Radioactivity levels in foods in environmental protection area around a decommissioned uranium mine in Yunnan province

Objective To investigate the radioactivity levels in foods in environmental protection area around a decommissioned uranium mine in Yunnan province, in order to timely discover the release of radioactive substances and to provide accumulated baseline data. Methods Radioactivity levels in grains, vegetables and fresh tea at 20 sampling points were measured in the environmental protection area within 3 km of a decommissioned the uranium mine. After field pretreatment and laboratory preparation, the radionuclides in samples were analyzed by means of γ spectrometry. Results Radionuclides in foods in the area mainly include natural radionuclides (238U, 232Th, 226Ra, 40K) and man-made radionuclide (137Cs). Radioactivity level of 238U, 232Th, 226Ra and 40K was(0.17±0.05), (0.25±0.17), (0.43±0.28)and (103.49±25.10)Bq/kg(fresh weight), respectively. Radioactivity levels of 232Th, 226Ra, 40K and 137Cs in fresh tea were all higher than those in grains and vegetables. Conclusions Radioactivity levels in foods around the area are lower than the relevant national limits. No man-made radionuclide other than 137Cs was found in the area. Key words: Decommissioned uranium mine; Commissioned environmental protection area; Foods; Radioactivity levels