Glyphosate

**Glyphosate Discovery and Synthesis:**
– Glyphosate first synthesized in 1950 by Swiss chemist Henry Martin at Cilag.
– Independently discovered in the U.S. at Monsanto in 1970 by John E. Franz.
– Monsanto patented glyphosate for weed control in the early 1970s.
– Glyphosate brought to market in 1974 under the Roundup brand.
– Glyphosate is an aminophosphonic analogue of glycine.
– Exists in different ionic states depending on pH.
– Soluble in water to 12g/L at room temperature.
– Main deactivation path is hydrolysis to aminomethylphosphonic acid.
– Synthesized via the Kabachnik–Fields reaction using iminodiacetic acid or glycine.

**Regulation and Usage of Glyphosate:**
– Regulatory bodies worldwide have approved glyphosate and formulations.
– WHO and FAO report in 2016 stated glyphosate use does not necessarily pose health risks.
– National pesticide regulatory agencies and scientific organizations find no evidence of human carcinogenicity.
– Glyphosate-resistant Roundup Ready crops enabled weed control without crop damage.
– Glyphosate usage increased significantly worldwide from late 1970s to 2016.
– Farmers adopted glyphosate for weed control after its introduction in 1974.
– Crops genetically engineered for glyphosate tolerance allow post-emergence weed control.
– Major usage in agriculture, horticulture, and silviculture.
– Used for invasive species eradication, habitat restoration, and crop desiccation.

**Glyphosate Formulations and Mode of Action:**
– Glyphosate marketed by various agrochemical companies worldwide.
– Over 750 glyphosate products available in 2010.
– Chinese manufacturers lead global glyphosate production.
– Key manufacturers include BASF, Bayer CropScience, and Syngenta.
– Glyphosate disrupts the shikimate pathway in plants and microorganisms.
– Inhibits the enzyme EPSPS crucial for amino acid production.
– Systemic activity crucial for effectiveness in plant killing.
– Absorbed through foliage, impacting actively growing plants.
– Glyphosate inhibits EPSPS enzymes in different species.

**Genetically Modified Crops and Environmental Impact:**
– Some microorganisms have glyphosate-resistant EPSPS.
– Glyphosate-resistant crops engineered to withstand herbicide.
– Concerns surround genetically modified crops and glyphosate.
– Contamination of surface water attributed to glyphosate use.
– Glyphosate used in coca eradication programs in Colombia.
– Glyphosate one of the most widely used herbicides globally.
– Significant usage in the United States agricultural sector.
– Glyphosate application for non-agricultural purposes.

**Glyphosate Toxicity and Environmental Effects:**
– Glyphosate exists mostly in zwitterionic forms in the environment.
– Sorbs strongly onto soil minerals with limited mobility in soils.
– Readily degraded by soil microbes to AMPA.
– Contaminates surface waters through aquatic use patterns and erosion.
– Persistence in soil ranges from 2 to 197 days.
– Glyphosate not regularly tested in U.S. monitoring programs for pesticide residues.
– Limited human data on skin irritation; inhalation may cause discomfort.
– Eye exposure may lead to mild conjunctivitis.
– Low acute oral toxicity for mammals, but fatalities from concentrated formulations.