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REG 603 UPDATE-7 3/24/92 <br /> I <br /> green coloration of the purged ground water from monitor wells <br /> MW2, MW3 and MW8. <br /> A. 2 . GROUND WATER: MARCH 10 , 1992 . <br /> The March, 1992 chemical results (sampled 3/10/92 ) indicate <br /> that dissolved benzene in monitor wells MW-2, MW-4 and MW--8 <br /> substantially exceeds the action level for drinking water of 1 . 0 <br /> ppb, set by the DHS, see Table 1. Monitor wells MW-6 and MW-9 <br /> have low levels of benzene ( 1. 3 and 4. 3 ppb respectively) and <br /> Monitor wells MW-5 and MW-7 are below the detection limit ( <0 . 3 ) <br /> for benzene. Since the start up of vacuum extraction from MWl and <br /> MW10 the benzene levels in the monitor wells have dropped in all <br /> of the wells, see Figures 5A and 5B and Table 1. Monitoring wells <br /> MW2 and MW3 were added to the vapor extraction system on January <br /> 14, 1992 . These wells are influencing the down gradient off site <br /> extent of the plume (MW7 and MW8 ) . Monitoring wells MW1, MW3 and <br /> MW10 contained floating product. Strong to moderate bio-odors <br /> were also noted along with a grey green coloration of the purged <br /> ground water from monitor wells MW2, MW4, MW7 and MW8 . <br /> A. 3 . FECAL COLIFORM <br /> Monitor wells MW2 , MW3, MW4, MW5, MW7 and MW8 were sampled on <br /> December 17-18 , 1991, January 21, 1992, and February 4, 1992, for <br /> analysis of fecal coliform. These samples were placed into 500 ml <br /> plastic containers and hand delivered that day to F. G.L. <br /> Environmental Laboratories for Fecal Coliform Analysis. The <br /> December, 1991 sampling showed MW-2 tested at 16 MPN/100 ml, while <br /> MW-3 and MW-8 test >16 MPN/100m1. All other wells wells tested <br /> below detection limits of 2 . 2 MDL/100ml. All wells (MW-2 , MW-3, <br /> MW-4, MW-5 , MW-7 and MW-8) tested below the detection limits of <br /> 2 . 2 MPN/100m1 from the January, 1992 sampling. The February, 1992 <br /> results showed MW-2 and MW-3 at >16 MPN/100m1, MW-4 and MW-8 at <br /> 5 . 1 MPN/100ml, MW-7 at 2 . 2 MPN/100ml and MW-5 <2 . 2 MPN/100ml . <br /> B. SOIL: <br /> As has been shown in the "Update Status Report, February 23, 1.990" <br /> soil contaminated with gasoline range hydrocarnons exists beileath <br /> the underground storage tank excavation from the 25 foot depth to <br /> top of ground water and at the 40 foot depth to top of ground <br /> water around monitor well MW10 . The capillary fringe area ( 50 <br /> foot depth) shows the spread of contaminant out to monitor wells <br /> MW1, MW2 and MW3, see Fence Diagram Figure 6 . <br /> PAGE 6 <br />