Radionuclide content of Las Vegas Wash sediments

The Las Vegas Wash is an excavated waterway channel which drains all surface water and effluent discharge from sewage-treatment facilitates from the greater Las Vegas Metropolitan Area to Lake Mead. Fine and course sediment samples were collected at 100-m intervals and analyzed to determine the distribution of gamma-emitting radionuclides in the lower 5,500 m of the Las Vegas Wash. Results indicate depletion of long-lived fission products in upstream Wash sediments. However, trace levels of ¹³⁷Cs measured in downstream sediments suggest the resuspension and transport of radioactive fallout within the Wash. Levels of ⁴⁰K, ²³²Th, ²³⁵U, and ²³⁸U found in Wash sediments were consistent with levels typically found in southeast Nevada soils.