Persistent and pervasive Environmental distribution and bioaccumulation of PFAS

Per- and polyfluoroalkyl substances (PFAS) comprise a large and diverse group of compounds with unique characteristics that have led to their extensive use and consequent release into the environment. Despite the constantly growing body of information on PFAS environmental occurrence and bioaccumulation, important knowledge gaps on these aspects still remain. This thesis addressed some of the main research priorities related to the environmental distribution and bioaccumulation of PFAS. By expanding the spectrum of targeted PFAS to include understudied structures, the widespread presence of many of these newly analyzed compounds across multiple abiotic and biotic compartments was confirmed. The inclusion of various primary producers and invertebrates from terrestrial and aquatic ecosystems showed very high bioaccumulation factors for specific PFAS-organism combinations. To the best of our knowledge, the food-web transfer study presented here is the first one to combine various low trophic level organisms from a combined terrestrial and aquatic ecosystem, while targeting a broad spectrum of PFAS. Few studies have experimentally investigated how sediment reworking processes, like bioturbation, can affect PFAS bioaccumulation and environmental distribution, even less so for such a variety of PFAS structures. Our findings showed that the arrow affecting the environmental distribution of PFAS branches into several directions, since organisms can modify their environment and adjust their behavior, thereby affecting the distribution of PFAS in ecosystems in various ways. In order to capture this multidimensional nexus, we proposed a conceptual equation, as a first step towards better describing and predicting the capricious environmental distribution of the persistent and pervasive PFAS.