Trace Metals and Pesticides in Edible Fish from the Djoudj National Bird Park in Senegal: Human Health Implications

Background and Objective: Freshwater wetlands located downstream of intensive agricultural zones are becoming increasingly exposed to chemical pollution, raising significant concerns for ecosystem and human health. This study examined trace metal and pesticide contamination in edible fish from Senegal’s Djoudj National Bird Park and assessed their implication to human health. Methodology: Fish belonging to the two most consumed families, Cichlidae and Clariidae, were collected during three sampling campaigns conducted between 2019 and 2020, coinciding with periods of agricultural drainage. Fish muscle tissues were analyzed for cadmium, lead, and mercury using atomic absorption spectrometry (AAS), whereas pesticide residues were quantified/measured by gas chromatography-mass spectrometry. Potential human health risks were then assessed using the health risk index (HRI) and target hazard quotient (THQ). Results: Results showed detectable contamination by both trace metals and pesticides. For pesticides, most HRI values remained below 100%, suggesting generally acceptable exposure levels. However, aldrin detected in Clariidae exceeded recommended intake limits. Trace metals showed a more critical situation, with cadmium presenting the highest risk with THQ values far above the safety threshold in both fish families. In contrast, mercury and lead showed THQ values below 1. Conclusion: Overall, these findings indicate that, despite its protected status, the Djoudj National Bird Park remains influenced by upstream contamination. Such exposure may affect food safety for local populations and likely disrupt the long-term ecological balance of the wetland, underscoring the need for strengthened environmental monitoring and improved management of agricultural inputs in the region.