Influence of agricultural countermeasures on the ratio of different chemical forms of radionuclides in soil and soil solution

The bioavailability of radionuclides derived from the Chernobyl accident is discussed in terms of their speciation in soils. A scheme representing transformation processes of different chemical forms of these radionuclides in soil and soil solution is proposed. The rate constants of the main transformation processes were obtained experimentally. Various agrochemical countermeasures are evaluated in terms of their influence on the ratio of different radionuclide forms in soil and soil solution. The influence of soil characteristics on the potential effectiveness of countermeasures is discussed. Practically all agrochemical countermeasures currently in use have positive and negative effects. The most effective countermeasures for radiocaesium and radiostrontium were liming of the soil and the application of potassium containing fertilisers at elevated rates.