Preprint: Glyphosate contamination in European rivers not from herbicide application? by Carolin Huhn, Marc Schwientek, Hermann Rügner1, Stefan Haderlein1, Wolfgang Schulz, Benedikt Wimmer, Lisa Engelbart, Sarah Bieger, and Eberhard Karls, 01 Jul, 2024, Research Square
https://doi.org/10.21203/rs.3.rs-3917957/v1
The most widely used herbicide glyphosate contaminates surface waters around the globe. Being toxic to aquatic organisms and a possible carcinogenic, mitigation strategies attempt to reduce river contamination, but their impact is not evaluated. Investigating long-term time series, we discovered that – in contrast to the USA – glyphosate river water concentration patterns in Europe contradict a dominant input from herbicide application. Our large meta-analysis clearly shows that for decades, the main source of glyphosate has been municipal wastewater, visible in the close correlation to concentration patterns of, e.g., pharmaceuticals, rather high and constant loads all over the year and failure of mitigation strategies. We suspect that glyphosate enters European rivers as a transformation product of aminopolyphosphonates, which are used in European but not U.S. detergents.
Detergent additives found to generate glyphosate in treated wastewater by Christfried Dornis, May 14, 2025, msn.com
Certain detergent additives known as aminopolyphosphonates can be transformed into glyphosate and other problematic substances when wastewater is treated.
A research team led by Professor Stefan Haderlein of the Geo- and Environmental Center at the University of Tübingen has made this fundamental finding.
To achieve this, the team carried out comprehensive experiments in the laboratory which also included conditions found in wastewater. The finding solidifies the suspicion that detergent additives are a significant source of the consistently high levels of glyphosate in European waters. It was previously assumed glyphosate was released into the environment almost exclusively during its use as an herbicide.
The study has been published in Nature Communications.
Glyphosate is considered the most widely used active ingredient in herbicides worldwide.
It prevents growth by inhibiting the formation of vital component proteins in plants and many microorganisms. When it leaches from the soil, glyphosate can get into ground and surface waters as well as the environment.
It is still unclear how severely this damages all sorts of life forms. Ecologists are warning of incalculable consequences.
Glyphosate is only slightly toxic to the human body, but a carcinogenic effect has been the subject of discussion.
Reality check:
… More than 67,000 of a total 181,000 claims involving Roundup remain outstanding….
I doubt there would be this many cancer lawsuits against Bayer (prev Monsanto), the maker of Roundup/glyphosate, and that politicians would protect Bayer from some cancer lawsuits in their states if “glyphosate is only slightly toxic to the human body” and that the carcinogenic effect of it has just “been the subject of discussion.”
End Reality Check.
In the EU, the use of glyphosate in agriculture, above all, has been criticized. “We noticed even in areas and times when hardly any glyphosate input could be expected from agriculture, the concentrations in the water did not decrease accordingly,” report Stefan Haderlein and his colleague Carolin Huhn of the Institute of Physical and Theoretical Chemistry of the University of Tübingen.
They suspected this could be related to precursor substances such as aminopolyphosphonates coming from wastewater.
Aminopolyphosphonates are used in detergents as complexing agents to soften water and improve cleaning. From the standpoint of water ecology, Haderlein questions whether they are an improvement on their predecessors, which also degrade poorly.
“After all, phosphates are also released from aminopolyphosphonates, which deplete oxygen in bodies of water because they promote algal growth,” he says. As an environmental mineralogist, Haderlein is interested in chemical reactions that take place on the surfaces of minerals.
He explains, “We knew from an earlier project that polyphosphonates can react with and adsorb at manganese minerals.”
Manganese as a reaction driver
The current study’s laboratory experiments showed manganese compounds, very commonly found in soil sediments, but also wastewater and sewage sludge, are the key to a multi-stage transformation of aminopolyphosphonates, of which glyphosate is a by-product.
The researcher reports, “In the lab we varied conditions, such as oxygen concentration and pH values, for example, and used wastewater in which many different substances could influence the reactions with manganese.
“Yet from DTPMP—the most important representative of the aminopolyphosphonates—we always got glyphosate, already with tiny amounts of dissolved manganese as long as oxygen was also present. And with mineral manganese, even in the absence of oxygen.”
Haderlein also questions previous laboratory results for the microbial decomposition of aminopolyphosphonates. He notes, “Manganese is mostly present in the nutrient media for the microorganisms.” As a result, what was supposedly observed as a biological breakdown of aminopolyphosphonates could be a purely chemical process, he continues.
“Now, we’ve produced the proof that certain aminopolyphosphonates which are used in detergents yield glyphosate in the presence of manganese. This is an important step. Next, we must test which role this glyphosate source plays in terms of quantity,” says Haderlein.
He goes on, “To do that, we need still better understanding of how environmental conditions in water and wastewater systems influence the quantity of glyphosate produced during the reaction of DTPMP and manganese.”
“With their research, Professor Haderlein, Professor Huhn and their colleagues have uncovered very exciting relationships that are attracting a great deal of attention from the interested public. The results are to help to better protect our environment,” says Professor Dr. Dr. h.c. (Doshisha) Karla Pollmann, President of the University of Tübingen.
More information: Anna M. Röhnelt et al, Glyphosate is a transformation product of a widely used aminopolyphosphonate complexing agent, Nature Communications (2025). DOI: 10.1038/s41467-025-57473-7
Provided by Universitaet Tübingen This story was originally published on Phys.org.
Glyphosate is a transformation product of a widely used aminopolyphosphonate complexing agent by Anna M. Röhnelt, Philipp R. Martin, Mathis Athmer, Sarah Bieger, Daniel Buchner, Uwe Karst, Carolin Huhn, Torsten C. Schmidt & Stefan B. Haderlein Nature Communications vol 16, Article number: 2438 (2025)
Abstract
Diethylenetriamine penta(methylenephosphonate) (DTPMP) and related aminopolyphosphonates (APPs) are widely used as chelating agents in household and industrial applications. Recent studies have linked APP emissions to elevated levels of the herbicide glyphosate in European surface waters. However, the transformation processes and products of APPs in the environment are largely unknown. We show that glyphosate is formed from DTPMP by reaction with manganese at near neutral pH in pure water and in wastewater. Dissolved Mn2+ and O2 or suspended MnO2 lead to the formation of glyphosate, which remains stable after complete DTPMP conversion. Glyphosate yields vary with the reaction conditions and reach up to 0.42 mol%. The ubiquitous presence of manganese in natural waters and wastewater systems underscores the potential importance of Mn-driven DTPMP transformation as a previously overlooked source of glyphosate in aquatic systems. These findings challenge the current paradigm of herbicide application as the sole source of glyphosate contamination and necessitate a reevaluation of water resource protection strategies.