Article

Fate and Transport of Glyphosate and Aminomethylphosphonic Acid in Surface Waters of Agricultural Basins

US Geological Survey, Pearl, MS, USA.
Pest Management Science (Impact Factor: 2.69). 01/2012; 68(1):16-30. DOI: 10.1002/ps.2212
Source: PubMed

ABSTRACT

Glyphosate [N-(phosphonomethyl)glycine] is a herbicide used widely throughout the world in the production of many crops and is heavily used on soybeans, corn and cotton. Glyphosate is used in almost all agricultural areas of the United States, and the agricultural use of glyphosate has increased from less than 10 000 Mg in 1992 to more than 80 000 Mg in 2007. The greatest intensity of glyphosate use is in the midwestern United States, where applications are predominantly to genetically modified corn and soybeans. In spite of the increase in usage across the United States, the characterization of the transport of glyphosate and its degradate aminomethylphosphonic acid (AMPA) on a watershed scale is lacking.
Glyphosate and AMPA were frequently detected in the surface waters of four agricultural basins. The frequency and magnitude of detections varied across basins, and the load, as a percentage of use, ranged from 0.009 to 0.86% and could be related to three general characteristics: source strength, rainfall runoff and flow route.
Glyphosate use in a watershed results in some occurrence in surface water; however, the watersheds most at risk for the offsite transport of glyphosate are those with high application rates, rainfall that results in overland runoff and a flow route that does not include transport through the soil.

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Available from: Paul Capel, Dec 03, 2015
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    • "equivalent basis and added to the glyphosate concentration to obtain the total extracted glyphosate (TEG) as follows (Coupe et al., 2011): "
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    • "AMPA (aminomethylphosphonic acid) is its main degradation product. Glyphosate mobility in the environment is supposed to be limited because of its high adsorption capacity in soils (Cheah et al. 1997; Vereecken 2005; Borggaard and Gimsing 2008), but some studies show that glyphosate may reach surface waters either by transport in dissolved form, or by particle-facilitated transport (Coupe et al. 2012; Aparicio et al. 2013). Analysis in drainage-water samples (Kjaer et al. 2005, 2011; Candela et al. 2010; Norgaard et al. 2014) or in leachates of soil-column experiments (Dousset et al. 2004; Landry et al. 2005) underscored the possible leaching of glyphosate and AMPA through the soil and thus the risk of groundwater contamination. "
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