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' 29 October 2002 <br /> • AGE-NC Project No 95-0167 <br /> Page 3 of 4 <br /> BTEX compounds were detected in the water samples collected from monitoring wells MW-1 and <br /> MW-2, the highest concentrations were detected in the sample from MW-1 at 3,300 µg/l benzene, <br /> 3,600 gg/1 toluene, 650 µg/1 ethylbenzene and 3,400 µg11 xylenes MTBE was detected by EPA <br />' Method 8260B in sample MW-1 at a concentration of 49µg/1 No other fuel additivies were detected <br /> in the ground water samples <br />' Analytical results of water samples collected in August 2002 are summarized on Tables 2 and 3 The <br /> laboratory report(CTEL LaboratoryH)s 0208-115-1 through 0208-115-6),QA/QC report and chain- <br /> of-custody form are included in Appendix B Figure 4 depicts the estimated areal distributions of <br /> impacted ground water containing TPH-g and benzene for 23 August 2002 <br />' 4.0 SUMMARY AND CONCLUSIONS <br /> Data collected at the site indicates that <br />' The ground water flow direction during this monitoring event was toward the northwest at <br /> ' �' g g <br /> • an average gradient of 0 03 ft/ft Ground water flow at the site has historically been towards <br /> the northwest Ground water flow direction is not well defined south of the former UST pit <br /> • Relatively high concentrations of TPH-g and BTEX occur in ground water in the area of <br />' monitoring wells MW-1 and MW-2 <br /> • MTBE was present in monitoring well MW-1 at a concentration of 49 µg11 <br />' • The contaminant plume appeared to be confined to the general area of the former UST <br /> location and MW-1 and MW-2 Petroleum hydrocarbons were not detected in perimeter <br />' wells MW-3, MW-4, MW-5 and MW-6 In addition, petroleum hydrocarbons were not <br /> detected in a grab ground water sample collected and analyzed in April 1997 from soil boring <br /> P4, south of the former UST location <br /> 5.0. RECOMMENDATIONS <br />' Based on present site conditions, AGE recommends <br />' Continued quarterly ground water monitoring at the site The next monitoring event should <br /> be scheduled for November 2002 <br />' Preparation of a Corrective Action Plan (CAP) The CAP should include a discussion and <br /> • recommendation of remediation options for the site (e g in-situ air or ozone sparging, soil <br /> vapor extraction, ground water extraction, or attenuation) <br />' Advanced GcoEnvuronmental,Inc <br />