Radioactivity in the Diet in High Background Areas of Brazil

Abstract

Abs tract-Two types of high background regions have been studied in Brazil-the monazite sand region along the Atlantic Coast and the zone of volcanic intrusives in the inland state of Minas Gerais. In both regions there are groups of people living on variable fields of radiation ranging from 0.03 to 1.0 mR/hr.T o evaluate the extent of the radioactive intake and internal contamination of representative populations, an extensive survey was carried out.In villages in the monazite sand region, the local production of food was found to be insignificant and the radioactive contents were practically within normal ranges. In the volcanic intrusive zone, two villages were selected for having extensive agriculture production cultivated, to a large extent, in soils containing thorium and uranium minerals. The radioactivity in local produce is appreciable, mostly due to 228Ra and daughters, which in some types of foodstuff reach two orders of magnitude above average normal values.A dietary inquiry conducted in a representative sample of the population allowed the classification of the inhabitants in groups, according to certain ranges of radioactive intake. In spite of the high levels in some local foods, mostly root vegetables, only 1376 of the inhabitants presented daily intakes of alpha emitters above 5 fold the average in normal regions. The maximum daily intake observed was elevated by a factor of 20. For the high intake group, the estimated 228Ra body-burdens were in the range of 1-3 nCi.

Evaluation of indoor radon gas levels in three Brazilian municipalities located in the state of Minas Gerais

“…This concern arose due to the discovery of uranium deposits and the establishment of a currently inactive plant for the commercial exploitation of this ore [5]. The Plateau region is widely acknowledged as an Area of High Natural Radiation [6][7][8].…”

Distribución ambiental de uranio y transferencia suelo-planta de radionúclidos (238U, 226Ra y 210Pb) en áreas uraníferas del oeste de Salamanca

“…Las áreas con alta radiactividad natural o zonas contaminadas ofrecen una buena oportunidad de examinar las consecuencias de una exposición prolongada a las radiaciones ionizantes (Penna-Franca et al, 1970). Estas áreas representan excelentes laboratorios naturales para estudios ambientales del comportamiento de radionúclidos naturales en con-diciones estáticas (Galvão et al, 1988).…”