Managing emerging chemicals of concern - changes in PFAS regulations in Europe

A little bit of chemistry

When you look at the periodic table of elements, you may be overwhelmed by all the information presented. To simplify things a little, it may help to think about general trends in chemical properties. One of these trends is what chemists call electronegativity, which defines how well an atom can attract electrons towards itself, more generally known as the ‘pulling power’. Electronegativities increase from left to right across a period and decrease from top to bottom of a group. Therefore, leaving the noble gases aside, the most electronegative element is fluorine.

This pulling power is the reason that the carbon fluoride (C-F) bond is one of the strongest in nature and becomes even stronger when a carbon atom is partially (poly-) or fully (per-) fluorinated. PFAS chemicals are exactly that: polyfluorinated or perfluorinated substances. As a result of these strong bonds, PFAS chemicals do not readily degrade in the environment.

The PFAS universe

In 2018, the Organisation for Economic Co-operation and Development (OECD) identified nearly 5,000 PFAS-related CAS numbers1 as part of a global database2. However, it is likely that there are many more PFAS than were identified at that time. In a recent webinar held by European Chemicals Agency (ECHA), the agency declared that, based on their own data, around 6,300 PFAS substances have been identified3.

Given this high number of individual substances, the PFAS family tree is complex. In 2017, Wang et al. published a comprehensive overview of the individual family members4. Firstly, it is important to distinguish between fluorotelomers, which may be a source of environmentally persistent PFAS (such as PFOA and PFOS), and fluoropolymers (like PTFE) are considered to be “polymers of low concern” due to certain properties, (e.g. insolubility in water, inability to cross the cell membrane) (Henry et al. (2018)5. Thus, there is an ongoing discussion if grouping fluoropolymers with other classes of PFAS is scientifically appropriate (Henry et al. (2018)5, Lohman et al. (2020)6).

The tricky part of PFAS is that, like in a real family, the members are related to each other. Therefore, some PFAS have been used to facilitate the production of others (in the early days, for example, PFOA was used in the production of PTFE) or that some PFAS degrade over time into other PFAS.

PFAS contain fully fluorinated carbon chains of various lengths attached to a functional group, like carboxylic or sulfonic acids. The most well-known PFAS, PFOA and PFOS, both contain 8 carbon atoms but have different functional groups, as shown below. Recently, other types of PFAS, including perfluoroethers (PFPEs), have also come under greater scrutiny.

PFAS uses

PFAS have been used since the 1940s in a variety of industries, from aerospace to clothing, due to their unique physical and chemical properties. PFAS are costly to produce (for example fluorosurfactants are up to 1,000 times more expensive compared with analogous hydrocarbon- surfactants, for example) and are often used where high performance is required, such as in extreme conditions or where non-reactivity is needed.

Many PFAS applications have made our everyday lives more convenient, for example non-stick pans, anti-stain for carpets and clothing, and water repellent items like outdoor jackets.

A recent publication by Gluege et al. (2020)7 identified 21 industry branches with more than 200 uses. Looking at these, it would be reasonable to assume that the majority of industries use PFAS in one way or another:

According to the US Environmental Protection Agency, there is evidence that exposure to PFAS can lead to adverse health outcomes in humans8. The most-studied PFAS chemicals are PFOA and PFOS. Studies indicate that at sufficiently high levels of exposure both chemicals can cause reproductive, developmental, liver, kidney and immunological effects in laboratory animals. Based on a study among exposed human

populations, USEPA also linked exposures to possible low infant birth weight, effects on the immune system, cancer (for PFOA) and thyroid hormone disruption (for PFOS)8.

In Europe, some PFAS are classified as persistent, bioaccumulative and toxic (PBT) and very persistent and very bioaccumulative (vPvB) under REACH9. The European Environment Agency highlights the main adverse effects of PFAS on human health as thyroid disease, increased cholesterol levels, effects on reproduction and fertility, immunotoxicity, liver damage, kidney and testicular cancer10. The European Food Safety Agency very recently published a draft scientific opinion on the risk to human health related to the presence PFAS in food. Based on the most critical adverse outcome – effects on the immune system – a very low tolerable weekly intake of 8 nanograms per kilogram of body weight per week was established11.

Chemicals that are resistant to degradation in the environment are called persistent. The unique properties of PFAS result in a high persistency and wide distribution in the environment. In addition, many PFAS substances are relatively water soluble, which enables transport via water and aerosols over long distances. PFAS also undergo long-range transport and as a result have even be found in the Arctic12.

In May 2020, a broad restriction of all substances that contain at least one aliphatic -CF2 or -CF3 group was proposed in the European Union. The proposal is being prepared by four Member States (Germany, Denmark, the Netherlands and Sweden) as well as Norway, and could come into force in 2025.

Companies producing or using PFAS, selling mixtures or products containing them, and those using alternatives to PFAS, have been invited to participate in a call for evidence, to provide information that will help refine the scope of the proposal and determine the effectiveness and socio-economic impact of different restriction options. Respondents can detail their current usages and indicate if they have information on an “essential use”: one that is necessary for health, safety or other important societal purposes, and for which an alternative chemical is not yet available.

The concept of essential use has not yet been implemented in the regulatory framework of REACH but is considered to be a driver of more health-protective and efficient regulation of PFAS substances.

Portfolio screening

Many companies will be overwhelmed by the potential number of PFAS-substances in their portfolio, as they have been used in almost all technical processes. Clients will need to identify PFAS substances, including pre-cursors, degradation products and impurities.

Alternative substance assessment

The ultimate aim of regulations such as REACH is to encourage and facilitate the transition to safer chemicals. Companies can enlist the help of advisers who will use comparative hazard assessment methods such as GreenScreen® to support informed decision-making on the use of chemicals in products and processes.

Making the case for essential use

The European Commission intends to introduce the essential use concept to the PFAS regulation in the EU, at which point companies will need to make their case for an essential use. In addition, companies need to gather data on potentially hazardous properties including measuring the degradability of their products and assessing the exposure to the environment – such as mass balances, releases to water and air, residuals in articles including end-of-life assessment – if they want or need to continue using a PFAS compound in the EU after 2025. The upcoming PFAS regulation would also cover articles containing PFAS, therefore companies based outside the EU but shipping articles containing PFAS into the EU would also be affected.

Footnotes

1. A unique numerical identifier assigned by the Chemical Abstracts Service to every chemical substance
2. An excel file containing all the substances, last accessed 17.11.2020
3. Webinar recording, last accessed 17.11.2020
4. Wang et al., 2017, last accessed 17.11.2020
5. Henry et al., 2018, last accessed 22.01.2021
6. Lohmann et al., last accessed 22.01.2021
7. A detailed overview is given in Gluege et al., 2020, last accessed 17.11.2020
8. USEPA evidence, last accessed 17.11.2020
9. Perfluorohexane sulphonic acid (PFHxS) and its salts, perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and its salts, nonadecafluorodecanoic acid (PFDA) and its salts, last accessed 17.11.2020
10. EUEA document, last accessed 17.11.2020
11. EUFSA document, last accessed 17.11.2020
12. Muir et al., 2019, last accessed 17.11.2020

Ramboll’s Health Sciences experts assist clients with PFAS and other chemicals-related use, issue and regulations challenges across the world. For more information or assistance, please contact us.