In Situ Estimation of Activity Concentrations and Gamma Radiation Dose Distribution for Environmental and Health Protection Purposes at a Fertilizer Factory, Asaba, Nigeria

Abstract Fertilizer production plays a vital role in supporting agriculture, yet its processes may introduce radiological risks that warrant careful monitoring. In this study, an in situ estimation of radionuclide activity concentrations and background gamma radiation levels was conducted at different sections of an inorganic fertilizer factory in Asaba, Nigeria, using a portable scintillation gamma radiometer. Three radionuclides, 238-U, 232-Th, and 40-K, were detected across all sections, with high mean activity concentrations of 238-U and 40-K in raw material and production areas exceeding world mean values (WMV). The absorbed gamma dose rate in the raw material section (56.98 nGy/h) approached the global limit of 59 nGy/h, while other sections remained below. Radiological hazard indices, including annual gonadal dose equivalent (0.36–1.11 mSv/y) and excess lifetime cancer risk (0.528–1.42), were above maximum permissible limits (MPL), indicating potential long-term health risks for workers and surrounding communities. These results highlight the novelty of direct, section-specific radiological assessment within fertilizer production facilities and underscore the need for continuous monitoring, restricted occupational exposure, and evaluation of finished fertilizer products to safeguard public health and the environment.