Radon-222 Concentration and Health Implication in Borehole Water of Ngumari Costain, Jere, Local Government, Borno State

This study investigates the concentration of Radon-222 (²²²Rn) in borehole water samples from Ngumari Costain in Jere Local Government Area, Borno State. Radon-222 levels were assessed using a Tri-Carb LSA-1000 liquid scintillation counter. Although Nigeria lacks specific guidelines for Radon-222 in drinking water, the U.S. Environmental Protection Agency (USEPA) advises a maximum limit of 11.1 Bq/L. The recorded concentrations ranged from 4.26 to 13.50 Bq/L, with an average of 8.83 Bq/L. Certain locations, including Layen D.J. and Layen Alau, showed slightly elevated levels above the recommended limit, while Layen Zamani recorded the lowest concentration. Despite these variations, the estimated annual effective dose from ingestion and inhalation of Radon-222 remains well within the World Health Organization (WHO) safety threshold of 0.1 mSv/year for radionuclides in drinking water. The annual effective dose for various age groups—infants, children, and adults—falls below the recommended limit, indicating that water consumption from this area is safe for human health. Additionally, calculated health risk parameters, such as Whole-Body Equivalent (WBE) and Excess Lifetime Cancer Risk (ELCR), are below international safety standards. These findings indicate that borehole water in Ngumari Costain does not pose significant health risks to the local population and is considered safe for drinking.