Grouping and Evaluation of PFAS

The conclusion of the Organization for Economic Co-operation and Development (OECD) and the United Nations Environment Programme (UNEP), as enunciated in their 2018 joint report, is that it is generally seen as an impossible task to evaluate 4,730+ chemicals. As a result, a number of regulatory bodies are lumping all fluorine compounds together as PFAS, even if they are not PFAS and do not fit the current definition.

In 2021, the Society of Environmental Toxicology and Chemistry (SETAC) published a study that identified a subset of the 4,730 PFAS chemicals numbering 256 (5.5 % of the total) that are “commercially relevant” in various countries and regions of the globe. While the current author is not in a position to pass judgement regarding the accuracy of this work, if it is accurate, it suggests, at the very least, that grouping PFAS using fundamental classification criteria based on composition and structure can be used to identify individual PFAS – or groups of PFAS – that are appropriate candidates for subjection to risk assessment protocols. This would go a long way toward countering the assertion that there are too many PFAS chemistries to conduct proper regulatory risk assessments for the commercially relevant substances (Figure 1).

Of paramount importance is that SETAC’s study determined that only 241 of the 256 commercially relevant substances met the definition of PFAS. Of these, 52 were polymers, which are of great importance to the paint and coatings industry and are, in this author’s personal opinion, unlikely to prove hazardous to either human health or to the environment.

Global Regulatory Approaches

Government regulators do not always give an appropriate level of consideration – or take the most logical steps – to deal with the information gleaned from even the most carefully conducted studies. With regard to PFAS, this is likely to be multiplied as a result of the different perspectives from which various countries and regions of the globe are viewing this subject. The EU, for example, is evaluating the PFAS issue under the purview of REACH/ECHA
(European Chemicals Agency), with particular emphasis on the following four chemicals but still within the context of banning all PFAS:

• Perfluorooctane sulfonic acid (PFOS – of significant concern in the U.S., China, and EU), subject in the United States to significant federal regulatory activity, along with PFOA, during the period 2000-2010
• Perfluorooctanoic acid (PFOA – of significant concern in the U.S., China, and EU) that, along with PFOS, was the earliest PFAS to cause a red flag to be raised, as well as the most extensively studied.
• In 2006, the EU Directive 2006/122/EC restricted the use of perfluorooctane sulfonic acid, and in 2019 the EU signed the International Stockholm Convention on Persistent Organic Pollutants, which banned the production and use of PFOA, its salts, and PFOA-related compounds, with exemptions only for medical textiles and some firefighting foams. This was later followed by the restriction of perfluorooctanoic acid (PFOA) by EU Regulation 2020/784.
• Perfluorohexane-1-sulphonic acid (PFHxS), its salts, and related substances (principally of concern in EU, at least currently)
• Undecafluorohexanoic acid (PFHxA), its salts, and related substances (principally of concern in EU, at least currently)
• There will be others—possibly even by the time this article is published.

Ban PFAS?

It currently seems to be the goal of ECHA to ban, or restrict to only a few critical uses, PFAS substances. The basis for this is the EU’s 2020 “Chemicals Strategy for Sustainability – Towards a Toxin-Free Environment.”  Currently, ECHA is conducting a “six-month consultation” on the proposal that started on 22 March, 2023, with public comments being accepted by 25 September. In contrast, the U.S. federal government appears to be satisfied that the regulatory activity during the period 2000-2010 centered principally on PFOS and PFOA was sufficient and is currently disinclined to pursue additional inquiries.

Instead, it has indicated that this should be an issue for the individual states, which promises to cause no end of confusion, leading to a patchwork of possibly contradictory state regulations. Leading the way, the State of Minnesota has enacted what is currently the broadest PFAS policy in the country. “The new law bans all uses of PFAS in products by 2023 – except those that are necessary for public health, requires manufacturers to report their use of PFAS in products to the state by 2026, and bans specific uses in several products starting in 2025.” The bill eliminates PFAS from 13 product categories: menstrual products, cleaning ingredients, cookware, dental floss, firefighting foam, food packaging, cosmetics, textiles, carpets, fabric treatments, upholstered furniture, children’s products, and ski wax. While “state-by-state regulation” may or may not ultimately be the situation in the U.S., it clearly indicates one of the many ways in which the EU and the U.S. differ with regard to their approach to the PFAS issue.

There can be no doubt that China will take action affecting either certain or possibly all PFAS, but current activity is less specific than what we are seeing in either the EU or North America. In 2008, the Ministry of Environmental Protection (MEP) listed a product believed to contain PFOA in the “High Pollution, High Environmental Risk Product Catalogue.” In 2011, the National Development and Reform Commission issued the “Catalogue for Guiding Industry Restructuring,” in which the production of both PFOA and PFOS were restricted, and in 2014 banned “production, transportation, application, imports and exports of PFOS, its salts, and perfluorooctanesulfonyl fluoride (PFOSF [also PFOS, which was formerly a key ingredient in “Scotchgard”), except for specific exemptions and acceptable use.”

Drinking water contaminated with PFAS

A 2020-21 study on the presence and levels of PFAS in 66 cities in China (containing a population of 450 million people) indicated that PFOA, PFOS, and PFBA (perfluorobutanoic acid) were the dominant PFAS species in Chinese drinking water. The study concluded that “Drinking water in many cities and regions in China is contaminated with PFASs [sic] at levels of concern. PFAS elimination of PFASs from drinking water in contaminated cities and affected regions in China is urgently needed.” Whether or not the results of this study are being considered by the regulatory agencies, however, does not appear to be a matter of public record, as far as the author is able to ascertain.

Do you want to know more about PFAS? Read more in our article series about PFAS Predicament: The PFAS Controversy (1): Navigating a Global Call for Ban Amidst Complex Challenges