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How is glyphosate made?
Glyphosate is produced by heating a mixture of phosphorous acid and a-amino acetic acid, and then adding formaldehyde.
What is glyphosate used for?
Glyphosate products are one of the most widely used weed killers worldwide in farms and in home gardens and lawns. These products typically contain glyphosate in combination with other ingredients that help improve the absorption of the glyphosate into the plant.
How much glyphosate was in runoff water?
Glyphosate was detected in runoff water along a California highway at an average concentration of 2.69 ug/L (1.36 to 9.44 ug/L range) from November 29, 2000 to January 26, 2001 (1).
How long does glyphosate biodegrade?
AEROBIC: When glyphosate was incubated in Williams silt loam soil (pH 6.4, 1.9% organic matter), 19% degradation occurred in 9 days. No degradation was noted in sterilized soil (1). In shake-flask metabolism studies, glyphosate was rapidly and completely biodegraded in the presence of soil microorganisms under both aerobic and anaerobic conditions (2). After 28 days under aerobic conditions, 45-55% of the glyphosate was mineralized using Ray silt loam soil, Lintonia sandy loam soil, and Drummer silty clay loam soil. Norfolk sandy loam mineralized glyphosate at a much slower, but still significant, rate. In greenhouse experiments, the half-lives of glyphosate in Ray, Drummer and Norfolk soil was 3, 27, and 130 days, respectively (2). The biodegradation half-life of glyphosate in a Kickapoo sandy loam and Dupo silt loam soil were 1.85 and 2.06 days, respectively, under aerobic conditions. The major degradation product observed was aminomethyl phosphonic acid. The aerobic and anaerobic biodegradation half-life of glyphosate in a flooded silty clay loam sediment was 7 and 8.1 days, respectively (3).
How does glyphosate release to the environment?
Glyphosate's production may result in its release to the environment through various waste streams; its use as a herbicide will result in its direct release to the environment. If released to air, a vapor pressure of 9.8X10-8 mm Hg at 25 °C indicates glyphosate will exist solely in the particulate phase in the atmosphere. Particulate-phase glyphosate will be removed from the atmosphere by wet and dry deposition. Glyphosate does not degrade by direct photolysis. If released to soil, glyphosate is expected to have slight mobility based upon a Koc range of 2,600 to 4,900. The pKa values of glyphosate are 2.0, 2.6, 5.6 and 10.6, indicating that this compound will exist almost entirely in the zwitterion form in the environment and zwitterions generally adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts. Volatilization from moist soil is not expected because the compound exists as an ion and ions do not volatilize. Glyphosate is not expected to volatilize from dry soil surfaces based upon its vapor pressure. Biodegradation half-lives in soil of 1.85 to 7 days under aerobic conditions indicate that biodegrdation is an important environmental fate process in soil. If released into water, glyphosate is expected to adsorb to suspended solids and sediment based upon the Koc range. The aerobic and anaerobic biodegradation half-life of glyphosate in a flooded silty clay loam sediment was 7 and 8.1 days, respectively, suggesting that biodegradation is an important environmental fate process in sediment. Biodegradation data in water were not available. Volatilization from water surfaces is not expected to be an important fate process because glyphosate exists as a zwitterion in water and ionic species do not volatilize. A BCF of 0.52 suggests bioconcentration in aquatic organisms is low. Glyphosate is stable to hydrolysis at pH 5, 7, and 9 at temperatures ranging from 5 to 35 °C. Occupational exposure to glyphosate may occur through inhalation and dermal contact with this compound at workplaces where glyphosate is produced or used. Monitoring data indicate that the general population may be exposed to glyphosate via ingestion of drinking water and dermal contact with consumer products containing glyphosate. The greatest potential for dermal and inhalation exposure to glyphosate is expected for pesticide applicators, farm workers, and members of the general population that have frequent contact with products containing glyphosate for commercial farming or home use. (SRC)
What is glyphosate a phosphonic acid?
Glyphosate is a phosphonic acid resulting from the formal oxidative coupling of the methyl group of methylphosphonic acid with the amino group of glycine. It is one of the most commonly used herbicdes worldwide, and the only one to target the enzyme 5-enolpyruvyl-3- shikimate phosphate synthase (EPSPS).
