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Le Geologlr.al Ted MICS l= Page 3 Groundwater Monitoring Report Project No. 662.2 ti` March 24,2005 of the site's wells and seven of eight wells were sampled. Extraction well Ew-1 is not sampled due to its long screen length that intercepts both the shallow and deep aquifer zones. +.. Before sampling was performed the wells were sounded for depth to water. The wells were purged of at least three well volumes of stagnant water using a centrifugal pump. Purging continued until the temperature, conductivity, and pH of the groundwater stabilized (<10% �- variation between three readings) indicating that formation water representative of aquifer conditions was entering the wells. These water quality parameters were measured at intervals of each well volume purged. Once purging was complete, a water sample was collected using a dedicated Waterra check- ball assembly and V2 inch tubing. Care was taken to minimize sample agitation. Once the sample container was filled and capped, the bottle was inverted, tapped, and checked for headspace bubbles. The sample container was identified and labeled with a unique designation, inserted into foam holders and placed in an ice chest cooled to 4°C for transport to the laboratory. All non-disposable sampling equipment was decontaminated using a hot water washer and detergent before and between uses. Disposable gloves were used by the technician to collect all samples and were changed with each sample collection. A chain of custody document, listing all samples collected, accompanied the samples from field to laboratory, thereby providing a means to track their movement and insure their �. integrity. All water purged from each monitoring well and not used as a sample, was placed in a 55 �- gallon DOT approved container, properly labeled and stored on site until its proper disposition can be arranged. Groundwater monitoring field logs are included in Appendix C. 1.3 Laboratory Analyses The groundwater samples collected on February 17, 2005, were delivered to Excelchem Environmental Labs (Department of Health Services Certification No. 2119) of Roseville, California, for analysis. W The groundwater samples were analyzed for: 0 Benzene,Toluene, Ethyl Benzene and Xylene (BTEX)by EPA method 8020 • Total Petroleum Hydrocarbons as Gasoline (TPH-G)by EPA method 80t5(M) • Oxygenated Fuel Compounds MTBE and TBA by EPA method 8260B • Ethanol & 1,2 DCA by EPA method 8260B W