What does PFAS mean in Environmental?

Per- and polyfluoroalkyl substances

Per- and polyfluoroalkyl substances (PFASs) are synthetic organofluorine chemical compounds that have multiple fluorine atoms attached to an alkyl chain. An early definition, from 2011, required that they contain at least one perfluoroalkyl moiety, –CnF2n+1–. Beginning in 2021, the Organisation for Economic Co-operation and Development (OECD) expanded their terminology, stating that "PFASs are defined as fluorinated substances that contain at least one fully fluorinated methyl or methylene carbon atom (without any H/Cl/Br/I atom attached to it), i.e. with a few noted exceptions, any chemical with at least a perfluorinated methyl group (–CF3) or a perfluorinated methylene group (–CF2–) is a PFAS."According to the OECD, at least 4,730 distinct PFASs are known, which contain at least three perfluorinated carbon atoms. The United States Environmental Protection Agency (EPA) toxicity database, DSSTox, lists 14,735 unique PFAS chemical compounds. PubChem lists approximately 6 million. The fluorosurfactants or fluorinated surfactants subgroup, has a fluorinated "tail" and a hydrophilic "head" and are thus considered surfactants. These are more effective at reducing the surface tension of water than comparable hydrocarbon surfactants. They include the perfluorosulfonic acids, such as perfluorooctanesulfonic acid (PFOS) and the perfluorocarboxylic acids like perfluorooctanoic acid (PFOA). Many PFASs were used in the mid-20th century in products and on materials due to their enhanced water-resistant properties, such as within Teflon or aqueous film forming foam. Only since the start of the 21st century has the environmental impact and toxicity to human and mammalian life been studied in depth. PFOS, PFOA and other PFASs are commonly described as persistent organic pollutants because they remain in the environment for long periods of time, and are also known as "forever chemicals". Residues have been detected in humans and wildlife, prompting concern about impacts to health. According to the National Academies of Sciences, Engineering, and Medicine, PFAS exposure is linked to increased risk of dyslipidemia (abnormally high cholesterol), suboptimal antibody response, reduced infant and fetal growth, and higher rates of kidney cancer.Health concerns related to PFASs have resulted in numerous litigations (see Timeline of events related to per- and polyfluoroalkyl substances). In 2021, Maine became the first U.S. state to ban these compounds in all products by 2030, except for instances deemed "currently unavoidable".

see more »