Assessment of primordial radionuclides and radon exhalation in granitic terrain of Bengaluru, India

Abstract

This study delves into an investigation of primordial radionuclides and radon exhalation potential in natural soil and rock samples collected from the granitic terrain of Bengaluru, Karnataka, India. Employing a Smart RnDuo monitor and HPGe-based gamma spectrometry, the analysis reveals significantly elevated average specific radium, thorium, and potassium activities compared to the global averages documented by UNSCEAR. The research work evaluates radiological parameters in these samples, confirming compliance with global safety limits. Absorbed dose rates, hazard indices, and dose levels align with recommended standards, underscoring the safety of the assessed environment. Notably, the radon exhalation potential of these samples spans a range of 17 ± 1.3 mBq/kg/h to 179.42 ± 10.6 mBq/kg/h, accompanied by corresponding radon emanation factors varying from 5.1 ± 0.3 % to 45.4 ± 3.1 %, with an arithmetic mean of 18.0 ± 1.1 %. Intriguingly, a positive correlation emerges between the radon exhalation rate and both radium content and emanation factor. This research sheds light on the unique radiological characteristics of the Bengaluru granitic terrain, offering insights into the local radon risk and contributing to the broader understanding of radionuclide distribution in geologically diverse regions.