Manual “Guide to drinking water preparation technology that ensures compliance with hygienic requirements regarding organochlorine compounds” . Organochlorine compounds (XOC) What are the organochlorine compounds in water?

Organochlorine compounds(CHOS) - halo derivatives of polycyclic hydrocarbons and aliphatic hydrocarbons. Previously widely used as pesticides.

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These substances have high chemical resistance to various environmental factors. COS - highly stable and superstable, which are most characterized by concentration in successive links of food chains.

Until the 1980s, in terms of scale of production and use in agriculture, (Lindane) occupied first place among others. This has become the cause of widespread contamination of all environmental objects with residual amounts of organochlorines. The situation is clearly characterized by the fact that even in the snow cover of Antarctica, by the end of the last century, more than 3,000 tons had accumulated.

Story

In 1939, Dr. Paul Müller, an employee of the Swiss chemical company Geigy (later Ciba-Geigy, now Novatis), discovered the special insecticidal properties of, better known as. This substance was synthesized earlier, in 1874, by a German chemist student, Othmar Zeidler. In 1948, Müller received the Nobel Prize for the creation of this insecticide.

Due to its ease of production and high resistance to most insects, this drug has gained great popularity and widespread use throughout the world in a short time. During the Great Patriotic War, many epidemics were stopped thanks to its use. More than 1 billion people were freed from malaria thanks to this drug. The history of medicine has never known such successes.

At the same time, the group of chlorine-containing compounds to which it belonged was actively studied. In 1942, it was replenished with a drug effective in destruction - and its gamma isomer - first synthesized by Faraday in 1825). Over the 40-year period, starting in 1947, when factories for the production of organochlorine preparations were actively operating, 3,628,720 tons of them were produced with a chlorine content of 50-73%.

However, it soon became clear that other organochlorine preparations also have high concentrations, are able to overcome long food chains and can persist in natural objects for many years, which was the reason for a sharp reduction in the use of organochlorine compounds around the world.

In the 1970s and early 1980s, after recognition of the danger to many living organisms, some industrialized countries introduced restrictions or complete bans on its use (in 1986, Japan and the United States released about 20% less organochlorines than in 1980 G). But in the world as a whole, the consumption of lindane has not decreased significantly due to the increase in their use in Asia, Africa and Latin America. Some states were forced to constantly use them to combat the pathogens of malaria and other dangerous diseases.

In our country in 1970, it was decided to remove highly toxic ones from the range that are used on forage and food crops, but they continued to be actively used in agriculture until 1975 and later in the fight against vectors of infectious diseases.

Much later, in 1998, at the proposal of the UN, as part of the environmental protection program, a convention was adopted that limited trade in hazardous substances such as organophosphates and mercury compounds. Numerous studies have shown that persistent organochlorine compounds are found in almost all organisms living in water and on land. 95 countries took part in the new international treaty. At the same time, the list of toxicants required for control included.

Physicochemical characteristics

COS are highly resistant to environmental factors (moisture, temperature, solar insolation, etc.).

In the body of insects, as well as other living beings, derivatives of chlorinated hydrocarbons occur in three main directions:

The toxicological properties of the compound and its selectivity depend on the direction of the processes.

Effect on harmful organisms

. The systematic use of organochlorines leads to the emergence of stable populations of insects, and a group acquired insect occurs.

Toxicological properties and characteristics

In the hydrosphere

. When released into water, COCs remain in it for several weeks or even months. At the same time, substances are absorbed by aquatic organisms (plants, animals) and accumulate in them.

In aquatic ecosystems, sorption of organochlorine ecotoxicants by suspensions occurs, their sedimentation and burial in bottom sediments. To a large extent, the transfer of organochlorine compounds into bottom sediments occurs due to biosedimentation - accumulation in the composition of suspended organic material. Particularly high concentrations of COCs are observed in sea bottom sediments near large ports. For example, in the western part of the Baltic Sea near the port of Gothenburg, up to 600 μg/kg was found in sediments.

In the atmosphere

. Migration of COCs in the atmosphere (photo) is one of the key ways of their distribution in the environment. Long-term observations have led to the conclusion that isomers are mainly present in the atmosphere in the form of vapor. The contribution of the vapor phase in this case is also very large (more than 50%).

At average temperatures, organochlorines are characterized by low saturated vapor pressure. But, once on the surface of plants and soil, COCs partially transform into the gas phase. In addition to direct evaporation from the surface, it is also worth considering their transfer into the atmosphere due to wind erosion of soils. Persistent compounds in aerosols and in the vapor state are transported over considerable distances, so today the contamination of continental ecosystems with organochlorines is global.

Washing out by precipitation is one of the main ways to reduce the concentration of COCs in the atmosphere. Contents of lindane in rainwater collected in the 1980s. on the European territory of the USSR in biosphere reserves, was 4-240 ng/l. This is noticeably higher than typical concentration levels (0.3 to 0.8 ng/L) in North America during the same years.

In the soil

. In the soil, preparations of this group last from 2 to 15 years, remaining for a long time in the upper layer and slowly migrating along the profile. Storage time depends on soil moisture, soil type, acidity (pH) and temperature. The number of microorganisms also plays a big role, since microbes decompose drugs.

From the soil, COCs penetrate into plants, especially tubers and root crops, as well as into reservoirs and groundwater. When introduced into the soil in large quantities, they can inhibit nitrification processes for 1-8 weeks and briefly suppress its general microbiological activity. However, they do not have a great influence on the properties of soils.

Due to the high sorption capacity of the soil, the dispersion and migration of any pollutants occurs much more slowly than is observed in the hydrosphere and atmosphere. The sorption characteristics of the soil are greatly influenced by the content of organic matter and moisture in it. Light sandy soils (sand, sandy loam) are less able to retain organochlorine ecotoxicants, which can therefore easily move down the profile, polluting groundwater and groundwater. In humus-rich soils, these components remain in the upper horizons for quite a long time, mainly in a layer up to 20 cm. As can be seen from the table.

COCs are widely used in agriculture as insecticides and acaricides in the fight against pests of grain, leguminous and industrial crops. Many of the compounds in this group are used to protect against pests and diseases of fruit trees, vineyards, vegetable crops, and forest plantations. These pesticides are used for pre-sowing seed treatment and soil fumigation.

Organochlorine pesticides are represented by a significant number of compounds of various structures. This includes chlorinated derivatives of polynuclear hydrocarbons (cycloparaffins), diene compounds, terpenes, benzene, etc. Based on the strength of their effect on warm-blooded animals, chloroorganic pesticides can be divided into 4 groups: potent (aldrin, chloropicrin), highly toxic (carbon tetrachloride, dichloroethane, heptachlor, hexachlorane, hexachlorobutadiene, thiodane, metalyl chloride), moderately toxic (perthane, methoxychlorokeltan, polychlorpinene, polychlorcamphene), low toxic (tedioium ethersulfonate, phthalan.

The most important property of most organochlorine pesticides is resistance to various external factors (insolation, temperature, moisture, etc.), which allows them to persist for a long time in soil, water, and on plants.

The main part of COS refers to moderately toxic compounds, only certain drugs (aldrin, dieldrin) are considered to be very dangerous, potent compounds, which is why their use in agriculture is prohibited. The use of highly toxic pesticides such as hexachlorobutadiene and heptachlor is also limited. Most COS are capable of material accumulation; the place of their accumulation in the body is organs and tissues rich in fats and lipoids.

