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`- 2,0 PROCEDURES <br /> Depth to ground water was measured in each well. The well volume was calculated by <br /> adding the casing volume to the annular volume (assuming a 30 percent porosity). Each <br /> well was purged of a minimum of three well volumes based on the recommendation of Mr. <br /> Harlin Knoll with the County who was in attendance. The minimum amount of water <br /> necessary to purge and the actual approximate amount purged (gallons) for each well is <br /> listed below. <br /> WELL 3 WELL VOLUME VOLUME PURGI D <br /> MW-1 41.8 65 <br /> MW-2 40.7 65 <br /> MW-3 54.0 65 <br /> A submersible pump was used for purging and the pumping rate varied between six and <br /> eight gallons per minute. This rate slightly exceeded the wells' capa:ity and occasionally <br /> the pump would shut off for a ten-minute interval while the well recovered. At three or <br /> four intervals for each well a sample of water was collected and measured for the ground- <br /> water quality parameters of conductivity, pH and temperature. The well was considered <br /> stabilized when the water ran clear and the parameters were within 10% of the previously <br /> recorded value. For decontamination between each well, the pump was run in a drum of <br /> Alconox solution and then a drum of tap water. Purge water was placed in a labeled drum <br /> and left on site. <br /> Disposable bailers were used to sample each well. Three 40-milliliter VOA bottles and <br /> an amber one-liter bottle were collected from each well. All samples were placed in cold <br /> storage with a trip blank and transported by chain-of-custody to Curtis and Tompkins, a <br /> California state-c rtified analytical laboratory. All samples were analyzed for Total <br /> Extractable Hydrocarbons JEH),diesel(California DOHS Method)and Benzene,Toluene, <br /> Ethylbenzene and Total Xylenes (BTEX) (EPA 8020, Extraction EPA 5030). <br /> 4 <br />