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15 July 2005 , • AGE-NC Project No 00-0769 s ' Page 6 of 7 BTEX compounds were detected in wells MW-4E and MW-5E at maximum concentrations of ' 290 µg/1 benzene (MW-4E), 150 pg/1 toluene'(MW-5E), 36 µg/1 ethylbenzene (MW-4E) and 151 µg11 total xylenes (MW-4E) No other constituents of concern were detected at or above laboratory reporting limits in the ground water samples collected during the fourth quarter sampling event Analytical results of ground water ' samples are summarized in Tables 2 through 5 The laboratory report (CTEL Project No CT214- 00503083), quality assurance/quality control (QA/QC) reports, and chain of custody forms are provided in Appendix C Documents confirming the upload of laboratory electronic deliverable ' format (EDF) files and depth to water measurements to GeoTracker are included in Appendix D r ' 4.0. SUMMARY AND CONCLUSIONS Based on data collected during the March 2005 ground water monitoring event, AGE concludes ' Ground water elevation at the site ranged from 14 23 feet to 17 17 feet below MSL during the March 2005 monitoring event 1 . The HU-1 potentiometnc surface is in the shape of a east-west trending ridge, ground water generally flowed cast,north and south away from this ridge at gradients between 0 004 ft/ft ' Ground water flow in HU-2 is generally south and southeast at a gradient of 0 003 ft/ft Ground water in HU-3 generally flows northwest at a gradient of 0 005 ft/ft The HU-4 potentiometric surface consists of a northwest-plunging ridge,ground water flows generally ' toward the northwest north at approximately 0 007 ft/ft to 0 008 ft/fl(Figures 3,through 6) • The most highly impacted ground water appears to be located near the former USTs ' Laterally, analytes of concern were detected at or'above laboratory reporting limits in all wells except multi-level wells MW-8 and MW-9,vertically,hydrocarbon-impacted ground, water was detected in each of the screened intervals of multi-level wells MW-4 through ' MW-7 • The lateral and vertical extents`of petroleum hydrocarbon-impacted ground water have not been defined The vertical extent of the fuel additive 1,2-DCA is not defined, however,the ' lateral.jex'tent of 1,2-DCA appears to be defined except to the southeast • BTEX compounds and 1,2-DCA are present in on-site monitoring wells at concentrations ' that exceed the DHS's Maximum Contaminant Levels (MCLs) for these contaminants in drinking water Advanced GeoEnwronmental,Inc. ,