Talk:Glyphosate/Temp
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Glyphosate (N-(phosphonomethyl) glycine, C3H8NO5P) is a non-selective systemic herbicide to kill weeds, especially perennials.
Glyphosate is the primary active ingredient in Monsanto's much used yet controversial herbicide, Roundup. Many crops have now been genetically engineered to be resistant to it. The chemical is only absorbed by the leaves of plants and it is not absorbed by roots from the soil. In the US 25 million applications are used every year on lawns and yards, and in US agriculture totally, estimates range from 18-48 million pounds are used yearly, with a 20% yearly growth rate in usage.
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[edit] Chemistry
Glyphosate is an aminophosphonic analogue of the natural amino acid glycine and the name is a contraction of glycine, phospho-, and -ate, given the C.A.S. number 1071-83-6. It was first discovered to have herbicidal activity in 1970 by John Franz, a scientist that worked for the Monsanto company. In 1987 Franz received the National Medal of Technology from Ronald Reagan for his discoveries [3], a medal given to american companies like DOW, DuPont, and IBM, and American company and university scientists, and in 1990 he received the Perkin Medal for Applied Chemistry [4], stated as the highest honor given for advances in American industrial chemistry.
[edit] Biochemistry
The full action of glyphosate is not yet fully known,(U.S. EPA. Office of Pesticide Programs. Special Review and Reregistration Division. 1993. Reregistration eligibility decision (RED): Glyphosate. Washington, D.C., Sept.)(Franz, J.E., M.K. Mao, and J.A. Sikorski. 1997. Glyphosate: A unique global herbicide. ACS Monograph 189. Washington D.C.: American Chemical Society.), yet glyphosate helps kill plants by inhibiting the enzyme 5-enolpyruvoyl-shikimate-3-phosphate synthase (EPSPS), which forms the aromatic amino acids: phenylalanine, tyrosine and tryptophan.[1] The production of Chorismate is ultimately stopped by the presence of the glyphosphate.[citation needed] EPSPS catalyzes the reaction of shikimate 3-phosphate (S3P) and phosphoenolpyruvate (PEP) to form ESP and phosphate.[citation needed]The aromatic amino acids are also used to make secondary metabolites such as folates, ubiquinones and naphthoquinones.[citation needed] The shikimate pathway is not present in animals, so it was thought it would have low toxicity to them, yet it has actually been found to affect other plant enzyme systems including detoxification enzymes, and also has been found to affect animal enzymes.(Su , L.Y. et al. 1992. The relationship of glyphosate treatment to sugar metabolism in sugarcane: New physiological insights. J. Plant Physiol. 140:168-173.)(Lamb, D.C. et al. 1998. Glyphosate is an inhibitor of plant cytochrome P450: Functional expression of Thlaspi arvensae cytochrome P45071B1/ reductase fusion protein in Escherichia coli. Biochem. Biophys. Res. Comm. 244:110114.)(Hietanen, E., K. Linnainmaa, and H. Vainio. 1983. Effects of phenoxy herbicides and glyphosate on the hepatic and intestinal biotransformation activities in the rat. Acta Pharma. et Toxicol. 53:103-112.).
[edit] Toxicity & Ecological Impact
Glyphosate is classed as a moderately toxic herbicide and in EPA toxicity class III [5]. In a comprehensive scientific review, american scientist Caroline Cox, in Journal of Pesticide Reform v. 108, n.3 [6] stated that "Glyphosate containing products are acutely toxic to animals, including humans". She goes on to state that it has conclusively demonstrated adverse effects in "all standards of laboratory toxicology testing" including medium term toxicity, long-term toxicity, genetic damage, reproductive toxicity, and carcinogenicity.[7]. She also questions the neutrality of the american EPA. On the other side a review was conducted in 2000 concluding that "under present and expected conditions of new use, there is no potential for Roundup herbicide to pose a health risk to humans"[2].The EPA, however, clearly states that in concentrations above its limits (which it currently sets at 0.7 parts per million in water): short term effects so far found include congestion of lungs, increased breathing rate, and long term effects have potential to cause kidney damage and reproductive effects.[8]There is currently no true consensus on the true toxicity & impact of glyphosate products, those that cite a consensus must cite sources that rely almost totally on Monsanto studies or studies they have funded. In terms of acute toxicity, however, it appears 100ml to 200ml ingested is fatal to humans (1/3 cup to a cup). The EUs current listing of glyphosate products is based mainly on Monsanto studies. Glyphosate products are argueably less toxic than many other herbicides and pesticides.
