Radionuclide Uptake by Plants: Soil-to-Plant Transfer Factors, Kinetics of Absorption, and Internal Radionuclide Distribution of 137Cs and 40K in South American Species

Abstract

Soil-to-plant transfer factors (F v ) are commonly used as a key link to estimate the transference of radionuclides along the human food chain. The use of F v assumes that the radionuclide concentration in plant is linearly related with the radionuclide concentration in soil. However, for different ecosystems and even considering similar soil type and plant species, a large variability in F v values has been reported, showing that other variables in addition to radionuclide soil concentration have influence on the radionuclide uptake by plants. Another possible source of uncertainty in F v could come from the heterogeneous distribution of the radionuclide in the plant. In this chapter, we analyze two situations: (a) the root uptake of Cs+ and K+ using electrophysiological techniques, for three grass species that grow in seminatural grassland of central Argentina and (b) the incorporation of 137Cs and 40K by tropical plants and their translocation to fruits. In both cases, we have considered components that are incorporated into the human food chain and, consequently, there is a need of adjusting their dosimetric contribution on the population.