Assessment of Radionuclides and Heavy Metals Concentration of Some Selected Fish Samples in River Komadugu of Gashua, Yobe State, Nigeria

Abstract

This study investigates the concentrations of heavy metals (Pb, Cd, Fe, Zn) and the activity concentrations of naturally occurring radionuclides (²²⁶Ra, ²³²Th, and ⁴⁰K) in fish samples from the Komadugu River. Gamma spectrometry, coupled with a sodium thallium iodide (NaI(Tl)) detector, and atomic absorption spectrometry (AAS) were employed to assess the levels of these contaminants. The mean activity concentrations of the radionuclides were found to range as follows: ⁴⁰K (61.54 ± 2.70 Bq/kg), ²³²Th (24.98 ± 3.57 Bq/kg), and ²²⁶Ra (17.90 ± 2.71 Bq/kg). Health risk assessment indices, including radium equivalent activity (Raeq), were below the permissible limit, while the annual effective dose (AED) and excess lifetime cancer risk (ELCR) exceeded the acceptable thresholds in some samples. The concentration of heavy metals in the fish samples varied as follows: Zn (245.25–145.0 mg/kg), Fe (1774.75–341.0 mg/kg), Cd (28.75–1.00 mg/kg), and Pb (162.75–3.5 mg/kg). The mean concentrations of heavy metals were: Fe (796.05 mg/kg), Zn (192.45 mg/kg), Pb (89.90 mg/kg), and Cd (10.65 mg/kg), with Fe being the most abundant, followed by Zn, Pb, and Cd. These findings highlight potential health risks associated with the consumption of fish from the Komadugu River, emphasizing the need for ongoing monitoring and risk management of aquatic food sources in the region.