Until recently most studies of glyphosate and glyphosate product toxicty have been carried out by Monsanto or funded by them. On two occasions the american EPA has caught scientists deliberately falsifying test results at research laboratories hired by Monsanto to study glyphosate, and Monsanto has been charged with illegally advertising, (falsely and misleadingly), glyphosate products calling them "safer than table salt", prompting a law suit by the New York State attorney general[9], and prompting several action groups to form in the United States against these products.[10]In the second incident of falsifying test results in 1991, the owner of the lab (Craven Labs), and three employees were indicted the following year on 20 felony counts, the owner was sentenced to 5 years in prison and fined 50,000 dollars, the lab was fined 15.5 million dollars and ordered to pay 3.7 million in restitution.[11]Craven laboratories performed studies for 262 pesticide companies including Monsanto. In the first incident involving "Industrial Biotest Laboratories", a reviewer stated after finding "routine falsification of data" that it was "hard to believe the scientific integrity of the studies when they said they took specimens of the uterus from male rabbits". The EPA performed this audit of IBT in 1976, yet the fraud did not make headlines until 1983.(U.S. Congress. House of Representatives. Com. on Gov. Oper. 1984. Problems palgue the EPA pesticide registration activities. House Report 98-1147)(U.S. EPA Office of pesticides and Toxic Substances 1983, Summary of the IBT review program. Washington D.C. July)(U.S. EPA 1978 Data validation. Memo from K LOcke, Toxicology Branch, to R Taylor, Registration Branch. Washington DC Aug 9)(US EPA Communications and Public Affairs 1991 Note to correspondents Washington DC Mar 1)(US EPA Communications, Education, And Public Affairs 1994 Press Advisory. Craven Laboratories, owner, and 14 employees sentenced for falsifying pesticide tests. Washington DC Mar 4)(US EPA Communications and Public Affairs 1991 Press Advisory. EPA lists crops associated with pesticides for which residue and environmental fate studies were allegedly manipulated. Washington DC Mar 29)(US Dept. of Justice. United States Attorney. Western District of Texas 1992. Texas laboratory, its president, 3 employees indicted on 20 felony counts in connection with pesticide testing. Austin TX Sept 29)
[edit] Acute symptoms of ingestion & unintentional contact exposure
The toxicity of Roundup has been questioned, in addition to its active agent (glyphosate), because of several of the inactive ingredients, including the surfactant polyoxy-ethyleneamine (POEA) [12]. These components may be responsible for some of the "acute" toxicity to humans such as eye irritation up to death. Ingestion of Roundup has been proven to cause many symptoms including diarrhea, vomitting, excess fluid in lungs, pneumonia, confusion, lung dsyfunction, erosion of the intestinal tract, kidney damage, damage to the larynx, destruction of blood cells, and other symptoms, with 200ml (less than a cup) typically leading to death and human fatality, yet cases of only 100ml (a little over 1/3 cup) of ingested glyphosate product have been fatal.[13] Unintentional low exposures cause symptoms such as, eye irritation (pain, burning, blurred vision), swollen face & eyes & joints, blisters, skin rash, rapid heartbeat & palpitations, elevated blood pressure, chest pain, congestion, coughing, headache, dizziness, fever, nausea, facial numbness, burning & itchy skin, & recurrent eczema. Inhalation is considered more toxic than ingestion. [14](Temple, W.A. and N.A. Smith. 1992. Glyphosate herbicide poisoning experience in New Zealand. N.Z. Med. J. 105:173-174.)(Giiordano-Labadie, F., C. Pech-Ormieres, and J. Bazek. 1996. Systemic contact dermatitis from sordid acid. Cent. Dermatit. 34:61-62.)(Monsanto Co. Undated. Monsanto backgrounder: Roundup herbicide ingredients. St. Louis, MO.)(Sigma Chemical Co., Aldrich Chemical Co., and Fluke Chemical Corp. 1994. Material safety data sheet: Isopropylamine. St. Louis, MO, Milwaukee, WI, and Ronkonkoma, NY.)(Sawada, Y., et al. 1988. Probable toxicity of surface-active agent in commercial herbicide containing glyphosate. Lancet 1(8580):299.)(Tominack, R.L. et al. 1991. Taiwan National Poison Center: Survey of glyphosate-surfactant herbicide ingestions. Clin. Toxicol. 29(1):91-109.)(Talbot, A.R. et al. 1991. Acute poisoning with a glyphosate-surfactant herbicide ('Roundup'): A review of 93 cases. Human Exp. Toxicol. 10:1-8.)(Menkes, D.B., W.A. Temple, and I.R. Edwards. 1991. Intentional self-poisoning with glyphosate-containing herbicides. Human Exp. Toxicol. 10:103-107.)(Hung, D., J. Deng. and T. Wu. 1997. Laryngeal survey in glyphosate intoxication: a pathophysiological investigation. Hum. Exp. Toxicol. 16:596599.)(U.S. EPA. Office of Pesticide Programs. Hazard Evaluation Division. Health Effects Branch. 1980. Summary of reported pesticide incidents involving glyphosate (isopropylamine salt). Report No. 373. Washington, D.C., Oct.)(Calif. EPA Dept of Pesticide Regulation 1998 Case reports received by the California Pesticide Surveillance Program in which health effects were attributed to glyphosate 1993-1995)
[edit] Human & mammalian toxicity
