تقييم النشاط الإشعاعي الطبيعي في تربة العراق باستخدام مطيافية أشعة غاما بكاشف يوديد الصوديوم المنشط بالثاليوم NaI(Tl): مراجعة شاملة

Natural radioactivity is a significant component of the environmental radiation exposure in soil. It is mainly caused by the naturally occurring radionuclides 238U, 232Th, 226Ra and 40K. This review aimed to evaluate in detail the published studies on the natural radioactivity of Iraqi soils using sodium iodide activated with thallium [NaI(Tl)] gamma-ray spectrometry. The characteristics of sampling, detector systems, activity concentrations of radionuclides and the related radiological hazard parameters in previous studies of several Iraqi governorates such as Najaf, Baghdad, Karbala, Babylon, Dhi Qar, Basrah, Nineveh and Wasit were reviewed. The investigated studies indicated the significant spatial variability of radionuclides concentrations, which is a consequence of the diversity of geological formations, soil composition, geographical conditions and land use. In general, the concentration of 40K was dominant in many of the studied locations while 238U and 232Th had relatively lower concentrations. Most of the radiological parameters reported such as radium equivalent activity, absorbed dose rate, annual effective dose and hazard indices were within the internationally recommended limits but some areas showed localized elevated values. In general, the NaI(Tl) gamma-ray spectrometry is a practical and useful tool for assessment of environmental radioactivity in Iraqi soils. The results underscore the importance of regular standardized monitoring and spatial surveys for a national baseline of natural radioactivity and to support environmental radiation protection in Iraq.