The toxic effect of compounds of this group is associated with changes in a number of enzyme systems, in particular respiratory systems, with disruption of tissue respiration. But according to some authors, they block SH groups of tissue proteins and disrupt protein biosynthesis.

COCs obtained by diene synthesis (heptachlor, etc.) during metabolism form the corresponding epoxides in the body, which are more toxic than the main compounds and are retained in organs and tissues for a longer time.

G.V. Kurchatov (1971) considers organochlorine pesticides as lipid-soluble non-electrolytes that are able to pass through all the protective barriers of the body.

The clinical symptoms of COS intoxication are characterized by a variety of symptoms and symptom complexes, which indicates the polytropic nature of the action of the substances included in this group.

The clinical picture of acute COC poisoning develops early (after 30 minutes, sometimes after 3 hours); cases of the development of the first signs of intoxication 40 seconds after accidental contact with the skin have been described. In some cases, manifestations of intoxication occur after a latent period, which sometimes lasts several hours.

In the picture of acute COC poisoning, several clinical syndromes are distinguished. The leading ones are the syndromes of toxic encephalopathy, acute gastritis or gastroenteritis, acute cardiovascular failure, acute toxic hepatopathy with symptoms of hepatic renal failure (P. L. Sukhinina, 1970). E. L. Luzhnikov (1977), B. M. Shchepotin and D. Ya. Bondarenko (1978) also distinguish syndromes of impaired external respiration and hemorrhagic.

Features of the clinical symptoms of acute intoxication with COS depend on the individual sensitivity of the body, route of entry and dose of the drug. When administered orally, the initial signs of intoxication are gastrointestinal disorders, followed by the development of pathology of the nervous system; when COS enters through the respiratory system, intoxication is expressed primarily by irritation of the mucous membranes of the eyes and upper respiratory tract; upon contact with the skin, hyperemia occurs, acute inflammation develops up to ulceration and even necrosis.

Following local manifestations of the toxic effect of COS, signs of damage to the central nervous system develop: headache, dizziness, tinnitus, cyanosis, hemorrhages on the skin may occur, and in severe intoxication - attacks of generalized clonic and tonic convulsions (which may be epileptiform in nature), collapse .

Toxic encephalopathy syndrome develops as a result of damage to the cortical and subcortical parts of the central nervous system. At the beginning of intoxication, it manifests itself as dizziness, heaviness in the head, drowsiness, and nausea. Later, stunning, loss of consciousness, tonic and clonic convulsions occur. In some cases, a coma may develop immediately. There is hyperemia of the sclera and upper half of the body, the pupils are dilated. Possible development of toxic encephalitis or meningoencephalitis, paralysis of the limbs.

Acute COS poisoning is characterized by depression of the medulla oblongata centers, in particular the respiratory center. In this regard, breathing problems are possible in severe forms of poisoning. Along with this, an obturation-aspiration form of asphyxia may develop, caused by increased salivation, bronchorrhea, aspiration of vomit and saliva, and retraction of the tongue. All this is aggravated by hypertonicity of the respiratory muscles and rigidity of the chest muscles.

The syndrome of acute gastritis and gastroenteritis is most often the first sign of oral COC poisoning. Nausea, frequent vomiting, sometimes mixed with bile, sharp pain in the epigastric region, frequent loose stools are characteristic of the clinical picture of such intoxications.

Acute cardiovascular failure syndrome is often observed in acute COC poisoning. It is especially characteristic of acute dichloroethane poisoning. There are muffled heart sounds, various forms of heart rhythm disturbances, and a drop in blood pressure below critical values ​​(for systolic - below 10.7 kPa, or 80 mm Hg). A picture of exotoxic shock develops.

A number of mechanisms are important in the pathogenesis of the development of acute cardiovascular failure. These include disturbances in the central regulation of cardiac activity due to toxic inhibition of the cardiovascular center of the medulla oblongata, as well as weakening of the contractile function of the myocardium as a result of the direct influence of COS on the metabolic processes in it (impaired processes of oxidative phosphorylation and energy metabolism). An important role is played by hypovolemia caused by fluid loss as a result of acute gastroenteritis. It leads to a decrease in circulating blood volume.

Developing metabolic acidosis against the background of inadequate respiratory compensation leads to the predominance of anaerobic oxidation processes and the occurrence of uncompensated acidosis, which is associated with impaired microcirculation.

In severe forms of intoxication, acute cardiovascular failure that cannot be corrected can cause death for victims.

Often, when large doses of FOS enter the body, toxic liver dystrophy develops with symptoms of hepatargia. In victims on the 2-5th day of acute poisoning, icterus of the sclera and skin appears, the liver becomes enlarged, which is painful on palpation. In the blood, the activity of transaminases, lactate dehydrogenase, aldolase, and bilirubin increases (due to its direct fraction).

One of the manifestations of liver failure is hemorrhagic syndrome, the occurrence of which is also promoted by toxic damage to the vascular walls, hypoxia, and thrombocytopenia.

The blood coagulation and anticoagulation systems undergo significant changes, hypocoagulation is noted (the heparin content and the fbrinolytic activity of the blood increase).

Impaired renal function in the early stages of acute intoxication is mainly due to a decrease in blood pressure, as a result of which renal blood flow decreases, oliguria and even anuria develop. However, on the 2-3rd day, these changes may be accompanied by signs of toxic nephropathy (proteipuria, microhematuria, cylindruria) with the development of azotemic uremia, which often causes the death of victims during the first 3 weeks of intoxication with carbon tetrachloride and dichloroethane.

When significant quantities of COS enter the body through the respiratory system, the clinical picture of poisoning can occur as acute tracheobronchitis with an increase in temperature and changes in the blood (neutrophilic leukocytosis, increased ESR).

Acute poisoning with chloropicrin, which has a pronounced irritant effect, is characterized by lacrimation, runny nose, cough, shortness of breath, chest pain, sometimes asthmatic conditions, scattered moist rales as a manifestation of pulmonary edema, which often develops in severe poisoning. These syndromes are usually accompanied by a significant increase in temperature, methemoglobinemia, and hemolysis. In the terminal stages, collapse develops like gray asphyxia.

The clinical picture of chronic COC poisoning is characterized by the sequential development of certain neurological syndromes. At the earliest stage of intoxication, neurological disorders fit into the syndrome of nonspecific toxic asthenia. Signs of asthenovegetative or asthenoorganic syndromes are often detected. The latter is characterized by microorganic symptoms indicating the predominant localization of the pathological process in the brain stem; gnposthenic manifestations of asthenia and episodic cerebral annodystonic paroxysms predominate: suddenly intense headache occurs with nausea, general weakness and profuse sweat or paroxysmal dizziness (rotation of surrounding objects), accompanied by pallor skin and bradycardia.

At a later stage of chronic intoxication with COS, the peripheral nervous system is involved in the pathological process. Common forms of pathology of the peripheral nervous system are autonomic-sensory polyneuritis. Common features for all identified forms are the development of pathology of peripheral nerves against the background of functional or organic disorders of the central nervous system, a relapsing course with a pronounced pain component, symmetry of lesions, predominant localization on the upper extremities, the absence of gross impairment of motor function and pronounced atrophy, frequent combination with pathology liver.

