Othmar Zeidler is a chemist through whose efforts this substance was synthesized in 1873. However, it was not used for a long time and only in 1939, thanks to the efforts of P. Müller, a Swiss chemist, the insecticidal properties inherent in dichlorodiphenyltrichloroethane were revealed. Already at the beginning of 1942, DDT went on sale, quickly gaining popularity around the world.
With its help, it was possible to effectively resist typhoid and malaria, diseases that at that time had the greatest degree of danger to humanity. Spraying alone was enough to ensure reliable protection territory over the next few months.
Muller's efforts were appreciated, and already in 1948 he received Nobel Prize in medicine. However, the substance DDT also had a number of negative characteristics, which led to significant environmental pollution in many countries. As a result, already in the early 70s of the last century, serious restrictions on its production and use came into force, which are still relevant today.
Among the main merits attributed to dichlorodiphenyltrichloroethane, one cannot fail to note the following:
Fighting epidemics with DDT spraying
DDT – chemical drug, included in the category of substances based on organochlorine-type compounds. It has a crystalline structure, its color can be different - gray, white or slightly brownish. It does not interact with water, although under the influence of most organic solvents, including ketones, aromatic hydrocarbons and others, it demonstrates excellent solubility.
In the natural environment, dichlorodiphenyltrichloroethane has a long decomposition period with negative impact on water resources, plants and the soil itself.
Its transmission occurs along the food chain, the pesticide has a tendency to mutate, and when it penetrates inside a living creature, it affects tissues and nervous system, negatively affecting reproductive abilities.
Over time, the pesticide accumulates in the body - it is impossible to remove it through cleansing systems.
As for how DDT is deciphered, there is a combination of three components at once - dichloro-diphenyl-trichloroethane, while the content of 4,4'-isomers reaches 75%.
Among the main analogues of this insecticide, the following are particularly distinguished:
When using the drug, you should adhere to certain rules, not forgetting about your own safety. It is important to remember that dichlorodiphenyltrichloroethane is extremely dangerous and toxic.
The pesticide DDT is especially effective in the following situations:
The manufacturer recommends storing dichlorodiphenyltrichloroethane in a dry and dark place. room temperature. It is important to exclude contact of DDT with products; children’s access to the chemical is also strictly prohibited. Before use, make sure the expiration date is up to date.
When treating exposed areas, the following factors should be considered:
Work with reliable protection
Processing is carried out in the following order:
DDT for home use from pests
DDT has the following advantages:
Effective pest control
For humans, the lethal dose of dichlorodiphenyltrichloroethane is 5-10 g, although very serious consequences are possible with a lesion of 1-1.5 g. Particularly dangerous are oil solutions, from which the pesticide is absorbed at maximum speed.
Dust poisoning causes a feeling of nausea, general weakness of the body, heart problems, pain in the limbs, fever, and a number of other symptoms. Possible problems with the liver and kidneys. In such a case, delay is unacceptable; you should seek qualified medical help as quickly as possible.
Before the medical team arrives, extensive gastric lavage should be performed. To do this, use a suspension of activated carbon or a solution based on sodium bicarbonate at a 2% concentration. After this, you should take a saline laxative. The use of castor oil is strictly contraindicated.
Effects of various pesticides on humans
The answer to the question of what dust is and how the drug affects people has been received. Its use, despite all its effectiveness, is fraught with many dangers, therefore, in the absence of proper knowledge and experience, you should abandon dubious experiments and entrust the work to professionals. This will make it possible to save not only time and money, but also health.
Dichlorodiphenyltrichloroethane, better known by the abbreviation DDT, was synthesized back in 1874, but it was only in 1937 that this compound was discovered to be highly toxic to insects.
The first case of widespread use of the new insecticide was the mass pollination of the Pacific Islands with DDT dust, undertaken by the American army before the liberation of the islands from the Japanese in 1942. This protected the paratroopers from malaria, dengue fever and other tropical diseases carried by insects. In the winter of 1944, American soldiers in Naples were sprayed with dust to kill lice.
