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' 08 October 2002 AGE-NC Project No. 98-0468• Page 4 of 6 2.6. WELL MONITORING PROCEDURES On 04 April 2002,a modified ground water monitoring event was conducted at the site. The ground ' water monitoring-activities included measurement of ground water levels and collection of ground water samples from site monitoring wells,MW-9 and MW-10. 2.6.1. Well Monitoring and Evacuation ' A Solinst water level meter was used to.measure the depth to ground water in each well relative to the top of the well casing. After water levels were gauged,approximately 21 and 28 gallons of water (a minimum of three casing-water volumes) were purged from wells MW-9 and MW-10, ' respectively,utilizing a Waterra pump.Temperature,pH,and conductivity were measured at regular intervals using an Oakton Water Analyzer.The field data sheets are included in Appendix B.Purged water was stored on site in 55-gallon drums. 2.6.2. Collection and Analysis of Ground Water Samples ' Water samples were collected from wells MW-9 and MW-10 using the Watterapump system after allowing the wells to achieve a minimum 80%recovery of the pre-purge water volume.The samples were transferred into 40-m1 EPA-approved vials containing 0.5 ml 18% hydrochloric acid as a sample preservative.The sample containers were then labeled with the monitoring well designation, date, time of sampling and the sampler's initials. The samples were subsequently transported in a ' chilled container under chain-of-custody to MIA for analysis for: • TPH-g in accordance with EPA Method 8015-Modified and ' • BTEX and MTBE in accordance with EPA Method 8020. 3.0. FINDINGS ' The contaminant impact to ground water was assessed from the laboratory analyses of the grab and monitoring well ground water samples. -, TPH-g and BTEX compounds were not detected in grab ground water samples collected from bonngs.138 and B9. However, MTBE was detected by EPA Method 8260M in grab ground water ' samples B8755, B8-70 and 139-55 at concentrations of210 micrograms per liter(µg/l), 1.6µg11 and 48 µg11, respectively. There were no reported detections of any other fuel oxygenating compounds 4� in the grab ground water sample's analyzed. ' Advanced GeoEnvironmental,Inc.