In isolated cases, diffuse damage to the nervous system is observed, such as encephalopolyneuritis, in the form of scattered, small-focal organic symptoms with static-coordinating disorders and involvement of the extrapyramidal system in the pathological process.

In more severe cases, the hypothalamic region, cervical autonomic nodes, and auditory nerves are affected.

Disorders of the cardiovascular system are characterized mainly by vegetative-vascular dystopia with a tendency to arterial hypotension, as well as extracardiac disorders of the heart rhythm (sinus bradycardia) and myocardial conduction function. Toxic myocardial dystrophy or myocarditis of a toxic-allergic nature often develops, especially in persons who have suffered acute intoxication with COS in the past.

Often, with chronic intoxication with COS, signs of pneumosclerosis can be found in the middle and lower parts of the lungs.

Already in the initial stages of chronic intoxication with COS, the secretory function of the stomach is disrupted; in later stages, the development of chronic gastritis is characteristic with inhibition of the secretory function of the stomach up to histamine-resistant achylia.

Disturbances in the functional state of the liver during chronic intoxication are first manifested by an increase in the activity of organ-specific enzymes in the blood serum (alanine and aspartate transferases), and later disturbances in carbohydrate and antitoxic function are added. In severe forms of intoxication, toxic hepatitis develops, usually occurring without jaundice, and is often accompanied by cholecystitis.

A certain phase pattern in the development of renal dysfunction has been established: the initial stage of intoxication is characterized by a slight increase in functional activity due to increased renal blood flow and glomerular filtration; at later stages, due to the development of toxic nephropathy, renal function is significantly impaired, and signs of azotemia may appear. In contrast to toxic necronephrosis, which is characteristic of severe acute poisoning with COS, in particular with carbon tetrachloride, dichloroethane, nephropathy during chronic intoxication with compounds of this group has a relatively benign course and, as a rule, does not lead to severe azotemic uremia.

Against the background of functional disorders of the central nervous system, various endocrine disorders are observed, including the most common inhibition of the activity of the adrenal cortex, hyperfunction of the thyroid gland, and less often - dysfunction of the insular apparatus of the pancreas. Severe forms of intoxication are characterized by pluriglandular insufficiency with leading hypothalamic disorders, hyperglycemia and arterial hypertension.

Under the influence of COS, significant changes occur in the blood. These include anemia, which most often has a hypochromic character, but in some cases acquires the features of a hypoplastic process, in the development of which, apparently, sensitization of the body with these compounds plays an important role. Along with this, the number of leukocytes changes: moderate leukopenia is accompanied by relative lymphocytosis and eosinopenia. The number of platelets also decreases, which is often combined with hemorrhagic vasculitis. ESR tends to slow down.

Chronic intoxication with COS is characterized by a protracted course and limits the ability to work for years.

In the diagnosis of intoxication with these compounds, the determination of individual pesticides and their metabolites in the blood and urine is important. However, the lack of parallelism between the severity of intoxication and the content of pesticides in biological media reduces the diagnostic value of such studies.

As is known, most of the centralized water supply in Russia is disinfected using chlorine or substances containing chlorine. Due to the fact that free chlorine is one of the substances harmful to health, hygienic regulations (SanPiN - Sanitary Rules and Norms) strictly regulate the content of residual free chlorine in drinking water from centralized water supplies. At the same time, SanPiN sets not only the upper limit of the permissible content of free residual chlorine, but also the minimum permissible limit. The fact is that, despite disinfection at a water treatment plant, ready-made “commercial” drinking water faces many dangers on the way to the consumer’s tap. For example, a fistula in an underground steel main, through which not only main water gets out, but also contaminants from the soil can get into the main. The minimum permissible content of residual free chlorine ensures additional disinfection along the entire path of water to the tap in the event that there is an additional source of contamination: the so-called. "disinfectant aftereffect". This minimum content of residual free chlorine is determined by SanPiN as 0.3 mg/l, and the maximum permissible concentration is set as 0.5 mg/l. During periods of spring floods and an increase in the risk and degree of water pollution at water supply sources at water treatment plants, the total amount of introduced chlorine increases based on the calculation of the indicated values ​​of the residual chlorine content of the consumer, but, of course, it is not possible to achieve absolute accuracy, and increased content values ​​may be observed for a short time residual free chlorine in water up to 1.0, and in rare cases up to 1.2 mg/l. Such water reveals itself not only in taste, but also in smell. For reference: with such values ​​of chlorine content in water, the smell from the stream of water from the tap is felt throughout the entire room, and with its content of 2 mg/l, even in neighboring rooms.

Until recently, it was believed that chlorination had no harmful effects on human health. But studies have shown that about 10% of the chlorine used in chlorination is involved in the formation of by-products (chlorine-containing compounds) - halogen-containing compounds (HCC), which are divided into three groups: high priority, relatively priority and low priority. The priority GSCs include: chloroform, carbon tetrachloride, dichloroethane, trichloroethane, tetrachlorethylene; perchlorethylene, bromoform, dichloromethane, dichloroethane, dichloroethylene, Most of the GSM are trihalomethanes (THM): dichlorobromomethane, dibromochloromethane and bromoform.

Education trihalomethanes is caused by the interaction of active chlorine compounds with organic substances of natural origin (fullic acids, humic acids, etc.). The quantity and composition of the resulting halogen-containing hydrocarbons are influenced by both the concentration and nature of the organic compound (industrial, agricultural, domestic wastewater, surface runoff of populated areas) and water treatment conditions: the dose of active chlorine, the time of its contact with water, temperature, pH, the presence of other halogens, etc.

In the total amount of THMs formed during water treatment, chloroform makes up 70 - 90%. It should be noted that in the source water entering water treatment, the chloroform content can be insignificant and increases only at the stages of water treatment after chlorination.

Chloroform is an important solvent and degreasing agent. It is used in small quantities as an anesthetic, in ointments, curlers, toothpastes and fumigants, and as an active ingredient and preservative for coughs. It enters water mainly due to chlorination, as well as as part of wastewater from pharmaceutical industry enterprises, production of varnishes and paints. Chloroform accounts for 90% of the halogenated hydrocarbons formed in water during chlorination. Thus, the content of chloroform in river water (Dnieper River) supplied for treatment does not exceed 0.87 μg/l.

After chlorination, the concentration of chloroform increases to 13.5 μg/l, which is 1.4 -32 times higher than the maximum permissible concentration.

Chloroform is moderately toxic (group 2B), but highly cumulative. Chloroform does not have mutagenic activity. The maximum concentration of chloroform that does not affect the sanitary regime of reservoirs is 50 mg/l. odor threshold concentration - 18.03 mg/l.

Chloroform causes occupational chronic poisoning with primary damage to the liver and central nervous system. Chloroform metabolism occurs in the liver, and significant storage occurs in adipose tissue. Chloroform, appears to be able to cross the placental barrier as its concentrations have been found to be higher in umbilical cord blood than in maternal blood. The main metabolites of chloroform were excreted through the lungs or through the kidneys (in the form of inorganic chlorides). Among the potential hazards associated with exposure to concentrations, the most serious are the carcinogenic effects observed in experimental animals and the suggestion of similar effects in humans exposed to elevated concentrations of trihalomethanes in drinking water.

During chlorination, there is a possibility of the formation of extremely toxic compounds that also contain chlorine - dioxins (dioxin is 68 thousand times more toxic than potassium cyanide). Chlorinated water has a high degree of toxicity and total mutagenic activity (TMA) of chemical contaminants, which greatly increases the risk of cancer.