One of the difficulties with assessing true glyphosate toxicity, is the fact that it is always used in formulations with several other ingredients, and therefore studies of pure glyphosate toxicty have little true relevance.[15]There is no product sold that is pure glyphosate and it only exists as such in the manufacturing process. Researchers looking for explanations as to why Canadian farm families exposed to glyphosate formulations had increased miscarriages and pre-mature births, found that glyphosate roundup formulations were twice as toxic as pure glyphosate. They also found viability of human placental cells considerably reduced & with estrogen synthesis interference, in the commonly used glyphosate formulations yet not with pure glyphosate.(Environmental Health Perspectives Vol. 113, No.6, 716-720)
Recent independent mammalian research indicates glyphosate induces a variety of functional abnormalities in fetuses and pregnant rats.[16]Also in recent mammalian research glyphosate has been found to cause interference in reproductive chemistry specifically interfering in male testosterone production in mice.[17]. There are currently few studies into the toxicity of glyphosate formulations, most are conducted by Monsanto, and Greenpeace's cautious 10 year old statement that glyphosate has little toxicity to mammals came before the more recent research: on the reproductive effects of the commonly used glyphosate formulations, and on pure glyphosate toxicity to male reproductive cells. Sleep problems caused by glyphosate exposure may be caused as glyphosate appears to mimic adrenaline as reported by the WHO and the EPA [18]Sublethal effects in mammals have included decreased activity of detoxification enzymes in the liver and intestinal system.[19]Glyphosate as a pure ingredient is of far less concern than many other herbicides, pesticides, and chemicals such as those from the organochlorine family.[citation needed]Monsanto states glyphosate is not carcinogenic (cancer causing), yet actually qualifies this statement in their document to say the "active ingredient" in glyphosate products and roundup ready products is not carcinogenic, and makes no comment on the total product.[20] Greenpeace states that poor quality testing methods are responsible for results that usually show little glyphosate contamination on food products or in other systems, yet makes no statement as to the harms of minor glyphosate contamination on human foods and only as to harms on ecology or farmworkers.[21]However, residues have been found by Monsantos own studies on lettuce 5 months after soil treatment, in barley four months after soil treatment, and the WHO found "significant residues" on wheat with residues not lost during baking.[22]Overall, glyphosate products are a clear and vast improvement, however, from Monsantos organochlorine herbicides such as DDT and agent orange, that were eventually forced to be discontinued and phased out of many nations, including the US and EU.[citation needed]
Many times issues of glyphosate toxicity may concern its co-ingredients. Its formulations are reported to cause many of the cases of toxic herbicide exposure in California, consistently rating in the top 10 most likely pesticide/herbicide formulation to cause incidents, with values from 3rd most likely to 8th most likely being reported, depending on year, yet these lead to few to no full hospitalizations in California and typically are eye related. In the UK it is the most frequently cited to cause incidents, yet all of this stems partly from the fact that glyphosate is one of the most frequently used herbicides, so incidents involving poisonings are bound to be high. Monsanto has been adjusting its formulations to address this, yet older more toxic formulations are still available, and especially in countries with lower standards than the UK. [23]Many of these cases are thought to partially be as of the many other ingredients in glyphosate formulations that have equal or greater toxicity than pure glyphosate and that are frequently unlisted as they are "trade secrets". Some report the direct toxicity of pure glyphosate to mammals and birds as reportedly low [24]. Others disagree however stating plainly "glyphosate is toxic to mammals", and also state its effect on flora can have a damaging effect on mammals and birds through habitat destruction[25]. Monsanto states its products are not harmful to anyone or anything.[26]Glyphosate formulations are also used in intentional harm situations. A letter to The Lancet (Feb 6 1988, pg 299) reported 56 toxic exposures to glyphosate formulations in Japan between 1984-1986 with adverse repsiratory, cardiovascular, and neurotoxic effects leading to 9 deaths. These most extreme examples of intentional poisonings in Japan (i.e., suicide), show around 10%-20% of those ingesting small quantities of glyphosate dying, compared to 70% of those ingesting paraquat, [3]. It takes about 200ml (3/4cup) of glyphosate product to cause rapid human death, yet cases of just 100ml (slightly more than 1/3 cup) of ingested roundup have resulted in human death. If a mammal (including a human) ingests enough glyphosate-product it will die. Inhalation of glyphosate products is regarded as far more toxic than ingestion.
