Two for the Price of One: Deriving Per- and Polyfluoroalkyl Substances (PFAS) Fillet and Whole-Body Conversion Equations in Fish

Per- and polyfluoroalkyl substances (PFAS) pose risks to both human and ecological health. Fish consumption advisories are typically based on fillet concentrations, whereas environmental risk assessment for biota depends on whole-body fish concentrations. Reliable equations for conversion between fillet and whole-body concentrations would allow for a single analysis of a fish to function for both human and ecological risk assessment. However, conversion equations do not exist for multiple species, and previous estimates are based on small sample sizes. Here, we assess relationships in 21 fish species and provide conversion equations for perfluorooctanesulfonic acid (PFOS), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnA), and perfluorododecanoic acid (PFDoA), four of the most common PFAS detected in fish from New York State. We analyzed 429 fish from 15 water bodies as separate fillet and remainder portions and then used the concentrations and weights of these portions to synthesize a whole-body fish concentration. Using linear models combining all species, the ratio of fillet to whole-body concentrations ranged from 1.77 to 1.91 across the four PFAS chemicals. Total PFAS conversion factors are 1.86 for fillet to whole-body and 0.52 for whole-body to fillet. These values showed consistency among PFAS chemicals, but values of models combining species were lower than those of species-specific models, suggesting the latter are ideal for risk assessment.