Paraquat
IUPAC name	1,1'-dimethyl-4,4'-bipyridinium dichloride
Other names	paraquat dichloride; methyl viologen dichloride; Crisquat; Dexuron; Esgram; Gramuron; Ortho Paraquat CL; Para-col; Pillarxone; Tota-col; Toxer Total; PP148; Cyclone; Gramixel; Gramoxone; Pathclear; AH 501.
Identifiers
CAS number	[1910-42-5]
SMILES	[Cl-].[Cl-].C[n+]1ccc(cc1)c2cc[n+](C)cc2
InChI	1/C12H14N2.2ClH/c1- 13-7-3-11(4-8-13)12- 5-9-14(2)10-6-12;;/ h3-10H,1-2H3;2*1H/ q+2;;/p-2/fC12H14N2.2Cl/ h;2*1h/qm;2*-1
Properties
Molecular formula	C12H14Cl2N2
Molar mass	257.16 g/mol
Appearance	off-white powder
Density	1.25 g/cm3, solid
Melting point	175 - 180 °C [1] Image File history File links Size of this preview: 800 × 399 pixelsFull resolution (1100 × 549 pixel, file size: 139 KB, MIME type: image/png) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File links Paraquat. ... IUPAC nomenclature is a system of naming chemical compounds and of describing the science of chemistry in general. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... The simplified molecular input line entry specification or SMILES is a specification for unambiguously describing the structure of chemical molecules using short ASCII strings. ... The IUPAC International Chemical Identifier (InChI), developed by IUPAC and NIST, is a digital equivalent of the IUPAC name for any particular covalent compound. ... A chemical formula is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... Molar mass is the mass of one mole of a chemical element or chemical compound. ... For other uses, see Density (disambiguation). ... The melting point of a crystalline solid is the temperature range at which it changes state from solid to liquid. ...
Boiling point	> 300 °C [1] Italic text This article is about the boiling point of liquids. ...
Solubility in water	high
Hazards
Main hazards	Toxic
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Paraquat is the trade name for N,N'-Dimethyl-4,4'-bipyridinium dichloride, a viologen. Paraquat is used as a quaternary ammonium herbicide. It is dangerously poisonous to humans if swallowed. Other members of this class include diquat, cyperquat, diethamquat, difenzoquat, and morfamquat. All of these are easily reduced to the radical ion, which generates superoxide radical that reacts with unsaturated membrane lipids. Solubility is a chemical property referring to the ability for a given substance, the solute, to dissolve in a solvent. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... The examples and perspective in this article or section may not represent a worldwide view. ... The plimsoll symbol as used in shipping In chemistry, the standard state of a material is its state at 1 bar (100 kilopascals exactly). ... Viologen, 4,4-bipyridylium salt, compound of the form R2C10H8N22+2X- , where R can be a substituent for a nitrogen atom and the anion needed to keep charge neatrality. ... An herbicide is used to kill unwanted plants. ... Structural formula of Paraquat Paraquat is the trade name for N,N-Dimethyl-4,4-bipyridinium dichloride, a quaternary ammonium herbicide. ... Lewis electron configuration of superoxide. ... Some common lipids. ...

History

Paraquat was first produced for commercial purposes in 1961 by ICI (now Syngenta) and is today among the most commonly used herbicides. Year 1961 (MCMLXI) was a common year starting on Sunday (link will display full calendar) of the Gregorian calendar. ... This article does not cite any references or sources. ... Syngenta AG is a large global agribusiness which markets seeds and crop protection products (pesticides). ...

The European Union allowed Paraquat in 2004. Sweden, supported by Denmark, Austria, and Finland, brought the European Union commission to court. On 11 July 2007 the court annulled the directive authorising Paraquat as an active plant protection substance.^[2]

Herbicide use

The compound is one of the most widely used herbicides in the world. It is quick-acting, non-selective, and kills green plant tissue on contact. It is redistributed within the plant but does not harm mature bark.

Being a herbicide, paraquat protects crops by controlling a wide range of annual and certain perennial weeds that reduce crop yield and quality by competing with the crop for water, nutrients, and light. Yellow starthistle, a thistle native to southern Europe and the Middle East that is an invasive weed in parts of North America. ...

The key characteristics that distinguish the non-selective contact herbicide paraquat from other active ingredients used in plant protection products are:

• Paraquat is non-selective, which means it kills a wide range of annual grasses and broad-leaved weeds and the tops of established perennial weeds.
• Paraquat is very fast-acting.
• Paraquat is rain-fast within minutes of application.
• Paraquat becomes biologically inactive upon contact with soil.^[3]

In the United States, paraquat is available primarily as a liquid in various strengths. It is classified as "restricted use," which means that it can be used only by licensed applicators. As with many chemicals, caution must be exercised during use. For other uses, see Grass (disambiguation). ...

