What Is Glyphosate?


Glyphosate (IUPAC name: N-(phosphonomethyl)glycine) is a broad-spectrum systemic herbicide and crop desiccant. It is an organophosphorus compound, specifically a phosphonate, which acts by inhibiting the plant enzyme 5-enolpyruvylshikimate-3-phosphate synthase. It is used to kill weeds, es

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Glyphosate (IUPAC name: N-(phosphonomethyl)glycine) is a broad-spectrum systemic herbicide and crop desiccant. It is an organophosphorus compound, specifically a phosphonate, which acts by inhibiting the plant enzyme 5-enolpyruvylshikimate-3-phosphate synthase. It is used to kill weeds, especially annual broadleaf weeds and grasses that compete with crops. Its herbicidal effectiveness was discovered by Monsanto chemist John E. Franz in 1970. Monsanto brought it to market for agricultural use in 1974 under the trade name Roundup. Monsanto's last commercially relevant United States patent expired in 2000.

 

Farmers quickly adopted glyphosate for agricultural weed control, especially after Monsanto introduced glyphosate-resistant Roundup Ready crops, enabling farmers to kill weeds without killing their crops. In 2007, glyphosate was the most used herbicide in the United States' agricultural sector and the second-most used (after 2,4-D) in home and garden, government and industry, and commercial applications. From the late 1970s to 2016, there was a 100-fold increase in the frequency and volume of application of glyphosate-based herbicides (GBHs) worldwide, with further increases expected in the future. This was partly in response to the global emergence and spread of glyphosate-resistant weeds,: 1  requiring greater application to maintain effectiveness. The development of glyphosate resistance in weed species is emerging as a costly problem.

 

Glyphosate is absorbed through foliage, and minimally through roots, and transported to growing points. It inhibits a plant enzyme involved in the synthesis of three aromatic amino acids: tyrosine, tryptophan, and phenylalanine. It is therefore effective only on actively growing plants and is not effective as a pre-emergence herbicide. An increasing number of crops have been genetically engineered to be tolerant of glyphosate (e.g. Roundup Ready soybean, the first Roundup Ready crop, also created by Monsanto), which allows farmers to use glyphosate as a post-emergence herbicide against weeds.

 

While glyphosate and formulations such as Roundup have been approved by regulatory bodies worldwide, concerns about their effects on humans and the environment have persisted. A number of regulatory and scholarly reviews have evaluated the relative toxicity of glyphosate as an herbicide. The German Federal Institute for Risk Assessment toxicology review in 2013 found that with regard to positive correlations between exposure to glyphosate formulations and risk of various cancers, including non-Hodgkin lymphoma "the available data is contradictory and far from being convincing". A meta-analysis published in 2014 identified an increased risk of NHL in workers exposed to glyphosate formulations.

 

The WHO and FAO Joint committee on pesticide residues issued a report in 2016 stating the use of glyphosate formulations does not necessarily constitute a health risk, and giving an acceptable daily intake limit of 1 milligram per kilogram of body weight per day for chronic toxicity. The European Chemicals Agency (ECHA) classified glyphosate as causing serious eye damage and as toxic to aquatic life, but did not find evidence implicating it as a carcinogen, a mutagen, toxic to reproduction, nor toxic to specific organs.

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