(PU)-P-239 fallout across continental Australia: Implications on (PU)-P-239 use as a soil tracer

摘要

At present there is a need for the development of new radioisotopes for soil erosion and sediment tracing especially as fallout Cs-137 levels become depleted. Recent studies have shown that (PU)-P-239 can be a useful new soil erosion and sediment radioisotope tracer. Pu-239 was released in the major atmospheric nuclear weapons tests of 1950's and 1960's. However (PU)-P-239 has a half-life of 24110 years and more than 99% of this isotope is still present in the environment today. In contrast Cs-137 with a half-life of 30.07 year has decayed to <35% of initially deposited activities and this isotope will become increasingly difficult to measure in the coming decades especially in the southern hemisphere, which received only about a third of the total global fallout from the atmospheric tests (UNSCEAR, 2000).