Evaluation of Uranium in Organs of Residents from an Uranium-Rich Region using Teeth as Bioindicators

Abstract

The Uranium extraction and processing plant of INB (Brazilian Nuclear Industries) is in Caetité, a city located in a region hosting the largest Uranium reserve of the country. The degree of Uranium contamination in the Caetité population was investigated before using teeth as bioindicator, where a quite high Uranium concentration was measured in this region, about 160 times higher than the world-wide average. Radiobiological risks are here evaluated from Uranium burdens in organs as skeleton, kidneys, liver, tissues and blood, which were estimated from transfer coefficients and effective internal doses. This was accomplished by means of calculations with the use of the STATFLUX/ICRP approach, plus a set of Uranium transfer rate parameters as function of individual’s age assuming an uninterrupted exposure over a period of 60 years. It was found that U ingestion rates by residents of Caetité are three orders of magnitude higher than worldwide average, indicating that food and water would exhibit high levels of contamination. Calculated effective internal doses range from a minimum of one to a maximum of three orders of magnitude higher than background doses, for blood and bones respectively. The likelihood that this circumstance could lead to serious health problems as e.g. neoplasia is addressed. The methodology presented in this work offers subsidies for further studies on environmental pollution by radionuclides.