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Synthetic (human-made or anthropogenic) chemicals that belong to the per- and polyfluoroalkyl substances (PFAS) group have a broad range of industrial and household uses. PFAS chemicals are used in countless manufactured products, such as water-resistant fabrics, nonstick coatings of cookware, stain repellents, firefighting foams, and plant protection products.
Laboratory analyses have revealed alarmingly high concentrations of PFAS contaminants in soil, water, and wildlife due to industrial emissions and historical use.
Chemical properties
The typical PFAS compound contains one or more fluorine atoms in its molecular structure. Certain economically essential pesticides, such as fungicides, insecticides, and herbicides, have this characteristic.
Fluorine, like bromine and chlorine, repels microbes that can degrade organic molecules, thereby enhancing the persistence of these molecules.
By 2020, more than 200 uses for over 1 400 PFAS compounds were identified. These substances are of concern due to their reported long persistence after application; certain transformation products (metabolites) are also persistent.
The colloquial term for PFAS is ‘forever chemicals’. Their prolonged persistence and accumulation increase exposure and, consequently, the potential risks for adverse impacts on human health and the environment. The use of PFAS is internationally regulated, with certain products destined for phasing out based on their listing in the 2023 Stockholm Convention on Persistent Organic Pollutants. According to a key deliverable of the European Green Deal, the European Union (EU) is committed to phasing out PFAS chemicals under the EU Action Plan: Towards a Zero Pollution for Air, Water, and Soil.
Fluorinated pesticides
By 2020, approximately 16% of global plant protection products (PPPs) were fluorinated, meaning they contain at least one fluorine atom in their molecular structure. This includes 424 organofluoride PPPs that are classified as PFAS. In 2024, the Pesticide Properties Database contained 1 934 records, of which 202 included a -CF3 group in the molecular structure.
Most pesticides with the trifluoro component yield trifluoroacetic acid (TFA) upon breakdown (degradation), which is highly stable with prolonged persistence and potential toxic effects on humans. Animal studies have found that TFA exhibits very low and low to moderate acute toxicity.
However, the chronic toxicity of TFA, due to its propensity to persist and accumulate, might still prove to be of genuine concern, as advocated by the Pesticide Action Network Europe.
Regulatory actions
Global pressure to discontinue the use of synthetic pesticides with long persistence characteristics, particularly those posing risks to human health, has reached a climax in 2025. The Danish Environmental Protection Agency recently imposed a ban on 23 fluorinated pesticides that could qualify as PFAS. Another ten pesticide-active ingredients are currently under scrutiny in Denmark, with a decision expected this year.
Before this pioneering step by Denmark, the regulation of PPPs – irrespective of whether they contain fluorine in the active molecule – occurred separately from other chemicals in all EU countries.
Therefore, until the independent Danish decision, PFAS pesticides escaped the scrutiny directed at other PFAS. Similarly, in other major economic regions, pesticide regulation occurs independently from that of other synthetic chemicals. The same applies in South Africa.
The unprecedented step by Denmark may prove to be a catalyst for similar interventions by other countries within the EU pesticide regulatory framework, as well as by countries exporting produce to the EU. Already, Sweden is scrutinising PFAS pesticides in accordance with the Danish model. The Danish Environmental Protection Agency’s drastic action comes at a time when the EU has stated its intention to exempt pesticide actives from the broad restrictions imposed under PFAS classification.
If the deregistration of PFAS pesticides were to achieve wide acceptance in the EU, it would likely trigger knock-on effects for trading partners dealing in agricultural commodities from outside the EU community. In this context, developing countries face the most significant challenges in maintaining sustainable agricultural production, given producers’ heavy dependence on ‘old’ pesticides that remain affordable amid rising input costs.
Risk, security and livelihoods
Scientific support for Denmark’s decision is based on the proven pervasiveness and persistence of PFAS contaminants, with trifluoroacetic acid (TFA) being a significant component. In several EU countries – including Sweden, Germany, Belgium, and the Netherlands – TFA is a contaminant in surface water, groundwater, and even potable water. TFA residues have also been found in a variety of foods.
It isn’t all plain sailing for the proponents of a PFAS pesticide ban. In Denmark, opponents of an outright ban cite potential impacts on crop production (particularly starchy potatoes, the foremost crop), farming profitability, and producer livelihoods. Reasoned arguments emphasise that PFAS-related regulation should adopt a comprehensive approach.
This includes weighing all relevant issues, considering alternative solutions, and applying accurate risk assessment methodologies, with the aim of balancing environmental protection and sustainable agricultural development.
Future of pesticides
One ambitious aim of the EU Green Deal is reducing pesticide use by 50% by 2030. Such a reduction would inevitably contract crop production, with an estimated reduction of 20% for cereals and oilseed crops, 20% for Spanish and Italian tomatoes, 30% for Italian olives, and 20% for vegetables cultivated under controlled conditions.
Organised agriculture within the EU anticipates that overall crop production will eventually contract by about 12%. This future scenario is likely to be marred by higher food prices, increased dependence on imported food, and decreased exports – all of which threatens long-term food security in the EU.
The guaranteed ripple effects on developing countries seeking to export agricultural products to the EU must also be considered.
In developing countries such as South Africa, crop production is already under pressure due to dwindling pesticide options, prohibitive costs of production inputs, and the growing problem of pests’ (insects, weeds, pathogens) resistance to pesticides, to name but three constraints. The outlook for novel chemistry to replace the ‘old’ pesticides is bleak across the spectrum, at least in the near future. The heyday of cheap pesticides as the primary means of crop protection is rapidly fading. Integrated pest management is now finding its long-awaited place, with increased focus on biological methods of pest control and modern technologies, such as sensor-driven targeted control systems.
Dr Charlie Reinhardt is a former professor and head of the Department of Plant Production and Soil Science at the University of Pretoria (UP), current project leader in the South African Herbicide Resistance Initiative at UP, and an independent consultant on herbicide use and problem plant management. Contact him at 083 442 3427 or dr.charlie.reinhardt@gmail.com