Assessment of Trace Metal Elements in Tilapia (Sarotherodon melanotheron) in the Urban Nature Reserve of the Grande Niaye of Pikine and Surroundings, Dakar, Senegal

Background: This study examines the contamination of Sarotherodon melanotheron (tilapia) by trace metal elements, cadmium (Cd), mercury (Hg), and lead (Pb), in the Grande Niaye of Pikine Urban Nature Reserve and its Dependencies (UNRGNPD), a highly anthropized urban aquatic ecosystem in Dakar, Senegal. Objectives: The primary aim is to quantify heavy metal concentrations in tilapia tissue and to assess the toxicological risks posed to human health through their consumption. Methods: Fish samples were collected during the dry and rainy seasons of 2021 and 2022. Concentrations of Cd, Hg, and Pb in muscle tissue were determined using atomic absorption spectrometry. The Metal Pollution Index (MPI) was used to evaluate the overall level of contamination, while the Target Hazard Quotient (THQ) was calculated to assess potential health risks for adult and child consumers. Results: Heavy metal concentrations were particularly elevated during the rainy season, often exceeding international safety limits set by the FAO/WHO. MPI values indicated significant seasonal and interannual variation, with 2021 showing the highest levels of contamination. THQ values for Cd and Hg exceeded 1, especially in children, indicating a substantial non-carcinogenic health risk. Conclusion: These findings underscore a serious environmental and public health concern. Urgent intervention is needed to mitigate metal pollution through stricter regulation of industrial and domestic effluents, improved wastewater treatment infrastructure, and community education regarding the risks of consuming contaminated fish.