Toward Understanding the Environmental Fate of PFAS Based on Their Partition and Sorption Properties

Abstract

Per- and polyfluoroalkyl substances (PFAS) are a major environmental concern due to their persistence and their potential to cause adverse health effects. This article reviews the current knowledge of the partition and sorption properties of PFAS and discusses how these properties influence their environmental fate. Perfluorination of an alkyl chain increases molecular size without significantly altering van der Waals interactions, resulting in greater hydrophobicity and higher volatility from condensed phases. Perfluorination also affects the electronic properties of nearby functional groups, with a notable outcome being the lowering of pK_a. In a generic terrestrial environment, neutral PFAS are expected to distribute primarily into the atmosphere because of their high volatility and low propensity to partition into the water phase, unless they contain a strongly polar functional group such as a sulfonamide group. Ionic PFAS exhibit complex partition behavior in atmospheric, soil, and biological compartments. This behavior is strongly influenced by the composition of the aqueous phase and the solid matrix and remains an area of further investigation.