![]() ![]() Insects with certain mutations in their sodium channel gene are resistant to DDT and similar insecticides. In insects, DDT opens voltage-sensitive sodium ion channels in neurons, causing them to fire spontaneously, which leads to spasms and eventual death. India is the only country still manufacturing DDT, and is the largest consumer. In 2009, 3,314 tonnes were produced for malaria control and visceral leishmaniasis. Usage peaked in 1959 at about 36,000 tonnes. More than 600,000 tonnes (1.35 billion pounds) were applied in the US before the 1972 ban. Production peaked in 1963 at 82,000 tonnes per year. In the United States, it was manufactured by some 15 companies, including Monsanto, Ciba, Montrose Chemical Company, Pennwalt, and Velsicol Chemical Corporation. įrom 1950 to 1980, DDT was extensively used in agriculture – more than 40,000 tonnes each year worldwide – and it has been estimated that a total of 1.8 million tonnes have been produced globally since the 1940s. ĭDT has been formulated in multiple forms, including solutions in xylene or petroleum distillates, emulsifiable concentrates, water- wettable powders, granules, aerosols, smoke candles and charges for vaporizers and lotions. DDT, DDE and DDD are sometimes referred to collectively as DDX. DDE and DDD are also the major metabolites and environmental breakdown products. Dichlorodiphenyldichloroethylene (DDE) and dichlorodiphenyldichloroethane (DDD) make up the balance of impurities in commercial samples. The o, p ' isomeric impurity is also present in significant amounts (15%). The major component (77%) is the desired p, p ' isomer. Due to the nature of the chemical reaction used to synthesize DDT, several combinations of ortho and para arene substitution patterns are formed. Isomers and related compounds Ĭommercial DDT is a mixture of several closely related compounds. DDT has been marketed under trade names including Anofex, Cezarex, Chlorophenothane, Dicophane, Dinocide, Gesarol, Guesapon, Guesarol, Gyron, Ixodex, Neocid, Neocidol and Zerdane INN is clofenotane. DDT does not occur naturally and is synthesised by consecutive Friedel–Crafts reactions between chloral ( CClģCHO) and two equivalents of chlorobenzene ( CĥCl), in the presence of an acidic catalyst. It is highly hydrophobic and nearly insoluble in water but has good solubility in most organic solvents, fats and oils. Properties and chemistry ĭDT is similar in structure to the insecticide methoxychlor and the acaricide dicofol. Īlong with the passage of the Endangered Species Act, the United States ban on DDT is a major factor in the comeback of the bald eagle (the national bird of the United States) and the peregrine falcon from near-extinction in the contiguous United States. DDT still has limited use in disease vector control because of its effectiveness in killing mosquitos and thus reducing malarial infections, but that use is controversial due to environmental and health concerns. Ī worldwide ban on agricultural use was formalized under the Stockholm Convention on Persistent Organic Pollutants which has been in effect since 2004. Although Carson never directly called for an outright ban on the use of DDT, its publication was a seminal event for the environmental movement and resulted in a large public outcry that eventually led, in 1972, to a ban on DDT's agricultural use in the United States. The book cited claims that DDT and other pesticides caused cancer and that their agricultural use was a threat to wildlife, particularly birds. It talked about environmental impacts that correlated with the widespread use of DDT in agriculture in the United States, and it questioned the logic of broadcasting potentially dangerous chemicals into the environment with little prior investigation of their environmental and health effects. Opposition to DDT was focused by the 1962 publication of Rachel Carson's book Silent Spring. Although it was promoted by government and industry for use as an agricultural and household pesticide, there were also concerns about its use from the beginning. ![]() īy October 1945, DDT was available for public sale in the United States. ![]() Müller was awarded the Nobel Prize in Physiology or Medicine in 1948 "for his discovery of the high efficiency of DDT as a contact poison against several arthropods". DDT was used in the second half of World War II to limit the spread of the insect-borne diseases malaria and typhus among civilians and troops. DDT's insecticidal action was discovered by the Swiss chemist Paul Hermann Müller in 1939. DDT was first synthesized in 1874 by the Austrian chemist Othmar Zeidler. Originally developed as an insecticide, it became infamous for its environmental impacts. Dichlorodiphenyltrichloroethane, commonly known as DDT, is a colorless, tasteless, and almost odorless crystalline chemical compound, an organochloride. ![]()
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