The ecological risk of Per- and Polyfluoroalkyl substances (PFASs) is a growing concern. As such, ecotoxicological studies are needed to fill data gaps and identify effects of PFASs on wildlife. While there are current published toxicity reference values for some PFASs, these values can be variable even within studies using the same model organism. Chemists and biologists teamed together to investigate factors that may impact the ability to reach target concentrations when preparing exposure solutions. Variables included the need to consider chemical form (e.g., salt) and purity, non-blank test organisms, issues regarding the dissolution of neat solid PFASs, storage conditions, and solution homogenization. A series of laboratory experiments were conducted to generate data to support selection of best practices for preparing exposure solutions for ecotoxicological investigations. The kinetics of dissolution of neat PFAS solids was the largest contributing factor that impacted the concentration of exposure solutions. Kinetic dissolution profiles of four PFASs (PFOA, PFNA, PFBS, PFOS) indicate that minimum mixing time depends on carbon-fluorine chain length; homogeneity of each exposure solution required a minimum of 5-8 h, depending on the analyte. Failure to allow for complete dissolution of solids resulted in greater variability and reduced accuracy when preparing exposure solutions. The impact of the other factors investigated will also be discussed.

Key considerations for accurate exposures in toxicological assessments of per- and polyfluoroalkyl substances

2019 Fall National Meeting

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