Radioactive springs in the watershed of a proposed reservoir in Sequoyah County, Oklahoma: Origin and environmental effect

Abstract

Radioactive (radium-rich) springs discharging in the watershed of a proposed impoundment on Lower Lee Creek in Sequoyah County, Oklahoma, were determined not to represent a significant radiological effect. The impact of these springs on the proposed lake will be negligible, owing to a combination of the following factors: extremely low rate of discharge of the springs even following periods of heavy rainfall, effective dilution of the spring water by the creek into which the springs discharge (dilution factor of about 1:100), and precipitation of radiobarite just below the mouths of the springs. The spring water probably rises to the surface along a fault and fracture system present in the study area. The presence of daughter products belonging to the /sup 238/U as well as the /sup 232/Th decay chains suggests that these nuclides are not a surface manifestation of buried sedimentary uranium deposits, because such deposits do not contain significant concentrations of thorium. The geologic setting of the area precludes the presence of vein-type uranium-thorium deposits. The primary factor responsible for the high radium content of the springs is most likely rock-to-fluid transfer of alpha-decaying nuclei in the /sup 238/U and /sup 232/Th series. In the deep, relatively static rock-fluidmore » system the fluid is a very sensitive indicator of this phenomenon taking place in a reducing environment in the absence of processes capable of removing radium isotopes from solution.« less