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' 01 November 2002 • AGE-NC Project No 95-0103 ' Page 3 of 6 ' 2 3 1 Well Monitoring and Evacuation A Solmst water level meter was used to measure the depth to ground water in monitoring wells MW-2 through MW-6 relative to the tops of the well casings(Table 2) The ground water elevation in each well was calculated by subtracting the measured depth to ground water from the surveyed casing elevation tAfter water levels were measured, between 4 and 10 gallons of ground water (a minimum of three casing water-volumes per well)were evacuated(purged)from wells MW-2 through MW-6 utilizing ' polyethylene disposable bailers Temperature,pH and conductivity were measured for stabilization at regular purge-volume intervals from each well using an Oakton water analyzer The monitoring equipment was washed in an Alconox solution and rinsed with tap water prior to purging Purged water was stored in 55-gallon drums on the site Field measurements of purged ground water are included in Appendix C 1 • 2 3 2 Ground Water Sample Collection and Analysis Water samples were retrieved from each purged well using the disposable bailers after allowing the well to achieve a minimum of 80 percent recharge prior to sample collection The samples were ' transferred into 40-ml EPA-approved volatile organic analysis(VOA)vials containing 0 5 ml of 18% hydrochloric acid as a sample preservative The samples were properly labeled and transported in ' a chilled container under chain-of-custody to Cal Tech Environmental Laboratories, Inc (CTEL), a DHS-certified laboratory, for analysis The ground water samples were analyzed for • TPH-g in accordance with EPA Method 8015-Modified, i • BTEX and MTBE in accordance with EPA Method 8021, and • The oxygenated fuel additives tertiary butyl alcohol (TBA), di-isopropyl ether (DIPE), ' MTBE, ethyl tertiary butyl ether (ETBE) and tertiary amyl methyl ether (TAME) in accordance with EPA Method 8260B 1 3.0. FINDINGS From field data collected at the ground water treatment system between 30 May and 22 August 2002, AGE determined the average TPH-g and benzene concentrations and the average flow rate, and ' calculated the approximate mass and volume of TPH-g and benzene removed Ground water flow • direction and gradient was determined from the field data collected on 09 September 2002, the contaminant impact to ground water was assessed from laboratory data ' Advanced GeoEnvironmental,Inc