- Perfluorinated chemicalSubset of PFAS. Have carbon chain atoms that are totally fluorinated. Examples are perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) (Buck et al. 2011).
- Perfluoroalkyl substanceFully fluorinated alkane (carbon chain) molecule. They have a chain (tail) of two or more carbons atoms with a charged functional group (head) attached at one end.
- PermeateThe water treated by a membrane filtration technology, which has passed through the membrane, and from which PFAS have been removed. The contaminants not passing the membrane accumulate in the filtrate, which also does not pass through the membrane.
- Polyfluorinated chemicalSubset of PFAS. Have at least one carbon chain atom that is not totally fluorinated (Buck et al. 2011).
- Polyfluoroalkyl substanceThe molecule has a nonfluorine atom (typically hydrogen or oxygen) attached to at least one, but not all, carbon atoms, while at least two or more of the remaining carbon atoms in the carbon chain tail are fully fluorinated.
- PolymerLarge molecules formed by combining many identical smaller molecules.