Radiological risk assessment and the implications for biodiversity inJabi Lake, Abuja Nigeria

In this study, the natural radioactivity and its ecological implications in Jabi Lake were assessed, focusing on radiological risks to humans and aquatic biodiversity. Ambient radiation dose rates were measured in situ using a GMC-800 survey meter, while water and sediment samples were analyzed for radionuclide content. Radon concentrations in water were determined using a Tri-Card LSA 1000 liquid scintillation counter, and sediment samples were analyzed with NaI(Tl) gamma spectrometry at the Centre for Energy Research and Training, Ahmadu Bello University, Zaria, Nigeria. The mean ambient dose rate was found to be $69.3\text{nGy}/\text{h}$ , which is below the global average of $84\text{nGy}/\text{h}$ . However, the excess lifetime cancer risk (ELCR) averaged $5.6\times {10}^{-4}$ is greater than ICRP's recommended limit by a factor of two, and it is attributed to a cumulative exposure over time. Radon in water ranged from $15.4\text{to}42.7\text{Bq}/\text{L}$ with a mean $\text{of}27.6\text{Bq}/\text{L}$ , exceeding the USEPA limit of $11\text{Bq}/\text{L}$ but below the WHO/UNSCEAR guideline of 100 Bq/L $100\text{Bq}/\text{L}$  Sediment analysis revealed mean activity concentrations of were 8.62 ± 2.63, 5.98 ± 1.11, and 202.6 ± 16.42 Bq/kg  respectively, all lower than the global averages. ERICA code assessment showed dose rates to aquatic organisms below the ecological dose rate screening criterion of 40 nGy/h. The findings indicate low ecological risk but highlight elevated human cancer risk, which suggest minimization of lifetime exposure, waste disposal control, wider scope assessment and monitoring around Jabi Lake, and stakeholder engagement to ensure optimized protection of biodiversity.