Where is glyphosate found in soil?
SOIL: The concentration of glyphosate on barley fields, two days after application in September, 58 days post treatment, and 7 months posttreatment were 1.6 ppm, 0.5, and 0.2 ppm (1). The corresponding levels of its main metabolite, aminomethylphosphonic acid were 0.2, 0.14, and 0.1 ppm (1). It was detected in soil samples collected near the Wuchuan River, China at levels of 0.03 to 0.73 ng/g (2). Glyphosate and its principal metabolite are present at 35 to 1,502 and 299 to 2,256 ug/kg, respectively, in soils of the farming region of the Province of Buenos Aires, Argentina (3).
How is glyphosate synthesized?
Two main approaches are used to synthesize glyphosate industrially, both of which proceed via the Kabachnik–Fields reaction. The first is to react iminodiacetic acid and formaldehyde with phosphorous acid (sometimes formed in situ from phosphorus trichloride using the water generated by the Mannich reaction of the first two reagents). Decarboxylation of the hydrophosphonylation product gives the desired glyphosate product. Iminodiacetic acid is usually prepared on-site by various methods depending on reagent availability.
What is glyphosate used for?
It is used to kill weeds, especially annual broadleaf weeds and grasses that compete with crops. It was discovered to be an herbicide 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.
What is the most widely used herbicide in Canada?
As of April 2017, the Canadian government stated that glyphosate was "the most widely used herbicide in Canada", at which date the product labels were revised to ensure a limit of 20% POEA by weight.
What crops are tolerant of glyphosate?
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.
Why is glyphosate used in sugarcane?
When applied appropriately, it can promote useful effects. In sugarcane, for example, glyphosate application increases sucrose concentration before harvest.
How long does glyphosate stay in the soil?
The half-life of glyphosate in soil ranges between 2 and 197 days; a typical field half-life of 47 days has been suggested. Soil and climate conditions affect glyphosate's persistence in soil. The median half-life of glyphosate in water varies from a few to 91 days.
How does glyphosate affect weeds?
It inhibits a plant enzyme involved in the synthesis of three aromatic amino acids: tyrosine, tryptophan, and phenylalanine.
What is the composition of glyphosate?
Composition. Glyphosate is a phosphonic acid derived from a reaction between the methyl group of methylphosphonic acid with the amino group of glycine. It is the only herbicide that attacks the enzyme 5-enolpyruvyl-3-shikimate phosphate synthase (EPSPS).
How does glyphosate work?
Glyphosate works by inhibiting the action of a plant enzyme that plays a role in the synthesis of three amino acids named phenylalanine, tyrosine, and tryptophan. Glyphosate is absorbed into plants primarily through its leaves, and only tiny amounts of it are absorbed into the roots. Consequently, glyphosate is actually only effective ...
What is glyphosate used for?
Glyphosate is a herbicide that’s used to control weeds and grasses. It’s the active ingredient in many herbicide products, including the popular Roundup. Glyphosate has been registered as a pesticide in the U.S since 1974, and It’s also commonly used in many other countries around the world. Herbicides containing glyphosate are also referred ...
How to apply glyphosate to weeds?
Glyphosate can be applied to plants and weeds through injection systems, sponge bars, aerial sprays, broadcast sprayers, shielded sprayers, wiper applicators, and controlled droplet applicators .
Why is glyphosate being studied?
Because of how widespread its usage is, glyphosate is continuously being studied for possible effects of long-term exposure to it by humans, animals, and insects.
What is a weed killer used for?
Its use as a herbicide isn’t limited to just agriculture though. It’s also utilized in public spaces like parks and playgrounds to prevent the growth of weeds and other unwanted plants.
Why do farmers use glyphosate?
Farmers use glyphosate to dry crops like beans, wheat, and oats right before harvesting them. They do this to speed up the harvest process and improve the harvest yield as a whole. In reality, however, glyphosate is not a true desiccant. It just functions like one for crops.
When was glyphosate first used?
Glyphosate was first registered in the United States in 1974 as the active ingredient in Roundup but is now available in many commercial herbicide products. There is currently increased concern about glyphosate impacts on human health, including risks of cancer.
