Bioaccumulation pattern of per- and polyfluoroalkyl substances (PFAS) in fish tissues from two freshwater systems

• PFAS were higher in Horseshoe Lake (HSL) than in Mississippi River (MSR). • PFBS and PFBA exceeded the EPA regulatory limit of 4 ng/L for drinking water in HSL. • Bioaccumulation in fish species correlated to their trophic levels and PFAS chemistry. • Liver and kidney recorded highest concentrations of PFAS. Per- and polyfluoroalkyl substances (PFAS) are known for their persistence, ubiquity, bioaccumulation in different matrices of the environment and their detrimental effect on human health. In this study, we used EPA 1633 to examine the prevalence of ten PFAS compounds in two freshwater systems and investigated their bioaccumulation pattern across different tissues of grass carp fish ( Ctenopharyngodon idella ), common carp ( Cyprinus carpio ), and flathead catfish ( Pylodictis olivaris ). Among the PFAS compounds analyzed, PFBS exhibited the highest concentration in the freshwater sample, exceeding the U.S. EPA regulatory limit of 4 ng/L for drinking water. The total PFAS concentrations in the muscle, kidney, and liver of each species are 2749.83 ng/kg, 5180.41 ng/kg, and 5815.79 ng/kg respectively for grass carp; 4081.04 ng/kg, 18,890.92 ng/kg, and 8210.76 ng/kg for common carp. Catfish had the highest concentrations at 16,826.79 ng/kg, 82,035.73 ng/kg, and 114,788.91 ng/kg for muscle, kidney and liver, respectively, which is consistent with them being a tertiary consumer. Overall, short-chain PFAS were more prevalent in the water samples, while the long chain sulphonic acids, specifically PFOS, were highly concentrated in the fish tissues. Given that ingestion via human consumption of aquatic organisms is one of the main entry routes of PFAS, this study provides insights into species-specific and tissue-specific PFAS accumulation in aquatic animals. The findings of this study further underscore the need for ongoing monitoring and risk assessment of PFAS in aquatic environments and food products.