Malathion 745387 223081902 2008-07-02T14:08:41Z Thijs!bot 1392310 robot Adding: [[ja:マラチオン]] {{Chembox new |ImageFile1=Malathion.png |ImageName1=Skeletal formula of malathion |ImageFile2=Malathion-3D-sticks.png |ImageName2=3D representation of malathion |ImageFile3=Malathion-3D-vdW.png |ImageName3=filling model of malathion, showing [[van der Waals radius|van der Waals radii]] for each atom |IUPACName=2-(dimethoxyphosphinothioylthio) butanedioic acid diethyl ester |OtherNames=Malathion<br>Carbofos<br>Maldison<br>Mercaptothion |Section1= {{Chembox Identifiers | CASNo=121-75-5 | PubChem=4004 | SMILES=CCOC(=O)CC(C(=O)OCC)SP(=S)(OC)OC }} |Section2= {{Chembox Properties | Formula=C<sub>10</sub>H<sub>19</sub>O<sub>6</sub>PS<sub>2</sub> | MolarMass=330.358021 | Appearance= | Density=1.23 g/cm<sup>3</sup> | MeltingPt=2.9 °C | BoilingPt=156-157 °C at 0.7 mmHg | Solubility= }} |Section3= {{Chembox Hazards | MainHazards= | FlashPt= | Autoignition= }} }} '''Malathion''' is an [[organophosphate]] [[parasympathomimetic]] which binds irreversibly to [[cholinesterase]]. Malathion is an [[insecticide]] of relatively low human [[toxicity]]. In the former [[USSR]] it was known as '''carbophos''', in [[New Zealand]] and [[Australia]] as '''maldison''' and in [[South Africa]] as '''mercaptothion'''.<ref>{{cite web |url=http://www.alanwood.net/pesticides/malathion.html |title=alanwood.net |accessdate=2007-09-16 |format= |work=}}</ref> ==Pesticide use== Malathion is a pesticide that is widely used in agriculture, residential landscaping, public recreation areas, and in public health pest control programs such as mosquito eradication.<ref>[http://www.epa.gov/opp00001/health/mosquitoes/malathion4mosquitoes.htm#malathion Malathion for mosquito control], US EPA</ref> In the US, it is the most commonly used organophosphate insecticide. <ref name="pmid17720683">{{cite journal |author=Bonner MR, Coble J, Blair A, ''et al'' |title=Malathion Exposure and the Incidence of Cancer in the Agricultural Health Study |journal= American Journal of Epidemiology|volume= 166|issue= |pages=1023|year=2007 |pmid=17720683 |doi=10.1093/aje/kwm182}}</ref> Malathion was used in the 1980s in [[California]] to combat the [[Mediterranean Fruit Fly]]. This was accomplished on a wide scale by the near weekly [[Aerial application|aerial spraying]] of suburban communities for a period of several months. Formations of three or four [[Agricultural aircraft|agricultural helicopters]] would overfly suburban portions of Alameda County, [[San Bernardino County, California|San Bernardino county]], and Santa Clara County <!-- other counties too? --> releasing a mixture of malathion and [[corn syrup]], the corn syrup being a bait for the fruit flies. Malathion has also been used to combat the Mediterranean Fruit Fly in Australia.<ref name="pmid16914134">{{cite journal |author=Edwards JW, Lee SG, Heath LM, Pisaniello DL |title=Worker exposure and a risk assessment of malathion and fenthion used in the control of Mediterranean fruit fly in South Australia |journal=Environ. Res. |volume=103 |issue=1 |pages=38–45 |year=2007 |pmid=16914134 |doi=10.1016/j.envres.2006.06.001}}</ref> Malathion was sprayed in many cities to combat [[West Nile virus]]. In the Fall of 1999 and the Spring of 2000, [[Long Island]] and the five boroughs of [[New York City]] were sprayed with several pesticides, one of which was malathion. While it was claimed by some anti-pesticide groups that use of these pesticides caused a lobster die-off in Long Island Sound, there is as of yet no conclusive evidence to support this.<ref>[http://www.seagrant.sunysb.edu/LILobsters/Oct04Meeting/summaries/LISLISummary-Pesticides.pdf ModelContaminants_Toxic Effec<!-- Bot generated title -->]</ref> Research, however, is still continuing on this topic. [[Manitoba]], [[Province of Canada]], ordered the city of [[Winnipeg, Manitoba]] to be sprayed in [[July 2005]] as part of the [[West Nile virus]] campaign. Prior to this, Malathion was used over the last couple of decades on regular basis during summer months to kill nuisance mosquitos, but homeowners were allowed to exempt their properties if they chose. Today, [[Winnipeg]] is the only major city in [[Canada]] with an ongoing Malathion nuisance-adult-mosquito-control program. Malathion is also used in conjunction with [[diesel]] fuel to fog an area where there is an infestation of [[mosquitoes]]. By diluting the mixture, it becomes much weaker. It is possible to dilute the mixture to the point where mosquitoes are not killed, but become more resistant to the mixture, making it less effective in subsequent foggings. ==Clinical use== Malathion in low doses (0.5% preparations) is used as a treatment for [[head lice]], [[body lice]], and [[scabies]]. Preparations include Derbac-M, Prioderm, and Quellada-M.