Comparative Toxicity of Seven Aqueous Film-Forming Foam to In Vitro Systems and Mus

Area of Science:

• Environmental toxicology
• Chemical safety assessment
• Toxicology

Background:

• Aqueous film-forming foams (AFFFs) historically contain per- and polyfluoroalkyl substances (PFAS).
• There is a critical need to evaluate the safety of PFAS-free AFFF alternatives to avoid regrettable substitutions.
• Understanding the comparative toxicity of different AFFF formulations is essential for environmental and human health protection.

Purpose of the Study:

• To comparatively evaluate the toxicity of six PFAS-free AFFFs against one PFAS-containing AFFF.
• To assess the in vivo and in vitro toxicological profiles of these AFFF formulations.
• To provide early data for the selection of potentially safer PFAS-free AFFF alternatives.

Main Methods:

• In vivo toxicity testing in an outbred mouse species.
• In vitro toxicological assays, including the Microtox® assay.
• Short-term, high-concentration exposure studies.

Main Results:

• The PFAS-containing AFFF reference product induced increased relative liver weights in mice.
• PFAS-free AFFFs were associated with decreased or unaffected relative liver weights.
• In vitro toxicity was largely uniform across PFAS-free AFFFs, with variability noted in the Microtox® assay.

Conclusions:

• The toxicological profiles of PFAS-free AFFFs differ significantly from PFAS-containing AFFF, particularly concerning liver weight effects.
• PFAS-free AFFFs may represent a less toxic alternative to traditional PFAS-containing foams, but further comprehensive testing is warranted.
• This study provides initial data to guide the selection of AFFF alternatives and prevent regrettable substitutions, highlighting the need for broader toxicological assessments across different species and life stages.