When PFAS and water are discussed, the focus is usually on PFOS, PFOA, and other low molecular weight PFAS associated with emissions and water contamination. While this is an important issue, there is far less awareness of the critical role other PFAS chemistries play in supporting the water supply, treatment, and sewage industries.
A recent Cefic report highlighted numerous industrial sectors dependent on PFAS, including water management. Unsurprisingly, fluoropolymers represent over 40% of PFAS volumes in this sector. However, other PFAS groups such as side-chain fluorinated polymers, fluorotelomer-based compounds, polyfluorinated alkanes/alkenes, F-gases, and perfluoropolyethers, also contribute significantly to maintaining clean water supplies. Unfortunately, the report offers limited detail on specific sub-applications, though some key uses of fluoropolymers are well established.
Chlorine Production: A Critical, Irreplaceable Use of Fluoropolymers
One essential use of fluoropolymers is in the production of chlorine via brine electrolysis. Chlorine, caustic soda, and hydrogen are generated using cell membranes built from PFAS chemistries, specifically, Ion Exchange Membranes (IEM) with fluoropolymer backbones and functional side groups. These membranes must withstand extreme conditions: corrosive chemicals, high temperatures, and electrical currents. Furthermore, they must ensure long-term durability, low electrical resistance, and reliable ion transport. IEMs replaced older, more hazardous technologies like mercury cells and asbestos diaphragms.
Fluoropolymers such as PTFE are also indispensable in these electrolysers for piping, seals, and gaskets. While alternatives exist for some applications, the extreme corrosion resistance and durability of fluoropolymers make them the only viable option in critical areas of the chlorine production process.
Chlorine’s Downstream Importance
Beyond chlorine production itself, the downstream use of chlorine is equally vital. Europe produces around 600,000 to 700,000 tonnes of chlorine each month. Approximately 90% of drinking water in the EU is disinfected with chlorine, and it plays a pivotal role in manufacturing half of all chemicals in Europe supporting industries from healthcare and cleaning products to PVC production where one use is water and sewage piping.
Other outputs of chlorine electrolysis, such as caustic soda, are crucial to paper, textiles, and food industries, reinforcing the essential nature of PFAS in these processes.
PFAS in Filtration: Niche, High-Purity Applications
Filtration is another area where PFAS, particularly fluoropolymers like PTFE and PVDF, are used for specialised applications. Despite concerns about wetting properties, their unique chemical resistance makes them indispensable in high-purity processes such as water treatment, bioprocessing, chemical production, and medical applications where non-PFAS alternatives often fall short.
The Challenge for RAC & SEAC in the Broader Context
As the RAC and SEAC review PFAS applications case by case, there is a risk that the holistic importance of PFAS across the water sector will be overlooked. For example, while the chlor-alkali process is flagged under the 'energy' category, the interconnected role of PFAS in water treatment, chemical production, and infrastructure may be missed.
Balancing environmental concerns such as emissions of PFOS and PFOA against the critical functions PFAS fulfil is complex. Applications like IEMs in chlorine production, with low emissions potential, clear traceability, and established monitoring, are strong candidates for conditional derogations. However, decisions become more complicated for applications like filtration and piping, where suitable alternatives exist for some, but not all, uses.
What's Next for PFAS & Water?
As the process unfolds into late 2025 and early 2026, it will be crucial to see how RAC and SEAC address these niche yet essential uses of PFAS within broad application categories. Will they adequately consider the entire water supply chain, or will decisions hinge solely on high-profile contaminants? The same challenge applies across many industrial sectors.
ECHA should anticipate significant engagement during the SEAC consultation phase as industry and other stakeholders respond to the provisional conclusions, particularly regarding the critical infrastructure and services supported by PFAS-based technologies, the availability of alternatives and derogation needs.
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