In the European Union, paraquat has been forbidden since July 11th 2007.

Health risks

Pure paraquat ingested is highly toxic to mammals and humans potentially leading to acute respiratory distress syndrome (ARDS), and there are no specific antidotes. However, fuller's earth or activated charcoal is an effective treatment, if taken in time. Death may be up to 30 days after ingestion. Diluted paraquat used for spraying is less so, thus the greatest risk of accidental poisoning is during mixing and loading paraquat for use.^[4] Fullers earth is any nonplastic clay or claylike material that can be used to decolorize, filter, and purify animal, mineral, and vegetable oils and greases. ... Activated carbon (also called activated charcoal) is the more general term which includes material mostly derived from charcoal. ...

In acute toxicity studies using laboratory animals, paraquat has been shown to be highly toxic by the inhalation route and has been placed in Toxicity Category I (the highest of four levels) for acute inhalation effects. However, the EPA has determined that particles used in agricultural practices (400 to 800 μm) are well beyond the respirable range and therefore inhalation toxicity is not a toxicological endpoint of concern. Paraquat is toxic (Category II) by the oral route and moderately toxic (Category III) by the dermal route. Paraquat will cause moderate to severe eye irritation and minimal dermal irritation, and has been placed in Toxicity Categories II and IV (slightly toxic) for these effects.^[5]

Even a single swig immediately spat out can cause death from fibrous tissue developing in the lungs leading to asphyxiation.^[6]

According to the Center for Disease Control, ingesting paraquat causes symptoms such as liver, lung, heart, and kidney failure within several days to several weeks that could lead to death up to 30 days after ingestion. Those who suffer large exposures are unlikely to survive. Chronic exposure can lead to lung damage, kidney failure, heart failure, and oesophageal strictures.^[7] Accidental deaths and suicides from paraquat ingestion are relatively common. For example, there have been 18 deaths in Australia from paraquat poisoning since 2000.^[8] The Centers for Disease Control and Prevention (CDC) in Atlanta is recognized as the lead United States agency for protecting the public health and safety of people by providing credible information to enhance health decisions, and promoting health through strong partnerships with state health departments and other organizations. ... A symptom is a manifestation of a disease, indicating the nature of the disease, which is noticed by the patient. ... The liver is the largest internal organ in the human body, and is an organ present in vertebrates and some other animals. ... Human respiratory system The lungs flank the heart and great vessels in the chest cavity. ... The heart and lungs, from an older edition of Grays Anatomy. ... The kidneys are the organs that filter wastes (such as urea) from the blood and excrete them, along with water, as urine. ...

Paraquat-induced toxicity in rats has also been linked to Parkinson's-like pathological degenerative mechanisms.^[9] A study by the Buck Institute shows a connection between exposure to paraquat and iron in infancy and mid-life Parkinson's in laboratory mice.^[10] Parkinsons disease (PD; paralysis agitans) is a neurodegenerative disease of the substantia nigra (an area in the basal ganglia of the brain). ...

Long term exposures to paraquat would most likely cause lung and eye damage, but reproductive/fertility damage was not found by the EPA in their review. Some suspect a possible link to a greater incidence of Parkinson's disease.

Emergency care

Persons exposed to or contaminated by paraquat, with any suspected ingestion or absorption, should be treated by emergency medical services immediately. Prehospital care should follow these guidelines: ^[11]

• Remove patient from further contact with substance.
• Decontaminate with large volumes of water; remove patient's clothing.
• Avoid secondary contamination by contact either with substance or runoff from decontamination efforts.
• Establish and maintain a patent airway.
• The administration of supplemental oxygen is advised against; however, prudent patient care dictates that oxygen should not be withheld from persons exhibiting clinical signs and symptoms of hypoxia. Emergency medical services personnel should consult with their medical control physician for specific case-by-case guidance.
• Provide supportive treatment as indicated.
• Consider evacuation to an appropriate hospital by helicopter; if air evacuation is not available, expedite transport by ground ambulance.
• In the case of contamination of the eye, irrigate the affected eye with normal saline solution for at least 15 minutes.

This article is about the chemical element and its most stable form, or dioxygen. ... The term symptom (from the Greek syn = con/plus and pipto = fall, together meaning co-exist) has two similar meanings in the context of physical and mental health: A symptom can be a physical condition which shows that one has a particular illness or disorder (see e. ... Hypoxia is a pathological condition in which the body as a whole (generalised hypoxia) or region of the body (tissue hypoxia) is deprived of adequate oxygen supply. ... An Emergency medical service (abbreviated to initialism EMS in many countries) is a service providing out-of-hospital acute care and transport to definitive care, to patients with illnesses and injuries which the patient believes constitutes a medical emergency. ... For other uses, see Doctor. ... For the town in the Republic of Ireland, see Hospital, County Limerick. ... For other uses, see Helicopter (disambiguation). ... An ambulance in San Jose del Cabo, Mexico A Helicopter used as an Ambulance. ... In medicine saline is a solution of sodium chloride in water. ...

