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r <br /> r <br />' Water-Level, Phase Separated Hydrocarbon, and Total Well-Depth Measurements <br />' Before purging and sampling, the depth to water, phase separated hydrocarbon (PSH) <br /> thickness, and the total well depth were measured using an electric sounder, a <br />' bottom-filling clear LuciteTM bailer, and/or an oil/water Interface probe The electric <br /> sounder, manufactured by Slope-Indicator, Inc , is a transistorized Instrument that uses a <br /> r reel-mounted, two conductor, coaxial cable that connects the control panel to the sensor <br /> Cable markings are stamped at one-foot Intervals An engineer's rule Is used to measure <br /> the depths to the nearest 0 01 foot The water level is measured by lowering the sensor <br />' into the monitoring well A low current circuit Is completed when the sensor contacts the <br /> water, winch serves as a electrolyte The current is amplified and fed across an Indicator <br />' light and audible buzzer, signaling contact with water A sensitivity control compensates <br /> for very saline or conductive water After the water level is determined, a bailer is <br />' lowered to a point just below the liquid level, retrieved, and Inspected for PSH <br />'• If PSH was encountered, its thickness was measured with an oil/water Interface probe <br /> This Instrument's dual-sensing probe utilizes an optical liquid sensor and electrical <br /> conductivity probe The Instrument ermts a steady tone when immersed In oil, and an <br /> oscillating tone when immersed in water If PSH greater than 1/32-inch in thickness was <br /> detected, a sample was not collected from that well <br />' All liquid measurements were recorded to the nearest 0 01 foot in the field logbook The <br /> q g <br /> I groundwater elevation at each monitoring well was calculated by subtracting the measured <br /> depth to water from the surveyed well-casing elevation Total well depth was measured <br /> by lowering the sensor to the bottom of the well Total well depth, used to calculate <br /> purge volumes and to determine whether the well screen is partially obstructed by silt, was <br /> recorded to the nearest 0 1 foot in the field logbook <br /> Well Purging <br /> Before sampling, standing water in the casing was purged from the monitoring well using <br /> a pump or hand bailer Samples were collected from the monitoring wells after three to <br /> A-2 <br /> E ICTI10212QTR96 DOC <br />