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' 24 September 1999 AGE-NC Project No. 96-0232 Page 12 of 12 ' an expendable vapor point placed into a point holder at the bottom of a 1-inch diameter hollow drive rods. The assembly will be advanced to the specified depth and retracted approximately six inches in order to engage the expendable point with the surrounding soil, thereby opening the point holder ' and adopter to an exposed column of strata from which soil gas can be extracted. A post run tubing adapter equipped with an 0-ring is attached to ensure a vacuum-tight seal, to a ''/<-inch diameter ' disposable polyethylene tubing. The sampling tube is lowered through the center of the hollow drive rods and secured by threading into the expendable point holder. This allows only soil gas below the holder at the end of the drive-rod assembly to enter the sample tubing. The polyethylene tubing is ' attached to a stainless steel T-valve and to a vacuum pump contained within the GeoProbe 5400 soil sampling machine. The vacuum pump will apply a negative pressure to the exposed soil and into a Tedlar bag attached at the vacuum chamber sampling point. The Tedlar bag will be sealed after ' collection of the gas sample, labeled, logged on chain-of-custody and placed into a dry cooler pending analysis by a DHS-certified laboratory. The soil gas vapor concentrations will be monitored and recorded on field notes from the polyethylene tubing for the presence of volatile organic ' compounds using a organic vapor meter (OVM) equipped with a photo-ionization detector (PID) pre-calibrated to isobutylene. ' 4.5. EQUIPMENT DECONTAMINATION PROCEDURES All sampling tools used for sample collection will be thoroughly rinsed with clean water after being washed with a solution of Alconox. All down-hole drilling and sampling equipment will be washed ' prior to starting the boring. ' 4.6. DRAWDOWN PILOT TEST A water drawdown pump will be utilized to induce a decline in static water level from the extraction ' well; pressure transducers will be deployed in all wells to measure difference in ground water levels before well pumping versus during well pumping. Ground water pumping rates will be increased at ' regular intervals to achieve optimum pumping rate for the greatest drawdown influence. Results of the drawdown pilot test will be included in a Corrective Action Plan (CAP) and submitted to PHS- EHD. ' Purged ground water will be containerized in a 20,000-gallon Baker tank; composite "grab" ground water samples will be collected from the Baker tank for analysis of TPH-g, BTEX and MTBE. The ' purged ground water will be discharged into the City of Stockton sewer system pending regulatory approval or will be transported to a suitable hazardous waste facility. The duration of the drawdown pilot test will be approximately 8-hours. Advanced CcoEnvironmental,Inc.