PFAS: frequently asked questions (FAQs)

PFAS are compounds that have been manufactured since the 1950s. These chemicals have a linear, branched or cyclic, polymeric or non-polymeric carbon chain that varies in length and contains at least one perfluorinated methyl group (-CF₃) or perfluorinated methylene group (-CF₂). They can contain various functional groups that give them specific physical, chemical and toxicological properties. There are several thousand different PFAS.

Examples of PFAS.

© BRGM

PFAS have the distinctive feature of containing carbon-fluorine bonds, which are characterised by their high stability and resistance. As a result, some of these substances do not break down after they are used or released into the environment and can persist for decades or even centuries.

Other PFAS are degradable – they are called PFAS “precursors” – but they produce highly stable degradation products (such as TFA, for example, or PFOA and PFOS, which have longer chains). These are what led to the term “forever chemicals”; they were the first to be monitored and regulated (PFAS in Directive (EU) 2020/2184 on the quality of water intended for human consumption, or WIHC).

PFAS have non-stick, waterproof, heat-resistant and surfactant properties. These substances are used for many applications, in around 20 industrial sectors. They are therefore found in many different everyday products such as:  

• Greaseproof food packaging (for hamburgers, kebabs, pizza, etc.),
• Non-stick coatings for kitchen utensils (including Teflon),
• Water-repellent and waterproof textiles,
• Certain cosmetics,
• Certain plant protection products,
• Certain pharmaceutical substances,
• Certain types of fire-fighting foams (aqueous film-forming foams).

Around 225,000 tonnes of PFAS were present in products placed on the market in Europe in 2020 (ECHA), including:

• Textiles: 92,000 tonnes
• Medical devices: 43,000 tonnes
• Transport, heavy industry, food packaging, solvents/aerosols, refrigeration, energy/electronics, air conditioning, etc.

Direct and indirect sources of PFAS emissions (Cavelan A. and Togola A. 2024, État des lieux des sources directes d’émission en PFAS).

© BRGM

The specific case of fire-fighting foams

The use of fire-fighting foams has long been a major direct source of PFAS dissemination in soil and water, on sites of industrial accidents but also on fire-fighter training sites and at airports. Currently, the “new” foams on the market are mostly PFAS-free, with some exceptions (essential uses). The European restriction voted in April 2025 provides for a gradual ban on all PFAS in fire-fighting foams, with maximum permitted residual concentration thresholds and time-limited exemptions.

Exemptions (essential uses)- main situations where the use of PFAS-containing foams remains permitted, with specific transition periods:

These exemptions are governed by the REACH Regulation (Regulation (EC) No 1907/2006).

Please note: BRGM is not involved in issues related to the use of PFAS or the impact of these chemicals on health and biodiversity.

The impact of PFAS exposure on humans and living organisms has been investigated in various studies aimed at identifying and characterising the potential risks to health and biodiversity. The interministerial action plan on PFAS provides, in particular, for the results of this work to be used to study the feasibility of monitoring the health effects that may be associated with exposure to PFAS in humans and living organisms (Action 9 of Key area 2 - Improve and strengthen monitoring and use the resulting data to take action).

The French Agency for Food, Environmental and Occupational Health & Safety (ANSES) is conducting a series of studies on PFAS that aim to characterise the most frequently found substances and the levels of contamination to which the population is exposed and identify the most toxic chemicals.

PFAS can be released in the environment: 

• During their production process,
• During the manufacture of products using these substances,
• During the use of these products (including certain fire-fighting foams): this can cause PFAS to end up in our wastewater and waste,
• In the management of wastewater containing PFAS: as they are unable to satisfactorily treat these chemicals, wastewater treatment plants can be an indirect source of PFAS dissemination, through release into the treated wastewater system and the use of recovered sludge as agricultural fertiliser, which can be a route of transfer to soil, groundwater and plants,
• In the management of waste containing PFAS: on waste storage sites, PFAS can be transferred to soil through leachate infiltration and runoff; at waste incineration plants, PFAS can be dispersed into the air in the event of incomplete combustion. 

