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ATC Associates Inc. <br /> Quality Assurance/Quality Control Plan <br /> Revised November 2002 <br /> yards of material to be sampled unless otherwise specified by the lead regulatory agency. <br /> The samples will be composited by the state certified laboratory personnel prior to testing. <br /> 12.0 GROUNDWATER SAMPLING PROTOCOL <br /> Prior to arriving at the sampling site, all sampling equipment will be washed with nonphosphate <br /> detergent (Alconox or equivalent), and rinsed twice with tap water, once with acetone, and once <br /> with deionized water. This procedure will be carried out on-site before sampling of other <br /> monitoring wells, if more than one well 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 <br /> thickness of product on top of the groundwater, if present, will be measured using an interface <br /> probe. The procedure for monitoring is presented in Section 9.0 (Groundwater Monitoring <br /> 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 <br /> be removed,an interval specific sampling device may be utilized to collect a sample from below the <br /> zone of free product. Before collecting groundwater samples from each well, the well will be <br /> purged until indicator parameters (temperature, conductivity, and pH) stabilize. This will entail the <br /> removal of at least four well casing volumes by bailing or pumping. The criteria for determining <br /> well casing volumes and temporary storage of purged water is outlined in Section 10.0 (Well <br /> Development Protocol). The indicator parameter measurements will be taken both before and after <br /> purging of each well casing volumes. Once the well is purged and indicator parameters have <br /> stabilized, a sample will be collected after the water level approaches 80 percent of its initial <br /> elevation. Where water level recovery is slow, the sample will be collected after stabilization is <br /> achieved and enough water is present to fill sample containers. <br /> w:\admin\shells\qaqc-02.doc <br /> 13 <br />