Absorbed Dose Rate Due to Intake of Natural Radionuclides by Tilapia Fish (Tilapia nilotica,Linnaeus, 1758) Estimated Near Uranium Mining at Caetite, Bahia, Brazil
- Coordenacao de Protecao Radiologica, Unidade de Tratamento de Minerios, Caixa Postal 961, CEP 37701-970, Pocos de Caldas, MG, BR Industrias Nucleares do Brasil (Brazil)
- Universidade Federal Fluminense, Programa de Pos-graduacao em Biologia Marinha (Brazil)
- Coordenacao de Protecao Radiologica, Unidade de Concentrado de Uranio. Caixa Postal 7, CEP 46.400-000 Caetite, Bahia, Brasil Industrias Nucleares do Brasil (Brazil)
The uranium mining at Caetite (Uranium Concentrate Unit--URA) is in its operational phase. Aiming to estimate the radiological environmental impact of the URA, a monitoring program is underway. In order to preserve the biota of the deleterious effects from radiation and to act in a pro-active way as expected from a licensing body, the present work aims to use an environmental protection methodology based on the calculation of absorbed dose rate in biota. Thus, selected target organism was the Tilapia fish (Tilapia nilotica, Linnaeus, 1758) and the radionuclides were: uranium (U-238), thorium (Th-232), radium (Ra-226 and Ra-228) and lead (Pb-210). As, in Brazil there are no radiation exposure limits adopted for biota the value proposed by the Department of Energy (DOE) of the United States of 3.5x10{sup 3} {mu}Gy y{sup -1} has been used. The derived absorbed dose rate calculated for Tilapia was 2.51x10{sup 0} {mu}Gy y{sup -1}, that is less than 0.1% of the dose limit established by DOE. The critical radionuclide was Ra-226, with 56% of the absorbed dose rate, followed by U-238 with 34% and Th-232 with 9%. This value of 0.1% of the limit allows to state that, in the operational conditions analyzed, natural radionuclides do not represent a radiological problem to biota.
- OSTI ID:
- 21152481
- Journal Information:
- AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 1034; ISSN APCPCS; ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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