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1 06 October 1997 AGE-NC Project No 95-0105 ' Page 3 of 4 ' collected from MW-4 at a concentration of 210 ppb Retesting the samples by EPA Method 8240/624, due to the detection of MTBE in MW-4 by EPA Method 8020, detected only benzene, toluene, and ethylbenzene and xylenes in MW-4 at concentrations of 120 ppb, 1,100 ppb, 1,800 ppb and 5,200 ppb, respectively MTBE was not confirmed in MW-4 by EPA Method 624/8240 None of the analytes of interest were detected by analysis of samples from MW-5 and MW-6 by EPA Method 624/8240 Oxygenated volatile organics were not detected in any of the three samples by analysis by EPA Method 8260 Petroleum hydrocarbons were not detected in the samples collected from the down gradient well MW-6, or in the cross-gradient well MW-5 The analytical results for the ground water samples are ' summarized in Table 2 -Analytical Results of G ound Water Samples The laboratory report (MAI Sample IDs 79718, 79719,and 79720),chain-of-custody form and QA/QC are included in Appendix B 4.0. CONCLUSIONS Based on data collected from the site, AGE has formed the following conclusions ' • The ground water flow direction is generally toward northeast • Depth to ground water averages 5 3 feet below the well casings, a decline of approximately 0 93 feet since the December 1996 monitoring event Between December 1996 and August 1997, concentrations of TPH-g, TPH-d, BTE&X increased in Monitoring Well MW-4 MTBE was also detected in MW-4 by EPA Method 8020, but was not confirmed by reanalysis by EPA Methods 624/8240 or 8260 Oxygenated volatile organics were not detected in any of the three samples analyzed ' • None of the analytes of interest were detected in MW-5 or MW-6, the down-gradient and cross-gradient wells 1 5 0. RECOMMENDATIONS ' Based on present site conditions, AGE recommends the following • Purged ground water from previous investigations should be disposed at a licenced • treatment/disposal facility 1