The study of natural and artificial radionuclides incorporation in teeth and head bones of animals lived nearby Caetite uranium mine, Brazil

摘要

This study aimed at assessing the incorporation of radionuclides in animals in the proximity of the uranium mine in Caetite, Brazil. In 2014, samples of bovine and equine teeth and skull bones were collected and their contents of natural and artificial isotopes were assessed using nuclear spectrometry techniques. Gamma ray emission from Ra-226,Ra-228 and K-40 isotopes was determined using high-purity germanium (HPGe) spectrometry, Sr-90 radioactivity was measured with liquid scintillation, and U-234,U-238, Th-232,Th-230,Th-228, Po-210 and Pu239+240 radioactivity was assessed with alpha-spectrometry. Prior to the measurements, sample dissolutions and isotope separations were performed. Our results indicate a high Th-228 isotope content in the skull bones and the teeth of animals, up to 179 Bq per kg of ash. The Ra-226 and Ra-228 concentrations were slightly lower. Activity concentrations of other isotopes were significantly lower or below the detection limit. We could not identify sources of technologically enhanced levels of Ra-228 in the area we investigated; therefore we suggest that their origin is natural. (C) 2016 Elsevier Ltd. All rights reserved.