Methamidophos
Encyclopedia
Methamidophos is an organophosphate
insecticide
.
Crops grown with the use of methamidophos include some Latin American rice. Many nations use methamidophos on crops, including developed nations such as Spain
, US, Japan
, and Australia
. Due to its toxicity, the use of pesticides that contain methamidophos is currently being phased out in Brazil
.
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.
It is classified as a WHO
Toxicity Class
"Class 1b, Highly Hazardous", and its parent chemical, acephate
, is "class III, Slightly Hazardous".
, 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.
Organophosphate
An organophosphate is the general name for esters of phosphoric acid. Phosphates are probably the most pervasive organophosphorus compounds. Many of the most important biochemicals are organophosphates, including DNA and RNA as well as many cofactors that are essential for life...
insecticide
Insecticide
An insecticide is a pesticide used against insects. They include ovicides and larvicides used against the eggs and larvae of insects respectively. Insecticides are used in agriculture, medicine, industry and the household. The use of insecticides is believed to be one of the major factors behind...
.
Crops grown with the use of methamidophos include some Latin American rice. Many nations use methamidophos on crops, including developed nations such as Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
, US, Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
, and Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
. Due to its toxicity, the use of pesticides that contain methamidophos is currently being phased out in Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
.
Toxicity
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. It is a cholinesteraseCholinesterase
In biochemistry, cholinesterase is a family of enzymes that catalyze the hydrolysis of the neurotransmitter acetylcholine into choline and acetic acid, a reaction necessary to allow a cholinergic neuron to return to its resting state after activation.-Types:...
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.
It is classified as a WHO
Who
Who may refer to:* Who , an English-language pronoun* who , a Unix command* Who?, one of the Five Ws in journalism- Art and entertainment :* Who? , a 1958 novel by Algis Budrys...
Toxicity Class
Toxicity Class
Toxicity Class refers to a classification system for pesticides that has been created by a national or international government-related or -sponsored organization...
"Class 1b, Highly Hazardous", and its parent chemical, acephate
Acephate
Acephate is an organophosphate foliar insecticide of moderate persistence with residual systemic activity of about 10-15 days at the recommended use rate. It is used primarily for control of aphids, including resistant species, in vegetables and in horticulture...
, is "class III, Slightly Hazardous".
Use
Methamidophos is used in great quantities in ricefields in China. Rice–fish culture is common in the southern parts of China as well as in many other rice-producing countries (e.g., ThailandThailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
, Malaysia, and the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
). 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.