How does glyphosate degrade?
Glyphosate is degraded in soil and water by microbes and binds tightly to soil particles, which prevents leaching of glyphosate into ground water. Glyphosate does not degrade quickly in plants. As a result, it is possible that glyphosate residues can occur in food products. However, glyphosate is generally not applied to crops that are produced for direct human consumption. The vast majority of glyphosate is applied to fallow fields or in crops that are used for animal feed (corn, soybean), energy (corn) or fiber (cotton) and is applied early in the growing season to young vegetative crops many weeks before plants produce grain or are harvested.
How many studies are required for herbicide registration?
The herbicide registration process requires EPA review of over 120 studies that focus on herbicide toxicological properties, environmental fate and the potential for non-target effects. These studies are used to conduct formal risk assessments that quantify the likelihood of adverse effects to humans using toxicological data and models of exposure. The Food Quality Protection Act (FQPA, passed in 1996) requires a " reasonable certainty that no harm will result from aggregate exposure " to pesticides and establishes enforceable residue standards based on models of food consumption. The USDA Food and Drug Administration actively monitors the level of glyphosate on foods in the marketplace.
What are the chemical properties of herbicides?
The chemical properties of an herbicide are a primary determinant of toxicity and persistence in the environment. The glyphosate molecule ( below) is unique among herbicides. Approximately 95% of registered herbicides are molecules made from aromatic ring structures. In comparison, glyphosate is a small molecule made of a linear carbon chain with weaker bonds, which makes glyphosate less persistent in the environment. In commercial products, glyphosate is formulated with salts to improve its water solubility and proprietary surfactants to improve plant uptake.
Is glyphosate a pesticide?
Likelihood of exposure. Glyphosate use has increased dramatically in the past 20 years due to its frequent use in Roundup Ready crops (corn, soybean, cotton). Consequently, the likelihood of glyphosate exposure has increased for pesticide applicators. However, the EPA has concluded that there is low potential for the general public ...
Is glyphosate a carcinogen?
In 2015, the World Health Organization's International Agency for Research on Cancer (IARC) concluded that "Glyphosate is probably carcinogenic to humans".
Is glyphosate toxic to humans?
Glyphosate has lower acute toxicity to humans than 94% of all herbicides 1 and many common household chemicals, including vinegar and table salt. Glyphosate also has lower chronic toxicity to humans than 90% of all herbicides 1.
What is the process of making glyphosate?
Plants use amino acids to build things like enzymes and proteins that it needs in order to grow, through a process called amino acid synthesis.
Who invented glyphosate?
Henri Martin, a Swiss chemist, was the first to synthesize glyphosate while trying to develop new pharmaceuticals in 1950, according to a review in the journal Pest Management Science. But the chemical didn't have much use in the pharmaceutical world.
Why are people concerned about glyphosate?
Although glyphosate has cut farmers' costs and helped landscapers remove invasive plants, people have grown increasingly skeptical about whether the benefits outweigh the risks to human and environmental health. Recent research has shown that the chemical may be harming the wrong plants, in addition to wildlife and people.
Why is glyphosate used in agriculture?
Farmers use the practical herbicide to kill weeds that compete with crops for sunlight, water and soil nutrients. Glyphosate has been used more than any other agriculture chemical, with an estimated 8.6 billion kilograms (19 billion lbs.) of it sprayed since 1974 to help grow everything from peppers to oranges.
What is the most commonly used agricultural chemical?
Glyphosate is the most commonly used agricultural chemical in the world. Farmers spray it on glyphosate-resistant crops to get rid of unwanted plants. (Image credit: Shutterstock) Glyphosate is a chemical compound that works as an effective herbicide, or weed killer. It's the most commonly used herbicide chemical in the world, ...
How does glyphosate get into plants?
From there, glyphosate can travel from cell to cell and spread to the stem and the roots, infecting the entire plant .
How long does glyphosate stay in the soil?
Glyphosate can persist in soil for months before microorganisms in the ground eat it and recycle it into carbon dioxide.
What are some products that contain glyphosate?
