I became aware of the ECHA proposal after reading an excellent article, The EU’s Per- and Polyfluoroalkyl Substances (PFAS) Ban: A Case of Policy over Science, published in the journal Toxics written by Tommaso A. Dragani.
Mr. Dragani is currently the Chief Scientific Officer of Aspidia, a company involved in “bioremediation of pollutants and the production and delivery of natural and synthetic enzymes and other proteins.” Before assuming this role, he was the Research Laboratory Director of "Genetic Epidemiology and Pharmacogenomics" at Italy’s National Cancer Institute, publishing over 189 scientific papers in peer-reviewed journals, mainly in toxicology and genetic epidemiology.
Mr. Dragani was extremely gracious and agreed to an interview where I asked him questions about the ECHA proposal and topics in his article. Our discussion has been lightly edited.
SG: You clearly believe that the European Chemicals Agency was in error in proposing to ban an entire class of chemicals, the PFAS. Could you please explain why?
TD: I believe that ECHA is wrong to propose to ban an entire class of chemicals because PFAS are not a small number of similar compounds, but the term covers about 12,000 compounds with very different physical, chemical, environmental, and biological properties. There is no evidence of health risks for most PFAS, but banning them has strong negative consequences. For this reason, I do not recommend a blanket ban.
SG: What are some unintended consequences if the proposed ban becomes law?
TD: In my opinion, there are two distinct and unintended negative consequences to consider:
First and foremost, the proposed ban, if implemented, will result in the discontinuation of the production of fluoropolymers in Europe. These materials, which pose no known health or environmental risks, play a vital role in several industries. They are used in medical devices, computers, cell phones, and in the development of high-performance materials for aerospace, automotive, photovoltaic cells, electric motors, and more.
Second, the search for potential alternatives to PFAS could lead to the introduction of less effective and potentially more hazardous substitutes. In the absence of thorough toxicity assessments, these alternatives could be rushed to market, raising concerns about their safety.
SG: What are fluoropolymers, and why should they be considered a separate group from other PFAS?
TD: Fluoropolymers represent a distinct category within the PFAS group due to their significantly larger molecular sizes, often exceeding 100,000 dalton (Da), and more complex molecular structures. These substantial molecular sizes provide a critical advantage: they limit the uptake of fluoropolymers by living organisms, thereby reducing the likelihood of bioaccumulation. In addition, the bulkiness of fluoropolymers results in lower solubility in water, further limiting their ability to disperse in the environment. As a result, fluoropolymers can be classified as low-risk polymers because they meet all the criteria for such classification.
SG: Your article makes clear that PFAS includes a wide range of heterogeneous chemicals. Is there a way that makes sense to divide these chemicals into smaller groups?
TD: Fluoropolymers are a different chemical category than the PFAS compounds like PFOS and PFOA that have contaminated our drinking water. Given this fundamental difference, I don't think it makes sense from a public health perspective to lump PFAS into smaller groups based on similar chemical and physical properties. Instead, it's critical to evaluate each specific substance independently to determine whether it raises toxicity concerns.
SG: How do the structures of these chemicals affect their toxicity? Why should we expect that different PFAS affect the human body differently?
TD: The toxicity of PFAS is indeed influenced by their chemical structures, as these structures dictate how PFAS compounds can interact with specific receptors or proteins in our bodies. While our understanding is still evolving, we can highlight some general characteristics that shed light on this issue:
- Carbon chain length: The length of PFAS carbon chains plays a role in toxicity. PFAS with longer chains tend to be less toxic because they are less likely to be absorbed by the body.
- Functional groups: The presence of functional groups, such as sulfonate or carboxylate, can affect the water solubility of a PFAS compound and thus, its potential for toxicity.
- Isomers: Some PFAS compounds exist as isomers, which means they have the same chemical formula but different structural arrangements. These structural differences can lead to different toxicity profiles because isomers interact differently with biological receptors.
However, it is important to recognize that our understanding of PFAS toxicity is still limited, and making accurate predictions can be challenging.
SG: What are Toxicity-Equivalent Factors (TEFs), and why shouldn’t they be used to evaluate the toxicity of PFAS?
TD: In my article, I discussed the concept of toxic equivalent factors (TEFs), which serve as a tool for regulators to assess the collective toxicity resulting from exposure to chemical mixtures. However, for TEFs to be scientifically valid, they should be applied to chemically related substances that act through the same mechanism of action and produce similar types of toxicity.
Unfortunately, this principle does not apply to PFAS because they are an extremely diverse group of chemicals. PFAS show significant variation in how they interact with our bodies (toxicokinetics) and may not share a common mechanism of action. In addition, mechanisms observed in laboratory rodents, which are typically used to derive TEFs, may not be directly applicable to humans.
In summary, PFAS present a unique challenge due to their heterogeneity, diverse toxicokinetics, and potential variations in their mechanisms of action. This complexity makes the use of TEFs in the toxicity assessment of PFAS mixtures inappropriate.
SG: What role can bioremediation play in removing PFAS?
TD: Bioremediation is a remarkable process that harnesses the metabolic power of microorganisms and their enzymes to break down contaminants. It's cost-effective and environmentally friendly - it doesn't rely on harmful chemicals or incineration.
I believe bioremediation is a promising but largely untapped opportunity that could significantly improve the management of PFAS contamination soon. This belief led me to found ASPIDIA, a startup company dedicated to conducting research projects focused on the bioremediation of PFAS.
Unfortunately, securing funding for such endeavors can be quite challenging in Italy. I am very grateful for your efforts to raise awareness of this issue. I hope that in the not-too-distant future, we will be able to raise the necessary funds to conduct important scientific research in bioremediation - a field with the potential for immense benefits to both our health and the environment. Your support is invaluable in making this vision a reality.
SG: If you were the regulator, what would your approach be to regulating PFAS?
TD: As a regulator, my approach would be targeted and strategic, focusing primarily on managing PFAS compounds known to pose high risks - of which there are few, less than a dozen. For the remaining PFAS, an individual assessment of their toxicological properties would be essential, looking at each substance on a case-by-case basis. Notably, manufacturers are already undertaking aspects of this assessment, and further implementation would not result in significant cost increases.
At the same time, I would like to emphasize the importance of industrial processes that minimize emissions of potentially toxic substances into the environment. I would like to encourage research and development efforts, particularly in the promising area of bioremediation.
This multi-faceted approach would ultimately lead to more effective protection of both human health and the environment, thereby significantly reducing potential adverse impacts on the well-being and quality of life of citizens.
[1] “PFASs consist of a fully (per) or partly (poly) fluorinated carbon chain connected to different functional groups.” European Chemical Agency
