Histopathological evaluation of sheep from deactivated uranium mines

Background: Until the beginning of the XXI century, 60 mines of uranium and radium (226Ra) have been explored in Portugal, producing waste contaminated with radioactive elements, sometimes in very high concentrations, abandoned in the debris deposited on the surface. The program to assess the environmental impact of waste, from old uranium mines, detected the existence of public health and environmental risks. Previous studies validated vertebrate species, as indicators of genotoxicity and exposure to metals, in mining areas. Objectives: The aim of this work was the detection of radioactive elements in specimens of autochthonous breed of Serra da Estrela sheep, grazing in areas with high environmental radioactivity and respective pathological study, with a view to predicting exposure and effects in humans. Methods: Necropsy of 3 adult specimens, from a flock in an area where there was uranium mining - Arcozelo da Serra (Gouveia municipality) was performed. The study of accumulation of radionuclides of uranium and its radioactive progeny was performed by radiochemical, followed by alpha spectrometry. Simultaneously, samples of several organs were fixed in 10% neutral-buffered formalin, for a maximum of 48 hours, embedded in paraffin wax, and 3µm sections were stained for routine histopathological diagnosis. Results: In the sheep studied, the presence of radionuclides in the uranium series, all in the internal organs, was registered and the liver and kidneys displayed the highest concentrations. The lesions observed were compatible with high parasitic infestation of several systems and lesions compatible with multisystemic process, most notorious interstitial pneumonia, apparently from viral aetiology - ovine pulmonary adenocarcinoma and chronic granulomatous enteritis and lymphadenitis - paratuberculosis. Conclusion: It was concluded that the levels of uranium remains high in areas of deactivated uranium mines, being present in the food chain, including in the tissues and internal organs of sheep raised in proximity but at lower concentrations than those reported to produce biological effects animals and their consumers. Histopathological diagnosis revealed the presence of infectious diseases which are common throughout the region, hypothesizing that these animals could have been more susceptible, given the increase expression and severity of the conditions presented. Introdução: Até ao início do século XXI foram exploradas 60 minas de urânio e rádio (226Ra) em Portugal, produzindo resíduos com elementos radioativos, por vezes em concentrações muito elevadas, abandonados nos escombros depositados à superfície. O programa de avaliação do impacto ambiental dos resíduos das antigas minas de urânio detetou a existência de riscos para a saúde pública e riscos ambientais. Estudos anteriores validaram espécies de vertebrados, como indicadores de genotoxicidade e exposição a metais em áreas mineiras. FCT (PTDC/AAC-AMB/114057/2009) and CI&DETS (PEst-OE/CED/UI4016)