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%%W. .MIW Site Background Information: Cherokee Truck Stop AGE-NC Project No. 97-0312 Page 10 of 11 Currently, the lateral extent of adsorbed petroleum hydrocarbon contamination is defined to the northeast by boring MW-3,to the northwest by borings B4 and B25,to the west by boring MW-2, and to the south by borings B29, B22, and MW-4. The soil data lacks significant detections of 1,2-DCA in the most recent data,possibly demonstrating the vertical migration of this contaminant through soil without substantial attenuation or adsorption to soil. The adsorbed petroleum hydrocarbon contamination appears to be adhered to fine-grained soil, based on the reduction of dissolved hydrocarbon contamination with upward fluctuations of the ground water table.Figure 9 illustrates the estimated lateral distribution of adsorbed TPH based on the maximum concentrations in soil samples collected at the site. R%4PACT TO GROUND WATER Significant concentrations of TPH-g,TPH-d,BTEX,and MTBE were detected in grab ground water samples collected at 65 feet bsg in soil borings B14,B15, and B17(Table 1). Historically,TPH-g has been detected in the on-site ground water monitoring wells at a maximum concentration of 3,400 µg/1 (MW-1, December 1992),but has been detected consistently only in well MW-5,with sporadic detections in wells MW-2 through MW-4;TPH-g was only detected in well MW-6 during its initial ground water monitoring event in June 1999. TPH-d was detected at a maximum concentration of 350,000µg/1 in MW-1 in September 1992,and was detected consistently in MW-1 until the well was abandoned in July 2002 and in UST-5 until February 2003,when concentrations permanently decreased below laboratory detection limits.Sporadic detections of TPH-d occurred in wells MW-2,MW-3,MW-4,and MW-6 until as late as May 2003.BTEX constituents were detected consistently only in well MW-5,with a maximum concentration of 840µg/1(benzene,March 1998), until December 2003.These detections ofTPH and BTEX generally corresponded with high ground water levels,near 55 feet bsg.Graphs illustrating TPH-g and TPH-d concentration and ground water data trends in the monitoring wells were included. Currently the only monitoring well with detectable concentrations of TPH-g is monitoring well MW-5.TPH-g and 1,2-DCA have been the only contaminants of concern reported above laboratory detection limits in MW-5 since March 2004; TPH-g is detected occasionally at concentrations of approximately 200µg/1,and 1,2-DCA is detected at concentrations between<0.5 and 200µg/1.Well MW-4 has remained non-detect since June 2001, well MW-7 has remained non-detect since December 2002,well MW-3 has remained non-detect since May 2003,well MW-2 has remained non-detect since March 2004, and no constituents of concern were detected in MW-8 and MW-9 over four quarterly monitoring events. Based on the April 2006 CPT investigation,the lateral and vertical extent of the 1,2-DCA plume is defined (Figures 7 and 8). Down-gradient, the 1,2-DCA plume does not extend to CPT-2, while MW-6 reported occasional low concentrations of 1,2-DCA;vertically,the 1,2-DCA plume does not Advanced GeoEnvironmental,Inc.