Anthropogenic ~(236)U and Pu at remote sites of the South Pacific

摘要

Anthropogenic radionuclides, like U-236 and Pu-239,Pu-240, are present in the environment as a result of global fallout from nuclear weapons tests conducted in the 1950s and 1960s and can potentially be used as tracers in soil erosion and sediment movement studies. Here, we report data on U-236 and Pu-239,Pu-240 in soil samples from the Motueka Valley (New Zealand) and for the first time from two remote islands Rarotonga and Atiu (Cook Islands) in the South Pacific. U-236 and Pu-239,Pu-240 were measured using Accelerator Mass Spectrometry (AMS) at the Australian National University. The U-236 and Pu-239 isotope concentrations versus soil depth and the Pu-249/Pu-239 and U-236/Pu-239 isotope ratios are discussed for each site. The radionuclide depth dependence revealed any soil disturbance, whereas the isotopic signatures indicated the source of the radionuclides' origin.