Abstract:Objective To investigate the radioactivity levels of tea-leaves in Lincang, Yunnan Province, estimate their influence on public health and accumulate base-line data of radioactivity levels of tea-leaves. Methods Radioactivity levels of 28 ripe tea-leaves and 15 fresh ones were measured in 2014 and 2015 with γ spectrometry method for analyzing radionuclides in biological samples. Results Natural (232Th, 226Ra, 40K) and man-made (137Cs) radioactive nuclides of the Pu'er tea held the lowest radioactivity levels[(0.95±0.99), (1.17±0.78), (571.33±9.10), <0.001 Bq/kg(fresh weight)]. Radioactivity levels of fresh tea-leaves presented seasonal characteristics and were higher in autumn [(0.72±0.12), (1.07±0.22), (161.16±13.35), (0.12±0.06) Bq/kg (fresh weight)]than spring[(0.52±0.11), (0.73±0.17), (133.35±30.74), (0.09±0.05) Bq/kg (fresh weight)]. Conclusion Radioactivity levels of 238U in ripe and fresh tea-leaves were below the limit of detection. Radioactivity levels of natural (232Th, 226Ra, 40K) and man-made (137Cs) radioactive nuclides in the tea-leaves were lower than the relevant national limits.