Gamma-spectroscopic assessment of radionuclides and radiological hazards in undisturbed and cultivated soils of Rupnagar, Punjab, India

Abstract

The current study provides a detailed comparison of radionuclides (238U or 226Ra, 232Th, and 40K) concentrations, elemental ratios, and radiological hazards in soil samples from undisturbed and cultivated lands in Rupnagar, Punjab, employing a high-purity germanium (HPGe) detector. The mean elemental concentration of 238U, 232Th, and 40K in undisturbed land was found to be 4.70 ± 1.16 ppm, 20.63 ± 4.53 ppm, and 1.44 ± 0.15%, respectively, whereas, in cultivated land, the concentrations were 3.25 ± 0.28 ppm, 15.90 ± 0.96 ppm, and 1.92 ± 0.25%, respectively. Moreover, the elemental ratios 232Th: 238U, 232Th: 40K, and 238U: 40K have been established to assess the depletion or enrichment of radionuclides. Key radiological parameters, including the internal hazard index (Hin) and external hazard index (Hex), gamma index (Iγ), and alpha index (Iα), were found to be below the safe limit of unity. However, gamma dose metrics such as the absorbed dose rate (Ḋ), annual effective dose (AD), annual gonadal equivalent dose (AGED), and excess lifetime cancer risk (ELCR) considerably exceeded the global average. The relationship between radionuclide concentrations and health risk metrics was analyzed through their correlation. The morphology of soil particles from both sites was interpreted considering their radioactive properties.