On the 137Cs bioavailability for the soil-plant transfer in soil treated with fertilizers

One of the most used agricultural countermeasures to reduce the uptake of adionuclides from soil into plants is the chemical treatment of the soil with fertilizers. The speciation of radionuclides in contaminated soils allows to assess the mechanisms governing the migration of radionuclide and their bioavailability. The paper presents the results of a laboratory experiment on the influence of several potassium fertilizers on the distribution of 137Cs in the soil fractions that are readily available for the uptake into the plant. By the sequential extraction method, the distribution of 137Cs has been determined in the water soluble and exchangeable fractions separated at the first moment of contamination. Most of the 137Cs has been bounded in the forms with a low accessibility to the plant, the differences in the distribution depending on the soils characteristics. Fertilizers releasing fast the potassium ions into the soil solution reduced the 137Cs concentration in the readily available fractions, whereas no modification has been produced by the application of adularia fertilizer. (author)