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' Geo(ogua(T"echnus Inc Page 2 Groundwater Monitoring Report Project No 507 2 July 28, 2000 1.2 Groundwater Sampling Procedure ' On June 16, 2000, Don Light of Del-Tech mobilized to the site to conduct groundwater monitoring of the eight existing monitoring wells ' Before sampling was attempted the wells were sounded for depth to water and then a clear disposable baiter was used to determine if floating product was present The wells were purged of at least three well volumes of stagnant water using a dedicated Waterra check-ball assembly and '/2" tubing Purging continued until the temperature, conductivity, and pH of the groundwater stabilized (c10% 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 from the Waterra tube 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 a foam holder 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 N 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 These drums were propeily labeled and will be stored on site until their proper disposition can be arranged ' Groundwater monitoring field logs are included in Appendix C 1.3 Laboratory Analyses - - ' The groundwater samples collected on June 16, 2000 were delivered to Sherwood Lab (Department of Health Services Certification No 1400), of Hilmar, California, for analysis ' The eight groundwater samples weie analyzed by Sherwood for ' + Benzene, Toluene, Ethyl Benzene, and Xylene (BTEX) by EPA method 602 0 Total Petroleum Hydrocarbons as Gasoline (TPH-G) by EPA method 5030/8015(M)