Determination of natural radionuclides mica stone and zeolite used in different industrial sectors

Mica and zeolite minerals are important additives that are widely used in different industries such as construction, paper, paint, automobile, textile, and fertilizer. In this study, distributions of 226Ra, 232Th and 40K natural radionuclides, radon emanation coefficient and radon mass exhalation rates of four zeolites and three mica quarries in Western Anatolia were determined using a gamma ray spectrometry with high purity germanium detector. Average activity concentrations of 226Ra, 232Th and 40K in 88 zeolite and 84 mica samples were measured as 70.9 ± 2.8 Bq/kg, 122.5 ± 3.0 Bq/kg and 1025.5 ± 24.9 Bq/ kg and 8.2 ± 0.9 Bq/kg, 37.6 ± 1.8 Bq/kg and 2706.8 ± 24.7 Bq/kg, respectively. The average radon emanation coefficients and the average of radon mass exhalation rates of the zeolite and mica samples were found as 4% ± 1% and 10 ± 1% and 5.95 ± 0.24 μBq/kg s and 1.78 ± 0.19 μBq/kg s, respectively. The activity index and the alpha index were calculated in order to radiological evaluation of the use of zeolite and mica samples as additives in building materials. In addition, annual effective radiation doses and lifetime cancer risks for zeolite and mica workers were evaluated. The data were compared with criteria or limit values. The results revealed that usage of the investigated zeolite and mica samples as building materials would not cause any significant radiological risk.