Acute, chronic, and behavioral toxicity of fluorine-free foams to earthworm species Eisenia fetida and Dendrobaena veneta.

Aqueous film-forming foams (AFFF) containing per- and polyfluoroalkyl substances (PFAS) are widely used as fire suppressants. Due to rising health and environmental concerns, fluorine-free foams (F3) are being developed and tested as safer alternatives. However, the impact of these replacement products on ecologically important earthworms has not been adequately studied. This study addresses this gap by comparing the acute, chronic, and behavioral effects of two F3 formulations, BioEx Ecopol and Angus Fire Jetfoam, with a commonly used PFAS-containing AFFF, Buckeye, on two species of earthworms. Soil treated with BioEx Ecopol and Buckeye at the maximum 3% concentration did not cause significant acute mortality in Eisenia fetida, whereas Angus Fire Jetfoam resulted in 100% mortality at the same concentration. In a 28-day chronic test, weight loss was observed in Dendrobaena veneta worms exposed to soil treated with Angus Fire Jetfoam. Additionally, both Eisenia fetida and Dendrobaena veneta demonstrated almost complete avoidance of soils treated with any of the three foams at 3% concentration, indicating potential ecological effects despite lack of acute toxicity by two of the products. The differences in toxicity are likely due to the distinct chemical compositions and surfactant concentrations in these foams. BioEx Ecopol and Buckeye, despite their differing surfactant mixtures, exhibited lower acute toxicity, whereas Angus Fire Jetfoam's high mortality rate points to a potentially problematic chemical formulation. By understanding the toxicity of current formulations, this study supports the ongoing development and evaluation of new fire suppression products, supporting the creation of safer technologies.