Radioactivity in Iberian Rivers with Uranium Mining Activities in their Catchment Areas

Rivers flowing through the uranium mining region of Portugal, such as the Mondego andZêzererivers,receive drainage from areas of old uranium mines. The international River Águeda, a tributary to River Douro, has also important uranium mining and milling facilities in its catchment basin in Spain. In order to assess the radioactive contamination of these river basinsresulting from uranium mining waste, uranium series radionuclides were measured in water, suspended particulate matter, and riverbed sediments.Results showed that significant radioactivity enhancement took place in sections of these rivers.This contamination persisted long time after environmental remediation implemented at some mine sites and cessation of mine discharges. The persistent risk of waste leaching and dam failure requires continued monitoring of radioactivity levels in these rivers.