Assessment of Seasonal Variations of Pesticides Residues in Water and Sediments From Hadejia-nguru Wetlands, Northern Nigeria

This study assessed seasonal variations in pesticide residues within water and sediment samples from the Hadejia-Nguru wetlands, Northern Nigeria, a critical ecosystem facing increasing anthropogenic pressures. Samples were collected monthly from March 2021 to October 2022 across three sampling stations, covering both dry and wet seasons. Pesticide extraction and cleanup were performed using the QuEChERS method, followed by analysis via GCMS. Results revealed significant seasonal variations in pesticide concentrations. Dichlorvos was exclusively detected in water during the dry season, indicative of its rapid degradation and dry-season agricultural application. Permethrin, however, persisted across both seasons, exceeding WHO drinking water guidelines, highlighting its environmental stability and potential human health risks. Sediment samples showed higher pesticide concentrations during the dry season, attributed to increased agricultural activity and reduced water volume, with certain pesticides persisting across all seasons, suggesting long-term accumulation. The findings underscore the impact of agricultural practices on wetland contamination and the necessity for effective monitoring and management. This study highlights the urgent need for sustainable agricultural practices and stringent regulations to mitigate pesticide contamination and safeguard the ecological integrity of the Hadejia-Nguru wetlands, protecting vulnerable populations dependent on these resources.