Laserfiche WebLink
' 24 August 2001 <br /> • <br /> j AGE-NC Project No 98-0465 <br /> Page 3 of 4 <br /> 3 2 ANALYTICAL RESULTS OF GROUND WATER SAMPLES <br /> Each sample was analyzed for TPH-g, TPH-d, BTEX, and for the suite of five oxygenated fuel <br /> ' additives TPH-g, TPH-d and BTEX were not detected at concentrations at or above the laboratory <br /> reporting limits in any of the ground water samples <br /> I <br /> ' MTBE was detected in the ground water samples collected from MW1, MW3, and MW4 at <br /> concentrations of 12 gg/1, 57 µg/1 and 8 7 µg/l, respectively MTBE detections were confirmed in <br /> the samples by EPA Method 8260 at concentrations of 13 µg/1, 56 µg/1 and 8 0 µg/l, respectively <br /> I ' No other fuel oxygenated compounds were detected in the groundwater analyses Figure 4 illustrates <br /> the approximate extent of MTBE-impacted ground water <br /> 1 Analytical results of water samples collected during July 2001 are summarized on Table 2, the <br /> laboratory report (MAI Lab No 72639 through 72642), QA/QC report and chain-of-custody form <br /> are included in Appendix B <br /> 4.0. SUMMARY AND CONCLUSIONS <br /> The following conclusions were drawn from the results of this investigation <br /> ' G The ground water elevations ranged from 7 98 to 8 07 feet below MSL Ground water is <br /> generally flowing toward the north varying uor_northwesr to northeast, under an average <br /> gradient of 0 0007 feet/feet The relative ground water elevation at the site decreased an <br /> average 2 19 feet between the April 2001 and July 2001 monitoring events <br /> 0 Concentrations of dissolved MTBE in samples collected from MW-1 and MW-3 have <br /> remained relatively stable since ground water monitoring began in July 2000 MTBE levels <br /> have decreased slightly since monitoring began in July 2000 <br /> ' 0 The lateral extent of MTBE-impacted ground water has been defined to the northeast of the <br /> former UST area, but not toward the east, south or west to northwest <br /> 1 <br /> 5.0. RECOMMENDATIONS <br /> ' Based on the findings of this investigation, AGE recommends continued quarterly monitoring of the <br /> ground water monitoring wells The next monitoring event should be performed in October 2001 <br /> Additionally, AGE is preparing a work plan for installation of additional monitoring wells to assess <br /> the lateral and vertical extent of MTBE-impacted ground water <br /> 1 <br /> Advanced GeoEnvwunmentai,Inc <br />