Glyphosate contamination in European rivers not from herbicide application?

Area of Science:

• Environmental Chemistry
• Water Quality Monitoring
• Ecotoxicology

Background:

• Glyphosate, a widely used herbicide, contaminates global surface waters from agricultural and urban sources.
• Understanding the specific origins of glyphosate is crucial for effective water resource management.

Purpose of the Study:

• To differentiate between agricultural and urban sources of glyphosate contamination in surface waters.
• To analyze long-term concentration data of glyphosate and its metabolite AMPA across diverse geographical regions.

Main Methods:

• Conducted a meta-analysis of approximately 100 long-term time series of glyphosate and AMPA concentrations in the USA and Europe.
• Compared concentration patterns with river discharge data and wastewater markers (e.g., pharmaceuticals).

Main Results:

• US data indicated glyphosate and AMPA pulses correlated with high river discharge, suggesting rain-induced runoff post-application.
• European data revealed seasonal patterns in glyphosate and AMPA concentrations, linked to wastewater markers, indicating municipal wastewater as a key source.
• Consistent, year-round glyphosate fluxes in European rivers suggest sources beyond direct herbicide application.

Conclusions:

• Municipal wastewater has been a major source of glyphosate in European surface waters for over a decade.
• The study proposes criteria to identify previously unrecognized sources of glyphosate contamination.
• A hypothesis is presented that glyphosate may be a transformation product of aminopolyphosphonates found in European laundry detergents.