While per- and polyfluoroalkyl substances (PFAS) have been found to negatively affect autotrophic and heterotrophic food webs, additional data are needed to improve the understanding of their ecotoxicity and set realistic criteria for protection of ecological receptors. This project will examine the survival, growth, reproduction and vitellogenin in a three generation exposure of zebrafish (Danio rerio) to perfluorooctanesulfonic acid (PFOS) via collection of additional value-added endpoints to enable better informed risk management decisions. The industry-sponsored study is designed to address shortcomings in an earlier study conducted by Keiter et al (2012) that is currently driving some international regulatory thresholds. Critical improvements to the experimental design (e.g., increased replication, expanded analytical confirmation and a larger number of concentrations) have been made to increase statistical rigor and ensure technically defensible results.
This study will enable the identification of molecular mechanisms of action and integration of effects into an adverse outcome pathway (AOP) framework and provide a measure of calibration with other sensitive species and standardized chronic/sublethal test endpoints.
The project team will perform additional testing and analysis to augment the current design to include: (1) measurement of tissue residues in the exposed zebrafish enabling development of residue-effect thresholds; (2) transcriptional point of departure (embryo), tissue specific mode of action and AOP development; (3) comparison of multi-generational study endpoints with standard 20-day Organisation for Economic Co-operation and Development 210 short term chronic endpoints and (4) testing of additional sensitive species to facilitate cross species sensitivity and standardized test endpoint comparisons.
The additional testing and analysis will fill key knowledge gaps within an under-represented research space of extended chronic and multi-generational exposures to PFOS, helping to elucidate bioaccumulation, mode of action and enable comparison to endpoints generated from a shorter-term standardized and routinely conducted toxicity test as well as to sublethal endpoints (i.e., growth and reproductions) generated for other sensitive species. (Anticipated Project Completion - 2023)