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Well Purging The wells were purged prior to sampling 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 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 contained in 55 gallon DOT drums and removed from the site by Reno Drain Oil Field measurements of pH, specific conductance, and temperature were recorded in a waterproof field logbook Figure A-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 The pH, specific conductance, and temperature meter were calibrated each day before • field activities were begun The calibration was checked once each day to verify meter performance Field meter calibrations were recorded on the water sample field data sheet Well Sampling A Teflon bailer was the only equipment acceptable for well sampling Because samples for volatile organic analysis were being collected, the flow of groundwater from the bailer was regulated to minimize turbulence and aeration Glass bottles of at least 40-milliliters volume and fitted with Teflon-lined septa were used in sampling for volatile organics These bottles were filled completely to prevent air from remaining in the bottle A positive meniscus formed when the bottle was completely full A convex Teflon septum was placed over the positive meniscus to eliminate air After the bottle was capped, it was inverted and tapped to verify that it contained no air bubbles The sample containers for other parameters were filled, filtered as required, and capped Sample Preservation and Handling The following section specifies sample containers, preservation methods, and sample handling procedures I SAC1E WACHEIREPORTSWACP102 DOC-98Vsg 2 C-3 mon Rev 0,5/21/99