Abstract

This study investigates the extent and nature of chemical contamination in the Djoudj National Bird Park, a Ramsar-listed wetland located in northern Senegal, focusing on agrochemical residues originating from surrounding rice cultivation systems. Sediment samples collected during three seasonal campaigns were analyzed for trace metals and a wide range of pesticides. Results revealed significant spatiotemporal variability, with peak concentrations of lead exceeding 7,000 µg/kg and alarming levels of banned pesticides such as lindane and dicofol, reaching up to 200,000 µg/kg, detected at multiple sites. The data suggest strong links between agricultural drainage, irrigation cycles, and contamination pulses, particularly during the dry season. Correlations between salinity and metal concentrations indicate that hydrological conditions play a critical role in pollutant mobility and bioavailability. The co-occurrence of persistent organic pollutants and modern pesticides underscores both historical and ongoing agrochemical inputs. These findings raise serious concerns for the ecological integrity of the park, particularly given its role as a major habitat for migratory birds and aquatic biodiversity. This study calls for urgent implementation of mitigation strategies, including buffer zones, integrated pest management, and stricter regulatory enforcement, to ensure the long-term sustainability of this protected wetland.