Glyphosate comes in many forms, including an acid and several salts. These can be either solids or an amber-colored liquid. There are over 750 products containing glyphosate for sale in the United States.
What is glyphosate used for?
Glyphosate is one of the most widely used herbicides in the United States. People apply it in agriculture and forestry, on lawns and gardens, and for weeds in industrial areas. Some products containing glyphosate control aquatic plants.
How might I be exposed to glyphosate?
You can be exposed to glyphosate if you get it on your skin, in your eyes or breathe it in when you are using it. You might swallow some glyphosate if you eat or smoke after applying it without washing your hands first. You may also be exposed if you touch plants that are still wet with spray. Glyphosate isn't likely to vaporize after it is sprayed.
What are some signs and symptoms from a brief exposure to glyphosate?
The other ingredients in the product can make the product more toxic. Products containing glyphosate may cause eye or skin irritation. People who breathed in spray mist from products containing glyphosate felt irritation in their nose and throat. Swallowing products with glyphosate can cause increased saliva, burns in the mouth and throat, nausea, vomiting, and diarrhea. Fatalities have been reported in cases of intentional ingestion.
What happens to glyphosate when it enters the body?
In humans, glyphosate does not easily pass through the skin. Glyphosate that is absorbed or ingested will pass through the body relatively quickly. The vast majority of glyphosate leaves the body in urine and feces without being changed into another chemical.
Are children more sensitive to glyphosate than adults?
As required by the Food Quality Protection Act, the EPA has determined that children are not more sensitive to glyphosate as compared to the general population.
How long does glyphosate stay in soil?
Glyphosate binds tightly to soil. It can persist in soil for up to 6 months depending on the climate and the type of soil it is in. Glyphosate is broken down by bacteria in the soil. Glyphosate is not likely to get into groundwater because it binds tightly to soil.
What is glyphosate used for?
Glyphosate is a non-selective herbicide that can control the growth of broadleaf weeds and grasses, according to the Environmental Protection Agency (EPA). First registered in 1974, glyphosate has been used in agriculture for decades and is the main ingredient in the once-popular weed killer Roundup, owned by Monsanto and then acquired by Bayer in 2018. Glyphosate inhibits the 5-enolpyruvylshikimate-3-phosphate synthase enzyme in plants, which allows farmers to eradicate weeds that compete with crops.
What Foods Have Glyphosate?
In 2019, oat-based breakfast cereals, granolas, oat bars, and instant oats by General Mills and Quaker were batch-tested for detectable levels of glyphosate. The EWG’s health benchmark of glyphosate levels is 160 parts per billion and of the 21 products tested, 16 of the products contained glyphosate levels over the recommended 160 pbb.
Do Cheerios Contain Glyphosate?
Honey Nut Cheerios are one of the worst offenders of too-high glyphosate levels. According to the original 2017 oat-based product review, Honey Nut Cheerios Medley Crunch was found to have detectable levels of 830 ppb of glyphosate, which is more than five times over the EWG’s recommended level of 160 ppb.
Do Almonds Have Glyphosate?
According to The Guardian, other foods with high contamination levels include almonds, beets, beet sugar, canola oil, carrots, corn and corn oil, quinoa, soy products, sweet potatoes, and vegetable oil.
Why is the German ban on glyphosate important?
Germany’s ban is particularly important because Bayer, who acquired Monsanto in 2018, is a German-based company. Germany announced that the ban would entail phasing out glyphosate fully by the year 2023. Despite all the movement to ditch, ban, and educate the public on the dangers of glyphosate, the herbicide has still found, alarmingly, ...
What percentage of tampons contain glyphosate?
Recently, concern for glyphosate in tampons has become more common. According to a petition on SumOfUs.com, a 2019 study in Argentina found 85 percent of tampons, pads, and other hygiene products were contaminated with trace amounts of glyphosate.
Is glyphosate still in food?
Despite all the movement to ditch, ban, and educate the public on the dangers of glyphosate, the herbicide has still found, alarmingly, a way to make it into our food. The Environmental Working Group reported in 2019 that widespread glyphosate contamination affected breakfast cereals, oat products, pasta, crackers, chickpea flour, pizza, ...
