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i I06 October 2005 AGE-NC Project No 99-0657 Page 4of6 3 1 GROUND WATER GRADIENT AND FLOW DIRECTION I At theim t e of the April 2005 sampling event, depths to ground water ranged from 37 23 (MW-3) I feet to 39 36 (MW-9) feet below the tops of the well casings Ground water elevation at the site averaged approximately 6 23 feet above mean sea level (MSL) During this monitoring event, the ground water levels in the wells were at least seven feet below the tops of the well screens,indicating that the wells are screened properly to yield representative shallow ground water samples Ground water flow was inferred to be flowing toward the southwest under an average hydraulic gradient of approximately 0 004 foot/foot(ft/ft) In the southern portion of the site the ground water gradient is approximately 0 006 ft/ft This flow direction remains consistent with the previous monitoring events Figure 3 shows the contoured ground water elevations as measured on 25 April I2005 and a rose diagram showing ground water flow directions from previous monitoring events 3 2 ANALYTICAL RESULTS OF GROUND WATER SAMPLES TPH-g was detected in the 25 April 2005 water samples collected from wells MW-1,MW-2,MW-4, . MW-5 and MW-6 at concentrations ranging from 100 micrograms per liter (µg/1) (MW-2 and MW-6) to 2,900 µg/l (MW-1) Benzene was detected in the samples collected from wells MW-1, MW-4 and MW-5 at concentrations of 19 µg/l (MW-1), 140 pg/l (MW-4) and 22 µg/l (MW-5) Toluene was detected in two of the April samples and eth lbenzene was detected in one water P P y sample this quarter, 8 9 µg/1 and 5 6 µg/1 toluene in wells MW-1 and MW-4, respectively and 5 9 µg/l ethylbenzene in well MW-4 Xylenes were detected in wells MW-1, MW-4 and MW-5 at a maximum concentration of 73 µg/l (MW-1) MTBE was detected in water samples collected from wells MW-1, MW-2, MW-4, and MW-6 at concentrations ranging from 57 pg/l (MW-6)to 370 µg/1 (MW-1) 1,2-DCA was detected in water samples collected from wells MW-1, MW-4 and MW-6 at concentrations ranging from 8 7 µg/1 (MW-1) to 27 pg/l (MW-4) No target analytes were detected in the samples collected from the vertical profile ground water wells Analytical results of the ground water samples collected in April 2005 are summarized in Table 2 The laboratory report (CTEL Project No CT214-0504241), quality assurance/quality I control (QA/QC) reports, and chain of custody forms are included in Appendix E Documents confirming the upload of laboratory electronic deliverable format (EDF) files and depth to water measurements to GeoTracker are included in Appendix F I Advanced GeoEnvironmentel,Inc