Environmental risk of per- and polyfluoroalkyl substances (PFAS) in freshwater ecosystems: Integrating predictive and empirical toxicity models

Per- and polyfluoroalkyl substances (PFAS) have garnered global attention due to their toxic nature, tendency to accumulate in organisms, and resilience to natural degradation processes in the environment. In this study, the distribution and risk assessment of ten (10) PFAS were determined in clean (Kuantan River) and moderately polluted (Kim Kim River) river. The toxicity data of aquatic organisms were obtained from the predictive Ecological Structure Activity Relationships (ECOSAR) and empirical Ecotoxicology Database (ECOTOX) databases to calculate the risk assessment. The highest PFAS concentration in the Kuantan River was in perfluorobutanoic acid (PFBA), with a mean value of 1.99 ± 0.44 ng/L. Meanwhile, the highest PFAS detected in the Kim Kim River was perfluoropentanoic acid (PFPeA), with a mean value of 35.80 ± 24.65 ng/L. Risk quotient (RQ) approaches were applied to assess the potential risk of PFAS in both databases. The RQ showed negligible risk towards all detected PFAS (RQ < 0.01) in both rivers. The output of this study produces extensive information on pollution risks, thereby providing valuable guidance to policymakers concerning regulatory choices, management of exposure, and reduction of PFAS in aquatic environments.