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I ` ' 1 I " 17 October 2003 AGE-NC Project No 96-0235 ' Page 4 of 5 E intervals, respectively The laboratory report (CTEL Laboratory IDs 0306-138-1 through 0306-138-24),sham-of-custody forms and the laboratory QA/QC report are included in Appendix B i 4.0.' SUMMARY AND CONCLUSIONS I Based on the data collected from the former UST cluster area, AGE finds • The shallow-screened data delineate a radial ground water flow pattern, with a net flow I towards the east at a gradient of 0 002 ft/ft,the deep-screened data delineated a radial ground water flow direction toward the northeast at a gradient of 0 003 ft/ft I • TPH-g was detected in ground water samples collected from MW-10 and EW-1 at concentrations of 440 µg/1 and 86,000 µg/1,respectively TPH-d was detected in the sample collected from EW-1 at a concentration of 29,000 µg/1 ' BTEX compounds were detected in water samples collected from MW-10 and EW-1 The maximum BTEX concentrations were detected in the sample from EW-1 The BTEX 1 . concentrations in sample EW-1 and the benzene concentration in sample MW-10 were above the DHS Maximum Contaminant Level (MCL) in drinking water MTBE was detected by EPA Method 8260B in the shallow-screened wells MW-10, ' MW-13A and EW-1 and in the deep-screened wells MW-9, MW-12B, MW-13B and MW-14B at concentrations as high as 340 µg/1 (EW-1) With the exception of MW-13A, ' the MTBE concentrations were above the DHS' Primary MCL of 13 µg/1 in drinking water, „ r ± "the MTBE concentration in MW-13A exceeded the DHS' Secondary MCL of 5 µg11 in drinking water ' F The concentrations of 1,2-DCA detected in ground water samples MW,1IB, MW-14B, EW-2 exceeded the DHS' MCL ' i • In the former UST cluster area, the most impacted ground water appears to be centered around EW-1 and MW-10 The vertical extent of the contamination plume, as well as the -- - - - -lateral-extent east and-south-of the former UST-cluster,-are-not well defined- Y Based on the data collected from the former UST No 3 area, AGE finds ' • The ground water flow direction at the shallow-screened level was inferred to be towards the southeast at a gradient of 0 005 ft/ft, ground water flow direction at the deep-screened level was inferred to be toward the south-southwest at a gradient of 0 015 ft/ft • TPH-g was detected 'in the samples collected from MW-1, MW-2 and EW-2 at . concentrations as high as 11,000 pg/l(MW-2), TPH-d was detected in the sample collected 1 Advanced GcoEnvironmentai,Inc ,