Overview
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 eff…
Discovery
Glyphosate was first synthesized in 1950 by Swiss chemist Henry Martin, who worked for the Swiss company Cilag. The work was never published. Stauffer Chemical patented the agent as a chemical chelator in 1964 as it binds and removes minerals such as calcium, magnesium, manganese, copper, and zinc.
Somewhat later, glyphosate was independently discovered in the United States at Monsanto in 1…
Chemistry
Glyphosate is an aminophosphonic analogue of the natural amino acid glycine and, like all amino acids, exists in different ionic states depending on pH. Both the phosphonic acid and carboxylic acid moieties can be ionised and the amine group can be protonated and the substance exists as a series of zwitterions. Glyphosate is soluble in water to 12 g/L at room temperature. The original synt…
Formulations
Glyphosate is marketed in the United States and worldwide by many agrochemical companies, in different solution strengths and with various adjuvants, under dozens of tradenames. As of 2010, more than 750 glyphosate products were on the market. In 2012, about half of the total global consumption of glyphosate by volume was for agricultural crops, with forestry comprising another important market. Asia and the Pacific was the largest and fastest growing regional market. As …
Mode of action
Glyphosate interferes with the shikimate pathway, which produces the aromatic amino acids phenylalanine, tyrosine and tryptophan in plants and microorganisms – but does not exist in the genome of animals, including humans. It blocks this pathway by inhibiting the enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), which catalyzes the reaction of shikimate-3-phosphate (S3P) and phos…
Uses
Glyphosate is effective in killing a wide variety of plants, including grasses and broadleaf and woody plants. By volume, it is one of the most widely used herbicides. In 2007, glyphosate was the most used herbicide in the United States agricultural sector, with 180 to 185 million pounds (82,000 to 84,000 tonnes) applied, the second-most used in home and garden with 5 to 8 million …
Environmental fate
Glyphosate has four ionizable sites, with pKa values of 2.0, 2.6, 5.6 and 10.6. Therefore, it is a zwitterion in aqueous solutions and is expected to exist almost entirely in zwitterionic forms in the environment. Zwitterions generally adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts. Glyphosate strongly sorbs onto soil minerals, and, with the excepti…
Toxicity
Glyphosate is the active ingredient in herbicide formulations containing it. However, in addition to glyphosate salts, commercial formulations of glyphosate contain additives (known as adjuvants) such as surfactants, which vary in nature and concentration. Surfactants such as polyethoxylated tallow amine (POEA) are added to glyphosate to enable it to wet the leaves and penet…
Composition
How It Works
- Glyphosate is a broad-spectrum herbicide. This means that it can’t be used to kill specific weeds or plants. Instead, it kills most broadleaf plants in the area it is used. Glyphosate works by inhibiting the action of a plant enzyme that plays a role in the synthesis of three amino acids named phenylalanine, tyrosine, and tryptophan. Glyphosate is absorbed into plants primarily thro…
Forms
- You can find herbicide products containing glyphosate in liquid, concentrate, and solid forms. Glyphosate can be applied to plants and weeds through injection systems, sponge bars, aerial sprays, broadcast sprayers, shielded sprayers, wiper applicators, and controlled droplet applicators.
Risks and Hazards
- Because of how widespread its usage is, glyphosate is continuously being studied for possible effects of long-term exposure to it by humans, animals, and insects. The U.S Environmental Protection Agency (EPA) has conducted extensive investigations into glyphosate and its effects on human health, the environment, and the safety of foods. After reviewing available data on gly…
Legality
- Glyphosate herbicides are legal in the U.S and most other countries around the world. Some countries hover, have either banned it completely or set out specific restrictions regarding its use: 1. In 2014, the legislature of the Netherlandsprohibited glyphosate from being sold to consumers to use at home. 2. As of June 30th, 2021the sale and use of glyphosate herbicides will be banne…
A Word from Verywell
- Many health and environmental agencies around the world have determined that glyphosate is safe for use as long as labeling instructions are followed. It is not necessary for you to stop using glyphosate herbicides, but it may be advisable to limit unnecessary exposure to it. Nevertheless, investigations will likely continue as to its safety.