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1 ' 13 September 2001 • AGE-NC Project No. 98-0450 ' Page 2 of 6 ' conductivity of purged water at regular purge-volume intervals. Stabilization data and field logs are included in Appendix A. Purged ground water was containerized in 55-gallon drums and stored on- site. 2.2. GROUND WATER SAMPLE COLLECTION The ground water levels in all six wells were allowed to recharged to a minimum of 80% of the initial well volume prior to sample collection. Ground water samples were collected from each well using new disposable plastic bailers. Each water sample was then transferred into a one-liter amber bottle and into three 40-m1 volatile organic analysis (VOA) vials containing 0.5 ml 18% HCl as a sample preservative. The samples were then labeled and placed in a chilled container for transport under chain-of-custody to McCampbell Analytical, Inc. (MAI) of Pacheco, California, a State of California- Department of Health Service(DHS)-certified laboratory. The samples were analyzed for the following: ' • Total petroleum hydrocarbons quantified as gasoline (TPH-g) and total petroleum hydrocarbons quantified as diesel(TPH-d) in accordance with EPA Method 8015 Modified ' . for gasoline and diesel, respectively, • Volatile aromatics - benzene, toluene, ethyl benzene and xylene (BTEX) and methyl tert- ' butyl ether(MTBE) in accordance with EPA Method 8020, • Fuel additives - di-isopropyl ether(RIPE), ethyl tertiary-butyl ether(ETBE), methyl tertiary- butyl ether (MTBE), tertiary-amyl methyl ether (TAME), tertiary butanol (TBA), ethyidibromide (EDB) and 1,2-dichloroethane (1,2-DCA) in accordance with EPA Method 8260 Modified, respectively. 1 2.3. SOIL-VAPOR EXTRACTION ' The SVE system was maintained and monitored monthly and during restart procedures. During each monitoring event,the flow rate of extracted soil-gas(influent)was measured using an electrical DPT ' flow meter. Vacuum potential was measured at the two and one-half inch influent line using a rnagnehelic vacuum gauge. - The_organic-vapor concentration in the extracted soil-gas stream was measured prior to entering the _ blower(influent stream) and after exiting the catalytic unit(effluent stream) using an organic vapor meter (OVM) equipped with a photo-ionization detector: PID (Thermo Environmental 580A, ' 10.0eV, calibrated to isobutylene 100 ppb). One set of soil-gas samples was collected during the month of May 2001. The 10 May 2001 samples ' were collected in Tedlar vapor bags using a vacuum pump attached to the influent and effluent Advanced GeoEnvironmental,lne. 1