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REG 603 UPDATE--6 2/21/92 • the 55 gallon drum storing the water "purged" prior to sampling the wells. Product thickness measurements obtained on subsequent site visits have shown only a sheen of product in MW1 until September, 1991 when 0. 02 feet of yellow-amber product was discovered, and also wells MW3 and MW10 have product sheens (showing up after the vapor extraction source test on MW10 ) . 3 . 2 SITE CONDITIONS A.a. GROUND WATER: September 18 , 1991 The September, 1991 chemical results ( sampled 9/18/91) indicate that dissolved benzene in monitor wells MW-2, MW-4, MW-6, MW-8, and MW-9 substantially exceeds the action level for drinking water of 1.0 ppb, set by the DHS, see Table 1. Monitor well MW--7 contains a lower benzene value of 4 . 9 ppb and monitor well MW5 is below the detection limit ( <0 . 3 ) for benzene. Monitor wells MW1, MW3 and MW10 contained a sheen of floating product ( <0. 011 ) . Strong to moderate bio-odors were also noted along with a grey green coloration of the purged ground water from monitor wells . MW2, MW7 and MW8 . A. b. GROUND WATER: December 17, 1991 The December, 1991 chemical results (sampled 12/17/91) indicate that dissolved benzene in monitor wells MW-2, MW-3, MW-4, MW-8, and MW-10 substantially exceeds the action level for drinking water of 1.0 ppb, set by the DHS, see Table 1. Monitor wells MW-6 and MW-9 have moderate levels of benzene ( 110 and 120 ppb respectively) and Monitor well MW-7 contains a lower benzene value of 4. 9 ppb. Monitor well MW5 is below the detection limit ( <0. 3 ) for benzene. Since the start up of vacuum extraction from MW1 and MW10 the benzene levels in the monitor wells have dropped in all of the wells with the exception of MW8. Monitoring wells MW2 and MW3 were added to the vapor extraction system on January 14, 1992. These wells should influence the down gradient off site extent of the plume (MWS ) .Monitor wells MW1, MW3 and MW10 contained a sheen of floating product (<0 . 011 ) . Strong to moderate bio-odors were 1 c., nn+cr7 1 nnrr .7-1 *h a rrreT rTrocn e-rNI^.rat�^n rif the rtivrrrcri rrrnijnA vLA haV iiV 4441 4.a1 via 4J �..... �y � yi .ria Y 7rr y� water from monitor wells MW2, MW3 and MW8 . FECAL COLIFORM Monitor wells MW2, MW3, MW4, MWS, 1W7 and MW8 were sampled on December 17-18, 1991 and January 21, 1992, for analysis of fecal coliform. These samples were placed into 500 ml plastic t containers and hand delivered that day to F.G.L. Environmental Laboratories for Fecal Coliform Analysis. The December, 1991 sampling showed MW-2 tested at 16 MPN/100 ml, while MW-3 and MW-8 PAGE 6