Tire chemicals, plasticizers and mysterious substances: There are micropollutants floating in the Rhine that have hardly been researched and for which there are no limit values. This is shown by data that Techzle\.com evaluated together with Correctiv.Lokal. What does this mean for our drinking water, some of which is obtained from the river?
The Rhine has a comparatively clean image today. In the 1950s and 1960s, Germany’s most important waterway was heavily polluted by growing industry. In the 1980s, around 20 tons of chemicals were released into the river along with firefighting water, with devastating consequences for the ecosystem. Since then, water quality has improved greatly – thanks, among other things, to stricter laws, environmental programs, wastewater treatment plants and international cooperation.
But not everything is pure in the Rhine. Monitoring stations along the river regularly record contaminants, including unexplored and unregulated micropollutants. Data that Techzle\.com evaluated together with the editorial network Correctiv.Lokal shows the extent.
In at least eight cases, drinking water suppliers were informed about the sources of pollutants and recommended self-responsible measures to protect drinking water. Techzle\.com asked what that means exactly.
These micropollutants contaminate the Rhine
Micropollutants
The term “micropollutants” is not clearly defined. But it usually refers to potentially harmful tiny particles that pollute water. These can be, for example, microplastics, drug residues or industrial chemicals.
The following pollutants were detected in the Rhine water by measuring stations in North Rhine-Westphalia, Rhineland-Palatinate and Baden-Württemberg from 2020 to 2025. This emerges from data that Correctiv.Lokal provided to us at Techzle\.com. This is a selection; the total of 65 measurement results demonstrated a large number of different micropollutants.
- Triacetonamine (TAA) is used as a stabilizer for polymers. According to the German Statutory Accident Insurance (DGUV), the substance is hazardous to water and poses acute or chronic health risks. TAA was detected ten times in Rhineland-Palatinate. The highest concentration measured was 8.6 micrograms per liter.
- About half of the 65 entries are declared as “unknown substances”. The material could not be clearly assigned here. The substances were present in concentrations of up to 8.3 micrograms/liter.
- 13 cases in North Rhine-Westphalia are probably DPGME isomers, i.e. solvents. These are, among other things, slightly hazardous to water.
- Substances for the production of plasticizers (α-methylstyrene) have also been detected; these are considered to be significantly hazardous to water.
- Benzothiazole was also detected. The material is primarily used for tire production. According to Correctiv, researchers cannot rule out the possibility that the chemical can also get into drinking water.
Some pollutants only develop their effects in high concentrations. But it is difficult to assess the risk, especially with unidentifiable substances. In some cases, the substances appeared in the measurements several days in a row.
Do micropollutants endanger our drinking water?
The Rhine is an important source of drinking water in many regions. The so-called “bank filtrate” is prepared as drinking water by various suppliers in Germany.
Between 2020 and 2025, conspicuous levels of micropollutants were discovered and analyzed by the state environmental authorities in 65 cases. In North Rhine-Westphalia, drinking water suppliers were informed eight times about the sources of pollutants and self-responsible measures to protect drinking water were recommended.
In the data from Baden-Württemberg, six findings state: A report was initiated which contained the measure recommended by the Baden-Württemberg State Environmental Agency to inform the waterworks about the incident. The data from Rhineland-Palatinate does not contain any information on measures.
Techzle\.com asked what measures drinking water suppliers specifically take and how they are monitored.
Tap water safe? That’s what utilities and authorities say
The Kleve-Bimmern measuring point in North Rhine-Westphalia is represented eleven times in the data; in five measurements, drinking water suppliers were informed about waves of pollutants. That’s why Techzle\.com contacted the nearby water supplier Stadtwerke Emmerich, among others. When asked what measures he took in response, we received no answer.
We have also contacted the Rhine Water Association (ARW), an association of water suppliers on the Rhine. A company spokesman for the drinking water supplier RheinEnergie from Cologne, which is the president and managing director of ARW, responded to our request.
