Per- and polyfluoroalkyl substances (PFAS) are a group of synthetic chemicals manufactured and used in a wide range of applications worldwide and found in the environment.
From a nomenclature perspective, a PFAS is defined as a substance with at least a perfluorinated methyl group (–CF3) or a perfluorinated methylene group (–CF2–). This terminology is the result of the harmonization process led by the OECD/UNEP Global Perfluorinated Chemicals (PFC) Group1.
Given their structural variety (carbon chain length, type of function...), the PFAS group includes several thousand substances, among which perfluorooctanoic acid (PFOA) and perfluoroctanesulfonic acid (PFOS) are the most studied, and which also includes perfluorohexane sulfonate (PFHxS) and perfluorohexanoic acid (PFHxA).
PFAS, due to the strength of the carbon-fluorine bond, are not very biodegradable, and can therefore contaminate the environment in an often-irreversible way. Most of these substances are easily transported in the environment over long distances, and their presence is generally observed on a large scale in all environments and ecosystems.
Due to their hydrophobic, oleophobic, chemical and thermal stability properties as well as their low surface tension, PFAS are useful in many industrial sectors:
- either as additives or auxiliaries for the production of fluoropolymers (such as PTFE, itself considered a PFAS) used in sectors of textile, aeronautical, automotive, electronic, paper, food packaging, etc. for the production of:
o oil and water repellent, stain release and flame-retardant coatings
o raw materials for components (low-friction bearings and seals, pipes, tanks, wires and electronic elements, etc.)
- or as co-formulants in phytosanitary products, maintenance products (floor polishes, etc.), metal treatment products (metal plating) in fire-fighting foams and in paints.
PFOA and PFOS are subject to worldwide bans and restrictions on use due to their inclusion in the Stockholm Convention on Persistent Organic Pollutants. In the European Union, the use of PFAS is subject to increasing regulatory oversight under the REACH Regulation.
Given the wide range of uses of PFASs, this site will first present alternatives to PFASs for applications that are a major source of emissions and diffuse exposure (in particular fire-fighting foams, protection of the surface of papers and textiles), illustrating them with specific examples of substitution based on practices or concrete experiments conducted in companies.
Note: This site will follow the news of the substitution of PFAS because of their properties of danger and persistence in the environment. For this reason, the question of the substitution of PerFluoroCarbons (PFCs) and HydroFluoroCarbons (HFCs) which is legitimate but essentially motivated by their important global warming power (they are greenhouse gases) will not be central.
Do not hesitate to share your experiences of substitution or your proposals of alternatives via the Contact section!
1 This group brings together experts from OECD (Organization for Economic Co-operation and Development) member and non-member countries in academia, governments, industry and NGOs (Non-Governmental Organization) as well as representatives from other international organizations
UNEP: United Nations Environment Program