In terms of cancer causing effects, the US Environmental Protection Agency, the EC Health and Consumer Protection Directorate, and the UN World Health Organization have all concluded that glyphosate is not carcinogenic, their conclusions were all based on Monsantos own studies so the independence of this result is not clear. The first studies submitted to the EPA by Monsanto found an increase in testicular cancer and an increase in thyroid cancer & kidney tumors of rats. The most recent Monsanto study (1990) found increase in pancreas and liver tumors and thyroid cancer, yet they were not rated as carcinogenic as Monsantos industry pathologist stated the 3 times the rate of cancer was too similar to the control group (4.5% cancer rate in control, 12.5% rate in treated).[27] Opponents of glyphosate-based pesticides frequently state that glyphosate is linked to cancer, citing a study in the British Journal of Cancer that showed three times the rate of hodgkins lymphoma in people occupationally exposed to glyphosate herbicides, and similar to the rate found in the very few animals studies that have been conducted by Monsanto.[28] There is controversy over what exactly in the products is causing the cancer, citing the human research of Hardell and Eriksson (Cancer 1999 85:1353–1360), this paper showed a link between glyphosate and lymphoma, Monsanto states the link was not statistically significant and was within the realm of random variation. The authors themselves concluded "definite conclusions cannot be drawn for separate chemicals, such as MCPA and glyphosate, from the multivariate analysis". Opponents of glyphosate also state that Roundup has been found to cause genetic damage, citing research including Peluso et al (Environ Molec Mutag 31:55–59). The authors concluded that the damage was "not related to the active ingredient, but to another component of the herbicide mixture", so some of Roundup toxicity may be as of the total product and not only the listed active ingredient.
Roundup has also been found by researchers at Texas Tech University to disrupt the expression of steroidogenic acute regulatory protein (StAR) which has a role in testosterone production in males [29], causing concern about its effects on reproductive function.