According to American experts, chlorine-containing substances in drinking water are indirectly or directly responsible for 20 cancers per 1 million inhabitants. The risk of cancer in Russia with maximum water chlorination reaches 470 cases per 1 million inhabitants. It is estimated that 20-35% of cancer cases (mainly colon and bladder) are caused by drinking water consumption. According to some researchers, from 30 to 50% of cases of malignant tumors may be associated with the consumption of contaminated water. Others cite calculations according to which consumption of river water can lead to an increase in cancer incidence by 15%.

Organochlorine compounds found in industrial waste are absorbed by particles of matter and soil, and in the hydrosphere by particles of organic and inorganic substances and sediments. [...]

Organochlorine compounds are gases, liquids or solids with a peculiar odor.[...]

Organochlorine compounds are absorbed by activated carbon. When the coal is subsequently calcined on a gas burner, its flame turns green. In this case, the duration of flame coloring is proportional to the concentration of organochlorine compounds in the air.[...]

Organochlorine compounds are widely used in many industries as solvents for varnishes, paints, fats, paraffin, artificial resins, as a starting product for organic synthesis and for other technological processes.[...]

Organochlorine solvents have the following valuable qualities: the ability to dissolve a variety of substances, easy to mix with other organic solvents, and significant resistance to fire. Their flammability decreases with increasing chlorine content in the molecule. The raw material for their production is chlorine, as well as petroleum cracking gases - ethylene and homologues. The properties of organochlorine compounds, production, use and toxicity are described by G. S. Petrov, A. B. Ashkinazi, N. D. Rosenbaum, N. V. Lazarev and others [...]

Organochlorine compounds, determination in air 82 words[...]

Organochlorine compounds have long played a major role among insecticides and acaricides. These include well-known and important compounds such as DDT, its much later discovered analogue methoxychlor, HCH, the active component of which is γ-HCH, or lindane (currently still important in plant protection), and diene compounds. row. Methyl bromide is also used as a means of controlling barn pests.[...]

Organochlorine compounds - hydrocarbons, are drugs, some act on internal organs (liver, kidneys), as well as on the nervous system. The maximum permissible concentrations of some chlorinated compounds are given in table. 47.[...]

Compounds of this group were the first to be widely used to control various agricultural pests. Until recently, these compounds (DDT, hexachlorane, heptachlor, etc.) were the most common. The reason for this was that these highly effective compounds were considered almost non-toxic. The massive use of chemicals in agriculture has shown that organochlorine compounds are not harmless. Currently, organochlorine compounds are used with great restrictions and are gradually being replaced by other, less toxic pesticides.[...]

Organochlorine compounds. DDT, HCH, polychlorpinene, aldrin, ethersulfonate and other organochlorine compounds are pesticides that have long been widely used in agricultural production. They are used in pest control of grains, legumes, industrial crops, vineyards, vegetables and field crops, in forestry, veterinary medicine and even in medical practice. Their distinctive feature is their resistance to various environmental factors (temperature, solar radiation, moisture, etc.). Thus, DDT can withstand heating up to 115-120°C for 15 hours and is almost not destroyed during cooking. This drug, having high cumulative properties, gradually accumulates in the environment (water, soil, food products). It was found in the soil 8-12 years after application.[...]

Organochlorine compounds do not interfere with the determination, but alcohols with the same retention time do.[...]

Organochlorine compounds have narcotic and general toxic effects.[...]

All these organochlorine compounds, found not only in inland seas, but also in oceans to a depth of 5000 m, already at concentrations of about 1 ng/l inhibit the photosynthesis of phytoplankton by 50-60%, i.e., they approximately halve their ability to assimilate CO2. In addition, persistent organochlorine compounds are prone to bioaccumulation and biomagnification - accumulation in the higher links of the trophic chain to levels of toxic effects. As a result, many species (for example, the white-tailed eagle, the Baltic seal) are on the verge of extinction, and the ecosystems in which they belong are largely disturbed.[...]

Note that organochlorine compounds are used in the production of dyes, for degreasing metals, as solvents for dry cleaning of clothing, and in extraction processes at food industry enterprises. Many of these processes occur at elevated temperatures, which pose a risk of dioxin formation. Thus, significant quantities of PCDD have been found in distillates of tri-chlorethylene used in textile factories for cleaning fabrics. [...]

Determination of organochlorine compounds by combustion method in a device from the Research Institute of Hygiene named after. F. F. Erisman.[...]

You can burn organochlorine compounds in a porcelain or quartz tube with a platinum spiral at 850-900°, followed by absorption of combustion products and determination of chlorine ion in them (absorption by arsenous acid, precipitation of AdNO3 and nephelometric determination). Combustion is also carried out in glass columns with hot platinum wire.[...]

Insecticides based on organochlorine compounds penetrate the human body through the digestive tract or skin if they are used in dissolved form. In this case, the membranes of nerve cells are positioned in such a way that they remain permeable for the osmotic transfer of the flow of Ka + ions. The resting potential, disturbed by the action of pesticides, after excitation either does not return to its original value at all or is partially reduced. Thus, organochlorine compounds change the excitability of nerve cells. First, motor nerve pathways are damaged, and then, at higher concentrations, sensory neurons. In humans, exposure to pesticides occurs only when significant amounts of pesticides are ingested; trace amounts have no noticeable effect. However, one must be careful about ingesting even trace amounts of organochlorine compounds, as they can accumulate and interact with other foreign substances.[...]

Device for determining organochlorine compounds (Fig. 14). The device consists of two parts - cleaning and analytical. The cleaning system consists of two absorption devices designed to clean the air from chlorine and hydrogen chloride. One of the absorption devices contains a 5% solution of caustic alkali, the other - a 0.01% solution of arsenous acid. The analytical system consists of two glass combustion columns into which 7 cm long platinum spirals with a cross section of 0.3 mm and microabsorbers are soldered. The microabsorber is a glass tube 70 mm long and 7-8 mm in diameter with a tapered end and a grind in the upper part, into which a glass spiral of 20 turns is tightly inserted. A tube with a spiral at the other end rests against the bottom of a test tube 40 mm long and 12 mm in diameter. Gas pipettes of 0.5-1 liter are used for air sampling. Equalization bottles with a capacity of 1 liter are used to displace the analyzed air from the pipettes.[...]

Along with individual organochlorine compounds, a study was carried out of the ability for biochemical oxidation of dichlorophenol wastewater from the production of 2,4-D, waste sulfuric acid from the production of monochloroacetic acid and the general effluent of a chemical plant. [...]

Another characteristic property of the organochlorine group of substances is the ability to accumulate in animal tissues and fat. Most drugs in this group belong to moderately toxic compounds. Only some of them (aldrin, dieldrin) belong to potent and very dangerous substances due to their volatility. Organochlorine compounds can cause acute or chronic poisoning with damage to the liver, central and peripheral nervous system and other vital organs and systems.[...]

Discoloration and reduction of the content of organochlorine compounds in wastewater from pulp and paper production is achieved by treating it with fungi - white mold. The purification process includes separation of wastewater by ultrafiltration, followed by treatment of the leachate with fungi for the purpose of disinfection and combustion of the isolated high-molecular compounds (concentrate). The cleaning efficiency within a short treatment time is several times higher than traditional cleaning methods. It is believed that this process will find industrial application in the near future.[...]

