A SYSTEMATIC REVIEW OF RADIONUCLIDE CONTAMINATION IN NIGERIAN FISH AND ITS IMPLICATIONS FOR PUBLIC HEALTH

This systematic review (2015–2025) synthesizes 111 peer-reviewed studies on radionuclide contamination in Nigerian fish, focusing mostly on catfish and tilapia across Lagos (Epe, Victoria Island), Rivers (Port Harcourt), Niger (Kainji), Ondo (Ilaje, Ijebu), Kwara (Ilorin), Osun (Eko-Ende), Ekiti (Ado Ekiti), Kaduna (River Kaduna), Gombe (Dadin Kowa), Kebbi, and Delta States. Elevated radionuclidelevels (²²⁶Ra, ²³²Th, ⁴⁰K, ²³⁸U) in Lagos (²³²Th: 299.33 Bq/kg) and Rivers (⁴⁰K: 2,305.84 Bq/kg) reflectindustrial and oil-related pollution, while Ekiti and Kaduna show minimal contamination. Catfish exhibited higher bioaccumulation than tilapia due to benthic feeding habits. Annual effective doses (AEDs: 5.5 – 416 μSv/y) and excess lifetime cancer risks (ELCR: 0.97×10⁻³ for catfish, 0.85×10⁻³ fortilapia) were below ICRP thresholds, indicating fish consumption is not toxic. Children in Gombe facehigher risks (AED: 66 μSv/y) due to higher absorption. Mitigation includes source control, water treatment (adsorption, ion exchange), sediment dredging, bioremediation, phytoremediation, permeable reactive barriers, fish monitoring, and consumption advisories. Research gaps include limited studies in northern/eastern regions (e.g., Plateau, Imo, Bayelsa), lack of temporal trend analysis, and noncarcinogenic risk assessments. Future studies should standardize protocols, explore aquaculture, and model climate-driven radionuclide mobilization to enhance food safety and public health policies.