Assessment of Naturally Occurring Radionuclides and Heavy Metals Level and Health Risks in Commonly Consumed African catfish, White Catfish and Nile Tilapia Fish Species from Epe Waterside Region of Lagos, Nigeria

Abstract

Elevated levels of radionuclides and toxic metals in water can potentially influence the growth of fish during their mature stages, posing a risk of human exposure through the consumption of contaminated fish. This investigation assessed the levels of health risk of naturally occurring radionuclides and heavy metals in commonly consumed African catfish, White catfish and Nile tilapia fish species in the Epe Waterside region of Lagos, Nigeria, using a sodium iodide detector and an atomic absorption spectrometer. The activity concentrations (Bq/kg) of 40K (29.1±21.0-823.5±18.2) were higher than 226Ra (27.1±87.8-202.7±50.3) and 232Th (52.9±7.4-600.2±7.0), with mean values exceeding the permissible limits set by WHO. The mean committed effective dose rate is above the 50 mSv recommended by ICRP. The mean annual intake and cancer risks for people who consume fish on a weekly basis (nutrition statistics for seven, five, three, and one day per week) were relatively high, surpassing the permissible limit of 1.0×10-6 as recommended by WHO. The concentrations of heavy metals (Zn: 0.026-1.344, Cu: 0.008-0.055, and Cd: 0.048-0.250 mg/kg) exhibited mean values that fell within the acceptable limits defined by FAO/WHO, with the exception of Pb, which recorded a higher concentration ranging from 2.51 to 3.39 mg/kg. The fish's natural habitats (lagoon) have been contaminated by toxins, likely originating from industries, waste disposal activities, agrochemicals, rusty pipes, and other fittings. Encouraging the cultivation of fishes in domesticated ponds around the study area can reduce the risk of consuming contaminated fish and other seafood.