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09 July 1998 <br /> AGE-NC Project No 95-0184 <br />' Page 3 of 4 <br /> _ppb and 960 ppb,t respectively 1,2-Dichloroethane (DCA) was detected in seven of the ten wells sampled at concentrations as high as 3,000 ppb (VW-2B) Eleven additional constituents were <br /> detected with EPA Method 8260 at concentrations as high as 2,400 ppb (1,2,4-trimethylbenzene, <br />' MW-4) Analytical results are summarized on Tables 2-and 3 The laboratory report (MAI sample <br /> Nos 88583-88592) and chain-of-custody forms are included In Appendix B <br />' Hydrocarbon concentrations detected in samples collected from MW-4,VW-213, VW-3, VW-4 and <br /> VW-513 are indicative of the presence of free product Lower hydrocarbon concentrations were <br /> detected in MW-7, located between MW-4 and the remaining wells The lower hydrocarbon <br />' concentrations detected in samples collected from MW-1, MW-2 and MW-3 are probably due to <br /> drowning of these wells <br /> 4 0.' DISCUSSION AND CONCLUSIONS <br />' Based upon data collected from the site, AGE concludes the following <br /> • Petroleum hydrocarbons were detected in each well sampled, at concentrations as high as <br /> 160,000 ppb Free product appears to remain at the site Additional monitoring wells will be <br /> necessary to delineate the horizontal extent of hydrocarbon-Impacted ground water <br />' The Inferred ground water flow direction was toward the northeast during the April 1998 <br /> monitoring event The Inferred flow direction has generally been toward the east to southeast <br />' at the site <br /> { Ground water is approximately,twenty feet above'the screened interval in monitoring wells <br />' MW-1 through MW-3, ten feet above the screened interval in MW-4 and five feet above the <br /> screened interval in MW-7 These wells recharge rapidly, possibly preventing significant <br /> drawdown during purging The hydrocarbon concentrations detected in these `drowned' <br /> ' wells may not be representative of shallower ground water where the maximum hydrocarbon <br />' impact would be expected <br /> • Ground water is currently within the screened interval in three vapor wells The data <br />' collected from these wells should be representative of shallow ground water conditions <br /> a <br /> • The lateral extent of hydrocarbon-impacted soil at the site has not been defined Soil samples <br /> collected during the installation of additional monitoring wells may be used to define the <br /> extent of impacted soil <br /> Advanced GcoEnwronmental,Inc <br />