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an electric sounder and a bottom-filling Teflon bailer may have been used to record floating hydrocarbon thickness and depth to water The electric sounder is a transistorized instrument that uses a reel-mounted, two-conductor, coaxial cable that connects the control panel to the sensor Cable markings are stamped at 1-foot intervals The water level was measured by lowering the sensor into the monitoring well A low- current circuit was completed when the sensor contacted the water, which served as an electrolyte The current was amplified and fed into an indicator light and audible buzzer, signaling when water had been contacted A sensitivity control compensated for highly saline or conductive water The electric sounder was decontaminated by being rinsed with deionized water after each use The bailer was lowered to a point dust below the liquid level, retrieved, and observed for floating hydrocarbon Liquid measurements were recorded to the nearest 0 01 foot on the depth to water/floating product survey form The groundwater elevation at each monitonng well was calculated by subtracting the measured depth to water from the surveyed elevation of the top of the well casing (Every attempt was made to measure depth to water for all wells on the same day ) Total well depth was then measured by lowering the sensor to the bottom of the well Total well depth, used to calculate purge volumes and to determine whether the well screen was partially obstructed by silt, was recorded to the nearest 0 1 foot on the depth to water/floating product survey form • Well Purging Before sampling occurred, a polyvinyl chloride (PVC) bailer, centrifugal pump, low-flow submersible pump, or Teflon bailer was used to purge standing water in the casing and gravel pack from the monitoring well Monitoring wells were purged according to the protocol presented in Figure B-1 In most monitoring wells, the amount of water purged before sampling was greater than or equal to three casing volumes Some monitoring wells were expected to be evacuated to dryness after removing fewer than three casing volumes These low-yield monitoring wells were allowed to recharge for up to 24 hours Samples were obtained as soon as the monitoring wells recharged to a level sufficient for sample collection If insufficient water recharged after 24 hours, the monitoring well was recorded as dry for the sampling event. Groundwater purged from the monitoring wells was transported in a 500-gallon water trailer, 55-gallon drum, or a 325-gallon truck-mounted tank, to EMCON's San .lose or Sacramento office location for temporary storage EMCON arranged for transport and disposal of the purged groundwater through Integrated Waste Stream Management, Inc, Field measurements of pH, specific conductance, and temperature were recorded in a waterproof field logbook Figure B-2 shows an example of the water sample field data sheet on which field data are recorded Field data sheets were reviewed for completeness by the sampling coordinator after the sampling event was completed SAM\PlM8OM8051460 XS-96,cib l B-4 Rev 0, 10/25/96