Per- and Polyfluoroalkyl Substances (PFAS): Significance and Considerations within the Regulatory Framework of the USA

Abstract

Per- and polyfluoroalkyl substances (PFAS) are an emerging environmental crisis. Deemed forever chemicals, many congeners bioaccumulate and are incredibly persistent in the environment due to the presence of the strong carbon-fluorine covalent bonds. Notable PFAS compounds include perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and GenX. Robust toxicological knowledge exists for these substances, but regulatory decisions based on this knowledge has fallen behind. The United States Environmental Protection Agency (EPA) has addressed this issue with the PFAS Action Plan and EPA Council on PFAS, but the regulatory framework is severely lacking. Currently, no federal regulations or standards exist. Many occupational and non-occupational human cohorts exist that can lend knowledge on the environmental implications of PFAS and associated health effects. Occupationally, firefighters face significant exposure risks due to use of PFAS containing aqueous film-forming foams (AFFFs) and personal protective equipment contamination. Non-occupationally, wastewater discharge in North Carolina led to chronic and widespread residential exposure to GenX via drinking water contamination. This public health review seeks to convey the current and future significance of PFAS as an environmental contaminate, to lend considerations on regulatory frameworks within the USA, and to help guide and promote the need for future epidemiological studies in order to tackle this environmental emergency. While the PFAS Action Plan creates a scientific and regulatory foundation, it is important to take these lessons and apply them to future environmental health issues.

A Machine Learning Model to Estimate Toxicokinetic Half-Lives of Per- and Polyfluoro-Alkyl Substances (PFAS) in Multiple Species

“…We hope that the resources presented here will be used as a starting point by the broader scientific community to develop additional data and models for PFAS TK. The term “forever chemical” has been applied to some PFAS with regard to their persistence in the environment, bioaccumulation, and long human half-lives [ 132 ]. For humans, this preliminary model distinguishes between those PFAS with t ½ greater than two months and those that are eliminated much faster from the body.…”

Adverse PFAS effects on mouse oocyte in vitro maturation are associated with carbon‐chain length and inclusion of a sulfonate group

“…Although the carbon backbones of PFAS are usually very stable due to their strong carbon‐fluorine bond, 33 the functional groups, such as carboxylate and sulfonate, may have a greater influence on the toxicity of PFAS chemicals. To examine the relative toxicity of PFSA to its corresponding PFCA with the same carbon chain length (Figure S2 ), we rearranged our data in Section 3.1 to compare PFAS with the same carbon length but different functional groups (carboxylate vs. sulfonate).…”

Adverse PFAS effects on mouse oocyte in vitro maturation are associated with carbon-chain length and inclusion of a sulfonate group

“…3.2. PFSA has higher and unique toxicity effects on mouse oocyte maturation compared to PFCA Although the carbon backbones of PFAS are usually very stable due to their strong carbon-fluorine bond 34 , the functional groups, such as carboxylate and sulfonate, may have a greater influence on the toxicity of PFAS chemicals. To examine the relative toxicity of PFSA to its corresponding PFCA with the same carbon chain length (Supplemental Fig.…”