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1 <br /> Ms Vicky McCartney <br />' September 27, 2005 <br /> Page 2 of 4 <br /> i <br /> 1 <br /> Prior to sampling, monitoring wells MW 1 through MW3 were purged of a minimum of three <br /> 1 well casing volumes During the purging process, temperature, pH and electrical conductivity <br /> parameters were measured Samples were collected after parameter stabilization, and 100% <br /> water level recovery Groundwater samples were delivered under chain of custody protocol to <br /> Argon Laboratories (ELAP #2359) for analysis of TPHg by EPA Method 8015M, BTEX by EPA <br /> Method 8021B, and gasoline oxygenates and additives by EPA Method 8260B Purge water <br /> was contained in a properly labeled DOT-approved 55-gallon drum The drum is currently being <br />' stored onsite Purge logs are included in Appendix A <br /> Groundwater Analytical Results <br />' Toluene, ethylbenzene, and xylenes were not detected in the samples from any site well Benzene <br /> was detected in samples from wells MW 1 and MW3 at concentrations of 4 5 parts per billion (ppb) <br />' and 17 ppb, respectively TPHg was reported in the sample from well MW1 at a concentration of <br /> 96 ppb TPHg was not detected in the samples from wells MW2 and MW3 _ <br />' 1,2-DCA was detected in the sample from upgradient well MW2 at a concentration of 1 3 ppb No <br /> other gasoline, oxygenates or additives were detected in any samples Groundwater analytical <br /> results are summarized in Table 2 A copy of the laboratory report including chain of custody <br /> . documentation is included in Appendix B <br />' Summary <br /> The three monitoring wells at the site were monitored and sampled on August 19, 2005 Results <br /> can be summarized as follows <br /> Ia Groundwater levels in the site monitoring wells fell since last monitored in March 2005 <br /> The average groundwater gradient across the site was 0 014 ft/ft (approximately 74 <br /> ft/mile) Groundwater flowed in a northeasterly direction, which is consistent with <br /> previous measurements I <br /> a Benzene was present at low levels in the water samples from wells MW1 and MW3 The <br /> benzene concentration in MW3 was the lowest recorded since August 2001 TPHg was <br /> I detected in the sample collected from well MW1 A very low level of 1,2-DCA was <br /> detected in the groundwater sample from upgradient well MW2 L7 3 �' <br /> IConclusions <br /> Data from the current investigation along with that from previous phasesf investigation have <br /> completely defined the lateral extent of groundwater contamination Figure�qualitatively depicts <br /> I the extent of dissolved benzene in groundwater utilizing data from all discrete groundwater samples <br /> I <br /> G IGROUNDZEIW-E1SAR12001\2SAR05 doc <br />