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REG 603 UPDATE-7 3/24/92 pulling and pushing the syringe plunger several times filling and depleting the syringe of that particular wells vapor stream. Then the syringe is filled, the sample valve closed and forceps are used to clamped onto the soft polytubing to create an air tight seal for the syringe before removing the syringe from the sample port. Once the 60 cc syringe is removed with the forceps clamped polytubing attached, the plunger is pushed into the syringe to create pressure within the syringe and released to allow the vapors that have been captured to reach equilibrium. A small dedicated needle attached to a dedicated 1 cc suringe is then inserted into the 60 cc syringe via the soft tubing for obtaining the sample to be injected into the PID-GC. Again the lcc syringe is purged numerous times prior to filling it with the sample. All but 0. 5 cc of the sample is e3ected into the air prior to injecting the remaining 0 . 5 cc syringe sample into the GC-PID (the calibrant injection as 0 . 5 cc) . Once the chromatogram has been recorded an instrument blank is run prior to the next sample. The instrument blank will indicate if residual peaks are being carried onto the next analysis. While the GC-PID analysis is running for a particular sample ( 15 • minutes per sample run) , vacuum influent readings are obtained from the wells by attaching a manometer calibrated in mm water to sample ports at the well heads. These readings show the mm water pressure or vacuum that is being created at each well. C. 3 . VAPOR RECOVERY OPERATIONS AND RESULTS As has been stated above, soil contamination exists from beneath the tank excavation to the top of the ground water. Overexcavation during the intial tank removal, removed contaminated soil to the 25 foot depth. Prior to replacement of the new double contained fiberglass tanks and dispensing system, 4 inch and 6 inch SCH 40 PVC 0 . 02 inch slotted pipes were placed vertically at the north corner and west corner of the excavation respectively and manifolded via underground to the treatment compound with SCH 40 2 inch and 4 inch PVC pipe. These pipes along with monitor wells MW1, MW2, MW3 and MW10 are being used for vapor extraction - soil and ground water remediation. On October 10, 1991 the vapor extraction system operated for 6 hours, to check the auto shut downs and percent destruction of the REMOX unit, utilizing monitor wells MW1, MW10, and the excavation wells. The system was restarted on October 17, 1991 for the initial inspection and operation of the system. The unit operated until November 5 , 1991, when it was shut down to replace a worn bearing. The system was restarted after the repairs on November 20 , 1991 and operated until December 24, 1991 . On this date someone turned off the main breaker that services the treatment PAGE 9