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GROUNDWATER SAMPLE COLLECTION <br /> 1 <br /> Sample collection procedures Included equipment cleaning, water-level and total well-depth <br /> 1 measurement, and well purging and sampling <br /> Equipment Cleanin <br /> 1 P <br /> re_cleaned sample bottles, caps, and septa were provided by a California Department of <br /> 1 Health Services (DHS)-approved laboratory All sampling containers were used only once <br /> and discarded after analyses were completed <br /> 1 Before the sampling event and between each event, all equipment to be placed in the well or <br /> to come in contact with groundwater was disassembled and cleaned thoroughly with <br /> 1 detergent water, steam cleaned with tap water, and rinsed with deionized water Any parts <br /> that may absorb contaminants, such as plastic pump valves or bladders, were cleaned as <br /> 1 described above or replaced The water-level sounder was washed with detergent and rinsed <br /> with distilled water before use in each well The rinse water was stored in 55-gallon drums <br /> on site pending proper disposal <br /> Water-Level, Phase-Separated Hydrocarbon, and Total Well-Depth Measurements <br /> 1 <br /> Before purging and sampling were performed, the depth to water, phase-separated <br /> hydrocarbon (PSH) thickness, and the total well depth were measured using an electric <br /> sounder, a bottom-filling clear LuciteTm bailer, and/or an oil/water interface probe The <br /> electric sounder, manufactured by Slope-Indicator, Inc , is a transistorized instrument that <br /> 1 uses a reel-mounted, two conductor, coaxial cable that connects the control panel to the <br /> sensor Cable markings are stamped at 1-foot intervals An engineer's rule was used to <br />' measure the depths to the nearest 0 01 foot The water level was measured by lowering the <br /> sensor into the monitoring well A low-current circuit is completed when the sensor contacts <br />' the water, which serves as an electrolyte The current is amplified and fed across an Indicator <br /> light and audible buzzer, signaling contact with water A sensitivity control compensates for <br />' very saline or conductive water After the water level had been determined, the bailer was <br /> lowered to a point just below the liquid level, retrieved, and inspected for PSH <br /> • <br />' 06I18199/1213821125997/DRILDONE DOC <br />