Per- and polyfluoroalkyl substances (PFASs) are a large and diverse group of synthetic chemicals characterized by strong carbon-fluorine bonds. These bonds make PFASs highly resistant to chemical, biological, and thermal degradation. As a result, PFASs are often referred to as “forever chemicals”. PFASs have been widely used in industrial applications and consumer products such as firefighting foams, non-stick cookware, textiles, food packaging, and surface coatings. Due to their high persistence, mobility, and toxicity, PFASs are detected globally in water, soil, air, wildlife, and humans.

Many researchers have reported that polyfluorinated substances used in aqueous film-forming foams (AFFF) can transform into perfluoroalkyl acids (PFAAs) such as perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA), which are among the most persistent PFASs due to the fully fluorinated nature of all carbons on the molecule. Some examples of polyfluorinated precursors that can biotransform into PFOA in the environment are shown below.

In this figure, eight precursors are shown as nodes leading to the final biotransformation product, PFOA. Although there are eight precursors presented here, this representation does not include all intermediates or other compounds that may biotransform into any of the shown precursors. The enviPath research team has collected and summarized experimental data from 60 peer-reviewed publications on the biotransformation of polyfluorinated PFASs in the environment and generated a FAIR database of biotransformation pathways with associated experimental conditions from these publications.

The enviPath-PFAS database provides users with a method to easily explore these additional intermediates and precursors due to its built-in data structure in which the biotransformation data are stored as interconnected nodes and edges in a graphical reaction network.

For more information, check out our open-access Global Perspective Article - Rich et al 2025.

The enviPath-PFAS package can be found at this link: enviPath-PFAS.

The enviPath team is currently developing a pathway prediction model for PFASs.