Per- and polyfluoroalkyl substances (PFAS) were first synthesized in the 1930s. They are useful additives for commercial and consumer products due to their ability to repel oil and water (food packaging, stain resistant fabrics, waterproof clothing), resist friction and thermal decomposition (nonstick cookware, oils and other lubricants), and extinguish fires.
The chemical structure of PFAS compounds includes the strongest bonds in chemistry, the carbon-fluorine bond, which is extremely difficult to break, especially by natural treatment processes. This chemical bond has earned PFAS compounds their “forever chemical” moniker and is the reason that many PFAS compounds are persistent in the environment and have been widely detected in human blood samples.
The two most widely studied PFAS compounds are perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). There is some evidence that exposure to high levels of PFOA and PFOS can lead to adverse health effects in humans, which prompted the U.S. Environmental Protection Agency to issue a health advisory level for drinking water of 70 ng/L.
In the early 2000s, U.S.-based manufacturers voluntarily phased out the use of PFOS and PFOA in their products. However, these PFAS compounds are still produced and used in manufacturing abroad, are found in imported consumer products, and continue to impact to our environment.
More than 5,000 chemicals are in the PFAS family. Many of these include replacement or substitute chemicals used in U.S. manufacturing products today. Some of these substitute chemicals, such as the shorter-chained GenX, are also causing concerns over their potential for adverse effects to human health and the environment, but more studies are needed to better understand their toxicology so that appropriate regulations may be developed.