After World War II, a new insecticide began to be widely used to destroy agricultural pests, but after some time it became clear that this substance decomposes in nature extremely slowly, according to the food chain is transmitted to other organisms, accumulates in them and slowly poisons them. In addition, DDT-resistant insect lines have emerged that can withstand even tenfold doses of the drug. Therefore, the use of DDT has been banned in most countries for almost thirty years (Sweden was the first to ban this insecticide in 1969). True, the World Health Organization has not banned DDT, but has not financed its purchases by developing countries for a long time. The World Bank doesn't even give loans to countries that still use this insecticide.
However, it is now discovered that there is no better way to control malarial mosquitoes than DDT. When South Africa, far behind other countries, banned the insecticide in 1996, malaria cases rose more than sixfold, and five years later it was allowed again. Just don’t spray it in tons from airplanes flying over cities, ponds, swamps and farmland. Experts now believe that careful use inside homes is quite acceptable. According to the World Health Organization, two grams of DDT per square meter of adobe wall reduces the likelihood of home residents contracting malaria by 90%. Spraying needs to be repeated only once a year. That's why the World Health Organization has endorsed the use of DDT for indoor spraying, saying it is not only the best weapon for fighting malaria mosquitoes, but also the cheapest and most effective of insecticides. If used correctly, DDT poses no threat to nature or humans.
In addition, recently we had to call into question the data on the accumulation of DDT and toxic products of its breakdown in wildlife.
About twenty years ago, ecologists monitoring the content of toxic substances in the fat of marine mammals began to discover unknown substances in fat samples. organic compounds with chlorine atoms in the molecule. Their structure resembled DDT, and it was concluded that the drug and its decomposition products were carried by rivers into the ocean and accumulated there in mammals.
And recently, in a bottle of whale oil, preserved in the last whaler sailing ship that was permanently laid up off the coast of Connecticut (USA), the same compounds were found - as many as 11 of their varieties. Since the fat sample dates back to 1921, when DDT was not produced or used, one can only conclude that these compounds are synthesized somewhere in the ocean. Where exactly is not yet clear, it is only known that something like DDT is produced by symbiotic bacteria that live in sea sponges and, apparently, thereby protect their hosts from being eaten.
DDT (DDT,ethane, dust) is a persistent organic pollutant, an organochlorine insecticide, which was previously used to kill mosquitoes, including malaria, agricultural pests, and locusts. With the help of this insecticide, a typhoid epidemic in Naples was avoided in 1944. The use of DDT also made it possible to reduce mortality from malaria in India, Greece, Italy, and the USSR. The use of this insecticide and several other measures have increased global agricultural production.
DDT is a man-made compound and does not occur in nature. It is quite simple to synthesize, and as an insecticide it is very effective: just getting the substance on the integument of insects. However, DDT is moderately toxic to mammals and humans. In other words, doses that are dangerous for insects when taken once will not cause harm to mammals.
However, in 1973, the use of DDT was banned in many countries around the world.
This decision was justified scientifically: in the course of detailed studies that began in 1962, it turned out that DDT is very dangerous. This substance is highly toxic to fish and aquatic invertebrates, and also inhibits the growth of green algae. It is of low toxicity to birds, but causes thinning in some species. eggshells, and birds of prey are especially sensitive to DDT.
DDT poisoning is characterized by damage to the nervous system, accompanied by convulsions and respiratory failure. This insecticide can also cause severe liver damage. There is evidence that DDT has carcinogenic properties, causes disturbances in the development of embryos and affects the body like the sex hormone estrogen.
The two main and most significant metabolites of DDT in organisms are DDD (dichlorodiphenyldichloroethane) and DDE (dichlorodiphenyldichloroethylene). DDD can be a skin irritant and is a possible carcinogen, according to the International Agency for Research on Cancer (IARC). The main route of its entry into the body is through food. DDE, according to some studies, affects the functioning of the endocrine system.
