Several per- and polyfluoroalkyl substance (PFAS)-free surfactant formulations with unknown ecotoxicological characteristics are currently being developed and evaluated for their ability to meet current Department of Defense (DoD) performance requirements for training and emergency response, related to Class B fires. These formulations are intended for use as alternatives to aqueous film forming foam (AFFF) formulations containing perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) that were linked to accumulation in terrestrial plants and soil invertebrates with the potential for biomagnification in terrestrial food-webs. The main objectives of this project are to develop ecotoxicological data for these candidate PFAS-free AFFF alternatives, and to determine the relative toxicities of PFAS-free AFFF alternatives, as compared with legacy AFFF formulations, by developing empirical data for chronic toxicity of these formulations for soil invertebrates and terrestrial plants.

The project team plans to conduct toxicity studies with soil invertebrates and terrestrial plants to generate chronic ecotoxicological data that can be used for evaluating relative toxicities of the candidate PFAS-free AFFF-alternatives and legacy AFFF formulations containing fluorinated compounds. Standardized toxicity tests will be conducted with ecologically relevant species using a natural soil expected to support high relative bioavailability of AFFF formulations. The test species were selected from International Organization for Standardization/Organization for Economic Co-operation and Development guidelines and were recommended in the Guide to Performing a Developmental Environment, Safety and Occupational Health Evaluation for collecting environment, safety and occupational health (ESOH) data for materials used in DoD technologies in development. The goals of this research will be achieved by conducting the following activities: 

1. Determining the chronic toxicities of the candidate PFAS-free AFFF-alternatives to soil invertebrates exposed in soil with characteristics (low clay and organic matter content) expected to support high bioavailability for these compounds;
2. Determining the chronic toxicity of PFAS-free AFFF-alternatives to terrestrial plants in the same soil;
3. Developing the toxicity benchmark data established using standardized single-species toxicity tests with candidate PFAS-free AFFF formulations in the studies and ranking the order of the relative toxicity of each AFFF formulation.

Ecotoxicological data developed in this project will fill the knowledge gaps regarding chronic toxicities of the candidate PFAS-free AFFF alternatives to soil invertebrates and terrestrial plants. These data will be contrasted with the toxicity benchmarks developed for legacy AFFF formulations in order to evaluate the relative environmental risks of exposure for each formulation. This research will provide critical data to decision makers for use in ESOH evaluations of new technologies and the risk-based decisions, thus streamlining transition to acquisition programs. Ecotoxicological data developed in this project for all AFFF formulations will be transitioned through the Tri-Services Environmental Risk Assessment Work Group.