Evaluation of Natural Radionuclides and Associated Health Risk Assessment in Soil and Rock Samples of Northeastern Rajasthan, India

The focus of this research is the measurement of terrestrial radionuclides (226Ra, 232Th, and 40K) in 15 soil and 15 rock samples collected from Alwar district, Rajasthan, India. The NaI(Tl) scintillation spectrometry technique was implemented to determine radionuclide levels. The levels of terrestrial radionuclides in soil samples ranged from 9.50 to 40.64 Bq kg-1 for 226Ra, 24.98 to 33.00 Bq kg-1 for 232Th, and 224.61 to 332.77 Bq kg-1 for 40K, having an arithmetic mean value 26.46, 28.44, and 275.90 Bq kg-1, respectively, while in rock samples, its levels varied from 5.87 to 91.11 Bq kg-1 for 226Ra, 18.32 to 37.81 Bq kg-1 for 232Th, and 194.94 to 609.34 Bq kg-1 for 40K, respectively, with a arithmetic mean value 22.47, 24.38, and 325.19 Bq kg-1. The observed mean values of soil as well as rock samples were well below worldwide mean values of 32, 45, and 420 Bq kg-1 for 226Ra, 232Th, and 40K, respectively, stated by the United Nations Scientific Committee on the Effects of Atomic Radiation. Radium equivalent activity in soil along with rock samples ranged from 68.57 to 104.66 Bq kg-1 and 55.87 to 177.38 Bq kg-1, having a mean value of 88.42 and 82.38 Bq kg-1, respectively, which is well below the recommended limit of 370 Bq kg-1 established by the Organization for Economic Cooperation and Development. Mean values of internal, external, gamma, and alpha indices were below unity, indicating negligible radiological risk from the soil as well as rock samples.