Radiation Safety of Old Uranium Mining Waste Dumps in Portugal

Abstract

The risks associated to uranium mining and milling wastes require the radiological surveillance of the areas with these residues and the assessment of the radiation risk to the populations living in the region. This radiological surveillance is based on an environmental monitoring programme implemented by ITN. Annually, soils, water, and plants including horticulture products from the uranium mine areas are sampled and analyzed for radioactivity. As part of this programme, analyses of soils, irrigation waters, agriculture products (lettuce), green pasture, and cheese were performed in samples collected in the area of the old Urgeiriça uranium mine and milling facilities near Viseu, Centre-North of Portugal, in order to assess the transfer of uranium series radionuclides to man. In the Urgeiriça area, some soils and vegetables display radionuclide concentrations higher than in reference areas 226Ra was the radionuclide more concentrated by vegetables. Through ingestion of these products 226Ra may be the main contributor to the increment of radiation dose received by local population. The solutions implemented for environmental remediation of tailings piles and mining waste dumps in Urgeiriça and in other old uranium mine sites, with time are expected to render safe these areas and to allow the release of old mining concession areas for other uses by the public without radiation risks.