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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 /> 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, which 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 emits 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 /> groundwater elevation at each monitoring well was calculated by subtracting the <br />' measured depth to water from the surveyed well-casing elevation Total well depth was <br /> measured by lowering the sensor to the bottom of the well Total well depth, used to <br />' calculate purge volumes and to determine whether the well screen is partially obstructed <br /> by silt, was 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 1CT110211QTR98 DOC <br />