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CLOSURE REQUEST 5-31-94 Poundage is then added to the accumulated poundage of the previous visit to update the total pounds removed to date, see Table 3 and Appendix C Sampling vapor Streams: The vapor samples are obtained by attaching a dedicated air tight soft polytubing to a sample port on the well side of the orifice plate on the vapor recovery manifold. The tubing is then connected to a tedlar bag placed inside a vacuum sampler The sample port is then opened and a vacuum placed on the outside of the tedlar bag from the sample vessel allows the tedlar bag to fill with the vapor stream from that particular sample port . Once the tedlar bag is full the valve is closed and the vacuum removed from the sample vessel The tedlar bag contains an air tight locking septum valve which is then closed and locked to secure the vapor sample. A small dedicated needle attached to a dedicated 1 cc syringe is then inserted through the sample septum into the tedlar bag. The 1cc syringe is purged numerous times before filling it with the sample. All but 0 . 5 cc of the sample is ejected from the syringe, into the air before injecting the remaining 0 5 cc syringe sample into the Shimadzu FID-GC (the calibrant injection is 0 . 5 cc) . Once the chromatogram is recorded, an instrument blank is run prior to the next sample . The analysis of the instrument blank will verify that no residual peaks are being carried onto the next analysis . Vacuum influence 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 SUMMARY Estimates of petroleum hydrocarbons remaining in the soil after the confirmation soil sampling that occurred on July 20, 21, 22, 1992 was approximately 3436 pounds in AREA A - (SB5) the area beneath the former western pump island and AREA B (SB3 , SB9 and SB11) the area southeast of the former underground storage tanks . Soil sample results from the most recent confirmation soil sample borings (SB13 , SB14 and SB15) obtained on February 2, 1994 indicated approximately 531 pounds of degraded gasoline remained in areas A and B. Vapor extraction has removed the lighter fractions of gasoline range hydrocarbons found in the soil and has greatly reduced the dissolved and hazardous heavy end contaminant (Xylenes) found in the ground water and the capillary fringe . Of the estimated 3436 pounds that remained in the soil after the July 22 , 1992 sampling, 4284 pounds had been removed by the VES through the vapor stream when the system was turned off on December 30, 1993 This indicates that the majority of degraded volatile gasoline range hydrocarbons has been removed from the soil and ground water at this site. page35