RADAL: a dynamic model for the transfer of radionuclides through agricultural food chains

The contamination of agricultural products by radionuclides is a mechanism which results in radiation dose commitment to the population, following fallout deposits from the atmosphere to the landscape. This paper describes the structure of the dynamic food chain model RADAL. This model simulates an acute environmental transport of fallout radionuclides through agricultural food chains to man and estimates the levels of radiation doses resulting from consumption of contaminated food. The development of RADAL was based on different existing models. For mathematical representation the transport of radionuclides was modeled through compartments representing environmental elements and/or food products. The model solves a set of linear, first-order, differential equations to estimate the concentrations of radionuclides in soil, vegetation, animal tissues and animal products as a function of time following their deposition. Dynamic physico-chemical processes of the model include the following: deposition and foliar interception, weathering, foliar absorption, soil resuspension, transfer from soil surface to the root zone, absorption by plant roots, transfer to deep soil, transfer to animal products, and human consumption of agricultural products. A parameter sensitivity analyses, performed for the main parameters of the model, showed that the foliar interception constant and resuspension factor are the most influential parameters over the radiation doses / model output. (author)