A rapid assessment bioaccumulation screening (RABS) study design for emerging per-and polyfluoroalkyl substances in mice exposed to industrially impacted surface water

The shift away from PFOS and PFOA production in the past 20 years towards shorter chain and replacement PFAS has led to the environmental release of complex mixtures of emerging PFAS for which bioaccumulation potential and toxicology are largely unknown. The rate at which emerging PFAS can be prioritized for research in these complex mixtures is often limited by the lack of available chemical standards. We developed a study design that rapidly assesses which emerging PFAS in an environmentally derived mixture have the potential for mammalian bioaccumulation and thus prioritize these emerging chemicals for standard synthesis and toxicity testing. Surface water was collected at an impacted site downstream of an industrial fluorochemical manufacturing outfall and concentrated 100-fold via weak anion exchange, solid-phase extraction. The concentrated extract contained 13 previously identified emerging PFAS, including hexafluoropropylene oxide-dimer acid (HFPO-DA). BALB/c mice were orally dosed with surface water concentrate once a day for seven days. Twenty-four hours after the last dose, liver, serum, urine, and feces were collected and the emerging PFAS were semi-quantified based on peak area counts. Of the 13 emerging PFAS, Nafion byproduct-2 (Nafion BP2), Hydro-EVE, PFO(4)DA, and PFO(5)DoA had the largest increases in percent composition when comparing serum and liver to the dosing solution, suggesting that these PFAS may have the highest bioaccumulation potential. This finding supports other studies that detected bioaccumulation of the same four PFAS in human serum collected from communities with contaminated drinking water. In the future, the Rapid Assessment Bioaccumulation Screening (RABS) study design can be extended to other complex industrial chemical mixtures impacting surface water in order to better inform chemical prioritization for acquisition and in vitro/in vivo toxicity testing of the potential pollutants.

Automated summary

The shift away from PFOS and PFOA production in the past two decades has led to the release of complex mixtures of emerging PFAS with unknown bioaccumulation potential and toxicology. The lack of available chemical standards often limits the prioritization of research on these emerging PFAS in complex mixtures. This study developed a rapid assessment method to prioritize emerging PFAS in an environmentally derived mixture based on their potential for mammalian bioaccumulation. The findings show that certain PFAS, such as Nafion BP2, Hydro-EVE, PFO(4)DA, and PFO(5)DoA, have a higher bioaccumulation potential, supporting previous studies on human serum from communities with contaminated drinking water.