He explained to Techzle\.com that water suppliers sometimes do not even have to react to such information. For example, “because a reported substance is not relevant to drinking water or swims past the wells so quickly that it does not even reach the groundwater.” Or individual collection systems or wells may be switched off briefly.
He refers to monitoring programs and event-related investigations. “If a substance from the Rhine water were relevant to drinking water, there would be several weeks to take countermeasures. That’s how long it takes for such a substance to reach a well near the bank.” Even then, it does not necessarily end up in the drinking water because of the treatment in the waterworks.
When asked whether RheinEnergie, as a water supplier, had itself received warnings about micropollutants and how it had responded in these cases, the company did not give a specific answer.
The State Office for Nature, Environment and Climate North Rhine-Westphalia (LANUK) also points out to Techzle\.com that drinking water is regularly tested by specialized laboratories. These are intended to ensure that the water meets the requirements of the Drinking Water Ordinance. Exceeding the limit values must be reported immediately.
Correctiv criticizes the lack of transparency and missing limit values
So the micropollutants in river water are not a problem for our drinking water? It’s probably not that easy. In joint research with other editorial teams (including Correctiv.Schweiz and the investigative medium Pointer from the Netherlands), Correctiv tried to reconstruct what happened in the case of the discovery of an “unknown substance” on March 8, 2023. The report about the substance reaches the water police and the Netherlands via the North Rhine-Westphalia State Environmental Office. But what happened after drinking water suppliers were informed can no longer be completely reconstructed, according to Correctiv.
The medium also criticizes the fact that only a fraction of the chemicals used in the EU have been thoroughly researched, namely 500 out of 100,000. The rest are either completely unknown or there is no information about how harmful they are to health.
“These are not routinely monitored and are often not subject to limit values, but rather only guideline values that are not legally binding,” writes Correctiv.
A look at the Netherlands, which the Rhine passes through to Germany, also reveals problems. According to Correctiv, drinking water suppliers have to turn off pumps there again and again; this happened thirteen times in 2024, for almost a month. The water quality is deteriorating, drug residues and substances from the chemical industry are particularly noticeable, criticized the local association of water supply companies RIWA-Rijn 2024.
Its director complains to Correctiv about the lack of limit values in Germany. The authorities relied on “voluntary measures by operators” instead of clear guidelines.
“Unknown substances could prove to be toxicologically questionable”
Around 20 million people in Germany use drinking water that comes at least partially from the Rhine. This is considered safe – but experts are still concerned.
“Many of the currently unknown substances could soon prove to be toxicologically questionable,” Werner Brack, ecotoxicologist at the Leipzig Helmholtz Center for Environmental Research (UFZ), tells Correctiv. They could make you fat, cause allergies, disrupt children’s learning behavior or promote diabetes.
“The unknown substances pose an invisible but serious danger,” warns the expert.
He refers to the eternal chemicals PFAS, whose health risks remained undetected for decades. Limit values have only been in place since the beginning of 2026. The researcher criticizes the fact that the industry is not obliged to report the substances used. Instead, they have to be analyzed in an expensive, complex and time-consuming manner.
There are currently no legal requirements for dealing with unknown micropollutants. This has consequences: The treatment of drinking water is becoming increasingly more expensive and complex, warns Correctiv. Consumers would also bear the costs.
Water suppliers, experts and authorities spoke to Correctiv in favor of stricter requirements for the industry, increased controls and the implementation of the precautionary principle.
Utopia says: Tighten laws to protect water
It is unclear whether current measures are sufficient to prevent micropollutants from entering drinking water.
Drinking water suppliers and the state office want to reassure people and point to a multi-stage system that is intended to ensure this. Correctiv criticizes the fact that many of the measures in this system are based on voluntary action. And downstream in the Netherlands there are regular problems with water quality.
All of this seems as if the supposedly clean Rhine could be a lot cleaner. And since local industrial groups, which according to Correctiv are responsible for the majority of micropollutants in river water, show little interest in doing their part, stricter legal regulations would be important. This has already helped to keep the Rhine clean in the past.
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