Target and non-target screening of poly- and perfluoroalkyl substances (PFAS) in fish liver samples from the River Nile in Sudan: A baseline assessment

Poly- and perfluoroalkyl substances (PFAS) are of global concern due to their persistence and harmful effects on human health and ecosystems. However, research on PFAS in the River Nile and across Africa is limited. This study provides the first assessment of PFAS contamination in fish livers from the River Nile in Sudan, using ultra-high-performance liquid chromatography and high-resolution mass spectrometry. Perfluorooctane sulfonate (PFOS), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), and perfluoroundecanoic acid (PFUnDA) were measured, with fish downstream of Jebel Aulia Dam showing the highest concentrations: PFOS at 331 ± 36 μg/kg wet weight (ww), PFNA at 143 ± 4 μg/kg ww, PFDA at 137 ± 12 μg/kg ww, and PFUnDA at 4.0 μg/kg ww. In contrast, fish from other locations, including local markets, had undetectable PFAS levels. Three additional PFAS were tentatively identified. These results emphasize the need for further monitoring to address PFAS contamination and related food safety risks in the region.