The objective of this Statement of Need was to solicit proposals to develop an improved understanding of the ecotoxicity of chemical mixtures associated with the release of aqueous film-forming foam, specifically mixtures of per- and polyfluoroalkyl substances (PFAS) found in environmental media. Proposed research should have focused on one or more of the following specific objectives in order to fill gaps in the current knowledge base:

• Produce data to determine the toxicity of PFAS mixtures considering mode of action, bioaccumulation kinetics, critical effects as well as cumulative effect on the quantitative dose-response (i.e., additive, synergistic, or antagonistic) for applicable model wildlife receptors.
• Develop or apply a mixtures methodology for predicting potential toxicity including toxic endpoints of PFAS mixtures considering the dose-response for specific PFAS, environmental media, and/or ecological receptor.
• Identify PFAS mixtures of most concern in order to enhance risk management decisions and address risk communication concerns. Identification of such mixtures should be associated with relevant environmental media and ecological receptor.

Proposals should have addressed one or more of the sub-objectives listed above. Proposers were required to provide the rationale and justification for the parameters of the study, including selected species, specific PFAS, biological endpoints, and environmental media. Substantial work has been conducted on understanding the ecotoxicity of specific PFAS. Investigators were encouraged to view past research and demonstrate how the proposed effort builds on previous efforts. A summary of SERDP funded efforts can be found on the SERDP website.

The ecotoxicity of PFAS mixtures at environmentally relevant concentrations was of particular concern and proposed efforts should have included such an assessment. 

The following projects were funded. Project overviews will appear below as they are posted to the website.

• Measuring and Predicting the Aquatic Toxicity of PFAS Mixtures Associated with AFFF
  • Principal Investigator: Dominic Di Toro, University of Delaware
• Body Compartment Partitioning and Ecological Effects of PFAS Mixtures in a Multi-Species System
  • Principal Investigator: Lindsay Holden, U.S. Army Public Health Center
• Development of an Efficient Testing Framework for Interpreting Toxicity of Complex Mixtures for Ecological Risk Assessment
  • Principal Investigator: Cheryl Murphy, Michigan State University