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13 June 2005 <br /> AGE-NC Project No 97-0351 <br /> Page 3 of 4 <br /> 3 1 GROUND WATER GRADIENT AND FLOW DIRECTION <br /> The elevation of ground water in each of the monitoring wells was calculated by subtracting the <br /> depth to ground water from the surveyed relative casing elevations(Table 1) Depths to ground water <br /> averaged approximately 8 28 feet below surface grade (bsg), indicating an increase to elevation of <br /> approximately 0 78 feet since the last ground water monitoring event in October 2004 Ground water <br /> ' elevations at the site ranged from 161 feet (MW-3) to 173 feet (MW-5) above mean sea level <br /> (MSL) The ground water flow direction was toward the north-northeast in the area of MW-1,with <br /> a calculated gradient of approximately 0 001 foot/foot (ft/ft) During this monitoring event, the <br /> ' ground water elevations were within the screened intervals of the wells Figure 3 illustrates the <br /> contoured ground water elevations as measured on 20 January 2005 <br /> ' 32 ANALYTICAL RESULTS OF GROUND WATER SAMPLES <br /> TPH-g,benzene, and xylenes were detected in the ground water sample collected from well MW-1 <br /> at concentrations of 1,200 micrograms per liter(gg/l), 5 6µg/l,and 7 6 µg11,respectively No other <br /> ie petroleum hydrocarbons were detected in ground water samples from the other monitoring wells <br /> l <br /> Analytical results of round water samples are summarized in Tables 2 and 3 The laboratory report <br /> yt g p <br /> (CTEL ProjectNo CT214-0501110), quality assurance/quality control report,and chain of custody <br /> ' form are included in Appendix D Documents confirming the upload of laboratory electronic <br /> deliverable format (EDF) files and depth to water measurements to GeoTracker are included in <br /> Appendix E <br /> ' 4.0. SUMMARY AND CONCLUSIONS <br /> Based on the environmental data collected at the site during the first quarter 2005,AGE concludes <br /> • Ground water elevation in the monitored area ranged from 161 feet to 173 feet above MSL <br /> Flow direction was inferred to be toward the north-northeast in the area of well MW-1 with <br /> a calculated gradient of approximately 0 001 ft/ft <br /> • TPH-g,benzene,and xylenes were detected in the ground water sample collected from well <br /> ' MW-1 at concentrations of 1,200 Vg/l, 5 6 gg/l, and 7 6 µg/l, respectively <br /> • The benzene concentration in well MW-1 was above the DHS's Maximum Contaminant <br /> Level of 10 µg/1 in drinking water <br /> • At the present time, the vertical extent of dissolved hydrocarbons has not been defined <br /> ' Advanced GeoEnvironmentai,Inc <br /> 1 <br />