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FIELD PROCEDURES Site Safety Plan This plan describes the safety requirements for field work performed at the site The site safety plan is applicable to personnel of Smith Environmental Technologies Corporation (Smith Environmental) who perform the field work A copy of the site safety plan is available for reference by appropriate parties during the work The on site representative of Smith Environmental acts as the Site Safety Officer Groundwater Well Purging and Sampling The static water level in each well was measured to the nearest 0 01 foot with a Solinst electric water-level sounder cleaned with a laboratory-grade, non-phosphatic detergent and deiomzed water before use in each well A clean bailer was used to obtain a sample from the surface of the water in the well for subjective analysis of hydrocarbons The sample was retrieved and visually examined for floating product, sheen, color, and clarity Approximately 3 well volumes of groundwater were purged from the wells using dedicated bailers or pump systems All downhole equipment such as pumps, cables, and hoses were cleaned with a • laboratory-grade, non-phosphatic detergent and water before use in each well The wells were purged until withdrawal was of sufficient duration to result in stabilized pH, temperature, and electrical conductivity of the water, as measured by portable meters calibrated to a standard buffer and conductivity standard The wells were allowed to recover to at least 80 percent of the static water level prior to sampling The groundwater purged from the wells was temporarily stored in 55-gallon liquid waste drums approved for this use by the Department of Transportation pending results of laboratory analyses The City of Stockton is responsible for the disposal of the purge water and has contracted to have purge water removed A sample of the formation water then was collected from the surface of the water in each of the wells with dedicated disposable bailers and slowly transferred to laboratory-cleaned sample containers Evaluation of Groundwater Gradient The elevation of the top of each well casing was measured by Smith Environmental using well MW-4 as the datum point The U S G S Quadrangle Map, Stockton West, California 1976, was used to evaluate the elevation of the ground surface around well MW-4 The tops of the monitoring and recovery wells were surveyed relative to mean sea level on September 9, 1992 The elevation of the well casing and the depth to groundwater measured in each monitoring well were combined to evaluate the relative elevation of the groundwater surface in each well and the slope of the groundwater surface across the site