[edit] Aquatic effects
Fish and invertebrates are more sensitive to formulations of glyphosate,[30] LC50s are 2ppm to 300ppm,(World Health Organization, United Nations Environment Programme, the International Labour Organization. 1994. Glyphosate. Environmental Health Criteria #159. Geneva, Switzerland) the surfactants can be responsible for much of the harm (Mitchell, D.G., P.M. Chapman, and T.J. Longs. 1987. Acute toxicity of Roundup and Rodeo herbicides to rainbow trout, chinook, and coho salmon. Bull. Environ. Contam. Toxicol. 39:10281035) leading to 20 to 70 times the toxicity of pure glyphosate,(Folmar, Sanders, & Julin 1979, Environ. Contam. Toxicol. 8:269-278) young fish are more sensitive, and increased water temperatures lead to greater toxic effect.(Wan, M.T., R.G. Watts, and D.J. Moul. 1989. Effects of different dilution water types on the acute toxicity to juvenile Pacific salmonids and rainbow trout of glyphosate and its formulated products. Bull. Environ. Contam. Toxicol. 43:378385.)(Holdway, D.A. and D.G. Dixon. 1988. Acute toxicity of permethrin or glyphosate pulse exposure to larval white sucker (Catostomus commersoni) and juvenile flagfish (Jordanella floridae) as modified by age and ration level. Environ. Toxicol. Chem. 7:63-68.)(Holtby, L.B. 1989. Changes in the temperature regime of a valley-bottom tributary of Carnation Creek, British Columbia, over-sprayed with the herbicide Roundup (glyphosate). In Reynolds, P.E. (ed.) Proceedings of the Carnation Creek Herbicide Workshop. Sault Ste. Marie, Ontario, Canada: Forest Pest Management Institute.) This difference is interesting in that the toxicities are similar to just pure glyphosate, in soft water (Wan, M.T., R.G. Watts, and D.J. Moul. 1989. Effects of different dilution water types on the acute toxicity to juvenile Pacific salmonids and rainbow trout of glyphosate and its formulated products. Bull. Environ. Contam. Toxicol. 43:378385.) or if the fish have not recently eaten.(Holdway, D.A. and D.G. Dixon. 1988. Acute toxicity of permethrin or glyphosate pulse exposure to larval white sucker (Catostomus commersoni) and juvenile flagfish (Jordanella floridae) as modified by age and ration level. Environ. Toxicol. Chem. 7:63-68.) Sublethal effects at far lower concentrations include erratic swimming & labored respiration which may impact feeding, migration, and reproduction, and also gill damage & and changes in liver structure.(Morgan et al. 1991, Environ. Toxicol. Chem. 10:73-79)(Liong, Hamzah, & Murugan 1988, Malaysian Ague. J. 54(3):147-156)(Neskovic et al. 1996, Environ. Toxicol. Chem. 56:295-302) [31] In Australia, there is controversy over glyphosate formulations used in or near water, most of this stems from ingredients in the formulations other than the actual pure active ingredient: glyphosate. Monsanto corporation had adjusted its formulations for Australia in the late 1990s to address this issue with its "Biactive" line of products.[32]Glyphosate is generally less persistent in water than in soil, with 12 to 60 day persistance observed in Candian pond water, yet persistance of over a year have been observed in the sediments of ponds in Michigan & Oregon.[33]
[edit] Effects on soil and on flora & fauna
Of nine herbicides tested for their toxicity to soil microorganisms, glyphosate formulations were found to be the second most toxic to a range of bacteria, fungi, actinomycetes and yeasts.[4] However, when glyphosate comes into contact with the soil it rapidly binds to soil particles and is inactivated.[citation needed] Unbound glyphosate is degraded by bacteria.[citation needed] Low activity because of binding to soil particles suggests that glyphosate's effects on soil flora will be limited.[citation needed] Other sources show that 80% of glyphosate absorbed by soil can be rapidly desorbed in just a two hour period, leading the study to conclude that the herbicide can be extensively mobile in soil.[34] Recent work shows that glyphosate can be readily released from certain types of soil particles, and therefore may leach into water or be taken up by plants. Low glyphosate concentrations can be found in many creeks and rivers in U.S. and Europe. In the US glyphosate has been called "extremely persistent" by its EPA, yet half lives vary from as little as 3 days at a soil site in Texas, 141 days at a site in Iowa, to between 1 - 3 years in Swedish forest soils being observed.[35] It appears that more northern sites have the longest soil persistances such as in Canada & Scandanavia.
The US EPA concluded that many endangered species of plants, as well as the Houston toad, may be at risk from glyphosate use, yet has a policy that most herbicides and pesticides have benefit outweighing the harms, including glyphosate products. It has been stated by opponents of roundup that glyphosate formulations can persist on foods & food crops for up to two years and that they also negatively impact earthworm and beneficial insect populations, and further drive farmers and gardeners away from natural farming methods to dependence on ecologically harmful crutches.[36]Their argument is that the costs and also potential harms outway the possible benefits of the herbicide. In New Zealand applications of glyphosate (1/20 of typically used applications), significantly affected growth and survival of earthworms, in other studies nitrogen fixing bacteria have been impaired, and also crop plant susceptibility to disease has been increased.(Springett & Gray 1992, Soil Biol. Biochem. 24 (12):1739-1744)(Santos & Flores 1995, Lett. Appl. Microbiol. 20:349-352)(Brammel & Higgins 1988, Can. J. Bot 66:1547-1555)(Johal & Rahe 1988, Molec. Plant Pathol. 32:267-281)(Mekwatanakarn & Sivassithamparam 1987, Biol. Fertil. Soils 5:175-180)(Kawate et al. 1997, Weed Sci. 45:739-743)(Bergvinson & Borden 1992, Can J. For. Res. 22:206-209)Monsanto would question this, or else state that any possible harms are outweighed by glyphosate products' weed fighting capabilities that would increase yields. Monsanto also firmly denies any negative impact on anything, including wildlife, and has many studies it has funded to back up its position.
