Activity Concentration of Natural Radionuclides and Health Risk Assessment in Selected Medicinal Plants and Associated Soil of Bidar, Karnataka

Medicinal plants can accumulate naturally occurring radionuclides from surrounding soil, potentially contributing to internal radiation exposure upon long-term consumption. In the present study, activity concentrations of 238U, 232Th, and 40K were determined in selected 3 medicinal plant samples and their associated 3 soil samples collected from different places in the Bidar region, Karnataka, India. Gamma-ray spectrometric analysis was carried out using a calibrated NaI(Tl) detector system. The mean activity concentrations in soil were found to be 28.5 ± 9.3 Bq kg−1 for 238U, 54.3 ± 37.4 Bq kg−1 for 232Th, and 603 ± 69 Bq kg−1 for 40K. In plant samples, 238U and 232Th were below the global detectable limit, while kg−1 were found to be 398± 38.2 Bq kg−1. Among the investigated species, Artocarpus heterophyllus Lam showed relatively higher 40K activity compared to Syzygium cumini and Hibiscus rosasinensis, which may be attributed to plant-specific potassium uptake mechanisms. Radiological hazard parameters, including radium equivalent activity (Raeq), absorbed dose rate (D), external hazard index (Hex), internal hazard index (Hin), and annual effective dose equivalent (AEDE), were calculated following UNSCEAR and ICRP guidelines. All evaluated indices were below internationally recommended safety limits .Statistical analysis indicated a positive correlation between soils and plant 40K concentrations. Overall, the results suggest that the selected medicinal plants from the Bidar region do not pose significant radiological health risks to consumers and are safe for traditional medicinal use.