Assessment of natural radioactivity in soil and sediments of Kurram Agency, Pakistan

This research examines environmental radioactivity levels in Pakistan’s Kurram Agency, a northwestern border area near Kabul, Afghanistan, where elevated natural radioactivity has been reported. The study aims to assess potential radiological health risks by analyzing the activity concentrations of naturally occurring radionuclides in soil and sediment samples. In soil samples, the activity concentrations of 232Th, 226Ra and 40K ranged from 28.42 ± 1.29 to 53.44 ± 1.82 Bqkg−1, 20.89 ± 0.94 to 52.60 ± 0.94 Bqkg−1 and 279.58 ± 10.58 to 654.36 ± 14.95 Bqkg−1, with mean values of 40.71, 34.45 and 448.36 Bqkg−1, respectively. These values are comparable to the worldwide averages reported by UNSCEAR (2008). The activity of 137Cs ranged from 6.24 ± 0.23 to 16.07 ± 0.40 Bqkg−1, indicating residual contamination from historical fallout events. For sediment samples, 232Th, 226Ra and 40K concentrations varied between 19.67–37.42, 30.95–63.68 and 295.18–570.51 Bqkg−1, with corresponding mean values of 26.97, 40.20 and 374.76 Bqkg−1, respectively. Calculated radiological hazard indices (Raeq, Hex, Hin, absorbed dose rate (D˙) and annual effective dose) remained within internationally recommended safety limits, indicating no significant radiological risk and supporting the suitability of these materials for construction purposes. Overall, the results reveal no evidence of cross-border radioactive transfer and provide an important baseline for future radioactivity mapping and long-term environmental monitoring in the region.