Roundup was once believed, or at least stated by Monsanto researchers, to have no effect on animals. However, as of 2005, research has shown that, when roundup is applied directly to water in contravention of the product labeling, the surfactant polyethoxylated tallow amine (POEA) can kill tadpoles [37] by interrupting amphibian respiration through their skins. A 1995 Australian study concluded that ‘Roundup’ a popular and supposedly ecofriendly herbicide “was extremely toxic to tadpoles and adult frogs” (The New Zealand Frog Survey).
[edit] Reproductive health concerns & EDC acticity
There are concerns about the effects of glyphosate (and Roundup) on possible human reproductive dysfunction.
[edit] Endocrine disruptor debate
In-vitro studies (Walsh, et al 2000) have shown glyphosate to have an effect on progesterone production in mammalian cells and can affect mortality of placental cells in-vitro (Richard, et al 2005). Whether these studies classify glyphosate as an endocrine disruptor is a matter of debate, with others pointing to studies, of even just pure glyphosate on Leydig cells showing harmful effects, to demonstrate conclusively that it is an endocrine disruptor.
Some feel that in-vitro studies are insufficient, and are waiting to see if animal studies show a change in endocrine activity, since a change in a single cell line may not occur in an entire organism. Additionally, current in-vitro studies expose cell lines to concentrations orders of magnitude greater than would be found in real conditions, and through pathways that would not be experienced in real organism. Many current toxicological studies results supportive of no endocrine activity were mainly provided by Monsantos own studies of pure glyphosate and not the chemical formulations of glyphosate that are actually used (EU 2002).
Others feel that in-vitro studies, particularly ones identifying not only an effect, but a chemical pathway, are sufficient evidence to classify glyphosate as an endocrine disruptor, on the basis that even small changes in endocrine activity can have lasting effects on an entire organism that may be difficult to detect through whole organism studies alone. Further research on the topic has been planned.
[edit] Glyphosate resistance in weeds & microoraganisms
The first documented cases of weed resistance were found in Australia, involving rigid ryegrass near Orange, New South Wales.[38]Some farmers in the United States have expressed concern that weeds are now developing with glyphosate resistance, with 13 states now reporting resistance, and this poses a problem to many farmers, including cotton farmers, that are now heavily dependent on glyphosate to control weeds.[39][40]
Some microorganisms have a version of 5-enolpyruvoyl-shikimate-3-phosphate synthetase (EPSPS) that is resistant to glyphosate inhibition. The version used in genetically modified crops was isolated from Agrobacterium strain CP4 (CP4 EPSPS) that was resisitant to glyphosate. The CP4 EPSPS gene was cloned and inserted into soybeans. The CP4 EPSPS gene was engineered for plant expression by fusing the 5' end of the gene to a chloroplast transit peptide derived from the petunia EPSPS. This transit peptide was used because it had shown previously an ability to deliver bacterial EPSPS to the chloroplasts of other plants. The plasmid used to move the gene into soybeans was PV-GMGTO4. It contained three bacterial genes, two PC4 EPSPS genes, and a gene encoding beta-glucuronidase (GUS) from Escherichia coli as a marker. The DNA was injected into the soybeans using the particle acceleration method. Soybean cultivar A54O3 was used for the transformation. The expression of the GUS gene was used as the initial evidence of transformation. GUS expression was detected by a staining method in which the GUS enzyme converts a substrate into a blue precipitate. Those plants that showed GUS expression were then taken and sprayed with glyphosate and their tolerance was tested over many generations.
[edit] Genetically modified crops
In 1996, genetically modified soybeans were available commercially([41]). This greatly improved the ability to control weeds in soybean fields since glyphosate could be sprayed on fields without hurting the crop. As of 2004, glyphosate was used on 80% of U.S. soybean fields to eliminate weeds.
