Most of the glyphosate found in rivers in Europe may not originate from farming, a new study by a German university has found.

The University of Tübingen research indicates that most glyphosate that ends up in European rivers likely does not come from herbicides, but may be the result of additives to detergents.

Until now, the use of glyphosate as a herbicide in agriculture was considered to be the main reason for its presence in bodies of water worldwide.

For the study, professor Carolin Huhn, alongside a research team, conducted a large-scale analysis on data from European and US water protection authorities.

The study, which has now been published in the journal Water Research, found European reduction measures have not led to any noticeable change in the environmental indicators.

It suggests that certain compounds, for example used in laundry detergents, are converted to glyphosate in the sewage sludge of wastewater treatment plants.

The group analysed glyphosate concentrations in rivers at 100 locations in Germany, France, Italy, Sweden, Luxembourg, the UK, the Netherlands and the USA. Some of the data sets reached back to 1997.

Detailed analysis

"The detailed analysis of the millions of individual values shows us that municipal wastewater plays a role," said Huhn.

“Some of the findings of the study also show us that we have to locate a source for glyphosate close to households."

She added that the researchers believe there must be a dominant input separate from the use of herbicides. The patterns in concentration could not be explained any other way.

"However, everything we cannot explain about the data disappears if we assume that we are not really looking at glyphosate which was previously used as a herbicide, but instead as glyphosate that has formed from a larger substance," said analytical chemist Huhn.

The researchers compiled a list of criteria from their data, and identified a substance chemically related to glyphosate, which would resolve all the questions raised from the analysis.

Their hypothesis is that glyphosate is a transformational product from compounds used in laundry detergents.

Next steps

Huhn pointed out that the new glyphosate source must be verified in independent studies.

“We are aware that our findings may have far-reaching implications, including for industry and policymakers, but also for how surface water monitoring can be improved,” Huhn added.

Furthermore, the situation in the USA is different from that in the EU.

The concentration patterns of glyphosate in US river water closely follows those of other herbicides, indicating a dominant agricultural input.