Short‐Chain Per/Polyfluoroalkyl Acids (C7 and Below)

Abstract

Abstract This chapter is about a series of short‐chain per‐ and polyfluoroalkyl substances (PFAS). In the past, PFAS were described as fluorinated fatty acids or sulfonates. The overall structure of PFAS is a carbon chain with fluorine atoms substituting for hydrogen atoms. The resulting chemicals are chemically stable, water and oil resistant, and useful for many industrial applications, such as in the formation of polymers. The most notorious in this group are the fluorinated fatty acids (carboxylates) or sulfonates. In biological systems, these chemicals are generally well‐absorbed by the oral route and resistant to metabolism but also have the unusual property of having drastically different elimination kinetics between mammalian species. The available literature on this group of PFAS (C7 and below) is modest. This chapter will not attempt to review all this literature. Rather, human studies will be emphasized. Since human studies often suggest associations between PFAS exposure and health outcomes, these studies will be followed by definitive experimental animal studies that give insights into the human evidence. Afterward, a summary of attempts to estimate potential human risk by various international agencies will be described. What will become obvious, however, is that the overall uncertainty in the database of some of these chemicals has led to widely divergent risk assessment positions that need to be resolved. Risk management decisions on specific members of this class of chemistries are seen to be premature without such scientific resolution.