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L <br /> i, 05 May 2004 <br /> 4%.e AGE-NC Project No. 01-0886 <br /> Page 6 of 6 <br /> 5.0. SUMMARY AND CONCLUSIONS <br /> LO <br /> Based on the results of the preliminary soil and ground water investigation AGE determined: <br /> L • The greatest concentrations ofpetroleum hydrocarbon contamination in soil are in the former <br /> UST locations.TPH-g and BTEX were detected at maximum concentrations of 1,800 mg/kg, <br /> 0.02 mg/kg, 22 mg/kg, 29 mg/kg, and 170 mg/kg, respectively in boring B2-30. Vertically, <br /> petroleum hydrocarbons have not been detected in soil samples below 50 feet bsg,therefore, <br /> the vertical extent of petroleum hydrocarbon contamination has been defined in the area of v rn <br /> the former USTs. � <br /> J <br /> • Laterally,petroleum hydrocarbon contamination in soil has been defined south of the former <br /> USTs but is undefined in all other directions. <br /> a TPH-g and BTEX compounds were detected in grab ground water samples at mvimum <br /> a concentrations of 180µg/1(TPH-g),5.6µg/l(toluene),3.0µg/l(ethylbenzene)and M µg/1 <br /> .L (total xylenes),respectively in boring B 1. MTBE was detected in ground water samples at <br /> a maximum concentration of 68 µg/1 in boring B 1. 1,2-DCA was detected in ground water <br /> samples at a maximum concentration of 170 µg/1 in boring B1. The migration route of <br /> \..+ hydrocarbons and fuel additives to the ground water has not been documented at the site. <br /> However, higher concentrations were detected near the northern end of the former USTs, <br /> suggesting the presents of an on-site hydrocarbon source at the former dispenser islands. ?S'¢-`1 <br /> J <br /> 6 6.0. RECOMMENDATIONS <br /> Based upon data collected from the site during the April 2003 site assessment, AGE recommends <br /> further investigation at the site.A work plan has been prepared and submitted to EHD for installation <br /> and sampling of ground water monitoring wells.In addition,AGE recommends the development of <br /> a site conceptual model to identify areas of concern, general lithology and migratory pathways. a <br /> iY <br /> 7.0. LIMITATIONS <br /> Y <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 mainly <br /> 11L upon analytical results provided by an independent laboratory. Evaluations of the geologic/ <br /> hydrogeologic conditions at the site for the purpose of this investigation are made from a limited <br /> ' number of available data points(i.e. soil and grab ground water samples)and subsurface conditions <br /> i 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 GeoEnvironmental,Inc. <br /> I1L <br />