ARCHIVED REPORTS XR0008167 - Laserfiche WebLink

Home Browse Search

R604 :UPDATE 26 1-21-1994 syringe is then inserted through the sample septum into the tedlar bag. The Icc 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 3027 pounds Soil sample results from the SB4 confirmation sample boring and vapor samples from the vadose zone well P1 have indicated that the former northeastern pump island area and the surrounding area (AREA C) is now remediated of the contaminant The two remaining areas of impacted soil are 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 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 3027 pounds that remained in the soil after the July 22 , 1992 sampling, 247 out of an estimated 72 pounds have been removed from AREA A (VSB5) and 3191 out of an estimated 2946 5 pounds have been removed from AREA B (MWS, VSB3 , VSB9 and VSB11) This indicates that the majority of degraded volatile gasoline range hydrocarbons has been removed from the soil and ground water at this site Dual instruments, GC FID and GC PID, have confirmed that benzene, toluene and ethylbenzene are no longer components of the vapor streams, which indicate the more volatile and mobil compounds of gasoline have been removed It is obvious that during our planned up coming confirmation drilling some of the heavier non hazardous compounents will be found in the soil It is expected that these less mobile non corcinogenic compounds will have concentrations low enough to be left in place. Monitoring of the ground water indicates that contaminated ground water associated with MW1 and MW5 has been remediated and meets the Title 22 and DHS standards Ground water gradients, corrected for vacuum influence, have shown potentiometric lows at the wells being used for vapor recovery (MW5) . Once the vapor recovery is shut off, normal flow directions again take place to the east-southeast or northeast , with the exception of the March 5, 1992 gradient, which flowed to the north-northwest and may page 6