Among pesticides, the most dangerous are persistent organochlorine compounds (DDT, HCB, HCH), which can persist in soils for many years and even their small concentrations as a result of biological accumulation can become dangerous to the life of organisms. But even in negligible concentrations, pesticides suppress the body’s immune system, and in higher concentrations they have pronounced mutagenic and carcinogenic properties. Once in the human body, pesticides can cause not only the rapid growth of malignant tumors, but also affect the body genetically, which can pose a serious danger to the health of future generations. That is why the use of the most dangerous of them, DDT, is prohibited in our country and in a number of other countries.[...]

Maximum permissible concentrations are established for individual organochlorine compounds depending on the degree of their toxicity.[...]

The annual consumption of chlorine in Russia reaches 2 million tons. Chlorine is used in the production of organochlorine compounds (vinyl chloride, chloroprene rubber, dichloroethane, chlorobenzene, etc.). In most cases, it is used for bleaching fabrics and paper pulp, disinfecting drinking water, as a disinfectant and in other industries. It is stored and transported in steel cylinders, containers and railway tanks under pressure.[...]

Along with the control of industrial enterprises, it is necessary to control the content of persistent organochlorine compounds (PCBs, DDT, HCHs, etc.) in agricultural landscapes. The latter are one of the main secondary sources of environmental pollution with these substances. The accumulation of OCPs in agricultural landscapes was the result of large-scale and long-term use of OCPs in agriculture. , a survey of agricultural areas of the Kuban Lowland showed that the pressure on the soil cover of residual quantities of OCPs is comparable to the load of industrial pollutants. Particularly noteworthy are the increased contents of PCBs and DDT residues in soils under certain agricultural crops and perennial plantings, as well as evaporation fields into which municipal and industrial wastewater containing COCs, G1AU, and carcinogenic metals are discharged. After the water evaporates, dirty layers of soil form on them, which are easily blown away in the form of dust powder even by a slight wind. In such conditions, dust particles can enter the lungs and esophagus of people living in the area and contribute to the occurrence of cancer.[...]

Insecticides are used mainly to treat crops of grain and legumes. Among insecticides, organochlorine compounds play an important role - DDT, hexachlorocyclohexane, the production of which is based on the domestic chlorine industry. Changes in pesticide consumption are shown in table. 162.[...]

Natural sediment and surface film are areas where water pollutants are concentrated. Water-insoluble compounds settle to the bottom, and the sediment itself is a good sorbent for many substances. For example, organochlorine compounds that are insoluble in water settle at the bottom and remain there for a long time. It is believed that water is a reservoir of persistent pesticides. Bottom sediments can have redox properties and biological activity, and can catalyze some reactions.[...]

Appendix 3 shows the results of experiments on fire neutralization in cyclone reactors of some types of wastewater, bottoms and aqueous solutions containing organochlorine compounds. In these experiments, the exhaust flue gases contained HC1 and Cb. According to data, organic chlorine compounds are present in exhaust gases in the presence of carbon monoxide and unburned hydrocarbons. In the experiments under consideration, only traces of CO were found in the flue gases, and hydrocarbons were absent. This gives reason to believe that the content of organic chlorine in the exhaust gases should be low. In an experiment on dianate production wastewater, carried out at low temperatures (/0.g = 1000 °C), the waste gases contained 80-160 mg/m3 of organic chlorine. For complete oxidation of organochlorine impurities, it is advisable to maintain the temperature of the exhaust gases at a level of 1100°C with an air flow coefficient of 1.05-1.1.[...]

Dioxins are highly toxic substances of a complex chemical structure, xenobiotics of technogenic origin, associated mainly with the production and use of organochlorine compounds and their disposal.[...]

Chlorine gas, upon exiting the electrolysis workshop, undergoes drying, where it is freed from water vapor and then transported through a pipeline to the production of bleach, liquid chlorine, organochlorine compounds, etc.[...]

During the industrial production of chlorine and alkalis by the electrolysis of chlorides, the processing of ores of titanium, niobium, tantalum and other metals by the method of chlorinating roasting, the production of hydrochloric acid and many organochlorine compounds, gases containing chlorine, hydrogen chloride and other chlorine compounds are emitted into the atmosphere. Recently, combustion furnaces of chlorine-containing industrial waste and household waste containing polymeric materials have become sources of HC1 entering the environment.[...]

The fight against the Colorado potato beetle is of great economic importance for our country and world agriculture. Until the end of the 50s. In Europe and the USA, DDT was mainly used against the Colorado potato beetle. The ban on a number of organochlorine compounds has led to more intensive use of carbamate and organophosphorus drugs. In 1976, evidence emerged that in a number of QIIÍA states, the use of carbofuran increased the population of the Colorado potato beetle.[...]

The environmental situation in the region has changed significantly in recent years. Thus, using the example of JSC "Caustic", the gross emission of pollutants was reduced by 1999 (compared to 1992) by 4320.797 tons (59.63%). Including, emissions of mercury (by 57.6%), for vinyl chloride (by 88.5%), for the amount of organochlorine compounds excluding vinyl chloride (by 77.60%), and for ammonia (by 17.10%) were reduced. Therefore, it is necessary to constantly monitor the state of various types of ecosystems and select a system of methods for monitoring and assessing the environment, in relation to the characteristics of a particular region.[...]

For more than 100 years, the method of water disinfection with chlorine has been the most common method of combating pollution in Russia. In recent years, it has been found that water chlorination poses a serious threat to human health, since it produces extremely harmful organochlorine compounds and dioxins. It is possible to reduce the concentration of these substances in drinking water by replacing chlorination with ozonation or treatment with UV rays. These progressive methods are widely implemented at water treatment plants in many countries of Western Europe and the USA. In our country, unfortunately, due to economic difficulties, the use of environmentally efficient technologies is extremely slow.[...]

The more persistent and toxic the pesticides, the more serious their negative impact on wildlife and humans. At the same time, resistance to environmental factors (sunlight, oxygen, microbiological decomposition, etc., the ability of pesticides to persist for a long time) largely determines their danger. Pesticides based on organochlorine, organophosphorus and carbamate compounds differ significantly in their persistence. DDT, a typical organochlorine compound, can circulate in the biosphere for more than 50 years. Moreover, its decomposition products (for example, DDE) are dangerous and persistent substances, sometimes more toxic than the original substance.[...]

A real picture of the presence of residual amounts of chemicals and plant protection in the most important part of the environment for humans - food - can only be obtained with the help of control tests. All of the pesticides mentioned are organochlorine compounds, the stability of which is well known.[...]

Since the rate of intensity of anthropogenic impact on nature increases exponentially, in a few decades it will completely determine the change in the composition of the atmosphere, suppressing the above-mentioned natural factors. Model studies have shown that already during the 21st 11-year solar cycle (1975-1986), fluctuations in the UV radiation of the Sun, caused by changes in solar activity and an increase in the content of active chlorine, which destroys ozone in these layers of the atmosphere. The last factor is the result of an increase in anthropogenic emissions of organochlorine compounds into the atmosphere, primarily CFC-11 and -12, which was very intense in the 70s and amounted to about 10% per year, in the 80s - 5% per year. Obviously, in the current 22nd (1986-1997) and especially in the next 23rd solar cycle, this anthropogenic factor will determine changes in the composition of not only the lower, but also the global upper stratosphere. Therefore, when assessing the most important long-term changes in the content of ozone and other radiation-active gases in the atmosphere, which determine their impact on the biosphere and climate, only changes in anthropogenic factors that shape the evolution of the composition of the atmosphere should be taken into account. Recently, several scenarios of expected anthropogenic emissions of CO2 and other MGs into the atmosphere and their content in its different parts have been compiled and published.[...]

