Population dose in the vicinity of old Spanish uranium mines

Regional surveys were conducted to determine exposure to natural sources of radiation for people in the vicinity of old Spanish uranium mines. The surveys evaluated indoor radon concentrations and outdoor and indoor external gamma dose rates. Indoor radon concentrations were measured in 222 dwellings by means of nuclear track-etched detectors. The terrestrial gamma ray dose rate was measured outdoors and indoors at a total of 256 points and 115 points, respectively. Estimates mean annual effective doses for the six areas studied ranged from 3.2 to 5.1 mSv per year, which is between 1.2 and 2 times higher than the average national value.