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All groundwater samples were submitted to Evergreen Analytical Laboratory, located in <br />Wheat Ridge Colorado, for analysis. Evergreen was recently acquired by Accu-Test <br />Laboratory, and a laboratory name change will be completed in 2009. Accu-Test <br />subcontracted analyses for radiochemical parameters to Hazen Research laboratory, located <br />in Golden, Colorado. <br />RESULTS AND DISCUSSION <br />Results of the groundwater sampling are provided in Table 1. Analytical results provided <br />by the contract laboratories are presented in Appendix A. <br />All samples were submitted for analysis of selected dissolved metals, general chemistry <br />parameters, and radiochemistry parameters. The results of these analyses are discussed in <br />the following sections. <br />Dissolved Metals <br />The following dissolved metals were not detected in any samples collected: Aluminum, <br />chromium, iron, nickel, silver, vanadium, zinc, antimony, arsenic, cadmium, copper, lead, <br />and thallium. Cobalt was detected in well MW-004 at a concentration just above the <br />t reporting limit in this event, though cobalt has not been previously detected. This suite of <br />metals has typically been reported as non-detect in all previous monitoring events. All <br />' dissolved metals detections are shown in bold text in Table 1. Due to a laboratory <br />oversight, mercury was not analyzed with the samples during this event. Mercury has only <br />been detected historically one time at MW004 a concentration well below applicable <br />standards. <br />Dissolved metals results for the second half, 2009 sampling at GCC are compared to values <br />presented in Tables 1, 2, and 3 of the Colorado Basic Standards for Groundwater. <br />) <br />(http://www.cdphe.state.co.us/regulations/Mccregs/index.html <br />The applicable values for the basic standards for dissolved metals are included in Table 1 <br />for reference. If there is no health-based standard for a metal, the secondary or agricultural <br />standard is listed. Any exceedances to the basic standards are shown as shaded cells in <br />Table 1. The only dissolved metal detection to exceed a primary drinking water standard is <br />that for selenium in alluvial well sample MW004. This selenium detection corroborates <br />similar results from the previous 2008 and 2009 events. Elevated selenium concentrations <br />associated with certain shallow sedimentary rock units in the Pueblo area have been well <br />documented, and include the St. Charles River alluvium (aril 2007, GEI Consultants, Inc, <br />Aauatic Biological Monitoring and Selenium Investigation of the Arkansas River, Fountain <br />Creek Wildhorse Creep and the, St. Charles River). <br />2