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:- Ug� <br /> iV c,{ ..—yammgg ,�.e �}' <br /> z ..; <br /> f <br /> FIELD PROCEDURES <br /> Measurement of the De th to Ground Water in Ma itori �Vells <br /> e The depth of the groundwater surface in a monitoring well is measured from the top of the <br /> well using to the nearest 0.01 foot with a Solinst water-level indicator. <br /> ub'ective Anal sis of auid-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 /> Purging and Sampling of Monitoring Wells <br /> Before sample collection, a minimum of 4 well volumes of ground water is purged from each <br /> monitoring well using an electric submersible pump. A sufficient volume is purged to allow <br /> temperature,pH, and conductivity of the purge water to stabilize. After the water level in the <br /> well is allowed to recover to at least 80 percent of tt., initial level, aground-water sample is <br /> collected by lowering a clean Teflon bailer past the air-water interface. The bailer is <br /> retrieved, and the sample is slowly transferred to laboratory-cleaned, 40-milliliter glass vials <br /> that contain concentrated hydrochloric acid as a preservative. The vials are completely filled <br /> so as to prevent headspace. The vials are labeled with the site identification number,the date <br /> and time of sample collection, the preservative used, and the sample identification number. <br /> The samples are promptly placed in iced storage and delivered tc a laboratory certified by the <br /> State of California. <br />