No Significant Elimination of Perfluoroctanesulfonate and Other Common Per- and Polyfluoroalkyl Substances by Adult Fathead Minnows, Pimephales promelas

Bioaccumulation dynamics of per- and polyfluoroalkyl substances (PFAS) remain poorly understood, and kinetic-based information is lacking across environmental gradients, particularly for Cyprinidae, the largest and most diverse fish family. We examined the influences of pH (6.5, 7.5) and salinity (0.3 g/L, 3.0 g/L) on uptake and elimination kinetics of 19 PFAS, which were selected at low concentrations not eliciting standardized adverse outcomes, in the common Cyprinidae, Pimephales promelas. These PFAS consisted of short- and long-chain perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl sulfonates (PFSAs), a sulfonamide, and fluorotelomer sulfonates. Water, whole-body tissue, and plasma were collected over time, and samples were analyzed via liquid chromatography tandem mass spectrometry. Rapid uptake was observed in tissue, reaching pseudo-steady-state conditions within 24–96 h of exposure initiation; uptake rates increased with chain length but were not influenced (p > 0.05) by pH or salinity. During four separate experiments, no significant (p > 0.05) elimination was observed for PFDA, PFDoDA, PFTeDA, total PFOS, PFOSA, and 8:2 FTSA. Kinetic-based bioaccumulation factors (BAFs) increased with chain length for PFCAs and PFSAs, and exceedances of BAF cutoff values were identified. No significant (p > 0.05) elimination of these PFAS indicates that Cyprinidae should be considered during future bioaccumulation studies.