Measurement of natural radioactivity and assessment of radiological hazard indices in soil from Tirunelveli District, Tamil Nadu, India with statistical approach

The activity concentrations of naturally occurring radionuclides ²³⁸U, ²³²Th, and ⁴⁰K were determined in 31 soil samples collected from the Tirunelveli District of Tamil Nadu using grid sampling method. Gamma-ray spectrometry was applied using NaI(Tl) detector and a PC-based MCA. The mean radioactivity concentrations of ²³⁸U, ²³²Th, and ⁴⁰K were found to be 12.98 Bq.kg^−1, 162.89 Bq.kg⁻¹ and 453.04 Bq.kg⁻¹, respectively. The spatial map of the radionuclides was drawn and is discussed. The radiological hazards associated with soils were determined using radium equivalent activity (Ra_eq), annual gonadal dose equivalent (AGDE), activity utilization index (AUI), internal hazard index (H_in) external hazard index (H_ex) and gamma representative level index (I_γ), were calculated. Results were discussed and compared with the internationally recommended approved values. Statistical method was used to determine the natural associations between samples and variables. This work may provide baseline data for future soil radioactive environmental monitoring and the results of the study can serve as a reference for future radiological assessments.