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Smith Environmental Technologies Corporation <br />Quality Assurance/Quality Control Plan <br />Revised February 1995 <br />procedure will be carried out on-site before sampling of other monitoring wells, if more than one well <br />is to be sampled with the sample sampling device. <br />Immediately prior to sampling, the depth to water (DTW) in the well will be recorded. The thickness <br />of product on top of the groundwater, if present, will be measured using an interface probe. The <br />procedure for monitoring is presented in Section 9.0 (Groundwater Monitoring Protocol). <br />If free product is detected, analysis of groundwater at the interface for dissolved product will not be <br />conducted. A product sample will be collected for source identification. If all free product cannot be <br />removed, an interval specific sampling device may be utilized to collect a sample from below the zone <br />of free product. Before collecting groundwater samples from each well, the well will be purged until <br />indicator parameters (temperature, conductivity, and pM stabilize. This will entail the removal of at <br />least four well casing volumes by bailing or pumping. The criteria for determining well casing volumes <br />and temporary storage of purged water is outlined in Section 10.0 (Well Development Protocol). The <br />indicator parameter measurements will be taken both before and after purging of each well casing <br />volumes. Once the well is purged and indicator parameters have stabilized, a sample will be collected <br />after the water level approaches 80 percent of its initial elevation. Where water level recovery is slow, <br />the sample will be collected after stabilization is achieved and enough water is present to fill sample <br />containers. <br />Cross contamination from transferring pumps (or bailers) from well to well will be avoided by utilizing <br />dedicated equipment. Where this is not feasible, thorough cleaning of equipment will be performed <br />between sampling rounds. Sampling will proceed from the least contaminated to the most <br />contaminated well, if information is available before sample collection, or if it is indicated by field <br />m:1...\shells\QAQC-95. WP5 <br />13 <br />• <br />SH <br />