Acute Toxicity of Eight Aqueous Film-Forming Foams to 14 Aquatic Species

:researchers have developed numerous per- andpolyfluoroalkyl substances (PFAS)-free aqueousfilm-forming foam(AFFF) formulations to replace PFAS-containing AFFF used forfire suppression. As part of the Department of Defense's StrategicEnvironmental Research and Development Program (SERDP), weexamined the direct lethal effects of seven PFAS-free AFFF and aPFAS-containing AFFF on 14 aquatic species using a series oflethal concentration (LC50) tests. We assessed the LC10, LC50,and LC90 values using log-logistic and logit analyses. Across allaquatic species tested, we discovered that exposure to at least onePFAS-free AFFF was more or as toxic as exposure to the PFAS-containing AFFF. For most cases, National Foam Avio F3 GreenKHC 3% and Buckeye Platinum Plus C6MILSPEC 3% were themost and least toxic formulations, respectively. Moreover, we found consistency among results from multiple experiments using thesame minnow species (Pimephales promelas) and among closely related taxa (e.g., daphnids, amphibians). Lastly, the LC50 values forAFFF formulations trended lower for tested marine species as compared to those of freshwater species. These results dramaticallyincrease the current knowledge on the potentially toxic effects of AFFF but also highlight the need for additional research and thedevelopment of new PFAS-free AFFF that are more"ecologically friendly"than those containing persistent PFAS.