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15 January 2006 <br /> AGE-NC Project No. 95-0106 <br /> • „ Page 3 of 3 <br /> . 4.0.. SUMMARY AND CONCLUSIONS <br /> The following conclusions were drawn from the results of the site investigation: <br />' On 10 December 2005, the ground water elevation was between 32.19 feet and,33.19 feet <br /> above mean sea level (MSL), which is a decrease'of approximately 0.17 feet'since the June <br /> 2005 monitoring event. Ground water was inferred to flow towards the north at a gradient <br />' of between 0.002'ft/ft and 0.01 ft/ft, which is consistent with the historical flow pattern. <br /> TPH-g and the BTEX compounds benzene and ethylbenzene were detected only in ground <br />' water sample MW-4, at concentrations of 200 pg/l, .15 µg/1 and 12 µg/l, respectively. The <br /> benzene concentration of 15 µg11 exceeds DHS-established Maximum Contaminant Level <br /> of 1.0 µg11 in drinking water. <br />' The fuel additive 1,2-DCA was not detected in the December 2005 ground water samples; <br /> the fuel additive MTBE has not been detected in site ground water since December 2003.' <br />' The concentrations of petroleum hydrocarbon contaminants have been consistently declining <br /> in the impacted site ground water monitoring wells MW-1 and MW74 since the abrupt <br /> increase of contaminants in these wells in 2001 (Figures 4 and 5). Petroleum hydrocarbons <br />' • were not detected in well MW-1 at the time of the fourth quarter 2005 monitoring event. w <br /> 5.0. RECOMMENDATIONS <br /> `Based on this and previous site investigations, AGE recommends continued quarterly monitoring <br /> of the well network. The next quarterly monitoring event is scheduled for,March 2006. <br /> G.O. 'LIMITATIONS <br /> Our professional services were performed using that'degree of care and skill ordinarily exercised by <br /> environmental consultants practicing in,this or similar localities'. The findings were based upon' <br /> analytical results provided by an independent laboratory. -Evaluations of the hydrogeologic <br /> conditions at the site for the-purpose of this investigation are made from a limited number of <br /> available data points (i.e. monitoring wells and ground-water samples),and subsurface conditions <br />' may vary away from these data points. No other warranty, expressed or'implied, is made as to the <br /> professional interpretations, opinions and recommendations contained,in this report. <br />' _ Advanced GeoEnvironmentai,Inc. r <br />