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ground-water contour map. All (or selected) monitoring wells were samp- <br /> led for chemical constituents after the water-level survey was completed. <br /> Water levels were measured with an electric sounder. The electric <br /> sounder is a transistorized instrument that uses a reel-mounted, two-con- <br /> ductor, coaxial cable that connects the control panel to the sensor. Cable <br /> markings are stamped at 1-foot increments. The water level was meas- <br /> ured by lowering the sensor into the monitoring well. A low-current circuit . <br /> is completed when the sensor contacts the water, which serves as an <br /> electrolyte. The current is amplified and fed into an indicator light and <br /> audible buzzer, signaling when water has been contacted. A sensitivity <br /> control compensates for highly saline or conductive water. The electric <br /> sounder was decontaminated by rinsing with deionized water after each <br /> use. <br /> Depth to water was recorded to the nearest 0.01 foot in the field logbook. <br /> The ground-water elevation at each monitoring well was calculated by <br /> subtracting the measured depth to water from the surveyed elevation of <br /> the top of the well casing. The total depth of the well was then measured <br /> in the monitoring wells scheduled for sampling by lowering the sensor to <br /> the bottom of the well. The total depth of the well, used to calculate purge <br /> volumes and to determine whether the well screen is partially obstructed <br /> y silt, was recorded to the nearest 0.5 foot in the field logbook. <br /> Sample Collection <br /> ' Sample collection procedures include equipment cleaning, water-level and <br /> total well-depth measurements, well purging and sampling, spring (or sur- <br /> face-water) sampling, leachate sampling, and lysimeter sampling. <br /> Equipment Cleaning <br /> Sample bottles, caps, and septa used in sampling for volatile or <br /> semivolatile organics were triple rinsed with high-purity deionized water. <br /> After being rinsed, sample bottles were dried overnight at <br /> 200°Celsius (°C). Sample caps and septa were dried overnight at 60°C. <br /> Sample bottles, caps, and septa were protected from solvent contact <br /> between drying and actual use at the sampling site. Sample bottles, caps, <br /> and septa were used only once and discarded after analysis was <br /> complete. <br /> pj9\939\9390111 c A-2 Rev. 0 September 9, 1992 <br />