Health Risk Assessment of Heavy Metals in African Catfish (Clarias gariepinus) from Fish Ponds in Port Harcourt, Rivers State, Nigeria

This study aims to evaluate the health risks linked to heavy metal concentrations in Clarias gariepinus harvested from earthen and concrete fishponds in Port Harcourt, Rivers State, Nigeria. The concentration of heavy metals was determined through atomic absorption spectrometry, and the associated health risks were evaluated using various exposure models, including Estimated Daily Intake (EDI), Target Hazard Quotient (THQ), and Hazard Index (HI). The results showed that in earthen ponds, cadmium (0.174–0.301 mg/kg) and lead (0.112–0.84 mg/kg) levels were below WHO/FEPA limits, while nickel, zinc, and copper concentrations were also within safe ranges. However, iron in sample B (11.464 mg/kg) exceeded the standard, posing potential risks. In concrete ponds, cadmium (1.257 mg/kg) and lead (5.376 mg/kg) levels were significantly above the recommended limits, highlighting serious health risks. Zinc and copper concentrations remained safe, but iron levels (10.068 mg/kg) surpassed the standard, indicating health concerns. Analysis of the EDI for all heavy metals across the earthen and concrete ponds revealed that all values were below safe limits, confirming the safety of consuming African catfish from these ponds. The THQ values for all metals were below 1, indicating no significant non-carcinogenic health risks. Similarly, the HI values for both pond types were well below the threshold of 1.0, confirming negligible cumulative risk from heavy metal exposure. In conclusion, there is no non-carcinogenic risk associated with the consumption of African catfish from earthen and concrete fishponds for the residents of Port Harcourt. Despite the low health risk, regular monitoring is recommended, especially due to the potential for bioaccumulation of cadmium and lead, which can pose long-term health concerns.