Evaluation of health hazards from radionuclides in soil and rocks of North Waziristan, Pakistan

Background: The aim & objective of this study is to evaluate the health hazards of the general public from the existence of the radioactive nuclides in soil of North Waziristan and to establish a reference line for future work on radioactivity concentration in this locality. Methods and Materials: A highly background radiation shielded HPGe system is used to measure radioactivity in the collected samples of the geographical study area. Results: The radioactivity concentration is found to be in the range 42.6–106.3 Bq/kg for Ra-226, 4.0–93.8 Bq/kg for Th-232, 49.9–645.5 Bq/kg for K-40, and 2.6–8.33 Bq/kg for Cs-137. The external and internal hazards indices (Hext & Hint), absorbed γdose rate (ADR) and average effective dose (AED) are estimated from the computed activities and determined the average Hext ~ 0.75 and Hint ~ 0.94. The mean absorbed dose rate was found to be 101 nGy/h. The Radium equivalent activity of Datta Khel (422.081 Bq/kg), Khaisur forest (407.938 Bq/kg), Jani Khel (379.213) specific regions and the corresponding outdoor annual effective dose rate was found to be 0.15 mSv/yr, which is higher than the world’s mean value of 0.07 mSv/yr. Conclusion: A strong possitive correlation amongst the radioactive nuclides and, corresponding radiological variables at P ≤ 0.01confirmed that Ra-226 and Th-232 were the significant contributors to γ-radiation emission. Radioactivity concentrations and corresponding radiometric parameters were found to be higher in the specific areas of North Waziristan compared to the world’s mean values poses possible radiological risks for the residents of those areas.