Synthetic fluorinated organics from commercial products have been detected in human blood since the late 1970s. The complex chemistry of per- and polyfluoroalkyl substances (PFASs) has made it challenging to fully understand their presence in humans and animals. This talk will explore the sources, exposure routes, and accumulation mechanisms of PFASs, aiming to predict and prevent environmental degradation and adverse health outcomes. Dr. McDonough will present the latest scientific insights into the PFAS body burden and discuss promising research directions and unresolved questions.