What is the UK doing about PFAS?

PFAS (perfluoro- and polyfluoroalkyl substances) have been hitting the headlines recently. The  growing awareness of their long life in the environment, and uncertainty over their long-term effects on human health, has led to the nickname “forever chemicals”. 

Certain PFAS have already been restricted as persistent organic pollutants (POPs), such as PFOS (perfluorooctane sulfonic acid) and PFOA (perfluorooctane carboxylic acid). However, PFAS is a wide-ranging class of molecules and the need to fill the gap left by the bans has led to worry over “regrettable substitution” – the act of replacing a substance of concern with one which appears to be preferable, but later becomes a substance of concern itself when more data becomes available.

Why are PFAS so persistent?

The reason PFAS remain in the environment for such a long time is down to the presence of fluorine atoms in these substances. The fluorine-carbon bond found in all these molecules is extremely strong and difficult to break. 

Without an easy degradation mechanism, PFAS persist for a long time in air, soil, and water, and are concentrated up the food chain since they cannot be easily excreted. Because of this, PFAS have been detected in indigenous groups of humans and wildlife in remote regions such as the arctic circle – places where PFAS have never been used.

Legislative action against PFAS

Governmental bodies are now trying to get to grips with the consequences of continued PFAS use and to decide on what regulatory action is necessary. The UK HSE (Health and Safety Executive) recently published an RMOA (Regulatory Management Options Analysis) detailing why PFAS are considered a problem, the technical difficulties in judging the extent of the problem, and what further action is needed to develop appropriate legislation to control these substances. 

How is the UK approaching PFAS?

The RMOA uses a grouping approach, which divides PFAS into sets of similar molecular structures. Each group contains “arrowheads” – PFAS for which the hazards are well known, and which are the endpoints for the breakdown of some other PFAS. 

This helps to manage the assessment of this wide-ranging group of chemicals, and to avoid regrettable substitution by assuming that grouped substances will have similar hazards. 

Substances which contain only a single isolated methylene (-CF2) group have been omitted as they are not expected to degrade to substances of concern.  

Key concerns about PFAS in the UK

It is difficult to assess the quantity of PFAS being imported or manufactured in the UK as many uses of PFAS are individually small amounts, or otherwise used in ways that do not require them to be registered. 

Human exposure to PFAS can come from many sources, including textile and furniture coatings, personal care and cleaning products, and food contact items (such as wrappers and older Teflon™ products). This means that the release of these chemicals comes from many dispersed sources that are difficult to control. 

Fire resistance is one of the key properties leading to the widespread use of PFAS, and legacy PFAS are still being detected at the sites of large fires (like the 2005 Buncefield fire) due to their use in fire-fighting foams. 

The RMOA emphasises that the unique properties of PFAS, which make them suitable for applications requiring fire- or water-resistance, stem from the carbon-fluorine bond–the same bond which makes them slow to degrade in nature. This means it will be difficult to replace them, as any alternatives with the same chemistry are likely to have the same problems. PFAS replacements will have to be carefully tested to ensure that they perform as needed, while breaking down harmlessly in the environment.

What is the HSE recommending about PFAS?

The RMOA makes the following recommendations in conclusion:

• Do the necessary work in phases due to its scale and prioritise areas where more data is available;
• Target fire-fighting foams as the first priority for the substitution of PFAS;
• Prepare background dossiers on uses most likely to cause a release, e.g. coatings application or cleaning agents;
• Consider exemptions where there is enough data to verify safety, or where there is no viable alternative;
• Use UK REACH legislation to authorise certain uses of PFAS in polymer processing while research is ongoing to find viable alternatives;
• Perform an investigation into TFA (trifluoroacetic acid), which has been highlighted as a concern due to potential for developmental toxicity; 
• Include fluorine-containing gases in the investigation as they may transform to TFA and are prolific in the UK; 
• Levy strategic collaborative work between government and stakeholders;
• Develop statutory standards for PFAS in drinking water.

See the full RMOA report here.