Conversion Models for Estimating Soil Redistribution Rates Using Plutonium Radionuclides (239 + 240Pu)

Quantitative and reliable estimates of soil degradation processes are essential not only for optimizing land management practices but also for ensuring and assessing their effectiveness and the sustainability of the agricultural systems impacted. Application of plutonium (239 + 240Pu) isotopes as new tracers in soil erosion and sedimentation research is a recent development. Compared to other isotopes, these offer such advantages as long half-life, availability in different environments, relatively easy determination methods using highly sensitive techniques, and consistent measurements at reference sites. However, appropriate conversion models are needed to convert the inventory of plutonium (239 + 240Pu) isotopes into soil redistribution rates. Given the few studies reported on the use of plutonium isotopes in soil erosion research, it is natural that only a limited number of models have been so far developed for computing soil erosion rates using plutonium, each of which has its own limitations. This review study will identify and introduce an appropriate model for converting (239 + 240Pu) inventories into soil redistribution rates by exploring the advantages and limitations associated with the models presently available. MODERN is, thus, selected from among the models reviewed and recommended for estimating soil erosion and sedimentation based on its advantages of independence from the type of land use, accurate determination of redistribution in the soil profile, simulation of the exact behavior of fallout radionuclides under different conditions, and its accessible and editable code, all of which make it superior to rival models.