Pollution: PFAS: In soil and groundwater forever

Per- and polyfluorinated alkyl substances (PFAS) – also known as PFCs – are particularly long-lasting, complex compounds with strong carbon-fluorine bonds that prevent efficient decomposition. There are more than 10,000 variants of them. The long-lasting substances are used in food packaging, cookware, rainproof clothing, textiles, furniture, toilet paper and in refrigerants that were until recently used in heat pumps. But they are increasingly found where they are undesirable: in wastewater, ground and drinking water and in food.

The materials were first used in the 1950s. Around ten years later, their most important manufacturer, the chemical giant DuPont, discovered that PFAS enlarged the livers of rats and rabbits. Finally, the substances were detected in the blood of the employees.

When processed in industry, PFAS enter the air and water via exhaust gases and wastewater. They penetrate the soil via rain, snow and agricultural irrigation and also pollute food via the food chain.

According to a 2023 study, PFAS in drinking water is a human health concern worldwide. For example examined Scientists in the USA took drinking water samples in which they detected the toxic substances in 45 percent of all cases. The extremely long-lasting toxins last for decades: highly concentrated in the blood, they damage the thyroid, liver and other organs. Some PFAS compounds can cause cancer, reduce the effectiveness of vaccinations and fertility, and cause immune deficiencies in children. They also promote obesity and overweight, high blood pressure, and sugar and lipid metabolism disorders.

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Remote sites

For a long time, the toxic substances were also used in fire extinguisher foam, from where they seeped into the ground. They spread across rivers and seas to the most remote places in the world. They reached Tibet or the Arctic via rainwater. The poisons were not only found in human blood, mother’s milk and plants, but also in polar bears.

Numerous studies have detected PFAS in wastewater or rivers downstream of wastewater treatment plant effluents. In addition, French scientists found… Nancy Laboratory for Hydrology 2016 Residues in wastewater from plants where the substances are manufactured. They enter the soil via sewage sludge, which is used as fertilizer in agriculture.

Ten years ago, water containing toxic fluorine compounds was discovered in the area around Rastatt and Baden-Baden, reported “Deutschlandfunk”. As it turned out, 470 hectares of farmland were contaminated with the problematic substances. Extremely high PFC levels were also found nearby, on an area at the edge of the gravel pit. The poisons slowly wash into the groundwater through rainwater. The groundwater flow brings them into the quarry lakes, where they eventually accumulate in fish. The chemicals have long since not directly poisoned areas contaminated with the substances via the groundwater. More than 60 farmers were affected, including organic farmers. The problem of the chemical-containing water they use to irrigate their fields will probably be with them for years, if not decades.

Short-chain PFCs can also be absorbed by plants. Experts from the Hessian State Laboratory allowed corn, barley, wheat and ryegrass to grow in contaminated soil: depending on the pollutant content in the soil, their growth was already externally impaired. The researchers found concentrated necrosis in ryegrass and wheat. In addition, plants that were exposed to very high concentrations had particularly low yields.

Industrial locations are most polluted

In Germany, PFAS are currently produced at six locations: in Leverkusen, Bad Wimpfen, Frankfurt/Main and in the Bavarian Chemical Park Gendorf. There is a great risk that the environment in and around these factories will be massively contaminated. All producers – with the exception of Archroma in Gendorf – assure that they comply with legal regulations and strive to reduce pollutants. However, Dyneon – a subsidiary of the 3M Group – recently announced that it would phase out PFAS production in Gendorf by the end of 2025.

While environmental authorities in some US states and France specifically search for PFAS residues, in Germany only individual authorities such as the State Office for Nature, Environment and Consumer Protection in North Rhine-Westphalia regularly test the water near industrial sites.

Across Europe, more than 17,000 places are contaminated with PFAS, including around 2,000 hotspots with significant risks to human health. A year ago, reporters from NDR, WDR and “Süddeutscher Zeitung” recorded in Germany as part of the Europe-wide »Forever Pollution Project« more than 1,500 sites contaminated with PFAS. These included 300 particularly heavily polluted hotspots such as airports and military sites where firefighting foam containing PFAS was used, or sewage treatment plants and landfills where wastewater and objects collect.

The textile industry, metal finishing and waste paper processing companies also sometimes use the toxic substances or use raw materials contaminated with PFAS. In their surroundings, studies suggest that the air, soil, drinking water and consequently also the food grown there, such as vegetables, are highly polluted.

The substances that are difficult to decompose can only be removed with great effort. If only the top 60 centimeters of soil in the Rastatt area were removed, it would cost over two billion euros across the entire area. A study by the Nordic Council of Ministers, which includes the countries Denmark, Finland, Norway, Sweden and Iceland, estimates the cost of cleaning up widespread contamination for Europe alone at $17 billion.

The annual costs for treating the health consequences are even higher. A comprehensive remediation of the contaminated sites is almost impossible. In 2020, remediation was only completed in less than one percent of all suspected PFAS cases in this country. In many contaminated places, residents were not even informed, apart from individual information events in places where the soil was particularly heavily contaminated.

Look for harmless substitutes

Four EU-funded projects are currently researching harmless alternatives. The “ZeroF” project, for example, deals with substitute materials for food packaging and textiles. The Fraunhofer Institute for Silicate Research is also significantly involved in the development of oil- and water-repellent and abrasion-resistant coatings for textiles. A new class of paints called “ORMOCER,” for example, is intended to combine a versatile base material with cellulose-based materials.

The challenge is to produce a water-repellent coating for textiles that can also be applied as a water-based solution, explains project manager Claudia S Tauch. As a result, the paint coatings have very good processing, surface and barrier properties. Inorganic and organic material properties can be easily combined in them.

Avoiding PFAS in everyday life

Consumers should avoid purchasing products containing per- and polyfluorinated alkyl substances if possible. Fish, seafood, meat and eggs are also often contaminated with PFAS, which is why they should only be eaten in moderation and no more than twice a week. Offal should not be consumed at all or only rarely. In addition, reusable packaging made of glass, ceramic or metal must be used for food.

When buying new outdoor clothing, shoes and waterproofing products, you should pay attention to labels such as “fluorine-free”, “free of PFC” or “without PFAS”. In addition, textiles, carpets, etc. with the references “stain-proof”, “water-repellent”, “oil-repellent” and cosmetics with “fluoro” in the name should be avoided.

The substances PFOS and PFOA, which also belong to the PFAS group, are already banned. However: If manufacturers advertise their products with the labels “PFOA/PFOS-free” or “GenX-free”, they often contain other PFAS, warns the consumer advice center.

The European chemicals agency ECHA is now examining a comprehensive ban on the toxic substances: a year ago, the EU authority presented a proposal from specialist authorities from five countries, including the German Federal Environment Agency, to ban the entire group of PFAS substances. According to the proposal, with a transition period of a few years, the more than 10,000 PFAS should no longer be allowed to be used. However, this ban is inconsistent because exceptions for medicines and pesticides should remain permitted. Once ECHA’s scientific review has been completed, the EU Commission must draw up a corresponding draft law, which will then be voted on by the member states.

The ban is not yet a sure-fire success. A request from the CDU parliamentary group in December that the federal government reject a blanket ban on PFAS already shows that headwinds are to be expected.