Emerging Perfluorinated Chemical GenX: Environmental and Biological Fates and Risks

Perfluorinated chemical GenX, formally known as hexafluoropropylene oxide dimer acid (HFPO–DA), has been applied as an alternative to the forever chemical perfluorooctanoic acid (PFOA). The applications of HFPO–DA have rapidly expanded from traditional nonstick coating industries into high-tech semiconductor manufacturing. Because of such facts in conjunction with its low biodegradation rate and high potential of long-distance atmospheric transport, the presence and accumulation of HFPO–DA have been ubiquitously detected in environmental media and biological species, including animals and human beings, posing alarming and urgent needs for the risk assessment of HFPO–DA. Building on the United States Environmental Protection Agency's evaluation of HFPO–DA in 2021, this review first summarizes the interaction of HFPO–DA with the environment, elaborates on its known toxicities and potential carcinogenicity, along with their possible mechanisms, and briefly addresses its current exposure assessment and risk management strategies. These lines of evidence support that the safety of HFPO–DA necessitates further investigation and monitoring, albeit being considered as a less toxic and low persistence substitute of traditional PFOA.