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27 December 2005 <br /> AGE-NC-95-0185 <br /> Page 3 of 4 <br /> 3.0. FINDINGS <br /> The ground water elevation gradient and flow direction were determined from the field data. <br /> Contaminant impact to ground water was assessed by field observations and laboratory analysis. <br /> ' 3.1. GROUND WATER GRADIENT AND FLOW DIRECTION <br /> During the August 2005 sampling event, the ground water elevation at the site ranged from <br /> 32.01 feet (MW-2) to 32.85 feet (MW-1 and MW-3) above mean sea level (MSL); the average <br /> i ground water elevation during the August 2005 sampling event was 32.56 feet above MSL; the <br /> average ground water elevation at the. site decreased approximately 2.19 feetsince the previous <br /> ' monitoring event in May 2005. However,the depth to ground water(27.05 feet)at well MW-4 was <br /> affected by the presence of free product; the depth was recalculated (26.97 feet) utilizing the <br /> measured thickness of free product in well MW-4: <br /> ' D = D - (t * d dw) <br /> j , • Dw= Corrected depth to water <br /> Din =Measured depth to water <br /> tg= Total thickness of.free product (---0.10 foot) <br /> ' dg=Density of free product (gasoline at--0.88 g/ml) <br /> dw=Density of water(-1.0 g/ml) <br /> The ground water flow direction was inferred to be toward the southeast at a gradient of <br /> approximately 0.009 foot/foot(ft/ft) near the former UST locations (Figure 3). <br /> 3.2. LABORATORY RESULTS OF GROUND WATER SAMPLES <br /> Significant concentrations of TPH-g and TPH-d were detected in the samples collected from wells <br /> ' MW-1 and MW-4 during the August 2005 sampling. On the site the concentrations were as high as <br /> 270,000 micrograms per liter(µg/l) and 1,200,000 41, respectively, both from well MW-4. <br /> ' No other constituents of concern were not detected in the samples taken from wells MW-I through <br /> MW-4. BTEX compound detected in the previous quarterly monitoring event were not detected in <br /> wells MW-1 through MW-4.Current and previous analytical results are summarized in Tables 2 and <br /> ' 3..The laboratory reports (CTEL Project No. CT214-0508116), quality control/quality assurance <br /> (QA/QC)reports and chain of custody forms are included in Appendix C. GeoTracker confirmation <br /> ' Advanced GeoEnvironmental,Inc. <br />