Currently, the anthropogenic load on natural reservoirs, which are sources for drinking water, is steadily increasing. The most dangerous pollutants for humans are various pathogenic microorganisms. Therefore, in water treatment technology, the most important role is played by the process of disinfection and, in particular, chlorination. However, the use of chlorine leads to the formation of organochlorine compounds, the dominant ones among which are trahalomethanes (THMs). The latter belong to toxic organic compounds and are classified in hazard class II. Therefore, knowledge of the general patterns of THM formation is necessary for sound management of water treatment technology in order to reduce the amount of THMs in drinking water.[...]

The diversity of environmental requirements and the complexity of production systems have created a unique situation in the last decade in which the likelihood of firms and companies being held accountable for various forms of liability for unintentional environmental violations has increased dramatically. Of interest in this regard is the lawsuit brought by Greenpeace against an English chemical company that was polluting the Irish Sea and the River Thames by illegally discharging wastewater from a number of its plants in Fleetwood and Wilton. An analysis of wastewater samples taken by Greenpeace from 34 outlets in September 1992 showed 100 organochlorines and other chemicals being discharged into the aquatic environment without permission. The Chemical Industry Association refutes Greenpeace's statement, citing strict control of both the activities of the enterprises and their discharges by the National River Authority. The situation turned out to be very strange: the presence of numerous illegal discharges under strict external control. The mentioned trial, according to English experts in the field of environmental law, indicates the need for self-control of enterprises through the so-called environmental auditing.[...]

Without going into details, I will list the main results of these works. The article provides the following data. It has been established that during 1990-1999. the content of cresols, chloroform and phenols in the water was significant and approached the maximum permissible concentration, and at times exceeded the corresponding standard.

Physicochemical properties of organochlorine compounds. Organochlorine compounds used as insecticides acquire special and independent importance in agriculture.

This group of compounds with a specific purpose has as its prototype the now widely known substance DDT.

Based on their structure, organochlorine compounds of toxicological interest can be divided into 2 groups - derivatives of the aliphatic series (chloroform, chloropicrin, carbon tetrachloride, DDT, DDD, etc.) and derivatives of the aromatic series (chlorobenzenes, chlorophenols, aldrin, etc.).

Currently, a huge number of compounds containing chlorine have been synthesized, which mainly owe their activity to this element. These include aldrin, dieldrin, etc. The chlorine content in chlorinated hydrocarbons averages from 33 to 67%.

The main representatives of this group of organochlorine compounds-insecticides are illustrated in table. 5.

The group of organochlorine insecticides given in the table does not exhaust the entire presence of these compounds.

But, limiting ourselves to only 12 main representatives (including various isomers or similar compounds), we can make some generalizations about their toxicity from the structure of these substances.

Of the fumigants (dichloroethane, chloropicrin and paradichlorobenzol), chloropicrin is particularly toxic; during the First World War it was a representative of a chemical agent with asphyxiating and tear-producing effects. The remaining 9 representatives are actual insecticides, mostly contact ones. According to their chemical structure, these are either derivatives of benzene (hexachlorane, chlorindan), naphthalene (aldrin, dieldrin and their isomers), or compounds of a mixed nature, but which include aromatic components (DDT, DDD, perthane, chlorene, methoxychlor).

All substances in this group, regardless of their physical state (liquids, solids), are poorly soluble in water, have a more or less specific odor and are used either for fumigation (in this case they are highly volatile) or as contact insecticides. The forms of their application are dusts for pollination and emulsions for spraying.

Industrial production, as well as use in agriculture, is strictly regulated by appropriate instructions to prevent the possibility of poisoning people and, to some extent, animals. Regarding the latter, many issues still cannot be considered finally resolved.

Toxicology. The toxicity of organochlorine compounds from the group of fumigants and insecticides is quite different. It has been fairly well defined and studied in laboratory animals, but in relation to farm animals and birds, information about the toxicity of this group of compounds is insufficient and sometimes contradictory. However, massive cases of animal intoxication have been repeatedly described in the veterinary literature of all countries where these drugs have been introduced into agriculture.

It is quite natural to make some general statements about the characterization of the toxic properties of organochlorine compounds on the basis of their physicochemical properties.

Of the physical properties, the volatility of substances and their solubility are primarily important. Volatile substances used as fumigants pose a risk when air containing dichloroethane, chloropicrin and chlorobenzene is inhaled. Solubility in fats and oils during resorption through the digestive tract determines lipoidotropic

a significant effect in the body, manifested primarily by damage to the nervous system.

The chemical properties of substances in this group are determined by the presence and amount of chlorine in a particular compound. The degree of strength of the chlorine bond in a given compound is also important. In relation to insects, these compounds most often exhibit a slightly slower effect than insecticides of plant origin (for example, pyrethrum, etc.). Through intact skin of animals, these substances can be resorbed in the form of oil solutions and emulsions. The ability to penetrate the cuticle of insects to a greater extent than through the skin of animals is the basis for the greater toxicity of these substances as insecticides.

After the substance enters the body, it begins to saturate the adipose tissue. The concentrations of this accumulation vary depending on the particular compound. In particular, methoxychlor hardly accumulates in adipose tissue at all, while DDT and many other compounds can appear in significant quantities in this tissue if they are contained in feed in very small quantities (about 1 mg per 1 kg of feed).

Accumulating in adipose tissue, these substances remain in it for a very long time (hexachlorane, for example, up to three or more months) after the exclusion of these intakes, which gives both fat and, in part, meat (with layers of fat) a specific taste. In the brain and nervous tissue, the accumulation of these substances, like

as a rule, is not observed, whereas in the endocrine glands (in the adrenal glands) they accumulate in the same quantities as in adipose tissue.

Absorption of organochlorine derivatives from the intestine occurs to a relatively weak extent. Most of them, when they enter the body through this route, are excreted in the feces. However, not all warm-blooded animals have this main route of elimination. In rabbits, a significant portion of DDT, when entering the body through the digestive tract, is excreted in the urine in the form of an acetylated compound. Minor amounts of DDT are also found in bile. In cats, on the contrary, almost no release of DDT occurs, and in rats DDT is converted into the acetylated form very weakly.

Significant amounts of some organochlorine compounds are excreted in milk, especially DDT, followed by the gamma isomer HCH, chlorindane and dieldrin. Methoxychlor e mulocke is practically absent. It has been established that with such insignificant amounts of DDT in hay as 7-8 mg per 1 kg of feed

in the milk of cows that eat it, the amount of the drug reaches 3 mg per 1 kg of milk, and since this substance dissolves in the fatty part of the milk, the oil can contain up to 60-70 mg per 1 kg of product, which poses a certain danger to calves (in suckling period), as well as for people.

The toxicodynamics of organochlorine compounds both in relation to insects and mammals has not been sufficiently studied. There are many assumptions about this in the literature published. In some cases, the toxicity of these compounds was associated with the amount of hydrochloric acid formed during the destruction and detoxification of these substances in the body, in others it was expressed the most probable assumption is that the toxic effect is caused by a disruption of enzymatic processes both by the substances themselves and by their breakdown products. The latter is based on the fact that aldrin and dieldrin (as well as their isomers) have many similarities in their effect to organophosphorus compounds.

