Biomagnification of per-and polyfluoroalkyl substances in aquatic food species from a tropical lagoon ecosystem

We investigated the occurrence, species-specific distribution, accumulation, and biomagnification of poly- and perfluoroalkyl substances (PFAS) in three teleost fish species (Sarotherodon melanotheron, Clarias gariepinus, and Chrysicthys nigrodigitatus), as well as molluscs (Pachymelania aurita), earthworms (Lumbricus terrestris), and sediment samples from the Ologe Lagoon in Nigeria, which receives complex mixtures of anthropogenic effluents from various sources. Total ∑PFAS concentrations (ng/g) were significantly highest in earthworms (16.2), compared to teleost species (S. melanotheron (1.8), C. gariepinus (1.2), and C. nigrodigitatus (1.8)) and molluscs (0.4). The novel precursor diSAMPAP was the dominant PFAS congener in S. melanotheron and C. gariepinus, while PFOS and diSAMPAP were highest in C. nigrodigitatus. In earthworms, molluscs, and sediment, diSAMPAP, PFBS, and PFOS were the dominant PFAS. We calculated the biota sediment accumulation factor (BSAF), revealing that diSAMPAP in S. melanotheron and 8:2 FTS in earthworms exhibited the highest BSAF values. Species-specific differences in PFAS biomagnification factor (BMF) suggest varying exposure routes among the examined fish species. Notably, PFOS concentrations in the liver were significantly higher than in flesh tissues for C. gariepinus and C. nigrodigitatus, indicating organ-specific accumulation. Risk analysis using the Risk21 tool showed that S. melanotheron had the highest public health risk, while C. gariepinus had the least risk. Our results highlight significant food safety concerns and public health risks associated with the occurrence, species-specific distribution, accumulation, and biomagnification of diSAMPAP, 8:2 FTS, and PFOS in the Ologe Lagoon and its aquatic food webs. This study contributes valuable insights to global PFAS monitoring efforts, particularly in fluvial tropical ecosystems such as those found in Nigeria.