Contents

Methamidophos

Methamidophos

Names
Preferred IUPAC name O,S-Dimethyl phosphoramidothioate
Identifiers
CAS Number	10265-92-6 Y
3D model (JSmol)	Interactive image
Beilstein Reference	1098870
ChEBI	CHEBI:38721 Y
ChEMBL	ChEMBL504888 Y
ChemSpider	3954 Y
ECHA InfoCard	100.030.538
EC Number	233-606-0
KEGG	C18667 Y
PubChem CID	4096
RTECS number	TB4970000
UNII	8Z083FM94W Y
UN number	3018 2783
CompTox Dashboard (EPA)	DTXSID6024177
InChI InChI=1S/C2H8NO2PS/c1-5-6(3,4)7-2/h1-2H3,(H2,3,4) Y Key: NNKVPIKMPCQWCG-UHFFFAOYSA-N Y
SMILES O=P(OC)(SC)N
Properties
Chemical formula	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
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H300, H311, H330, H400
Precautionary statements	P260, P264, P270, P271, P273, P280, P284, P301+P310, P302+P352, P304+P340, P310, P312, P320, P321, P322, P330, P361, P363, P391, P403+P233, P405, P501
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

Chemical compound

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

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[edit]

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[edit]

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]

Consumer Toxicity[edit]

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

See also[edit]

• GS-7

References[edit]

External links[edit]

• Methamidophos in the Pesticide Properties DataBase (PPDB)