The main danger of DDT is that this compound is extremely resistant to exposure. Its half-life in soil ranges from 2000 to 6200 days, and its complete decay period has not been determined. At 185°C, DDT evaporates but does not decompose. sunlight has no effect on him. Enzymes that neutralize hazardous substances also practically do not decompose it.
This persistence determines the ability of DDT to migrate - to move long distances from the places of application. It was even found in the liver of penguins in Antarctica, where no one had ever used dust. Just over 20 years of widespread use of DDT has led to the spread of the substance throughout the planet.
In addition, DDT is very poorly soluble in water, but is highly soluble in organic substances, such as cyclohexanone and dichloromethane, as well as in fats. The latter property allows this substance to concentrate in living organisms, entering them from the environment. With each level of the food chain, the level of DDT in the body increases 10 times. Several years after the start of the use of DDT, its content in subcutaneous tissue people reached 20-30 mg/kg, and this substance began to be excreted in breast milk.
The ability to accumulate in living organisms also means that DDT can cause chronic and, at high concentrations, acute poisoning. In other words, this substance turned out to be much more dangerous than one might have expected.
Despite this, after the use of DDT was limited, it continued to be produced and used in many countries, including the territory of the former USSR.
In 2001, during the discussion of the Stockholm Convention on Persistent Organic Pollutants, it was decided not to ban the use of DDT completely, but to limit it, allowing its use to combat vectors of infectious diseases.
Currently, DDT is used in countries in Africa and the Asia-Pacific region. It is especially actively used in India. Some countries continue to use DDT, but do not notify the WHO, as required by the Stockholm Convention.
The persistence of this substance and its metabolites, as well as its continued use, makes it necessary to control the content of DDT in food and in the environment.
IN Russian Federation and in the countries of the Customs Union the content of DDT in food products regulated Technical Regulations of the Customs Union "On the safety of food products", "On grain safety" And "On the safety of milk and dairy products" which defines the relevant standards for dairy products. Current legislative standards can be found on the website compact24.com.
Thin-layer or gas-liquid chromatography (GLC) is commonly used to determine DDT and its metabolites, including DDE, in samples. These complex methods analyzes that require expensive equipment.
As an alternative to analyzing DDT and DDE, we can offer an enzyme-linked immunosorbent assay method, which is much simpler to perform, faster and has high sensitivity.
This is not about Shevchuk, but about the world-famous chlorohydrocarbon 1, 1, 1-trichloro-2,2-bis-(4-chlorophenyl)-ethane, also known as dichlorodiphenyltrichloroethane, DDT, in common parlance - dust.
There were times when humanity could not imagine its life without this pesticide or toxic chemical. Dust powders containing DDT were sprayed in fields, forests, swamps, and apartments; they were added to soap, fabrics, and water used to wipe the floors.
DDT appeared in 1874 in the laboratory of the Austrian chemist Omar Zeidler. The “Birth Certificate” was the “Reports of the German Society of Chemists”. Nobody noticed this. Still harmful insects destroyed up to half the crop and distributed dangerous diseases. Tropical farmers, who suffered more from these scourges than Europeans, did not read chemical journals, and organic chemists did not engage in agriculture.
First World War found a fundamentally new application for the ideas of scientists involved in organic synthesis. They began to create chemical warfare agents. Finally they made peace. Mustard gas and phosgene are no longer required; production conversion is necessary. At this time, insect pests proliferated to the extreme. In our country, at the end of the 20s, meadow moth caterpillars damaged beet crops in such areas that a sad joke appeared - “the moth ate the Dnieper Hydroelectric Station.” (I mean, the same money.)
Organic chemists, seasoned in the battles of the imperialist war, met a new enemy fully armed, and when in 1939 the Swiss Paul Müller reported that 1,1,1-trichloro-2,2-bis-(4-chlorophenyl)-ethane has insecticidal properties, he did not surprise anyone - tens of thousands of compounds have already been tested for this purpose, and thousands have been prepared for production. And yet the choice fell on DDT.
