Assessment of natural radioactivity in soil around Khetri copper belt of Rajasthan, India

The concentration of natural radionuclides (²²⁶Ra, ²³²Th, ⁴⁰K) in the fifty soil samples around the Khetri copper belt is measured using an HPGe detector. The values of ²²⁶Ra, ²³²Th, and ⁴⁰K are found to be lying in the range of 5.2 ± 0.3 to 27.5 ± 0.6 Bq kg⁻¹, 12.9 ± 0.4 to 38.8 ± 1.3 Bq kg⁻¹, and 113.3 ± 27.8 to 308.5 ± 31.2 Bq kg⁻¹ respectively. The radium equivalent activity ranged from 38.63 to 93.35 Bq kg⁻¹ with a mean value of 56.21 Bq kg⁻¹. The values of absorbed dose rate, annual effective dose, and annual gonadal dose rate are also estimated, which comes out to be less than their corresponding world average values. Hazard indices (internal and external) and level indices (alpha and gamma) are also observed to be less than unity. The soil of the study area can be considered safe for people living there because of its low radiological risk.