compounds (VOCs)to include BTEX and naphthalene in accordance with EPA Method 8260B and/or Method TO-15. After collection of the sample, soil gas from the polyethylene tubing will be monitored for the presence of volatile organics using a photo-ionization detector(PID) pre-calibrated to isobutylene. Advanced GeoEnvironmental,Inc.