30
Jul
Artificially Narrow EPA Definition of PFAS Mischaracterizes Widespread Threat to Health and Environment
(Beyond Pesticides, July 30, 2025) The definition of per- and polyfluoroalkyl substances (PFAS), also known as “forever chemicals†due to their persistence, continues to be debated in regulatory agencies, with many scientists arguing that certain types of chemicals in this vast group are not accurately captured in risk assessments. A wide body of science on the adverse health and environmental effects of PFAS exists, as these synthetic chemicals have become ubiquitous in nature, wildlife, and humans, as demonstrated by biomonitoring studies. Recent research, documented in a literature review in Environmental Science & Technology and additional articles, highlights the importance of a universal, cohesive definition of PFAS that incorporates all fluorinated compounds, including the long carbon chain PFOA (perfluorooactanoic acid) and PFOS (perfluorooctanesulfonic acid) as well as the ultrashort-chain perfluoroalkyl acids (PFAAs). In order to protect health and the environment from the ever-increasing threat of both long and short chain PFAS’ adverse effects, including cancer, endocrine-disrupting effects, and immune system damage, a comprehensive definition of the compounds causing harm is critical to adequate protection and regulatory decisions.
The multitude of sources of PFAS and various exposure routes leads to widespread contamination of the environment and organisms. PFAS in agriculture represents a large source, as PFAS can be pesticide active ingredients, used in the plastic containers pesticides are stored in, and as surfactants in pesticide products. Additionally, PFAS are used in many other plastic storage containers and food packaging, personal care products, nonstick cookware, cleaning supplies, treated clothing, firefighting foam, and machinery and equipment used in manufacturing—all of which contaminate food, water, soil, and the air.
A previous Daily News piece, titled “Science on ‘Forever Chemicals’ (PFAS) as Pesticide Ingredients and Contaminants Documented,” shows how and to what extent PFAS can be introduced into pesticide products, and how this impacts health and the environment. The findings are gleaned from public records requests to state and federal agencies in the U. S. and Canada, as well as from publicly accessible databases discussed in the commentary “Forever Pesticides: A Growing Source of PFAS Contamination in the Environment.” According to the authors: “The biggest contributor to PFAS in pesticide products was active ingredients and their degradates [chemical breakdown products]. Nearly a quarter of all U.S. conventional pesticide active ingredients were organofluorines and 14% were PFAS, and for active ingredients approved in the last 10 y[ears], this had increased to 61% organofluorines and 30% PFAS.â€
In 2025 alone, the U.S. Environmental Protection Agency (EPA) has proposed the registration of four new PFAS active, or fluorinated, ingredients: cyclobutrifluram, isocycloseram, diflufenican, and trifludimoxazin. Beyond Pesticides’ comments to EPA regarding these chemicals, including 20 signatories on the isocycloseram submission, are available here, here, here, and here.
The definition of PFAS used by the Organization for Economic Co-operation and Development (OECD) encompasses a wide variety of fluorinated compounds (containing the element fluorine) and is “scientifically grounded, unambiguous, and well suited to identify these chemicals,†as described by scientists in a commentary published in Environmental Science & Technology Letters. As the researchers describe, excluding certain fluorinated chemical subgroups does not properly represent the scope of PFAS, which they estimate to include millions of theoretical structures, but more practically, several thousand that are actually manufactured.
The OECD chemical definition of PFAS states:
PFASs are defined as fluorinated substances that contain at least one fully fluorinated methyl or methylene carbon atom (without any H/Cl/Br/I atom attached to it), i.e., with a few noted exceptions, any chemical with at least a perfluorinated methyl group (−CF3) or a perfluorinated methylene group (−CF2−) is a PFAS.
This definition of PFAS encompasses gases, pesticides, and pharmaceuticals, many of which can degrade to form additional PFAS, such as trifluoroacetic acid (TFA), that regulatory bodies like EPA do not include in their definitions.
In the literature review in Environmental Science & Technology, peer-reviewed scientific evidence points to five ultrashort-chain PFAAs as examples of harmful compounds that are historically overlooked and not included in all definitions of PFAS. The PFAAs, which all contain less than four carbon atoms, include TFA, perfluoropropanoic acid (PFPrA), trifluoromethanesulfonic acid (TFMS), perfluoroethanesulfonate (PFEtS), and perfluoropropanesulfonate (PFPrS). Of these, TFA is the smallest perfluoroalkyl acid with only two carbon atoms.
The authors report: “Our data mining and analysis reveal that (1) ultrashort-chain PFAAs are globally distributed in various environments including water bodies, solid matrices, and air, with concentrations usually higher than those of longer-chain compounds; (2) TFA, the most extensively studied ultrashort-chain PFAA, shows a consistent upward trend in concentrations in surface water, rainwater, and air over the past three decades; and (3) ultrashort-chain PFAAs are present in various organisms, including plants, wildlife, and human blood, serum, and urine, with concentrations sometimes similar to those of longer-chain compounds.â€
Ultrashort-chain PFAAs are created both intentionally and unintentionally as byproducts through the process of the synthesis of other PFAS and are not captured in all regulatory assessments. Yet, studies extensively document the presence of ultrashort-chain PFAAs in water, soil, air, and dust. One study finds both TFA and PFPrA (perfluoropropionic acid) in ice caps in remote locations, showing the widespread contamination present with these compounds.
Like other PFAS with long chains of carbon atoms, ultrashort-chain PFAAs are very stable due to carbon-fluorine bonds. The shorter-chain compounds, however, have unique properties that create additional threats. With increased hydrophilicity (attraction to water) and enhanced water solubility (ability to dissolve), ultrashort-chain PFAAs within global waterways and the atmosphere are more easily able to circulate and be widely distributed. An additional risk with ultrashort-chain PFAAs contamination in water is that these properties result in ineffective removal by conventional water treatment methods.
