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FIELD PROCEDURES <br /> Measurement of the Depth to Groundwater in MQnitoring�Well� <br /> The depth of the groundwater surface in a monitoring well was measured from the top of <br /> the well casing to the nearest 0.01 foot with a Solinst water-level indicator. <br /> Subjective Analysis of Monitoring Wells <br /> Groundwater samples are collected for subjective analysis from the air-fluid interface <br /> in a monitoring well by lowering approximately half the length of a clean bailer <br /> through the interface. The bailer is retrieved and the water sample is visually <br /> examined for floating product, sheen, and other subjective evidence of hydrocarbon <br /> contamination. <br /> Purging and Sampling, of-Monitoring Wells <br /> Before sample collection, a minimum of 3 casing volumes of ground water is purged from <br /> each morutonng well using a bailer. The volume should be sufficient to produce <br /> stable temperature,pH, and conductivity measurements on field instruments. After the <br /> well is allowed to recover to near static levels, a groundwater sample is collected by <br /> lowering a clean bailer past the air-water interface. The bailer is retrieved and the <br /> sample is slowly transferred to laboratory-cleaned, 40-milliliter glass vials. The <br /> vials are filled so as to prevent headspace. Labels which show the site <br /> identification number, the date and time of sample collection, and the sample <br /> identification number are affixed to the vials. The samples are promptly stored in an <br /> ice chest with ice. The field geologist initiates a Chain of Custody Record listing <br /> each sample number, the site identification number, and the date sampled. This record <br /> will accompany the samples to the analytical laboratory. <br />