Species‐ and Tissue‐Specific Chronic Toxicity Values for Northern Bobwhite Quail (Colinus virginianus) Exposed to Perfluorohexane Sulfonic Acid and a Binary Mixture of Perfluorooctane Sulfonic Acid and Perfluorohexane Sulfonic Acid

Abstract

Per-and polyfluoroalkyl substances (PFAS) are globally distributed and present in nearly every environmental compartment. Characterizing the chronic toxicity of individual PFAS compounds and mixtures is necessary because many have been reported to cause adverse health effects. To derive toxicity reference values (TRVs) and conduct ecotoxicological risk assessments (ERAs) of PFAS-contaminated ecosystems for wildlife, species-specific PFAS chronic toxicity values (CTVs) are needed. The present study quantified PFAS residues from liver and eggs of birds chronically exposed to perfluorohexanoic acid (PFHxA) or a mixture of perfluorooctane sulfonate (PFOS) and PFHxA that produced a no-observable-adverse-effect level (NOAEL) and/or a lowest-observable-adverse-effectlevel (LOAEL). The CTVs we present are lower than those previously reported for birds and should be considered in future regulatory evaluations. From the estimated species-and tissue-specific PFAS CTVs, we found that PFOS and perfluorohexane sulfonate (PFHxS) were more bioaccumulative than PFHxA in avian tissues, but PFHxA was more toxic to reproducing birds than either PFOS or a PFOS:PFHxS mixture. We further determined that avian toxicity was not necessarily additive with respect to PFAS mixtures, which could have implications for PFAS ERAs. The PFAS LOAEL CTVs can be used to predict reproductive and possible population-level adverse health effects in wild avian receptors.

Mixture Effects of Per- and Polyfluoroalkyl Substances on Embryonic and Larval Sheepshead Minnows (Cyprinodon variegatus)

“…Conversely, Menger et al [ 35 ] observed only reduced toxicity in zebrafish embryos exposed to a mixture of nine PFAS compared to individual PFAS. There are few PFAS mixture studies utilizing fish, but even in non-fish models, such as the American bullfrog ( Rana catesbeiana ) [ 33 ], Northern leopard frog ( Rana pipiens ) [ 34 ], mouse ( Mus musculus ) [ 36 ], and Northern bobwhite quail ( Colinus virginianus ) [ 37 , 38 , 39 ], there are no clear patterns of antagonistic, additive, or synergistic effects of PFAS mixtures.…”

“…Furthermore, the expression of the same enzyme can either be upregulated or downregulated depending on the PFAS compound or species [ 7 ]. While there is a limited number of PFAS mixture studies conducted in saltwater fish, many other freshwater fish and non-fish species have been used to assess PFAS mixture toxicities, although there is no clear trend towards additive, synergistic, or antagonistic effects [ 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ]. To reduce uncertainty in PFAS risk assessments, it is pertinent to better understand the effects of PFAS as mixtures and how selected components can affect toxicity.…”