In agricultural production for the control of pests and pathogens of cultivated plants, as well as for the destruction of weeds are widely used organic and inorganic compounds of directional action, combined under the common name - toxic chemicals.
Depending on the directional action, insecticides (substances for the destruction of harmful insects), herbicides (means for the destruction of weeds), fungicides (means for controlling fungal diseases of plants), etc. are distinguished among pesticides.
The severity of poisoning with pesticides depends on the dose, toxicity, route of entry into the body and other conditions. They can enter the body through the respiratory tract in the form of vapors (hexachlorane, ethyl mercurcloride, ethyl mercurphosphate, hydrocyanic acid, formalin , carbon disulfide, etc.), aerosols (toxic chemicals), in the form of tiny droplets (poisons in solution or suspended). Many toxic chemicals can be absorbed through intact skin and have a toxic effect (mercury fungicides — ethyl mercurphosphate, ethyl mercurcloride), phosphorus compounds — FOS (thiophos, metaphos, octamethine), organochlorine compounds (hexachlorine, chloride). Of great importance is the absorption of pesticides through the mucous membrane of the eyes, mouth and nasopharynx. Most pesticides are well absorbed through the mucous membrane of the gastrointestinal tract.Go
When released into the blood, pesticides are unevenly distributed in the body. Well soluble in lipids and fats in large quantities penetrate the nervous tissue and have a predominant effect on the central nervous system.
In the body, pesticides undergo various chemical transformations, which are reduced to the processes of oxidation, hydrolytic cleavage, deamination, and in some cases - restoration. As a result of these transformations, some pesticides are neutralized (thiophos, etc.), in others, the metabolites are more toxic (octamethyl, chloride). An important role in the process of neutralization of toxic chemicals is played by the liver. Of particular importance in neutralization is the ability of the liver to synthesize conjugated compounds with sulfuric and glucuronic acids from toxic chemicals. This function of the liver is associated with the content of glycogen in it.
Many heavy metals and metalloids are released through the gastrointestinal tract ( mercury , copper, arsenic). Volatile, gaseous and vaporous toxic chemicals (chloropicrin, hydrogen sulfide , arsenic hydrogen) are removed from the body through the lungs. The skin is involved in the elimination of heavy metals and metalloids (mercury, copper, arsenic), hydrogen sulfide, phenol, and many fat-soluble drugs from the body. Some fat-soluble substances may be excreted in milk (hexachlorane, chloride, etc.). Poorly soluble chemically inert toxic chemicals (mercury, arsenic, lead, hexachlorane, etc.) are slowly excreted from the body and are retained for a long time in the tissues of the body. Part of toxic chemicals can cumulate (mercury and organochlorine preparations, arsenic compounds, etc.). Most toxic chemicals can cause chronic poisoning (arsenic compounds, alkaloids, etc.). There are sex and age differences in the body's sensitivity to pesticides.Go
Organochlorine toxic chemicals are poorly soluble in water, good - in most organic liquids and solvents . They enter the human body orally or through the respiratory tract, as well as through intact skin. There are chronic poisoning, especially when eating fruits and vegetables, previously treated with these funds. Excreted from the body mainly with feces , in part - with the urine.
Organochlorine pesticides (hexachlorane, chloride, aldine, heptachlor, etc.) are parenchymal poisons and affect the central nervous system, liver, kidneys, myocardium, mucous membranes of the stomach and intestines, adrenal glands, testicles, thyroid gland . The severity of morphological changes (from minor circulatory disorders and reversible degenerative changes to foci of necrosis) depends on the dose, the concentration of the drug and other conditions. In the CNS, degenerative and non-microbiotic changes in nerve cells are noted. In the development of morphological changes of great importance is the occurrence of hypoxia, a decrease in the activity of alkaline phosphatase , a decrease and uneven distribution of RNA in the cells of organs.
When the chemical enters the respiratory tract, irritation of the mucous membranes of the nose, larynx, trachea , bronchi is noted, and nosebleeds may occur. When it enters the gastrointestinal tract, pains behind the sternum and in the epigastric region, nausea and vomiting appear. Then signs of a dysfunction of the nervous system join - weakness, headache, dizziness, insomnia, pain in the extremities, fever, and in severe cases - toxic encephalitis . Death can come in a few hours. At the section and under microscopy, signs of circulatory disorders, vasodilation and plethora, plasmorrhagia, perivascular edema, focal hemorrhages, and stasis are noted.