Regarding each of the 12 substances listed in the characteristics of their toxicity to farm animals, it should be noted substances with relatively low toxicity: DDD, methoxychlor and perthane. The remaining compounds are more toxic and can cause both acute and chronic poisoning of animals. Chronic intoxications are most often observed from compounds that are slowly removed from the body's adipose tissue (DDT and hexachlorane). Methoxychlor is destroyed relatively quickly in the body, and because of this, chronic methoxychlor intoxication is excluded. Animals with less fat deposits are more sensitive than fatty animals, in which insecticides are deposited in fat depots and, as a result, become relatively inert for the body. This also occurs in emaciated animals of the same species, in particular under the influence of DDT. Animals are more sensitive at a young age. This is especially true for calves 1-2 weeks old, who are poisoned through milk if there are insecticides in the cows’ feed.

The toxicity of insecticides containing chlorine largely depends on the form in which the substance enters the body. Thus, with plant M1 oil, the substance turns out to be more toxic than with mineral oil or in the form of an aqueous emulsion. Dusts have the least toxicity. DDT, in particular, is 10 times less toxic in aqueous emulsions than in an oil solution.

Toxic doses of drugs from the group of organochlorine insecticides on average for laboratory animals are expressed

in quantities per 1 kg of animal weight: DDT about 200 mg, DDD - 1 g, methoxychlor - 6 g, perthane - 8 g. The given doses indicate the different toxicity of these four compounds.

However, farm animals are more resistant to the most toxic of them, DDT. Symptoms of poisoning in sheep begin at 500 mg per 1 kg. the weight of the animal, and even amounts up to 2 g per 1 kg of weight do not always cause death. Goats are even more resilient than sheep. Approximately the same doses of DDT cause poisoning in adult cattle. However, in calves 1-2 weeks of age, doses are reduced to 250 liters per 1 kg of weight. Garner lists the following animal sensitivity to DDT: mouse, cat, dog, rabbit, guinea pig, monkey, pig, horse, cattle, sheep and goat. Fish are more sensitive to DDT, but birds, on the contrary, are more resistant.

Sheep, goats, cows and horses tolerate doses of DDT in the range of 100-200 mg per 1 kg of body weight, given over several days, without noticeable signs of poisoning. Naturally, the remaining 3 drugs (DDD, methoxychlor and perthane) can cause poisoning in farm animals if they are supplied with food for a long time and in much larger quantities than DDT.

The toxicity of hexachlorane varies depending on the isomerism of this compound. The most toxic of the isomers is the gamma isomer. The average single lethal dose of hexachlorane (containing 1 to 12% gamma isomer) is approximately 1 g per 1 kg of weight. But different animals have different resistance to this pesticide. Thus, cases are described when dogs died from 20-40 mg per 1 kg of weight, and horses died from 50 g of powder containing 21% hexachlorane. Calves are especially sensitive to hexachlorane, and their minimum toxic dose is about 5 mg per 1 kg of their weight, while for adult cattle (cows, sheep) it is 5 times higher. In general, young animals of all species are more sensitive than adults. However, calves are still less resilient than lambs and piglets. Malnourished animals also show increased sensitivity to hexachlorane. Birds, after being exposed to a concentration of 0.002% of the gamma isomer of hexachlorane in the air for 0.5-2 hours, showed symptoms of poisoning, and a double concentration caused their death (Karevich and Marchand, 1957).

Organochlorine compounds that are derivatives of naphthalene (aldrin, dieldrin and their isomers) represent a special group in terms of toxicity, significantly different from previous drugs.

The presence of aldrin and dieldrin in the diet in amounts up to 5 mg per 1 kg of feed, as a rule, does not cause symptoms of intoxication. An increase to 25 mg per 1 kg of feed slows down growth in young animals, and above 100 mg per 1 kg of feed causes signs of poisoning.

Chlorindan is the least toxic drug, but its toxicity largely depends on the forms of the drug used. Average toxic doses for sheep are 200-250 mg per 1 kg of weight, and for calves - from 25 mg per 1 kg of weight. However, when sheep were repeatedly treated with 1-2% emulsions and dusts, chronic poisoning very often occurred. Poisoning has also been observed in birds.

Other drugs in this group of insecticides do not differ in toxicity from the above. Polychlorcamphene (Toxaphene), which has low toxicity, causes toxic symptoms in sheep. Its toxic doses are 25 mg per 1 kg of weight in sheep, and 50 mg per 1 kg of weight in goats. However, even such high doses as 250 mg per 1 kg of weight do not always cause death. Calves are especially sensitive to polychlorcamphene, and their toxic symptoms can appear from 5 mg per 1 kg of weight. Chickens are relatively resistant to polychlorcamphene. In dogs, chronic poisoning was not observed even in cases where they were given polychlorcamphene for three months at a dose of 4 mg per 1 kg of weight. The use of emulsions and suspensions of this drug at a 1.5 percent concentration for bathing and washing horses, cattle, sheep and goats 8 times with a 4-day interval did not cause symptoms of poisoning. When treating calves with 0.75 and 1% solutions of polychlorcamphene, intoxication may occur,

but to kill insects, it is quite sufficient to use lower concentrations - 0.25-0.5 percent (Garner).

Poisoning with organochlorine compounds. Clinical signs. Acute poisoning is primarily observed when using the most toxic organochlorine compounds (HCCH, aldrin, dieldrin, etc.). Basically, clinical manifestations are expressed in excitation of the central nervous system, but in this case they differ in significant diversity.

Naturally, the onset of symptoms is noted at different times after the toxic substance enters the body). In some cases, the appearance of signs is noted within the first hour, but their detection is possible after a day or more. The nature of the body's reaction can manifest itself as a gradual deterioration in the general condition, but it can also immediately become very severe.

Animals first of all become fearful and show increased sensitivity, and sometimes aggressiveness. Then there is damage to the eyes (blepharospasm), twitching of the facial muscles, convulsive contractions of the muscles of the neck, front and back of the body. Muscle spasms are repeated at more or less certain intervals or are expressed in separate attacks of varying strength. The secretion of saliva increases, chewing movements intensify, foam appears, sometimes in significant quantities.

With a more intense influence of a toxic substance, the animal becomes highly agitated, with signs of violence and loss of coordination of movements. It bumps into foreign objects, stumbles, makes circular movements, etc. Often the animal in this case takes abnormal poses, lowering its head low towards the forelimbs.

Intensifying, such varied symptoms reach clonic convulsions, accompanied by swimming movements, grinding of teeth, moaning or mooing. Attacks of convulsions are sometimes repeated at regular intervals or are irregular, but once they begin, each of them can end in the death of the animal.

Some animals have a tendency to lick their own skin.

Sometimes the onset of symptoms of intoxication occurs suddenly. The animal jumps up sharply and falls in a fit of convulsions without any preliminary symptoms of the disease.

Often poisoned animals remain in a comatose state for several hours before death.

If the attacks of convulsions continue for a considerable time, then the body temperature quickly rises, shortness of breath appears, and death occurs mainly from cardiac failure associated with respiratory failure, which is characterized by severe cyanosis of the visible mucous membranes.

