ARCHIVED REPORTS XR0006542 - Laserfiche WebLink

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R603 UPDATE-13 2/15/93 Mg/L and xylenes 7 362 Mg/L. On January 21, 1993 , a sample of the water being treated by air stripping inside the "ConVault" was obtained for certified laboratory analysis, before dumping approximately 600 gallons of this water to the City of Stockton' s sanitary sewer, see Table 4 and Appendix A As of January 19, 1993 , a total of 14, 890 . 25 gallons of gasoline range hydrocarbons have been removed from the soil and ground water beneath this site. Previously removed floating product (40 .25 gallons) , projected petroleum hydrocarbon in situ oxidation CO2 vapor recovery (39046 pounds/6 25 pounds/gallon 6247 4 gallons) and vapor extraction--destruction of hydrocarbons (53766 pounds/6 . 25 = 8602 . 6 gallons) No chlorinated solvents were detected in chromatogram comparisons, "i e " 1, 2 , - Dichloroethane (DCE) - retention time 2 079 minutes, Trichloroethylene (TCE) - retention time 3 . 023 minutes and Tetrachloroethylene (PCE) - retention time 3 75 minutes . 4 . 0 DISCUSSION AND CONCLUSIONS As stated in earlier reports, the soil is contaminated with gasoline range hydrocarbons beneath the tank field (MW10) and along the capillary fringe of the ground water, (MW1, MW2, MW3 and MW10) . Ground water beneath the site contains the dissolved constituents of gasoline range hydrocarbons and had spread to the north (MW-6) , to the south (MW-7) to the west (MW-9) and to the east (MW-12) . The latest ground water sampling, December 9, 1992, shows the continual decline in the lateral extent of the plume, see Table 1 . Vapor extraction started October 17, 1991 and has operated for 6349 hours (January 19, 1993) out of a possible 10340 . 25 hours, 6115 run time, destroying 53766 pounds of gasoline range hydrocarbons Since the last status report, December 18 , 1992 , 5456 pounds of gasoline range hydrocarbons have been removed/destroyed and an estimated 3515 pounds of oxidized hydrocarbons as CO2 removed (averaged 1 . 515 in influent stream) in 416 hours of operation (averaging 21 . 56 pounds per hour or 51.7 pounds per day of operation) DCE, TCE and PCE screening show that these compounds are not present in the vapor stream, see Appendix A - Air Monitoring Report a c-.ou ro,,en shot- t'he ground [+IatPY' - q -1n a I.SlpilI1C1 Wc1tCi Gle'va�.ivi+ i114�-i..�++.�r�1��r++�+u �-� recharge cycle, which is normal for this site during this time of the year, with a basin forming at MW2, while the overall flow direction is to the east from the tank area towards monitoring well MW12 Results of ground water samples collected on December 17, 1991, approximately 1473 hours after commencement of vapor extraction, compared to the results of ground water sample collected on December 9, 1992, 9355 . 5 hours (390 days) after commencement of PAGE 9