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Description
Aquaculture environments can serve as pathways for naturally occurring radionuclides to enter the human food chain through fish consumption and water use. This study quantified the activity concentrations of polonium-210 (Po-210) in catfish tissues and radon-222 (Rn-222) in pond water from selected aquaculture habitats in Ekiti State, Nigeria. A longitudinal sampling design was adopted, with samples collected weekly over a four-week period from five aquaculture sites. Tissue-specific Po-210 activity in catfish was determined using alpha spectrometry, while Rn-222 concentrations in pond water were measured using a RAD7 electronic radon detector. Key physicochemical parameters of the aquaculture systems, including pH, salinity, electrical conductivity, biochemical oxygen demand, and chemical oxygen demand, were evaluated for their association with radionuclide levels. The mean Rn-222 concentration in pond water was 3.33 Bq L⁻¹. Detectable levels of Po-210 were observed in both fish tissues and pond sediments, indicating transfer of radionuclides within the aquaculture environment and bioaccumulation in aquatic organisms. The committed effective ingestion dose to humans from consumption of contaminated catfish was estimated, and the associated lifetime cancer risk was evaluated. This study provides baseline data on naturally occurring radionuclides in aquaculture systems in Ekiti State, Nigeria. The findings highlight the importance of routine radiological monitoring of aquaculture environments to support food safety and protect public health.
Keywords: Radon-222; Polonium-210; Aquaculture; Catfish; Ingestion dose; Radiological risk; Alpha spectrometry.