General sensitivity to irritation during the period of onset of symptoms of poisoning in animals can be significantly increased (especially in case of poisoning with aromatic chlorine-containing compounds). On the contrary, in other cases there is severe depression, a sleepy state, a complete lack of appetite, gradual exhaustion, and reluctance to move. These symptoms may remain until death or may be followed by severe, sudden agitation.

The severity of the detected symptoms in these poisonings does not always reflect the general condition of the body in relation to the prognosis. In foreign literature (Radelev and others) there are cases where animals died after the first and short-term attack of convulsions and, on the contrary, experienced multiple attacks of the same strength.

When poisoned with less active organochlorine compounds (DDT, DDD and methoxychlor), animals initially show anxiety and become more agitated and highly sensitive than animals poisoned with drugs of higher toxicity. Twitching of the facial muscles (especially the eyelids) is noted soon after poisoning. Then this tremor spreads to other areas of the muscles, becoming stronger, and is accompanied by a sharply increasing shortness of breath. After such severe convulsive attacks, animals are in a stage of depression and numbness.

In case of moderate poisoning, the tremor is either subtle or absent altogether. In animals there is a connection of movements. Reflexes are reduced. Fatness decreases quickly.

Symptoms of poisoning most often appear within 5-6 hours after intake of the toxic substance. But this largely depends on the incoming compound and the sensitivity of the animal to it. Symptoms of DDT poisoning in sheep and goats may not appear for 12 to 24 hours, and they sometimes do not appear in cattle for up to a week. Death from HCH in dogs occurs within the first two days, and sometimes after a few days. In laboratory animals (rats, rabbits and dogs), death from Aldrin poisoning occurs within 24 hours, but there have been cases where after a single dose the animal died only on the 8th day. When treating sheep with dieldrin, death occurred after 10 days, but it could happen earlier. According to the literature, dieldrin has a particularly long “latent” period of its influence (up to 14 days) after treating animals.

Chlorindane poisoning resulting in death may sometimes not become clinically apparent until two weeks after a single dose. Toxicosis with polychlorcamphene after a single dose, on the contrary, is manifested by a violent reaction on the part of the body, and animals with signs of typical poisoning completely recover within 24-36 hours. The appearance of such a delayed pattern of chlorindane poisoning, leading in some cases to death, suggests that these insecticides may persist and be slowly excreted from the body, representing cumulative poisons.

Clinical signs of chronic poisoning are quite similar to those of acute intoxication with organochlorine insecticides, in which muscle twitching is also observed on the head, neck and other parts of the body. Occasionally, convulsions of varying strength may occur. There is a general depression, gradually increasing. Deaths from chronic poisoning have been rare.

Diagnosis. Poisoning with organochlorine insecticides is diagnosed on the basis of anamnesis, during the collection of which the issue of contact of animals with these pesticides is investigated. In doubtful cases, and especially in cases of chronic poisoning, the examination of milk in lactating animals may be important in making a diagnosis, since many of the substances of this group are excreted in milk. For this purpose, a biological test on flies is used, with which the presence of very small quantities of insecticides can be determined.

Forecast. In case of acute poisoning and the most potent insecticides, the prognosis is unfavorable. In case of chronic poisoning and timely diagnosis, the prognosis is favorable.

Treatment. In acute cases of poisoning in animals, therapeutic measures should be aimed at eliminating seizures with the help of substances that depress and calm the central nervous system. The most suitable for this purpose are barbiturates (sodium pentothal). However, it is not always possible and not in all animal species to relieve seizures using barbiturates. All chlorine-containing preparations for acute poisoning have the peculiarity that, as in case of poisoning with chlorine gas, the most life-threatening

the period is the first day after the poison arrives. If the animal survives 24-48 hours, then in the future the danger of its death is almost eliminated.

It is advisable to empty the gastrointestinal tract of contents, but only by using saline laxatives, not oils. The latter, promoting the dissolution and absorption of chlorine-containing compounds, accelerate the death of animals. If poisoning occurs when substances are absorbed through the skin, it is necessary to remove these substances from the coat and thereby prevent their further entry into the body.

Poisoning of large animals by these insecticides is unlikely, but it can occur. In foreign literature, it is recommended in such cases to prefer intravenous administration of calcium and glucose borogluconate to the use of barbiturates. It is also recommended to use laxatives from the anthraquinone group (isticin) in combination with glucose - isticine at the rate of 0.1 g per 1 kg of animal weight, in an aqueous suspension (Garner). When dogs are poisoned with DDT, intravenous administration of 2-3 g of calcium borogluconate gives particularly good results.

Pathological changes. When autopsying the corpses of animals that died from acute poisoning with organochlorine insecticides, no particularly characteristic changes are found. In cases where death occurs after a significant increase in body temperature and a generally violent reaction of the body, swelling of the mucous membranes and pallor of the color of some organs may occur. Small hemorrhages are also detected, especially under the epicardium and endocardium. Along the course of the coronary vessels, these hemorrhages are sometimes of considerable size. The cardiac muscle of the left side of the heart is contracted and pale. The muscles of the right half of the heart are somewhat stretched and flabby, especially with prolonged poisoning.

The lungs are collapsed, or have foci of emphysema and atelectasis. In some cases, which quickly end (within the first day) in death, severe pulmonary edema occurs with the presence of a significant amount of foamy fluid in the bronchi and trachea. There are hemorrhages under the mucous membrane of the latter, as well as under the pleura.

With oral intake of organochlorine toxic substances, gastroenteritis is observed to varying degrees. Brain and spinal cord with signs of congestive hyperemia.

In chronic poisoning, degenerative changes in the liver and kidneys are observed.

Histological changes: congestion, cloudy swelling and hemorrhages in organs, fatty degeneration, especially in the liver and kidneys. In the liver, necrotic lesions are found in the center of the lobules, but no cirrhotic changes are observed.

In case of chloridane poisoning, significant vascular damage is found in the form of many petechiae and ecchymosis in the intestine, myocardium and parenchymal organs. The same thing is observed in birds with poisoning with naphthalene derivatives (aldrin and di-eldr'in).

Therefore, to prevent poisoning, treatment of animals with organochlorine insecticides must be carried out in accordance with existing instructions; it is necessary to store pesticides in conditions that prevent accidental contact of animals, especially young animals, with them. When using these preparations to treat plants, it is necessary to take appropriate measures to prevent animals of all species and birds from coming into contact with them. When using pesticides of both this group and organophosphorus insecticides, it is necessary to pay special attention to prevent bees from visiting plants treated with these preparations.

Analysis. Analysis of feed products containing organochlorine insecticides in order to clarify the diagnosis is practically not carried out. There is no need for this.

There is a need to establish the DDT content in food products (through the sanitary service) and in grain. The use of grain in which the presence of DDT has been established for animals and birds should be excluded. If the grain contains hexachlorane above 1-1.5 mg per 1 kg, it can be used for feed.

DDT is determined in special laboratories using the Kullberg and Shim method according to established instructions, and hexachlorane is determined using the Svershkov method.

It has been established that the residual amount of methoxychlor in milk should not exceed 14 mg per 1 kg of milk.

Bibliography:

Bazhenov S.V. “Veterinary toxicology” // Leningrad “Kolos” 1964

Golikov S.N. “Current problems of modern toxicology” // Pharmacology Toxicology – 1981 No. 6.-p.645-650

Luzhnikov E.A. “Acute poisoning” //M. "Medicine" 1989