Environmental pathways of radionuclide transfer in food chains in west Africa: Current knowledge and research gaps

Radionuclide transfer through food and water pathways remains an important but undercharacterized source of internal radiation exposure in West Africa. The region is influenced by both natural geological enrichment and anthropogenic activities such as mining, oil and gas operations, and fertilizer use, all of which can mobilize naturally occurring radionuclides into environmental media and subsequently into the human diet. This review synthesizes published evidence on the transfer of key radionuclides, including uranium series radionuclides, thorium series radionuclides, potassium-40, radium-226, radon-222, lead-210, and caesium-137, through major dietary pathways in West Africa, with specific attention to rice, cassava, fish, and potable water. A structured literature review approach was applied using Scopus, Web of Science, PubMed, and the IAEA International Nuclear Information System, with studies from West African countries screened for relevance, methodological clarity, and reported activity concentrations in food and water matrices. The evidence indicates that potassium-40 is commonly the dominant contributor to measured activity concentrations, while radium-226, uranium isotopes, and radon-222 present more significant concern in mining influenced areas, granitic terrains, and other high-background settings. Available studies suggest substantial spatial variability, but the regional evidence base remains fragmented, with limited longitudinal monitoring, inconsistent analytical reporting, and insufficient integration of local dietary patterns into dose assessment. The review identifies critical research gaps, including the need for locally derived soil-to-plant transfer factors, improved assessment of processing effects on staple foods, stronger groundwater surveillance, and national baseline monitoring frameworks. Strengthening these areas is necessary to support realistic exposure assessment, food safety regulation, and public health protection in West Africa.