Evaluation of protective measures for tropical environments

Abstract

Nuclear and radiological accidents have demonstrated the need for prior planning for exposure assessment as well as guidelines for the implementation of protection and remediation measures of contaminated areas. Typically, the description of the efficiency of the measures in the literature is associated with the reduction of the concentration of the environmental media where they are applied. In order to verify the efficiency related to the reduction in doses, some basic scenarios were established, taking into account aspects of a typical tropical climate, such as building materials (urban areas) and types of crops and farming practices, considering the seasonality and soil type typical of the southeastern region of Brazil. The Integrated System for Emergency (SIEM) program was used to perform the simulations. The results indicate that decision-making processes must be made in accordance with the actual conditions of contamination and use of the affected area. For rural areas, the effectiveness of measures depends on many factors specific to each site, such as seasonality, produced crops, diet habits and degree of subsistence on the items in the diet, which make it unfeasible to develop generic predefined scenarios. The criteria for classification of measurements were defined as: (i) the efficiency in reducing the doses in the first year, in which largest dose rates are observed; (ii) the efficiency in reducing the long-term dose, considering 50 y for adults and (iii) the effect of delay in implementation of the measures on the reduction of doses.