PFAS leave fingerprints in your blood—researchers are beginning to read these clues

Virtually every living thing on Earth, from Patagonian penguins to newborn human babies, has been touched by the synthetic chemicals known as per- and polyfluoroalkyl substances, or PFAS. In fact, you would be hard pressed to find a sample of human blood, tissue, or breast milk without detectable levels of at least one type of PFAS.