<ref>British National Formulary 54th Ed. Sept 2007. ISBN 9780853697367. ISSN0260-535X </ref> It is claimed to effectively kill both the eggs and the adult lice, but in fact has been shown in UK studies to be only 36% effective on lice, and less so on the eggs.<ref>{{cite journal |author=Downs AM, Stafford KA, Harvey I, Coles GC |title=Evidence for double resistance to permethrin and malathion in head lice |journal=Br. J. Dermatol. |volume=141 |issue=3 |pages=508–11 |year=1999 |pmid=10583056 |doi=10.1046/j.1365-2133.1999.03046.x}}</ref> ==Risks== ===General=== Malathion itself is not toxic; however, absorption or ingestion into the human body readily results in its metabolism to [[malaoxon]], which is toxic in high amounts. Chronic exposure to low levels of malathion have been hypothesized to impair memory, but this is disputed. There is currently no reliable information on adverse health effects of chronic exposure to malathion.<ref>{{cite web |url=http://www.atsdr.cdc.gov/MHMI/mmg154.html |title=US Department of Health and Human Services: Agency for Toxic Substances and Disease Registry - Medical Management Guidelines for Malathion |accessdate=2008-04-02 |format= |work=}}</ref> Acute exposure to extremely high levels of malathion will cause body-wide symptoms whose intensity will be dependent on the severity of exposure. Possible symptoms include skin and eye irritation, cramps, nausea, diarrhea, excessive sweating, seizures and even death. Most symptoms tend to resolve within several weeks. Malathion present in untreated water is converted to malaoxon during the chlorination phase of water treatment, so malathion should not be used in waters that may be used as a source for drinking water, or any upstream waters. In [[1976]], numerous [[malaria]] workers in [[Pakistan]] were poisoned by [[isomalathion]], a contaminant that may be present in some preparations of malathion. <ref name="pmid74508">{{cite journal |author=Baker EL, Warren M, Zack M, ''et al'' |title=Epidemic malathion poisoning in Pakistan malaria workers |journal=Lancet |volume=1 |issue=8054 |pages=31–4 |year=1978 |pmid=74508 |doi=}}</ref> It is capable of inhibiting [[carboxyesterase]] enzymes in those exposed to it. It was discovered that poor work practices had resulted in excessive direct skin contact with isomalathion contained in the malathion solutions. Implementation of good work practices, and the cessation of use of malathion contaminated with isomalathion led to the cessation of poisoning cases. ===Carcinogenicity=== Malathion is classified by US EPA as having “suggestive evidence of carcinogenicity but not sufficient to assess human carcinogenic potential.”<ref>[http://www.epa.gov/pesticides/reregistration/REDs/malathion_red.pdf Reregistration Eligibility Decision for Malathion], US EPA</ref> This rating implies that insufficient evidence is available to either rule out malathion as a carcinogen, or to state that it is a carcinogen. No studies on carcinogenicity have been performed in humans; however, studies in rats and mice have yielded conflicting results. Liver tumours were found to be induced in rats, but only at excessive doses. On the other hand, malaoxon, a structurally related chemical, was found not induce tumour formation in rats. A review of the classification of malathion as 'suggestive' was carried out in 2000, by the FIFRA Scientific Advisory Panel. The conclusion of this panel was that there was still insufficient evidence to either declare malathion as non-carcinogenic, or to declare it a carcinogen. ==See also== *[[Pesticide toxicity to bees]] ==References== {{reflist}} ==External links== *[http://npic.orst.edu/factsheets/malatech.pdf Malathion Technical Fact Sheet - National Pesticide Information Center] *[http://npic.orst.edu/factsheets/malagen.pdf Malathion General Fact Sheet - National Pesticide Information Center] *[http://extoxnet.orst.edu/pips/malathio.htm Malathion Pesticide Information Profile - Extension Toxicology Network] *[http://www.atsdr.cdc.gov/tfacts154.html ATSDR ToxFAQs] {{Ectoparasiticides}} [[Category:Antiparasitic agents]] [[Category:Organophosphate insecticides]] [[Category:Insecticide brands]] [[cs:Malation]] [[de:Malathion]] [[es:Malatión]] [[fa:مالاتیون]] [[fr:Malathion]] [[it:Malatione]] [[nl:Malathion]] [[ja:マラチオン]] [[pt:Malathion]]