Human Health Risk assessment from the Tilapia fish in Heavy Metal-Contaminated lagoon: Case study of Ebrié lagoon (Côte d'Ivoire)

This study analyses the health risks associated with the consuming Tilapia contaminated with heavy metals in the Ébrié Lagoon, an ecosystem under strong anthropogenic pressure. The aim is to evaluate human exposure and identify the non-carcinogenic and carcinogenic risks associated with the metals mercury (Hg), cadmium (Cd), lead (Pb), zinc (Zn), copper (Cu), chromium (Cr) and nickel (Ni). Data were obtained from samples collected at eight lagoon stations during both the dry and rainy seasons. Metal concentrations were used to calculate the Estimated Daily Intake (EDI), the Target Hazard Quotient (THQ), the Hazard Index (HI), and the Carcinogenic Risk (CR), in accordance with FAO/WHO and US-EPA guidelines. EDI values varied by metal and site, with higher levels recorded during the rainy season. THQ values were generally below 1, except for Hg at Yopougon, wich indicates a localised non-carcinogenic risk. The HI exceeded 1 only at Yopougon, revealing a concerning combined effect. Carcinogenic risk (CR) values were mostly within the acceptable range (10⁻⁶–10⁻⁴), but slightly exceeded the threshold at Cosrou. In conclusion, the study indicates a moderate chronic exposure, which warrants continuous monitoring of fish quality and strengthened management of lagoon pollution sources.