A meta-analysis of glyphosate and its transformation product AMPA in European and U.S. rivers reveals that glyphosate contamination in European rivers is not primarily from agricultural herbicide applications but from municipal wastewater. European data show consistent seasonal patterns of glyphosate and AMPA, correlated with wastewater markers like pharmaceuticals, indicating a significant contribution from wastewater treatment plants. In contrast, U.S. data show pulses of glyphosate and AMPA during high river discharge, likely due to agricultural runoff. European river data show high and constant mass fluxes of glyphosate throughout the year, not expected from herbicide application. The study defines criteria for a hidden source of glyphosate, suggesting that aminopolyphosphonates, used in detergents, may be an important source in Europe. These compounds are known to transform into AMPA, which is frequently detected in wastewater treatment plants. The study highlights that municipal wastewater is a major source of glyphosate in Europe, with consistent mass fluxes even during dry periods. The findings challenge the common perception that glyphosate contamination in rivers is solely due to agricultural applications. The results suggest that wastewater, particularly from domestic sources, is a significant and constant contributor to glyphosate contamination in European rivers.A meta-analysis of glyphosate and its transformation product AMPA in European and U.S. rivers reveals that glyphosate contamination in European rivers is not primarily from agricultural herbicide applications but from municipal wastewater. European data show consistent seasonal patterns of glyphosate and AMPA, correlated with wastewater markers like pharmaceuticals, indicating a significant contribution from wastewater treatment plants. In contrast, U.S. data show pulses of glyphosate and AMPA during high river discharge, likely due to agricultural runoff. European river data show high and constant mass fluxes of glyphosate throughout the year, not expected from herbicide application. The study defines criteria for a hidden source of glyphosate, suggesting that aminopolyphosphonates, used in detergents, may be an important source in Europe. These compounds are known to transform into AMPA, which is frequently detected in wastewater treatment plants. The study highlights that municipal wastewater is a major source of glyphosate in Europe, with consistent mass fluxes even during dry periods. The findings challenge the common perception that glyphosate contamination in rivers is solely due to agricultural applications. The results suggest that wastewater, particularly from domestic sources, is a significant and constant contributor to glyphosate contamination in European rivers.