The transfer process varies depending on the type of PFAS:  

• Long-chain PFAS (C > 7-8) accumulate in soil and sediments, forming a stock that is gradually released and infiltrates into groundwater. These PFAS also accumulate in living organisms (bioaccumulation),
• Short-chain PFAS (C < 7-8), which are more mobile, migrate – sometimes over long distances – to the subsurface and groundwater,
• Very short-chain PFAS (C < 3) are highly mobile and migrate rapidly to groundwater.

These classifications, based on the length of the carbon-fluorine chain, are not strict because most PFAS have additional functional groups that greatly affect their properties and therefore their behaviour in the environment.

Processes affecting the fate of PFAS following their release during the use of aqueous film-forming foams (AFFF) (Cavelan A. et Togola A. 2025. État des lieux sur la méthodologie de diagnostic des sites pollués aux PFAS par l’utilisation des mousses anti-incendie).

© BRGM

Although the regulations on PFAS are becoming increasingly restrictive, the use of these substances over the past few decades has led to long-term contamination of soil and water near the sites where they are used. As a result, PFAS are now found in all compartments of the environment, including water (surface water, rainwater and groundwater), air, soil and sediments.

As part of the interministerial action plan on PFAS, BRGM has developed a tool for visualising PFAS monitoring data in water throughout all of France. Considered a major receptor of PFAS, water is currently the most closely monitored environmental compartment. Designed to meet an objective of transparency in identifying PFAS emission sites and measuring these substances, this tool can be used to visualise sampling points and provide an overview of the associated results. In July 2025, more than 2.3 million analyses were made available to everyone, including citizens, local elected officials and decentralised governmental services.

It is important to distinguish between the decontamination of environmental compartments (water, soil, etc.) and the degradation of PFAS:

• Soil and groundwater treatment involves reducing PFAS concentrations to a level that is as close as possible to pre-pollution levels, at an acceptable technical and economic cost.
• PFAS degradation consists in using physical, thermal, chemical or biological techniques to transform these substances into less hazardous or even non-hazardous chemicals (such as fluorine). 

The treatment of an environmental compartment does not automatically imply the degradation of PFAS! And while solutions for decontaminating the environment are available, techniques for destroying PFAS are still being refined in laboratories. 

Methods for degrading PFAS directly in soil and groundwater are currently coming up against the difficulty of breaking the C-F bond characteristic of PFAS, bearing in mind that it takes 1.5 times more energy to break the C-F bond than the carbon-hydrogen (C-H) bond! And while some techniques can initiate degradation, it is crucial to prevent this from being incomplete, as this could generate shorter-chain PFAS, which are often more mobile and whose impact on health and the environment is still poorly understood. In addition, chemical methods usually involve the addition of reagents and/or the maintenance of temperature and pressure conditions that are potentially harmful to the environment. As for the biodegradation of PFAS by micro-organisms, the results are currently mixed at laboratory level, although some recent work has been more encouraging. 

The alternative to PFAS degradation directly in soil and groundwater consists in extracting these substances and concentrating them in liquid or solid residues. However, these residues from treatment can be a new source of pollution or, at the very least, can constitute waste that needs to be managed. For example, water can be treated by circulating it through granular activated carbon, which is capable of retaining some – but not all – of the PFAS. Once used, the activated carbon becomes a concentrated residue, which must be managed properly to prevent any further pollution.

Several techniques can be used to separate PFAS from water sampled after pumping (whether on-site or off-site). The most mature are: granular activated carbon, ion exchange resins and membrane filtration (in particular nanofiltration and reverse osmosis). The first two techniques are based on the much greater chemical affinity of PFAS for the substrate (carbon or resin) than for the aqueous medium: this is known as adsorption (accumulation of PFAS on the surface of the substrate). Filtration, on the other hand, is mainly based on size exclusion.

These techniques have long been used for other micropollutants and are effective for many PFAS. They are also among the few to have reached the maximum level (9) on the Technology Readiness Level (TRL) scale, corresponding to a technology that is fully operational and used in real-life conditions. That being said, a great deal of research is currently being undertaken to make these techniques more effective against short-chain and ultra-short-chain PFAS, as these chemicals have less affinity with surfaces and are therefore more difficult to separate from the aqueous medium. 