[edit] Tradenames
It was first sold by Monsanto under the tradename Roundup but is no longer under patent so is now marketed under various names (for example TOP UP48 in Thailand).
[edit] Other uses
Glyphosate is one of a number of herbicides used by the United States government to spray Colombian coca fields through Plan Colombia. Its health effects, effects on legal crops, and effectiveness in fighting the war on drugs have been widely disputed.
[edit] The RoundUp formulation
Roundup is the brand name of a systemic, broad-spectrum herbicide produced by the U.S. life sciences giant Monsanto. It is the most used herbicide in the world, and the top-selling agrichemical of all time. Monsanto developed and patented the glyphosate molecule in the 1970s, and marketed Roundup from 1973. It retained exclusive rights in the US until its US patent expired in September, 2000, and maintained a predominant marketshare in countries where the patent expired earlier.
The active ingredient of Roundup is the isopropylamine salt of glyphosate. Glyphosate's mode of action is to inhibit an enzyme involved in the synthesis of the amino acids tyrosine, tryptophan and phenylalanine. It is absorbed through foliage and translocated to growing points. Weeds and grass will generally re-emerge within one to two months after usage. Because of this mode of action, it is only effective on actively growing plants; it is not effective as a pre-emergence herbicide. Due to the absorption being limited to foliage, soil-bound glyphosate is effectively inert. (See main article glyphosate)
Monsanto also produces seeds which grow into plants genetically engineered to be tolerant to glyphosate which are known as Roundup Ready crops. The genes contained in these seeds, although naturally occurring in other species, are patented (See Glyphosate). Such crops allow farmers to use glyphosate as a post-emergence pesticide against both broadleaf and cereal weeds. Soy was the first Roundup Ready crop and was produced at Monsanto's Agracetus Campus located in Middleton, Wisconsin. Current Roundup Ready crops include maize (corn), sorghum, cotton, soy, canola and alfalfa.
The largest single user of Roundup reportedly is the U.S. Government, which sprays huge quantities of the herbicide over the northern countries of South America in an effort to discourage cultivation of the coca plant. (See article Plan Colombia).
[edit] References
- ^ Herbicide Mode of Action. DE Peterson, DL Regehr and CR Thompson, Kansas State University 2001 [1]
- ^ Williams GM, Kroes R, Munro IC. (2000) Safety evaluation and risk assessment of the herbicide Roundup and its active ingredient, glyphosate, for humans. Regulatory Toxicology and Pharmacology, 31 (2): 117-165. PMID 10854122.
- ^ Nagami et al. (2005). Hospital-based survey of pesticide poisoning in Japan, 1998--2002. Int J Occup Environ Health, 11(2):180-4.PMID 15875894
- ^ Northwest Coalition for Alternatives to Pesticides. 2004. Herbicide Factsheet: Glyphosate (Roundup). Journal of Pesticide Reform, VOL. 24, NO. 4 [2]
- EU (2002). Review report for the active substance glyphosate. Retrieved October 28, 2005.
- U.S. EPA ReRegistration Decision Fact Sheet for Glyphosate. http://www.epa.gov/oppsrrd1/REDs/factsheets/0178fact.pdf]. Retrieved Nov 13, 2005.
- Walsh, et al (2000). "Roundup inhibits steroidogenesis by disrupting steroidogenic acute regulatory (stAR) protein expression.". Environmental Health Perspectives 108-N8: 769-776.
- Sophie Richard, Safa Moslemi, Herbert Sipahutar, Nora Benachour, Gilles-Eric Seralini (2005). "Differential effects of glyphosate and Roundup on human placental cells and aromatase". Environmental Health Perspectives 113-N6: 716-720.
- JP Giesy, KR Solomon, S Dobson (2000). "Ecotoxicological Risk Assessment for Roundup Herbicide". Reviews of Environmental Contamination and Toxicology 167: 35-120.
- GM Williams, R Kroes, JC Munro (2000). "Safety evaluation and risk assessment of the herbicide Roundup and its active ingredient, glyphosate, for humans". Regulatory Toxicology and Pharmacology 31-N2: 117-165.
- KR Solomon, DG Thompson (2003). "Ecological risk assessment for aquatic organisms from over-water uses of glyphosate". Journal of Toxicology and Environmental Health 6: 289-324.
- World Health Organization. (1994) Environmental Health Criteria 159: Glyphosate. [42]
- Monsanto History of Glyphosate.[43]
