Modelling the fate of gaseous radionuclides in crops

Department of Environmental Science and Technology, Imperial College of Science Technology and Medicine, Prince Consort Road, London SW7 2BP, U.K.

Abstract

Models to predict the fate of gaseous radionuclides have received considerable attention in the literature. They vary considerably in their complexity from simple models with little attempt to reflect processes within the system to those with a high level of mechanistic complexity. The following paper describes an approach that is a compromise between simplicity and realism. In the proposed model deposition is treated traditionally as the multiple of the air concentration, deposition velocity and exposure time but the subsequent allocation of radioactivity to different plant parts is determined by the growth rate of individual plant components relative to the total growth rate of the plant. The construction of the model is described along with its validation against independent data sets for the allocation of ³⁵S and ¹⁴C in cabbage and bean following deposition in the form of CO³⁵S and, ¹⁴CO₂ at a number of discrete points in the growth season.