A study in Northern California reports that TFA concentrations in surface water increased by an average of 6-fold between 1998 to 2021. Additional research finds ultrashort-chain PFAAs omnipresent in groundwater throughout North America, Europe, and Asia, with TFA as the most detected compound. (See here, here, here, and here.)
Drinking water is also an exposure route for ultrashort-chain PFAAs that threaten human health. Research finds both tap water and bottled water contamination in the U.S. and China. (See studies here, here, here, and here.) A study of dust and drinking water samples from residential homes in Indiana, as well as blood and urine samples of the residents, shows TFA as the predominant PFAS in all of the samples, also noting the concentrations surpass those of longer-chain compounds.
Previous scientific literature indicates PFAS can cross into the placenta and accumulate in the fetus, with a higher potential for short-chain PFAS revealed in recent research. (See here, here, and here.) While some researchers have hypothesized that ultrashort-chain PFAAs have a lower risk of bioaccumulation in animals than compounds with longer chains, studies find evidence that they accumulate within plants, wildlife, and humans at comparable or elevated levels. (See studies here, here, here, and here.) The presence of these compounds in food sources throughout various trophic levels poses a risk to both humans and ecological health.
Proving further evidence of TFA’s prevalence and subsequent health threats, a viewpoint article in ACS ES&T Water highlights additional scientific research. One study identifies several fluorinated pharmaceuticals and pesticides in sewage sludge (biosolids) that transform into TFA, which contributes to the long list of sources for exposure to ultrashort-chain PFAAs.
Another study assesses TFA formation from “plant protection products†(PPP), another name for pesticides, across Europe, the U.S., and China. The results find that any PPPs that contain trifluoromethyl groups can lead to substantial TFA emissions. The study also finds higher levels of TFA from groundwater monitoring data that correlate with agricultural areas.
Daily News coverage of pesticide contamination in waterways highlights the most recent report on the Chesapeake Bay Watershed in which PFAS are recognized as a contaminant of concern. The report notes, “Within the Chesapeake Bay watershed, PFAS were detected in every smallmouth bass plasma sample amongst four varying land use locations (agriculture versus developed land).†This adds to the growing body of research identifying the deleterious effects of PFAS on ecosystems and individual species, including humans.
The Daily News also points out that despite the evidence and EPA’s own admission of PFAS’s toxicities, the number of products containing PFAS is burgeoning out of control to replace banned organochlorines, such as DDT and methoxychlor. In 2020, fluorinated agrochemicals comprised about nine percent of the pesticide market, and have now reached almost 70 percent of newly-approved pesticides, according to a 2025 review in the Journal of Agricultural and Food Chemistry.
A guest editorial piece in Archives of Toxicology also references the upward trend in PFAS contamination, including ultrashort-chain PFAS (US-PFAS) like TFA. The authors conclude that: “[R]egulatory agencies should unify in the classification of US-PFAS within the broader category of PFAS. The current omission of TFA and TFMS [trifluoromethanesulfonic acid] from the EPA PFAS definition contributes to different regulatory strategies between Europe and the United States and hinders a unified and standardized approach to this global growing problem.â€
The authors of the ACS ES&T Water viewpoint piece agree, saying: “As the scientific community grapples with the challenges posed by TFA and other ultra-short-chain PFAS, there is a growing consensus on the need for more comprehensive research and regulatory action… The emerging concerns surrounding TFA and other ultra-short-chain PFAS call for a reevaluation of our approach to chemical regulation and environmental protection.â€
The persistence and pervasiveness of these compounds are public health and environmental threats that cannot be ignored. “As we continue to unravel the complex environmental fate and potential health impacts of TFA, it is crucial that we adopt a precautionary approach, prioritizing research into safer alternatives,†the researchers summarize.
With EPA’s failure to perform its statutory duties to adequately protect the health of the environment and all organisms within it, as extensively covered by Beyond Pesticides, the call to truly safeguard ecosystems and public health with the elimination of pesticides, including all PFAS, takes on a greater urgency. As noted in a previous Action of the Week, instead of creating a complicated workaround that will not address the urgent health, biodiversity, and climate crises, EPA must cancel registrations of pesticides that harm endangered species, and all organisms including humans, and facilitate a widescale conversion to organic practices.
The holistic, systems-based organic solution for land management and agriculture offers numerous health and environmental benefits. Learn more about how to take action and have your voice heard on governmental efforts that are harmful to the environment and public and worker health, increase overall pesticide use, and undermine the advancement of organic, sustainable, and regenerative practices and policies here.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source:
Jagani, R. et al. (2025) Trifluoroacetic Acid: An Ultra-Short PFAS with Emerging Environmental and Public Health Concerns, ACS ES&T Water. Available at: https://pubs.acs.org/doi/10.1021/acsestwater.5c00599.
Maerten, A. et al. (2025) Tiny molecules, big concerns: ultrashort-chain PFAS on the regulatory radar, Archives of Toxicology. Available at: https://link.springer.com/article/10.1007/s00204-025-04126-9.
Sigmund, G. et al. (2025) Scientists’ Statement on the Chemical Definition of PFASs, Environmental Science & Technology Letters. Available at: https://pubs.acs.org/doi/10.1021/acs.estlett.5c00478.
Zhi, Y. et al. (2024) Environmental Occurrence and Biotic Concentrations of Ultrashort-Chain Perfluoroalkyl Acids: Overlooked Global Organofluorine Contaminants, Environmental Science & Technology. Available at: https://pubs.acs.org/doi/10.1021/acs.est.4c04453.
