Highlights

•A comprehensive meta-analysis of glyphosate concentration patterns in rivers revealed new sources.

•European river concentration patterns cannot be explained by herbicide application.

•Seasonal concentration patterns resemble those of wastewater markers.

•Glyphosate enters European rivers dominantly via wastewater.

•Glyphosate may be a transformation product of European laundry additives.

Our large meta-analysis clearly shows that for more than a decade, municipal wastewater was a very important source of glyphosate. In addition, European river water data show rather high and constant base mass fluxes of glyphosate all over the year, not expected from herbicide application.

From our meta-analysis, we define criteria for a source of glyphosate, which was hidden so far.

AMPA is known to be a transformation product not only of glyphosate but also of aminopolyphosphonates used as antiscalants in many applications.

As they are used in laundry detergents in Europe but not in the USA, we hypothesize that glyphosate may also be a transformation product of aminopolyphosphonates.