Modeling radionuclide effluxes from agricultural and natural ecosystems in Belarus

A mathematical model is described which is appropriately constructed to calculate effluxes of radionuclides from agricultural and natural ecosystems. The application of this model is demonstrated by estimating effluxes in the Bragin region and in the Narovlya region in the Republic of Belarus both highly affected by the Chernobyl accident fallout. Depending on the nature of the area and the deposition, the total efflux and the exported radioactivity are calculated. It is shown that the exported radioactivity for natural foodstuffs represents more than 64% (Bragin region) and 86% (Narovlya region) of the total Cs-137 efflux, and for agricultural products 2.7% and 2.3%, respectively. The contribution of the different foodstuffs deriving from natural and agricultural used land to the individual and collective dose for Cs-137 and Sr-90 are estimated and presented. In the Bragin region for the collective annual dose the highest contribution is due to milk and meat consumption (Cs-137) and flour and milk (Sr-90), for individual annual dose milk and mushrooms (Cs-137), and milk and flour (Sr-90) contribute most. In the Narovlya region this contribution for the collective and individual annual dose is due to milk and mushroom consumption (Cs-137) and flour and milk (Sr-90).