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11 December 2003 AGE-NC Project No. 03-1109 Page 4 of 5 reports of both soil vapor and soil analyzes, testing methods, laboratory quality assurance/quality control(QA/QC)reports, and sample chain of custody documentation will be presented in a report with the findings and recommendations. 4.0. FIELD PROCEDURES All field procedures will be overseen byan AGE representative under the supervision of a California Registered Geologist. Procedures for the advancement/destruction of borings, soil sampling, equipment decontamination and sample shipment are outlined below. 4.1. PROBE BORING ADVANCEMENT Probe borings will be advanced to depths of 15 feet bsg using a van-mounted Geoprobe 5400 direct- push probing unit equipped with 1.25-inch probing rods.The Geoprobe advances soil probe borings using a hydraulic hammer to drive soil sampling tools to specified depths. 4.2. COLLECTION OF SOIL GAS SAMPLES Soil gas samples will be obtained at a depth of approximately 15 feet bsg in each 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 of strata 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'/< 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 expendable in soil and creating a void open boring. Above ground,the polyethylene tubing is attached to vacuum sampling chamber.A Tedlar bag will placed into a 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. Advanced GeoEnvimrnnental,Inc.