Radioactivity and radiological impact of industrial raw materials in Korea

Natural radionuclides of 226Ra (238U), 232Th, and 40K in raw materials used in building and cosmetic materials produced in Korea were measured using a γ-ray spectrometer (HPGe). The radionuclide concentrations ranged from 0.06 ± 0.01 to 4.13 ± 0.21 Bq g−1 for 226Ra, 0.08 ± 0.01 to 33.6 ± 1.9 Bq g−1 for 232Th, and from minimum detectable activity to 4.06 ± 0.36 Bq g−1 for 40K, respectively. The 226Ra and 232Th contents in a majority of samples were higher than the exemption level recommended by the International Atomic Energy Agency of 1 Bq g−1 for 226Ra and 232Th and 10 Bq g−1 for 40K; however, the 40K content in all the selected raw materials was lower than this level. Moreover, it was observed that these materials were richer in thorium than uranium, which implies that these raw materials contain variable amounts of monazite ore. Radiological indices of radium equivalent, gamma-index, absorbed radiation, and equivalent gamma-doses were also calculated. The results indicate a potential radiation hazard, which highlight the necessity of radiation-regulation and routine monitoring.