Some treatment techniques take the opposite approach, which involves reversing the process by recovering PFAS adsorbed onto soil. This can be done by injecting water and using hydrocarbon surfactants for greater effectiveness (studies are in progress). These surfactants replace PFAS at the soil interface, allowing these chemicals to be transported to extraction points. The hydrocarbon surfactants must be chosen carefully to avoid any secondary pollution of the media. As the extracted water is loaded with PFAS, it must be managed with care, in the same way as the used activated carbon.

Lastly, other techniques are being deployed on-site in Europe, including thermal soil treatment, incineration and in situ immobilisation (activated carbon).

Please note: The range of techniques presented in these FAQs, which focus on the most mature ones, is not exhaustive. Many other methods are currently being developed in laboratories – a recent survey counted 25 for the treatment of liquids and 11 for the treatment of solids, not including the many variations and combinations of techniques, which implement a particularly promising approach. 

Apart from containment in waste storage facilities, which carries the risk of further impacting the environment, the incineration of waste containing PFAS is currently the only alternative for PFAS disposal. However, due to the high resistance of these chemicals, it is necessary to use hazardous waste incinerators or cement kilns to be able to reach temperatures exceeding 1,000°C for at least three seconds. This technique is therefore energy-intensive and also generates by-products in the combustion gases, which are still being studied. 

Among the degradation techniques currently being developed, supercritical water oxidation can break down a large number of PFAS at a lower energy cost than incineration. This technique involves passing water through an intermediate state between gas and liquid, which triggers the oxidation of PFAS. However, it requires very high temperature and pressure conditions (> 375°C and > 218 bar) and therefore uses a relatively large amount of energy. Energy demand is also high for treatment by sonocavitation; this is a process that uses ultrasound to create microscopic bubbles which, when they implode, generate pressure and temperature levels capable of degrading PFAS.

Please note: BRGM focuses mainly on groundwater.

Reminder: Groundwater quality is monitored by various stakeholders, including BRGM. In accordance with the European Water Framework Directive (WFD) published in 2000, more than 110 substances are monitored in groundwater at least twice a year. These substances are associated with domestic or industrial wastewater discharges (emerging pollutants, drug residues), urban soil leaching (metals, hydrocarbons, PCBs) and agricultural pollutants (nitrates, pesticides). Every six years, 110 additional substances are measured in metropolitan France and the French overseas territories, in addition to 50 others for specific monitoring in these areas. This brings the number of substances included in the regular groundwater quality monitoring programme in France to around 320. These analyses are supplemented by specific local measurements and other measurements taken as part of research programmes. The national portal for access to groundwater data (ADES) lists several thousand substances that have been analysed at least once. 

Regulations on PFAS in water intended for human consumption: Directive (EU) 2020/2184, transposed in France via the Decree of 30 December 2022

These lay down a list of 20 PFAS whose total concentration (the sum) must not exceed a certain value (0.1 µg/L) in water intended for human consumption (WIHC). Monitoring of these substances will become mandatory on 1 January 2026 and will be carried out by France’s Regional Health Agencies (ARS), which are responsible for overseeing the quality of WIHC. However, quality limits are already in force and must be applied for substances that are currently being monitored.

Instruction notes for the management of WIHC: DGS/EA4/2024/30 of 12 March 2024 and DGS/EA4/2025/22 of 19 February 2025.

Environmental regulations: European WFD and French Decree of 26 April 2022

This decree requires regular monitoring of PFAS in surface water (five compounds) and groundwater (20 compounds since 2022, compared to six in 2015) as part of the water monitoring programme. Although it is being developed, the monitoring of PFAS in groundwater is still in its infancy and does not yet provide sufficient historical data to be able to analyse changes in their levels in this resource. 

Regulation relating to the monitoring of industrial sites: Ministerial Decree of 20 June 2023

This decree steps up the monitoring of PFAS in industrial discharges to water. All facilities classified for environmental protection (ICPE) that are subject to authorisation and that use, produce, treat or release PFAS into the environment, via their process water or rainwater, must screen for and identify these substances. This applies to the 20 compounds listed in Directive (EU) 2020/2184 on WIHC, as well as to the other compounds used in their processes. These analyses must be carried out every month for three consecutive months. The data are freely available on the websites of the Regional Directorates for Environment, Planning and Housing (DREALs). The main emitters of PFAS will be required to put in place an action plan to limit discharges and improve the monitoring of these substances. Efforts are currently under way to make this exploratory exercise permanent.