Paraquat Pot

During the late 1960s, a controversial program sponsored by the US government sprayed paraquat on marijuana fields in South America. Since much of this marijuana was subsequently smoked by Americans, the US government's "Paraquat Pot" program stirred much debate. Perhaps in an attempt to deter people from using marijuana, representatives of the program warned that spraying rendered the crop unsafe to smoke. However, independent bodies have studied paraquat in this use. Jenny Pronczuk de Garbino, ^[12] stated: "no lung or other injury in marijuana users has ever been attributed to Paraquat contamination". Cannabis, also known as marijuana[1] or ganja (Hindi: गांजा),[2] is a psychoactive product of the plant Cannabis sativa. ...

On this topic, D.P. Morgan states in a United States Environmental Protection Agency publication that: "Smoking Paraquat-contaminated marijuana does not result in lung damage as the herbicide is pyrolyzed to dipyridyl (which does not present a toxic hazard) during smoking". ^[13] EPA redirects here. ... Cannabis, also known as marijuana[1] or ganja (Hindi: गांजा),[2] is a psychoactive product of the plant Cannabis sativa. ... Bipyridines form a family of chemical compounds with the formula (C5H4N)2. ...

References

1. ^ ^{a b} Paraquat dichloride. International Programme on Chemical Safety (October 2001).
2. ^ COURT OF FIRST INSTANCE OF THE EUROPEAN COMMUNITIES, PRESS RELEASE No° 45/07
3. ^ Revkin, A. C. 1983. Paraquat: A potent weed killer is killing people. Science Digest 91(6):36-38, 42, 100-104.
4. ^ PAN UK, Paraquat, accessed 13 October 2006.
5. ^ EPA, [1], accessed 16 August 2007.
6. ^ Buzik, Shirley C.; Schiefer, H. Bruno; Irvine, Donald G. (1997). Understanding Toxicology: Chemicals, Their Benefits and Risks. Boca Raton: CRC Press, 31. ISBN 0-8493-2686-9. 
7. ^ Center for Disease Control, Facts about Paraquat, accessed 13 October 2006.
8. ^ "Poisoned Latrobe," Gary Stevens, Valley Express Feb. 8, 2008.
9. ^ K. Ossowska, M. S'Mialowska, K. Kuter, J. Wieron'ska, B. Zieba, J. Wardas, P. Nowak, J. Dabrowska, A. Bortel, I. Biedka, G. Schulze and H. Rommelspacher (2006). "Degeneration of dopaminergic mesocortical neurons and activation of compensatory processes induced by a long-term paraquat administration in rats: Implications for Parkinson's disease". Neuroscience 141 (4): 2155-2165. doi:10.1016/j.neuroscience.2006.05.039. 
10. ^ Buck Institute for Aging Research (June 2007). "Combined Exposure to Environmental Toxics Accelerates Age-related Development of Parkinson's Disease in Mice". Press release.
11. ^ Halpin, Ted; Eric Hallman, Ellen Abend, Tonya Van Slyke (2005). Cornell Farmedic Training Program Student Manual. Ithaca, NY: Cornell University Press. 
12. ^ Pronczuk de Garbino J, Epidemiology of paraquat poisoning, in: Bismuth C, and Hall AH (eds), Paraquat Poisoning: Mechanisms, Prevention, Treatment, pp. 37-51, New York: Marcel Dekker, 1995.
13. ^ Reigart, J. Routt and Roberts, James R. Recognition and Management of Pesticide Poisonings, 5th edition. Washington, DC: United States Environmental Protection Agency, 1999. Book available online

EPA redirects here. ... The Centers for Disease Control and Prevention (CDC) in Atlanta is recognized as the lead United States agency for protecting the public health and safety of people by providing credible information to enhance health decisions, and promoting health through strong partnerships with state health departments and other organizations. ... Drawing of the cells in the chicken cerebellum by S. Ramón y Cajal Neuroscience is a field that is devoted to the scientific study of the nervous system. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... For information on Wikipedia press releases, see Wikipedia:Press releases. ... EPA redirects here. ...

External links

• Safety (MSDS) data for paraquat. Oxford University.
• Sweden announces legal challenge to EU position on paraquat. European Public Health Alliance (8 March 2004).
• Stop Paraquat. The Berne Declaration.
• The Paraquat Information Center. Syngenta Crop Protection AG.