Alpha emitter concentrations of natural radionuclides and radiological hazard assessment of soil samples in the Halabja governorate, Iraq.

Abstract

Naturally occurring radioactive gases in soil, such as radon, are recognized for their significant impact on local air quality and potential health risks to nearby populations. The disturbance of the Earth's surface through excavation activities can enhance the release of these gases, increasing the likelihood of radon exposure. This study investigates soil samples collected from various sites across the Halabja governorate in Iraq to provide a comprehensive evaluation of the area's radiological profile. The primary objective is to measure alpha emitter concentrations of radon, radium and uranium present in the soil. Alpha particle tracks emitted from radon gas were recorded using a CR-39 detector. To enlarge and reveal the alpha tracks, the samples underwent chemical etching using a 6.25 N NaOH solution at 70 °C for seven hours, after which the tracks were analysed under a microscope. The findings demonstrate that alpha emitter concentrations of ²²²Rn, ²²⁶Ra and ²³⁸U ranged from 119.76 to 228.55 Bq/m³, 0.22 to 0.42 Bq/kg and 2.92 to 5.57 ppm, respectively. These results were within the safe limit. Radiological hazard parameters for indoor and outdoor (annual effective dose, excess lifetime cancer risk and effective dose rate to different body organs) were computed to assess the health risks associated with selected soil samples. The results of the study indicate that the levels of alpha-emitting radionuclides in the soil samples are below the recommended safety thresholds, suggesting that the surveyed area does not pose a radiological hazard. These findings offer important baseline data to support Iraqi public health initiatives and radon management strategies.