Methamidophos

Methamidophos, trade name "Monitor," is an organophosphate insecticide.

Methamidophos
Names
IUPAC name
O,S-Dimethyl phosphoramidothioate
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.030.538
KEGG
UNII
Properties
C2H8NO2PS
Molar mass 141.1 g/mol
Density 1.31 g/cm³
Melting point 44.5 °C (112.1 °F; 317.6 K)
Boiling point thermally unstable
Hazards
R-phrases (outdated) R20, R21
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

Crops grown with the use of methamidophos include potatoes[1] and some Latin American rice[2] Many nations have used methamidophos on crops, including developed nations such as Spain, United States, Japan, and Australia. Due to its toxicity, the use of pesticides that contain methamidophos is currently being phased out in Brazil. In 2009, all uses in the United States were voluntarily canceled.[3]

Toxicity

LD50 rates of 21 and 16 mg/kg for male and female rats, respectively. 10–30 mg/kg in rabbits, and dermal LD50 of 50 mg/kg in rats. It is rapidly absorbed through the stomach, lungs, and skin in humans, and eliminated primarily through urine.[4] It is a cholinesterase inhibitor.

Breakdown in soil is 6.1 days in sand, 309 days in water at pH 5.0, 27 days at pH 7.0, and 3 days at pH 9.0. Sunlight accelerates breakdown. It is uptaken through roots and leaves of plants.[4]

It is classified as a WHO Toxicity Class "Class 1b, Highly Hazardous", and its parent chemical, acephate, is "class III, Slightly Hazardous".

Use

Methamidophos is used in great quantities in ricefields in China.[5] Rice–fish culture is common in the southern parts of China as well as in many other rice-producing countries (e.g., Thailand, Malaysia, and the Philippines). Brown rice (unpolished) in this study contained double the concentration of polished rice. Both plants and animals did not degrade the pesticide well, and fish for human consumption in these cases contains methamidophos in concentrations roughly similar to brown rice.[5]

Use in poisoning

Methamidophos was found in dumplings (gyoza) manufactured in China for the Japanese market after a number of consumers became sick.[6]

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gollark: Technologies have a lot of prerequisites.
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gollark: The people in the past *were actually quite smart*.
gollark: Well, DRAM wasn't used for most of computing history.

References
  1. name="http://pmep.cce.cornell.edu/profiles/insect-mite/fenitrothion-methylpara/methamidophos/insect-prof-methamidophos.html"
  2. Did Your Shopping List Kill A Songbird? Bridget Stutchbury, New York Times March 30, 2008
  3. "Federal Register / Vol. 74, No. 183 / Wednesday, September 23, 2009 / Notices" (PDF). US EPA. 23 September 2009. Retrieved 13 February 2018.
  5. International Development Research Center Archived 2009-03-14 at the Wayback Machine
  6. Japan Times http://www.japantoday.com/category/crime/view/china-launches-contaminated-dumplings-probe
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