Ground water quality and glyphosate
Two primary factors determine whether a chemical is likely to leach through soil to groundwater -- the rate of degradation in the soil, and the chemical’s tendency to bind to soil. Slow degradation and a low tendency to bind to soil can result in leaching of a chemical, whereas higher degradation rates and tight binding to soil both limit the movement of a chemical by leaching. With its combination of degradability and strong binding to most soils typically used in agriculture, glyphosate has low potential to move through the soil profile and has rarely been detected in groundwater 1. The leaching of glyphosate and AMPA has been largely studied through lab experiments 6, lysimeters 5, 7, 14 field leaching 13 and modeling studies 4, 12. The results from these studies confirm that both compounds are unlikely to move to groundwater.
With the improvement of analytical detection methods, glyphosate and AMPA have been occasionally reported in groundwater, but rarely above the 0.1 µg/L threshold. Detections of these substances seem to occur only in shallow groundwater or wells with direct surface water influence, sometimes associated with contamination incidents and linked with unsuitable sampling sites and inadequate analytical techniques.
To date, there is no evidence of any persistent and confirmed groundwater contamination with glyphosate or AMPA according to ground water monitoring data available for 14 European countries 8.
Last update: 25 October 2012