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FIELD PROCEDLIM <br /> Measmement of the Depthto Ground Water in MonitoringWells <br /> The depth of the ground-water surface in a monitoring well is measured from the top of the <br /> well casing to the nearest 0.01 foot with a Solinst water-level indicator. <br /> ui; ective Analysis of round-Water <br /> Groundwater samples are collected for subjective analysis from the air-fluid interface in a <br /> monitoring well by lowering approximately half the length of a clean Teflon bailer through <br /> the interface. The bailer is retrieved and the water sample is visually examined for floating <br /> product, sheen, and other subjective evidence of hydrocarbons. <br /> Purein¢_� and Sampling of Monitcring Welk <br /> Before sample collection, a minimum -if 4 well volumes of ground water is purged from <br /> each monitoring well using an electric s,ibmersible pump. A sufficient volume is purged to <br /> allow temperature, pH, and conductivity of the purge water to stabilize. Auer the water <br /> level in the well is allowed to recover to at least 80 percent of the initial level, a ground- <br /> water sample is collected by lowering a clean Teflon bailer past the air-water interface. The <br /> bailer is retrieved and the sample is slowly transferred to laboratory-cleaned, 40-milliliter <br /> glass vials that contain concentrated hydrochloric acid as a preservative. The vials are <br /> completely filled so as to prevent headspace. The vials are labeled with the site <br /> identification number,the date and time of sample collection,the preservative used,and the <br /> sample identification number. The samples are promptly placed in iced storage and <br /> delivered to a Iaboratory certified by the State of California. <br /> AUO1ieIY G,20SYSt,&,WS - <br />