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R604 •UPDATE 23 10-20-1993 <br /> corrected for vacuum influence, have shown potentiometric lows at <br /> the wells being used for vapor recovery (MWS) . Once the vapor <br /> recovery is shut off, normal flow directions again take place to <br /> the east-southeast or northeast, with the exception of the March <br /> 5, 1992 gradient, which flowed to the north-northwest and may <br /> represent a recharge and/or a decline in water usage of the <br /> municipal wells located east of the site. <br /> Fecal coliform has been analyzed for monitoring wells MW3 , MW4 , <br /> MW5 and MW6 on a monthly basis from December, 1991 through <br /> February, 1992 . Only trace amounts of fecal coliform have been <br /> occasionally detected in any of the wells during those 3 months, <br /> see Table 2 . <br /> RECOMMENDATIONS <br /> 1. Discontinue vapor recovery on MW5 and the newly <br /> installed vadose wells VSB3, VSB5, VSB9 and VSB11 at <br /> this time. <br /> 2 Continue to sample the ground water until closure is <br /> granted to confirm that the current Primary MCLs for <br /> water quality have been met <br /> 3 . Perform monthly monitoring and sampling of the vapor <br /> stream using the WEGE portable lab FID-GC and <br /> confirmation for benzene and toluene with the PID 10s50 <br /> chromatograph and include the results in a monthly <br /> update status report, until system is turned off . <br /> 4 Confirmation boring will be performed and coordinated <br /> with turning off and removing the vapor extraction <br /> system (VES) . <br /> 5 Arrange a meeting with RWQCB to finalize closure needs <br /> HEALTH AND SAFETY <br /> This site has been classified as Class D personal protection <br /> Hard hats, gloves, steel toed boots and ear protection are <br /> to be worn In the event that field screening indicates that <br /> volatile organic compounds (VOC' s) exists at the site, all <br /> personnel shall wear appropriate half face cartridge respirator <br /> with the black organic compound cartridges and particle filters . <br /> All personnel must carry their identification card showing that <br /> they are current with OSHA/SARA training <br /> TIME FRAME <br /> October 26, 1993 Depth to ground water, vacuum <br /> influence and air sampling. <br /> page 7 <br />