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

Abstract

This work was carried out mainly to analyze radioactive elements 40 K, 232 Th, and 226 Ra 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 226 Ra, 232 Th, and 40 K 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, 226 Ra, 232 Th, and 40 K radioactivities were lower than the worldwide average limits. The 226 Ra, 232 Th, and 40 K 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 226 Ra and 232 Th and a modest correlation between 226 Ra and 40 K. Meanwhile, no association between 226 Ra and 40 K 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.