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S21 November 2001 AGE-NC Project No 00-0769 Page 4 of 5 from MW-1 at concentrations of40,000 gg/l(toluene),2,300 gg/l(ethylbenzene) and 12,000 gg/l (total xylenes) ' 1,2-DCA was detected in groundwater samples collected from MW-1,MW-2A and MW-2B at concentrations of 3,800 gg/l, 19 µg/1 and 200 µg/1, respectively EDB was not detected in any of the ground water samples collected during the September 2001 monitoring event 1 , Laboratory results of water samples analyzed for petroleum hydrocarbons are summarized in ' Tables 2 and 3 The laboratory reports. for the quarterly monitoring event (MAI Lab IDs 78860 through 78863) QA/QC reports and chain-of-custody form are included in Appendix D S.D. SUMMARY AND CONCLUSIONS ' The findings of the June and September 2001 site investigation events include the following • Contamination by TPH-g and BTEX constituents was encountered in ground water samples lie collected from four of the five on site monitoring wells (MW-1, MW-2A, MW-2B and MW-3A), a parked vehicle prevented sampling MW--3B Concentrations as high as 220,000 gg/l (TPH-g), 30,000 gg/l (benzene), 40,000 µg11 (toluene), 2,300 gg/1 (ethylbenzene) and ' 12,000 gg/1 (total xylenes) were detected 1,2-DCA was detected in ground water samples collected from monitoring wells MW-1, ' MW-2A and MW-2B at concentrations as high as 3,800 pg/1(MW-1) EDB was not detected in any of the ground water samples collected during the September 2001 monitoring event • Concentrations of contamination have remained relatively stable since ground water ' monitoring began in May 1998 + The horizontal and vertical extent of contamination related to the former UST has not yet ' been defined in soil or ground water I I ° r • Measured ground water elevation was approximately'13 4 feet and 14 4 feet below msl in ' the shallow screened wells (MW-1, MW-29 and MW-3B) during the June and September Y 2001 monitoring events, respectively Ground water was within the screened interval of monitoring wells MW-2B and MW-3B and was approximately 5 feet above the screened ' interval of MW-1 Ground water was approximately 0 10 feet and 0 40 feet lower in the deeper screened monitoring wells (MW-2A and MW-2B) than iii the shallow screened wells during the June and September 2,001 monitoring events, respectively ' During the June 2001 monitoring event, the ground water gradient was Inferred to be ` 0 003 ft/ft with a flow direction toward the west northwest,`during'the September 2001 ' monitoring event, the ground water gradient was Inferred to be 0 0015 ft/ft with a flow Advanced GeoEnvironmentwi,Inc t