Per- and polyfluoroalkyl substances (PFAS) are a large group of industrial chemicals that have been used ubiquitously since the 1950s.
PFAS are ingredients or intermediates of surfactants and surface protectors that are used for a variety industrial and consumer applications.
PFAS can be found in cleaning agents, polishes, lubricants, non-stick coatings, water and oil/grease repellant coatings, paints, and firefighting foams, to name just a few uses.
PFAS are characterized by containing one or more perfluoroalkyl structures (‑CnF2n+1). The fluorine molecules bound to carbon create a very strong chemical backbone that is resistant to breaking down. This durability is very desirable for industrial and consumer applications and for manufactured products, but this resistance to degradation causes PFAS pollution to accumulate in the environment.
Most PFAS are water-soluble so they rapidly disperse into the environment and contaminate both surface water and groundwater that are used a sources of drinking water.
While contamination of drinking water and pollution of rivers, lakes and the oceans is recognized as being widespread, only a handful of the 1000’s of different PFAS manufactured have been tested for toxicity. Of those few that have been examined, many exhibit toxic effects.
Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are members of the PFAS family of compounds that have harmful effects on the liver and the immune system and increase incidence of some cancers. These compounds are sometimes referred to as “C8” compounds because their chemical structure contains of eight repeated perfluoroalkyl structures linked together. PFAS with 7 or more perfluoroalkyl groups are considered “long-chain” and recognized as likely to persist in the environment. PFOS has been listed under Annex B of the Stockholm Convention since 2009, and its use and production has been restricted. Due to their persistence, ability to bioaccumulate into living organisms, and their toxicity, PFOA and perfluorohexane sulfonic acid (PFHxS) are currently being reviewed for listing under Annex B of the Stockholm Convention.
While active manufacture and use of those long chain PFAS has been decreasing, contamination of different PFAS with alternative chemical structures has increased, even though little is known about the toxic properties of these chemicals.
Water sampling data suggests a rather significant prevalence of GenX and other emerging PFAS contaminants within the Cape Fear watershed in North Carolina. The toxic potential and exposure profiles of these newly recognized contaminants however are poorly defined.
There is a lack of critical scientific data necessary to define exposure, levels, and potential sources of legacy and emerging classes of PFASs within the aquatic environments from which public water supplies originate.