Availability of radiocasium in plant from soil: Facts, mechanisms and modelling

Abstract

Radiocaesium is an isotope that can enter the food chain after having been absorbed by plants from soil. Our ability to predict the consequences of an accidental release of 137Cs depends mainly on the level of understanding of the mechanisms involved in 137Cs interactions with different components of agricultural and natural ecosystems and their formalization into predictive models. In this study the impact of some environmental and physiological factors, such as root density and presence of AM (Arbuscular mycorrhizal) fungal hyphae, on the ability of plants to uptake and accumulate radiocaesium through the roots was investigated. Three plant species were used: pea, soybean and oats. Experimental data suggested that, as roots explore new volumes of soil during growth, the plant will continue to accumulate this radionuclide at high rates in the early stages of ontogenesis. If plants are established on a contaminated site they may not be able to remove all of this radionuclide from soil, especially if a substantial amount of the radionuclide has been leached below the root zone which is commonly 30-40 cm in depth. Laboratory experiments indicate that certain plants may be able to remove radionuclides, especially 137Cs, from soil over a time period of 5-20 years. © 2009 Global NEST.