[en] Following an accidental release of radionuclides to the atmosphere with the contamination of large areas, a detailed and fast methodology to assess the prognosis of public exposure is needed to estimate radiological consequences and optimize decisions to the protection of the public. The German model ECOSYS has been chosen to integrate the SIEM - Integrated Emergency System, developed by IRD/CNEN to assess the doses to the public after an accidental contamination of rural areas. The use the model demands a considerable effort in adapting scenarios to fit the specific conditions of a location, considering the differences related to climate, environmental characteristics, agricultural calendar and practices, along with population diet. The area selected to start this adaptation considers the characteristics of the 50 km radius area surrounding the nuclear power plants at Angra dos Reis, Rio de Janeiro. At a first stage, the concentration on vegetal food products has been studied. This work describes the methodology used to select scenarios and presents results of the dynamics of the predicted concentration of radionuclides in different kinds of animal derived food products. The work provides guidance to the need of radioecological research needed to improve the adequacy of the estimates to actual Brazilian scenarios. (author)