It “won” because of its toxicity to all insects without exception. The Second World War was already underway, and to the danger of famine was added the threat of epidemics - typhus, malaria, and other diseases spread by arthropods. A universal poison was required - against locusts, lice, tsetse flies, cockroaches.
The smell of the dust did not repel the insects; they calmly sat on the surfaces treated with the drug, where they ended up life path. By the way, DDT did not spoil polished furniture at all, which is important when you are fighting household insects. The unusual persistence of the pesticide did not go unnoticed - once the surface was pollinated, it remained lethal to hexapods for many months. Another advantage that distinguished DDT from other candidates for “main” insecticides was its relatively low toxicity to humans and other warm-blooded animals. A single dose of 500 - 700 mg was considered completely safe, so it was almost impossible to accidentally get poisoned. It should be noted that no cases of fatal DDT poisoning have been recorded in the entire history of its use.
The last trump card for the doubting owners of chemical companies was the extreme simplicity and low cost of producing this pesticide. Feedstock served as chloral, which was obtained by passing chlorine through ethyl alcohol:
C2H5OH + 4Cl2 -> CCl3CHO + 5HCl
Then chloral, in the presence of a dewatering agent, reacted with chlorobenzene:
CCl3CHO + 2C6H5Cl -> CCl3CH(C6H5Cl)2 + H2O
and the desired dichlorodiphenyltrichloroethane was obtained. Since all the reagents were cheap and available, DDT quickly began to be produced in many countries around the world. Has arrived new era- the era of man’s total chemical struggle against representatives of the animal and plant world that prevent him from living peacefully.
Indeed, DDT saved millions of lives. The terrible scourge of all warm regions, the malarial plasmodium, has almost lost its distributor - the mosquito. The tsetse fly and other insects that carry dangerous diseases are not in a better position. The 1948 Nobel Prize in Medicine was deservedly awarded to Paul Müller.
DDT was by no means superfluous in public utilities, veterinary medicine, and crop production. It seemed that the path to a well-fed and healthy future had opened for humanity.
Only house flies, which were the first to experience the insecticidal properties of DDT, suddenly stopped reacting even to horse doses of the dust, which was first noticed in 1946. But since exceptions should only confirm the rule, no one seriously thought about this fact.
The first dark spots on DDT's reputation began to appear in the mid-50s. US scientists looked at them especially diligently. Indeed, if in 1942 there was no DDT in the tissues of the inhabitants of this country, then in 1950 its content jumped to 5.3 mg/kg, and in 1953 it tripled. Insects immune to the drug became more and more numerous: in 1956 - 36, in 1958 - 85. Some toxicologists discovered a clear relationship between the amount of the drug used and the increase in the incidence of hepatitis and pneumonia in agricultural districts.
Doctors again began studying this pesticide, but now their reviews had a completely different tone. The frightening term “long-term consequences” was heard. So far it only meant the ability of DDT to accumulate, that is, accumulate in the tissues of animals and humans. Of particular concern was the drug's ability to increase its concentration as it moved through the food chain. Thus, the fat of freshwater fish contained five orders of magnitude more of it than the water in which they were caught.
The saddest event associated with the use of this insecticide was the death of entire populations of birds. The DDT content in their tissues exceeded background levels tens of thousands of times. This concentration was still not enough for acute poisoning, but it had a side effect - the egg shells became thinner. That is why in the nesting area of brown pelicans in Southern California (the volume of DDT used at that time was at its maximum), only five chicks were hatched from 550 pairs; the remaining embryos were crushed by the females during incubation. Insectivorous birds were also hypersensitive to the drug: three days after treating a forest in New Hampshire, up to three-quarters of robins, woodpeckers and other birds were poisoned by the dust. In September 1962, the book Silent Spring, a future bestseller, was published. Its author, Rachel Carson, spoke so convincingly about the sad consequences that the use of chemical pesticides in general and DDT in the first place brings to nature that the American Congress and President Kennedy created parliamentary and government commissions to hear the “pesticide case.”
