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generally associated with leaching from granitic bedrock masses that underlay many <br />aquifers in the state. The Dakota formation in the Denver basin, which extends from <br />Pueblo to Wyoming, is also host to minor Uranium roll front deposits. These deposits form <br />when groundwater containing dissolved uranium comes into contact with reducing <br />conditions, causing precipitation of the Uranium. Such naturally occurring conditions are <br />the likely cause of the elevated gross alpha activities in the Dakota aquifer beneath the GCC <br />Facility. <br />Field Parameters <br />Field parameters including temperature, pH, and conductivity were collected during the <br />April 2010 sampling. The data collected indicate that pH at the site is very close to neutral. <br />Conductivity is highest in the alluvial wells where some turbidity was noted. <br />Quality Control <br />One set of field duplicate samples was collected during the monitoring event. Sample <br />Dup-01 was submitted as a blind field duplicate of primary alluvial well sample MW002. <br />Precision between the results of the primary and duplicate samples was very good for all <br />parameters tested. <br />One equipment rinsate blank was collected during the monitoring event. The blank was <br />collected by pouring laboratory-supplied de-ionized waxer through a new bailer and into the <br />' appropriate sample bottles. No target constituents were detected in the equipment blank. <br />All laboratory data packages were reviewed to ensure that quality control elements (holding <br />times, blanks, control samples, and matrix spikes), impacting precision and accuracy of the <br />groundwater results presented were within appropriate control limits. Data from the <br />contract laboratories was found to be acceptable in terms of data quality and industry <br />' standard presentation. <br />