Natural Radioactivity of Granitic Rocks and Their Health Risk around Ingesana Mountains, Sudan

Abstract

Abstract This work was carried out mainly to analyze radioactive elements 40K, 232Th, and 226Ra and non-radioactive elements in some granitic rocks and study their health risk for humans and non-humans. Radioisotope activity was evaluated using a high-purity germanium (HPGe) detector, and various radiological hazard indices were calculated. We also measured some non-radioactive elements using x-ray fluorescence analysis and performed Pearson correlation analysis to examine the relationships between the radionuclides and the non-radioactive elements. Furthermore, we used the ERICA software to estimate the total dose rate per organism for some non-human biota. The means of 226Ra, 232Th, and 40K are 25.13 ± 5.22 Bq kg−1, 29.01 ± 6.95 Bq kg−1, and 323.07 ± 97.83 Bq kg−1, respectively. Hence, 226Ra, 232Th, and 40K radioactivities were lower than the worldwide average limits. The 226Ra, 232Th, and 40K levels were under the global average values. The hazardous radiometric variables were computed, and the findings observed that the mean absorbed dosage was 23.48 ± 7.36 nGy h−1, the yearly effective dose rate was 29.82 ± 10.46 μSv y−1, and the radium equivalent activity was 88.88 ± 18.64 Bq kg−1. The average dose and yearly effective dose rates were lower than the global average absorbed dose rate of 60 nGy h−1 and the ICRP standard of 1.0 mSv y−1. The results of Ra-equivalent activity were lower than the recommended maximum criterion for building materials limit of Ra-equivalent activity (370 Bq kg−1) proposed by UNSCEAR. Tests of Pearson correlation coefficients indicate a substantial positive relationship between 226Ra and 232Th and a modest correlation between 226Ra and 40K. Meanwhile, no association between 226Ra and 40K and non-radioactive components has been identified. Thorium-232 exhibits a moderately favorable connection with Ti, Fe, and Ni. The estimated total dose rate per organism for the studied non-human is less than the ambient dose rate. However, the total dose rate for small burrowing mammals and reptiles exceeds the background exposure rate. In accordance with the findings, granite rocks may be safe to use as construction materials and pose no threat to human health.