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i <br /> 13 June 2001 <br /> AGE-NC Project No 99-0637 <br /> Page 6of7 <br /> • Toluene was detected in the soil samples collected from MW1, MW3 and MW4 at <br /> concentrations as high as 0 025 mg/kg(MW 1-15) MTBE was detected in the 20-foot and 25- <br /> foot soil samples collected from MW4 No other analytes were detected at or above <br /> laboratory reporting limits in the soil samples The lateral and vertical extent of petroleum <br /> hydrocarbon-Impacted soil has been fairly well delineated Petroleum hydrocarbon-impacted <br /> soil does not extend vertically past 20 feet bsg and MTBE-Impacted soil does not extend <br /> vertically past 25 feet bsg The lateral extent Is confined mainly to the monitoring well <br /> network on-site (Figures 4 and 5) MTBE-Impacted soil may extend further to the west and <br /> southwest of the former UST area <br /> • TPH-d was detected in the ground water sample collected from MWl at a concentration of <br /> 53 gg/l, dust exceeding the laboratory reporting limit MTBE was detected in the ground <br /> water sample collected from MW4 at a concentration of 4,700 gg/l(EPA Method 8260) No <br /> other analytes were detected in the ground water samples collected at the site The lateral <br /> extent of TPH-d-Impacted ground water has been defined in all directions from the former <br />' UST area with the exception of the north The lateral extent of MTBE-Impacted ground <br /> water has been defined In all directions with the exception of toward the west The current <br /> TPH-d and MTBE isocontour maps are depicted on Figures 6 and 7 <br /> lie <br /> 5.0. RECOMMENDATIONS <br /> Based on the findings of the environmental activities recounted in this report, AGE recommends <br />' • Quarterly monitoring of the ground water monitoring wells on-site The next monitoring <br /> event should be performed in July 2000 <br />' a Two additional monitoring wells be installed southeast of boring B2 and northwest of <br /> monitoring well MW4 to further assess the lateral and vertical extent ofMTBE-Impacted soil <br />' and the lateral extent of MTBE-Impacted ground water <br /> • Advancement of a deep soil boring in the vicinity of boring B2 and well MW4 to assess the <br /> vertical extent of MTBE-impacted ground water <br /> 6.0. 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 Evaluation of the hydrogeologic conditions <br /> at the site for the purpose of this investigation was made from a limited number of available data <br /> Advanced Geo Envi ron mental,Inc <br /> 1 <br />