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<br />1 <br /> <br /> <br />1 <br /> <br /> <br />1 <br /> <br /> <br />1 <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br />and zinc concentrations in the groundwater. For -he most part, <br />it appears that observation of metals in groundwater samples <br />is related to drilling bias. High initial concentrations were <br />identified in some wells, but they did not persist over time. <br />The most noticable differences between the groundwater <br />quality and the surface water quality are the degree of <br />mineralization in the groundwater and the presence of <br />radiological activity. Radiological activity ~n several of <br />the wells persisted for several samples and, whEn gross alpha <br />and gross beta concentrations were above drinking water <br />standards (15 picocuries per liter and 50 picocuries per liter, <br />respectively), additional analyses were conductE~d to identify <br />specific constituents that were contributing to ~ilpha and beta <br />emissions. Generally, uranium was identified as the principal <br />source of alpha emissions, with minor contributions from radium <br />226 and radium 228. Lead 210 was thought to be the principal <br />beta emitter, based on the geologic conditions from which this <br />water was extracted; however, lead 210 was not identified as <br />the major beta emitter. Further beta analyses were not <br />conducted, as it o~as judged that identification of specific <br />constituents was not necessary at this time. <br />Although surface water and groundwater samples exhibit <br />the same general type water (calcium-bicarbonate), there are <br />significant differences between the surface water and <br />groundwater quality. Based on flow data in Rito Seco, and the <br />water quality differences between the ground watE~r and surface <br />water it does not appear that significant contributi~ ns are_ <br />being made from the bedrock aquifer to Rito Se.o throughout <br />this reach. Conversely, based on water levels in the Santa Fe <br />Conglomerate monitoring wells, and the associated water quality <br />differences, it does not appear that appreciable quantities <br />o water are being lost to the alluvium and the adjacent Santa <br />Fe Conglomerate. <br />G-51 <br />