Please note: The regulations on PFAS are currently evolving, both in Europe and in France. In France, exploratory campaigns similar to those carried out for discharges to water from ICPEs are in progress (for gaseous discharges from ICPEs) or in the development stage (for urban wastewater, as part of the Urban Wastewater Directive).

In April 2024, to structure actions addressing growing concerns about the impacts of PFAS on human health and biodiversity, France adopted an interministerial action plan.

This plan is organised around five key areas: 

• Key area 1: Gain knowledge about methods for measuring emissions, dissemination and exposure
• Key area 2: Improve and strengthen monitoring and use the resulting data to take action
• Key area 3: Reduce the risks associated with exposure to PFAS
• Key area 4: Innovate by joining forces with economic stakeholders and supporting research
• Key area 5: Stay informed for better action

PFAS management involves monitoring these chemicals and reducing them at the source by regulating their production and use. 

PFOA, PFOS and their derivatives are among the most toxic PFAS and have been used in fire-fighting foams; they are already banned internationally. New measures to restrict or ban PFAS are currently under discussion. However, they raise the question of substitute products, on which few studies are currently being conducted.

At European level: in the wake of the 2014 Madrid Agreement, which proposed ending the production and use of PFAS for all “non-essential” uses, several countries (Denmark, Germany, the Netherlands, Norway and Sweden) are calling for PFAS to be phased out in the European Union, unless it can be proven that their use is essential for society.

In France: a law adopted in February 2025 aims to ban the use of PFAS in certain consumer products from 1 January 2026 (food packaging, cosmetics, clothing, ski wax, etc.) and from 1 January 2030 (textiles, except those used in defence or civil security missions) and to better inform the public, in particular through a map of sites that emit or have emitted PFAS into the environment. The text also provides for the creation of a levy collected from industrial companies that emit PFAS, intended to finance water agencies in order to meet the drinking water treatment needs of local authorities.

BRGM has been involved in the issue of PFAS for around 15 years, drawing on several of its areas of expertise relating to the subsurface. Its work involves gaining a better understanding of these substances and how they behave in the environment, particularly in soil and groundwater, with a view to developing remediation solutions. This is a particularly complex subject due to the wide variety of PFAS and the heterogeneity of their physical and chemical properties, which lead to different mechanisms of interaction with water, soil, sediments and air. BRGM is also striving to identify issues related to the transfer of PFAS into the environment, from their point of emission to the receiving compartments, with the aim of predicting how these substances will evolve in soil and groundwater.

Please note: BRGM, the French geological survey, is the French public institution responsible for ground and sub-surface studies. Its scientific work focuses on underground space, through research and in support of public policy. In the areas of water and risks, it is committed to developing optimal management and remediation solutions in terms of implementation and cost, in order to promote resource conservation and sustainable land use planning. It is not involved in issues related to the use of PFAS or the impact of these chemicals on health and biodiversity.

BRGM, a stakeholder in the interministerial action plan on PFAS

Moreover, BRGM is a stakeholder in the interministerial action plan on PFAS, launched in the spring of 2024. It is heavily involved in Key area 1, on the development of knowledge and methods for measuring PFAS, and has already produced several reports in this context:

• an inventory of the various PFAS likely to be present on sites using fire-fighting foams around the world,
• an overview of the methods and results of international campaigns to determine background levels of PFAS in soil,
• and a summary of the practices implemented around the world to screen for, identify and quantify these chemicals in a given environment.

In connection with Key area 2 of the PFAS plan (Action 7), BRGM has developed a prioritisation methodology based in particular on the vulnerability of groundwater, using data from national water databases. This approach, which has been tested at several airports under the authority of the General Directorate for Civil Aviation (DGAC), aims to classify the sites that are the most at risk and require an investigation. It is intended to be applied to other sites that potentially emit PFAS, such as military sites, departmental fire and rescue services (SDISs) and ICPEs. At the same time, work is being carried out to identify the composition of fire-fighting foams, in collaboration with the various users (SDISs, army, industrial companies willing to participate) in order to improve monitoring strategies for these emitting sites in terms of the PFAS monitored and the sampling protocols used.

