Bioavailability of Cs radionuclides in forest regions - data acquisition and modelling. Applications and appendix 1-4

A model of radiocaesium soil-plant transfer is proposed, combining two separate approaches to describe radionuclide distribution in soil-soil solution system and soil solution-plant system. According to the model radiocaesium concentration in soil solution is determined by abilities of soil to fix and selectively sorb radiocaesium as well as cationic composition of soil solution. Soil solution - plant transfer is determined by Cs concentration in soil solution and also by cationic status of soil solution. It is derived that soil-plant transfer factor should be a linear function of availability parameter A of the soil which is a combination of soil parameters and cationic status of soil solution. The parametrisation is tested against the field data on soil-plant transfer for various forest sites in Germany, Russia, Sweden and Switzerland. Satisfactory agreement has been achieved. A simplified method of the parameterisation based on the application standard argochemical characteristics of soil is presented and experimentally tested. The approach can be used in radioecological GIS to map radiocaesium soil-plant transfer factor. (orig.)