| Revision as of 08:32, 5 February 2007 view sourceTtguy (talk | contribs)Extended confirmed users1,190 edits →Toxicity - update the reference for the Journal of Pesticide Reform to a 2004 version of the document because this version is on line← Previous edit | Revision as of 15:36, 5 February 2007 view source Benjiwolf (talk | contribs)940 edits everything in there is referenced by the articles/links i added...the japanese deaths are already referenced...i added a range of ref., even monsantos,taking out what is critical is patheticNext edit → | ||
| Line 13: | Line 13: | ||
| == Toxicity== | == Toxicity== | ||
| Glyphosate is classed as a moderately toxic ] and in EPA toxicity class 2. It is reported to cause many of the cases of toxic herbicide exposure in California and is the third most likely pesticide/herbicide formulation to cause incidents |
Glyphosate is classed as a moderately toxic ] and in EPA toxicity class 2. Issues of its toxicty usually concern its co-ingredients. A letter to the lancet reported 56 toxic exposures to glyphosate formulations in Japan between 1984-1986 with adverse repsiratory, cardiovascular, and neurotoxic effects leading to 9 deaths. It is reported to cause many of the cases of toxic herbicide exposure in California and is the third most likely pesticide/herbicide formulation to cause incidents. In the UK it is the most frequently cited to cause incidents, yet all of this stems partly from the fact that gyphosate is one of the most frequently used herbicides. Monasanto has been adjusting its formulations to address this, yet older formulations are still available, and especially in countries with lower standards than the UK. ]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 unlisted as they are "trade secrets". The direct toxicity of ''pure'' glyphosate to ] and ] is reportedly low . However, its effect on flora can have a damaging effect on mammals and birds through ] destruction. The ] concluded that many endangered species of plants, as well as the Houston toad, may be at risk from glyphosate use. It has been reported 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. | ||
| ⚫ | ] and ] are more sensitive to formulations of glyphosate. As with humans, the surfactants are responsible for much of the harm . Toxicity is increased with higher water temperatures, and pH. 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 glyphosate, Monsanto corporation had adjusted its formulations for Australia in the late 1990s to address this issue with its "Biactive" line of products. | ||
| The surfactant of roundup has been reported to be toxic to Fish and aquatic invertebrates<ref> | |||
| ⚫ | |||
| Of nine ] tested for their toxicity to ], glyphosate formulations were found to be the second most toxic to a range of bacteria, fungi, actinomycetes and yeasts.<ref>Northwest Coalition for Alternatives to Pesticides. |
Of nine ] tested for their toxicity to ], glyphosate formulations were found to be the second most toxic to a range of bacteria, fungi, actinomycetes and yeasts.<ref>Northwest Coalition for Alternatives to Pesticides. 1998. Herbicide Factsheet: Glyphosate (Roundup). Journal of Pesticide Reform, vol. 18</ref> However, when glyphosate comes into contact with the soil it rapidly binds to soil particles and is inactivated. Unbound glyphosate is degraded by bacteria. Low activity because of binding to soil particles suggests that glyphosate's effects on ] will be limited. However, some recent work shows that glyphosate can be readily released from certain types of ], 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. | ||
| Glyphosate as a pure ingredient is of far less concern than many other herbicides, pesticides, and chemicals such as those from the ] family. 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. 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. | Glyphosate as a pure ingredient is of far less concern than many other herbicides, pesticides, and chemicals such as those from the ] family. 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. 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. | ||
| ==Health concerns== | ==Health concerns== | ||
Revision as of 15:36, 5 February 2007
Glyphosate (N-(phosphonomethyl) glycine, C3H8NO5P) is a non-selective systemic herbicide to kill weeds, especially perennials.
Glyphosate is the primary ingredient in Monsanto's much used 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.
Chemistry
Glyphosate is an aminophosphonic analogue of the natural amino acid glycine and the name is a contraction of glycine, phospho-, and -ate. It was first discovered to have herbicidal activity in 1970 by John Franz, a scientist that worked for the Monsanto company, who in 1987 received the National Medal of Technology for his discoveries.
Biochemistry
Glyphosate kills plants by inhibiting the enzyme 5-enolpyruvoyl-shikimate-3-phosphate synthase (EPSPS), which forms the aromatic amino acids: phenylalanine, tyrosine and tryptophan. The production of Chorismate is ultimately stopped by the presence of the glyphosphate. EPSPS catalyzes the reaction of shikimate 3-phosphate (S3P) and phosphoenolpyruvate (PEP) to form ESP and phosphate. The aromatic amino acids are also used to make secondary metabolites such as folates, ubiquinones and naphthoquinones. The shikimate pathway is not present in animals. CAS: 1071-83-6
Toxicity
Glyphosate is classed as a moderately toxic herbicide and in EPA toxicity class 2. Issues of its toxicty usually concern its co-ingredients. A letter to the lancet reported 56 toxic exposures to glyphosate formulations in Japan between 1984-1986 with adverse repsiratory, cardiovascular, and neurotoxic effects leading to 9 deaths. It is reported to cause many of the cases of toxic herbicide exposure in California and is the third most likely pesticide/herbicide formulation to cause incidents. In the UK it is the most frequently cited to cause incidents, yet all of this stems partly from the fact that gyphosate is one of the most frequently used herbicides. Monasanto has been adjusting its formulations to address this, yet older formulations are still available, and especially in countries with lower standards than the UK. ]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 unlisted as they are "trade secrets". The direct toxicity of pure glyphosate to mammals and birds is reportedly low . However, its effect on flora can have a damaging effect on mammals and birds through habitat destruction. The US EPA concluded that many endangered species of plants, as well as the Houston toad, may be at risk from glyphosate use. It has been reported 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.
Fish and invertebrates are more sensitive to formulations of glyphosate. As with humans, the surfactants are responsible for much of the harm . Toxicity is increased with higher water temperatures, and pH. 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 glyphosate, Monsanto corporation had adjusted its formulations for Australia in the late 1990s to address this issue with its "Biactive" line of products.
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. However, when glyphosate comes into contact with the soil it rapidly binds to soil particles and is inactivated. Unbound glyphosate is degraded by bacteria. Low activity because of binding to soil particles suggests that glyphosate's effects on soil flora will be limited. However, some 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.
Glyphosate as a pure ingredient is of far less concern than many other herbicides, pesticides, and chemicals such as those from the organochlorine family. 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. 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.
Health concerns
There are concerns about the effects of glyphosate (and Roundup) on non-plant species even including on possible human reproductive dysfunction. For more information, see the Roundup article.
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.
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. Current toxicological studies of higher order mammals (EU 2002) have suggested no endocrine disruption even at high doses.
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, and should shed more light on the debate.
Glyphosate resistance
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.
Genetically modified crops
In 1996, genetically modified soybeans were available commercially(). 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.
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).
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.
References
- Northwest Coalition for Alternatives to Pesticides. 1998. Herbicide Factsheet: Glyphosate (Roundup). Journal of Pesticide Reform, vol. 18
- 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.
{{cite journal}}: Explicit use of et al. in:|author=(help) - 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.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - JP Giesy, KR Solomon, S Dobson (2000). "Ecotoxicological Risk Assessment for Roundup Herbicide". Reviews of Environmental Contamination and Toxicology. 167: 35–120.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - 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.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - 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.
- Monsanto History of Glyphosate.
External links
- Monsanto Website - Background Information about Glyphosate and Roundup
- US weighs costs of Plan Colombia
- Effect of Glyphosate on human placental cells in culture
- Website of the SynBioC research group, working on different types of aminophosphonates