In connection with Key area 3 of the PFAS plan (Action 17), BRGM has included PFAS in the ActiviPoll database, which lists and classifies correlations between industrial activities and the pollutants that may be associated with them, by cross-referencing various sources of information (French databases and specialist international literature). A complete export of the GIDAF database dating from 10 June 2024 enabled all PFAS data available in this database on that date to be integrated into ActiviPoll. A total of 18,529 PFAS quantifications were used, resulting in 2,100 correlations between 53 compounds and 115 activities. In the current version of ActiviPoll, 38 new substances are linked to the PFAS category. 

BRGM is also involved in Key area 5 of this plan, for Action 23: The gradual development of a tool for visualising data and sites, and investigation of the possibilities and obstacles to interoperability between PFAS measurement data sources in different environments. To this end, the institution has developed a mapping tool accessible to all, which displays all the available monitoring data associated with sites across the country where PFAS are monitored in water: sampling point coordinates, PFAS measurement results in water, etc.

BRGM’s skills and expertise are mobilised in three areas relating to PFAS:

• Assisting with decision-making by government departments and local authorities, by providing scientific and technical support for understanding and managing the presence and fate of PFAS in groundwater. This involves making data and knowledge available and proposing suitable methodologies;
• Supporting the drafting of national and international regulations governing PFAS monitoring, through technical support for the identification of substances to be monitored and the development and validation of methods to be implemented whose analytical performance can be achieved at an acceptable cost;
• Researching remediation solutions through the development of technologies for soil and groundwater decontamination and PFAS destruction.

As part of its research activities, BRGM is conducting several projects related to PFAS. The most recent include:

The H2020 PROMISCES project (2021-2025)

The European PROMISCES project, coordinated by BRGM, aims to contribute to the deployment of the circular economy by reducing the risks associated with certain persistent and mobile pollutants of industrial origin, in particular PFAS.

Its main objectives are to: 

• Develop analytical methods for quantifying and characterising PFAS in various environmental matrices (water, wastewater, sludge, sediments, soil, etc.),
• Better understand the behaviour and fate of PFAS in soil and groundwater, as well as their transfer when natural resources are reused, in order to better assess their impact on humans and the environment,
• Develop treatment methods for soil and water, particularly in contexts where sites have been polluted by the use of PFAS-containing fire-fighting foams,
• Propose a decision-support tool for decision-makers and managers concerned with the issue of PFAS.

Find out more about the PROMISCES project

The PERMUTE project (2024-2027)

The winner of Ademe’s GESIPOL call for research projects, which encourages innovation to improve the management of polluted sites and the ecological rehabilitation of contaminated brownfield sites, the PERMUTE project aims to develop a solution (foam) capable of effectively extracting PFAS from contaminated soil and treating polluted effluents using a combination of chemical and physical methods (adsorption), to replace the incineration or storage of soil containing PFAS.

Find out more about the PERMUTE project

The PFAStwin project (2022-2026)

The main objective of the PFAStwin project is to enhance the skills of the University of Belgrade's Faculty of Chemistry (UBFC) in the field of PFAS analysis and bioremediation, through collaboration with institutions in partner countries, including BRGM for France. The aim is to increase the Republic of Serbia’s ability to mitigate PFAS pollution and design innovative strategies addressing the complex issues associated with these persistent substances.

Find out more about the PFAStwin project

The Concerto project (2020)

The Concerto project was a partnership between BRGM and Colas Environnement that involved testing a chemical process for decontaminating groundwater containing PFAS. The tests reduced concentrations of some of these compounds by up to 70%. An analytical method was also developed for 18 PFAS found in groundwater at low concentrations (20 to 100 ng/l).

Find out more about the Concerto project

The PRIME platform

Following analytical developments and laboratory experiments, BRGM’s PRIME platform carries out tests on a multi-metric scale, facilitating in situ demonstration and modelling. This state-of-the-art equipment is able to test monitoring methods under controlled conditions, study PFAS migration in an aquifer and soil, and test remediation techniques.

Find out more about the PRIME platform

The performance of the PFAS removal methods currently under study varies depending on the matrix and chemical being treated. These methods also encounter real obstacles, related in particular to their complex implementation and the amount of energy required to trap or destroy these persistent substances. BRGM’s work therefore aims to optimise these processes from a technical standpoint, to improve their efficiency and yield, but also in economic terms (energy, equipment, etc.) in order to reduce their cost and develop their large-scale application.