But four million tons produced and dispersed over fields, forests, swamps cannot be destroyed with the stroke of a pen. Thanks to the “persistence of the drug in the environment,” the dust that entered the atmosphere remained there for centuries, partially settling in ocean waters, soil, and the organisms of living beings. The period of revolution of its particles around globe was three to four weeks.
DDT turned out to be one of the first global pollutants, showing humanity how small the world is. In Antarctica on every square meter found 4*10-9 grams of this substance; in some parts of the ice continent there was hundreds of times more pesticide. The naive Swedes, who decided to determine the content of DDT in their soils, were guided by six hundred tons used throughout the country. They were wrong five times, and on the larger side.
It was soon proven that in the bodies of people suffering from hypertension and other diseases of the cardiovascular system, the concentration of the pesticide is slightly higher than in the tissues of a healthy person. When they found out that mothers in whose milk DDT was found had premature babies twice as often and dead babies one and a half times more often, doctors demanded that the drug be immediately banned. Already in the mid-60s, most developed countries in one way or another limited the use of this pesticide on their territory. By 1970, the entire civilized world, including the USSR, declared DDT “outlaw.”
The validity of this was immediately doubted, and not only by chemists. The American N. Borlaug, who received the Nobel Prize for creating high-yielding varieties of grain specifically for tropical countries, titled his speech at the UN Committee on Food and Health: “DDT or famine?” Having listed the merits of the drug to ungrateful humanity, he mentioned a more than curious fact - the remains of DDT were found in soil samples preserved in 1911.
There were others amazing facts. Even though winds from abroad brought more than two thousand tons of pesticide to Sweden, how can we explain the fact that the adipose tissue of city residents contains more DDT than that of rural residents?
The most incomprehensible news came from Los Angeles. The shells of the crabs that chose to live in the city's sewage discharge into the sea contained 45 times more dichlorodiphenyltrichloroethane than the chitinous shells of their fellow crabs that lived nearby in the irrigation systems of the rice fields where the pesticide was used. The key to the sewer crab mystery is PCBs. This refers to a whole class of compounds - polychlorinated biphenyls. Extremely dangerous pollutants contained in plastics, chemical production emissions and many other places. The waters of the Californian coast are heavily polluted with these same PCBs, and armored marine life accumulates polychlorinated biphenyls in significant quantities (lobster, for example, up to 68 parts per million by weight).
“The complete identity of the behavior of PCBs and organochlorine pesticides (which includes DDT) with any analysis methods are the reasons for a false conclusion about environmental pollution by the latter,” say the Temporary guidelines on soil pollution control, published in 1983.
Still, the decision made in 1970 was correct. The fact is that with the method of synthesis of the drug available at that time, the desired 1,1,1-trichloro-2,2-bis-(4-chlorophenyl)-ethane was only 70%. The rest is a mixture of various PCBs, absolutely harmless to insects, but very dangerous to humans. In addition, if pure 1,1,1-trichloro-2,2-bis-(4-chlorophenyl)-ethane decomposes in plants up to 90% within a month, then it takes at least 180 years for the technical preparation to decompose.
If only the synthesis technology had been changed in time or perfect methods for purifying DDT had been invented, there would have been no planetary bans. By the way, already in the 70s, some methods for separating technical DDT and even special additives appeared that accelerate its decomposition under the influence of soil moisture. Alas, public opinion did not heed the voice of reason, and DDT had to disappear.
The organophosphate insecticides that replaced it more than once caused severe and even fatal poisoning of those who worked with them, but they quickly decomposed in the environment - so quickly that spraying had to be repeated many times. Let us remind you that the most advanced military agents with a nerve-paralytic effect are the closest relatives of karbofos, chlorophos and other organophosphorus pesticides.
