Volatilisation Potential of Per- and Poly- Fluoroalkyl Substances from Airfield Pavements and During Recycling of Asphalt

By Trevor P. Bastow, Grant B. Douglas, Greg B. Davis
ET&C
July 4, 2022
DOI: 10.1002/etc.5425

PFAS (per- and poly- fluoroalkyl substances) in water are typically present in their ionic (non-volatile) forms, however, these can transition to their non-ionic (volatile) forms when in contact with organic solvents and organic matrices. In particular, when PFAS is dissolved in organic solvents such as residues left from fire-fighting foams, fuels and bitumen present in asphalt, the equilibrium between ionic and non-ionic forms can trend towards more volatile non-ionic forms of PFAS. Here we assess the volatility of common PFAS based on calculated and available experimental data across ambient temperature ranges experienced by airfield pavements and at elevated temperatures associated with reworking asphalts for reuse. Volatilities are shown to be comparable to hydrocarbons in the semi-volatile range, and suggests volatilisation is a viable loss mechanism for some PFAS that are non-volatile in water. The research points to future investigative needs for this unexplored mass loss mechanism and potential exposure pathway.

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