Assessment of radiation hazard indices due to naturally occurring long-life radionuclides in the coastal area of Barra de Valizas, Uruguay.

Abstract

The Uruguayan east coast has several mineral resources, which include black sand ores in the Barra de Valizas-Aguas Dulces area. Cancer in Uruguay shows non-homogeneous geographical distribution, with the highest standardized mortality ratio (SMR) in the northeast and east region, which includes the aforementioned area and the town of Barra de Valizas. The activity concentration of natural radionuclides (226Ra, 232Th and 40K) in Barra de Valizas´soil was determined by gamma spectrometry in order to evaluate the radiological hazard for inhabitants and tourists. The outdoor annual effective dose (AEDE), excess lifetime cancer risk (ELCR), and annual gonadal dose equivalent (AGDE) were evaluated for inhabitants with a life expectancy of 77.7years, a 0.2 and 0.5 occupancy factor, and using the conversion coefficients recommended by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). The annual effective dose was also evaluated for both summer and fortnight tourists. The radiological hazard indices for Barra de Valizas inhabitants are higher than the worldwide mean and recommended values. This may contribute to Rocha's higher SRM value, although a direct correlation cannot be assured with the epidemiological information currently available. Social, medical and anthropological studies will be carried out in future to provide data and verify this correlation.