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

Researchers
have developed numerous per- and polyfluoroalkyl substances
(PFAS)-free aqueous film-forming foam (AFFF) formulations to replace
PFAS-containing AFFF used for fire suppression. As part of the Department
of Defense’s Strategic Environmental Research and Development
Program (SERDP), we examined the direct lethal effects of seven PFAS-free
AFFF and a PFAS-containing AFFF on 14 aquatic species using a series
of lethal concentration (LC50) tests. We assessed the LC10, LC50,
and LC90 values using log–logistic and logit analyses. Across
all aquatic species tested, we discovered that exposure to at least
one PFAS-free AFFF was more or as toxic as exposure to the PFAS-containing
AFFF. For most cases, National Foam Avio F3 Green KHC 3% and Buckeye
Platinum Plus C6MILSPEC 3% were the most and least toxic formulations,
respectively. Moreover, we found consistency among results from multiple
experiments using the same minnow species (Pimephales promelas) and among closely related taxa (e.g., daphnids, amphibians). Lastly,
the LC50 values for AFFF formulations trended lower for tested marine
species as compared to those of freshwater species. These results
dramatically increase the current knowledge on the potentially toxic
effects of AFFF but also highlight the need for additional research
and the development of new PFAS-free AFFF that are more “ecologically
friendly” than those containing persistent PFAS.