Preliminary assessment of uranium mining legacy and environmental radioactivity levels in Sabugal region, Portugal

An environmental radioactivity survey carried out in the Sabugal region, Portugal, showed enhanced radioactivity levels in surface water streams related to water discharges from old uranium mines. Water from irrigation wells in this region displayed variable radionuclide levels due to natural occurrence of radionuclides and to contamination by mine water drainage. Horticulture products grown near the uranium mine sites contained elevated radium (226Ra) concentrations, but lower concentrations of uranium and other radionuclides. Despite the relatively high radioactivity in irrigation water, the absorption and accumulation of radionuclides in agriculture products were limited. Nevertheless, taking into consideration the volume of uranium waste piles, it is considered as necessary to improving the management of mine wastes and mine drainage to prevent further increase of environmental radioactivity in the area. The assessment of environmental impact and radiation issues lasting from the past uranium mining shall be used as lessons to improving future mining activities.