Radon in Water: A Comprehensive Review of Exposure Risks, Research Gaps, and Policy Implications in Nigeria

Radon in water represents a significant yet understudied public health risk, particularly in Nigeria, where groundwater reliance is high and regulatory frameworks are lacking. This review synthesizes current research on radon concentrations in Nigerian water sources, highlighting exposure risks, health implications, and policy gaps. Radon-222 (222Rn), a carcinogenic gas from uranium decay, poses both inhalation and ingestion risks, with inhalation linked to lung cancer and ingestion causing stomach cancer. Despite global guidelines from the WHO and EPA, Nigeria lacks comprehensive regulations, and research remains little, with studies concentrated in only a few states (e.g., Ekiti, Ogun, Kwara). Findings reveal variable radon levels, often within safe limits, though some areas exceed recommended doses. The review identifies critical gaps, including the absence of baseline data in high-risk geological areas like Delta State, limited epidemiological studies on ingestion risks, and insufficient public awareness. This review calls for urgent action: expanded research, radon monitoring, and policy development to mitigate risks. By addressing these gaps, Nigeria can effectively protect vulnerable populations, particularly in rural communities dependent on groundwater. This review underscores the need for interdisciplinary collaboration to bridge science, policy, and public health in addressing radon-related hazards