Livestock meat as a bioindicator of natural radionuclide exposure and cancer risk near the Manyoni uranium deposit, Tanzania

Naturally occurring radionuclides associated with uranium mineralization can enter terrestrial food chains and pose potential radiological risks to exposed populations. This study evaluated livestock meat as a bioindicator of natural radionuclide exposure in communities surrounding the Manyoni uranium deposit in central Tanzania. Activity concentrations of 238 U, 226 Ra, 232 Th, and 40 K were measured in livestock meat collected from four villages at varying distances from the mineralized zone, with a control site located outside the influence of uranium-bearing formations. Gamma spectrometric analysis revealed elevated U- and Th-series radionuclide concentrations in villages proximal to the deposit, particularly Mwanzi. To assess potential health implications, annual committed effective ingestion doses and excess lifetime cancer risks were estimated based on consumption of livestock meat. The pooled ingestion dose for the villages surrounding the Manyoni mineralized zone was 0.129 ± 0.006 mSv·y -1 , below the ICRP public exposure limit but above global average ingestion doses from natural radionuclides. 226 Ra was the dominant contributor to ingestion dose and exhibited significant spatial variability. These findings demonstrate that livestock meat effectively integrates environmental radionuclide exposure and can serve as a practical bioindicator in uranium-bearing regions. The results underscore the importance of routine food-chain monitoring to support radiological protection and public health planning in areas targeted for future uranium development.