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R604 .UPDATE 21 9-1-1993 <br /> creates an anomalously high concentration at this well . With <br /> this in mind, the "Present California Water Quality Goals" have <br /> been met for over 6 months, see Table 1 <br />`. Fecal Col2form: <br /> From December, 1991 through February, 1992, monthly fecal <br /> coliform samples were collected from monitor wells MW3 , MW4 , MWS <br /> and MW6 . Samples were again collected in June, 1992 , from <br /> monitoring wells MW3 , MW4 and MW6 During the September 11, 1992 <br /> sampling, MW3 and MW6 were dry; no fecal coliform samples were <br /> obtained Table 2 shows the results of these samples As of <br /> June, 1992 all these wells are below detection limits, ¢2 2 MPN, <br /> for fecal coliform <br /> VAPOR EXTRACTION <br /> Vapor Recovery Results: <br /> The vapor extraction system was shut down on November 21, 1991 on <br /> completion of operation under Initial Variance ##91-19 and 90 day <br /> Variance ##91-20 . A total of 13 , 116 pounds of gasoline range <br /> hydrocarbons were removed from the soils and ground water beneath <br /> this site by that time <br /> The vadose zone vapor recovery wells (P1, P3-Swarm and EX) <br /> contributed little to the total recovered hydrocarbons during <br /> this time period. P1 = 1 3 pounds, P3-Swarm = 561 . 4 pounds and <br /> EX = 127 pounds <br /> The system was restarted under the Authority to Construct Permit <br /> (AP 91-106) on March 31, 1992 <br /> On July 21, 22 , and 23 , 1992 , four new vadose zone vapor recovery <br /> wells were installed and manzfolded to the recovery system As <br /> of July 22, 1992 the existing vapor extraction system (MW5, P1, <br /> P3-Swarm and EX) had produced 13902 8 and the newly installed <br /> well VSB3 produced 3 6 pounds of gasoline range hydrocarbons <br /> Since that time only the newly installed wells (VSB3 , VSB5, VSB9 <br /> and VSB11) and MW5 have been used for vapor extraction. As of <br /> the latest sampling (July 19, 1993) the new wells and MW5 have <br /> removed 3857 pounds of gasoline range hydrocarbons, for a total <br /> recovery of 17759 pounds, see Table 3 and Charts of vapor <br /> recovery <br /> Vacuum Influence <br /> As was stated earlier, vapor recovery has removed the lighter <br /> fractions of gasoline range (through ethylbenzene) petroleum <br /> hydrocarbons from the soil and has greatly reduced the petroleum <br /> hydrocarbons dissolved in the ground water beneath this site . <br /> Figure 3 represents the vacuum influence generated from the vapor <br /> recovery system, as measured before obtaining depth to ground <br /> water measurements, on July 19, 1993 <br /> i <br /> page 3 <br />