Accumulation of ⁹⁰Sr by Plants of Different Taxonomic Groups from the Soils at the East Ural Radioactive Trace

Abstract

The East Ural Radioactive Trace (EURT) is a result of the accident at the “Mayak” Production Association (PA) in 1957 (the so-called Kyshtym accident ). Among the long-lived radionuclides, ⁹⁰Sr was the primary emission contaminant at the time of the accident. At present, the density of soil contamination within the EURT varies over a wide range (10–70,000 kBq m⁻²); the spatial distribution of ⁹⁰Sr with increasing distance from the epicenter of the accident is satisfactorily approximated by an exponential function. The essential amount of this radionuclide is located in the 15–20-cm layer of the soil. We estimated the content of ⁹⁰Sr in plants growing at sites with different levels of soil contamination. The densities of soil contamination mainly determined the absorption of ⁹⁰Sr by plants.

We investigated ⁹⁰Sr accumulation by plants of major taxonomic groups, which included tree species, herbaceous plants, mosses and lichens. The results showed that the maximum concentrations of ⁹⁰Sr were found in surface mosses and in the leaves of woody plants; the large branches of trees, herbaceous plants and epiphytic lichens accumulated 2–4 times less ⁹⁰Sr, and the content of ⁹⁰Sr in fungi was minimal. We evaluated the contribution of the species specificity of herbaceous plants to ⁹⁰Sr accumulation using the Fabaceae family as an example. The variability of the accumulation capacity of most species of this family was small.