Classification.

I. By purpose distinguish:

1. Insecticides - insecticides

3. Herbicides - weed killers

4. Bacteriocides - drugs that destroy bacterial pathogens of plant diseases

5. Zoocides - substances that kill rodents

6. Acaricides - preparations that kill ticks, etc.

P. Po chemical structure:

1. Organophosphorus compounds

2. Organomercury compounds

3. Organochlorine compounds

4. Arsenic preparations

5. Copper preparations

Organophosphorus compounds.

TO organophosphorus compounds (OPCs) include karbofos, chlorophos, thiophos, metaphos etc. FOS are poorly soluble in water and highly soluble in fats.

Enter the body mainly by inhalation, as well as through the skin and orally. Distributed in the body mainly in lipid-containing tissues, including the nervous system. Stand out FOS by the kidneys and through the gastrointestinal tract.

Mechanism of toxic action FOS is associated with inhibition of the enzyme cholinesterase, which destroys acetylcholine, which leads to the accumulation of acetylcholine and excessive stimulation of M- and H-cholinergic receptors.

Clinical picture is described by cholinomimetic effects: nausea, vomiting, cramping abdominal pain, salivation, weakness, dizziness, bronchospasm, bradycardia, constriction of the pupils. In severe cases, convulsions, involuntary urination and defecation are possible.

Organomercury compounds.

These include substances such as granosan, mercuran and etc.

Substances of this group enter the body Stand out kidneys and through the gastrointestinal tract. Organomercury compounds have pronounced lipoidotropy and, therefore, are prone to cumulation, primarily in the central nervous system.

IN mechanism of action the main role is played by the ability to inhibit enzymes containing sulfhydryl groups (thiol enzymes). As a result, protein, fat, and carbohydrate metabolism in the tissues of various systems and organs is disrupted.

In case of poisoning with organomercury compounds patients complain for headache, dizziness, fatigue, metallic taste in the mouth, increased thirst, pain in the heart, tremors, etc. In addition, bleeding and loosening of the gums are observed. In severe cases, internal organs are affected (hepatitis, myocarditis, nephropathy).

Organochlorine compounds.

arrive by inhalation, through the skin and orally. Stand out accumulate

At acute poisoning

For chronic poisoning

Prevention.

1. Technological activities - mechanization and automation of work with pesticides. Manual spraying of plants with pesticides is prohibited.

2. Strict compliance with the rules storage, transportation and use of pesticides.

3. Sanitary measures. Large warehouses for storing pesticides should be located no closer than 200 meters from residential buildings and livestock yards. They are equipped with supply and exhaust ventilation.

4. Use of personal protective equipment. Those working with chemicals are provided with special clothing and protective equipment (gas mask, respirator, goggles). After work, be sure to take a shower.

5. Hygienic standardization. The concentration of pesticides in warehouses and when working with them should not exceed the maximum permissible concentration.

6. Length of working day I set it within 4-6 hours depending on the degree of toxicity of the pesticides. During the hot season, work should be done in the morning and evening hours. It is prohibited to cultivate crop areas in windy weather.

7. Familiarization of workers with the toxic properties of chemicals and ways to safely work with them.

8. Therapeutic and preventive measures. Preliminary and periodic medical examinations. Teenagers, pregnant and lactating women, as well as persons with hypersensitivity to toxic chemicals should not work with chemicals.

12. Behavior of pesticides in the natural environment. Comparative hygienic characteristics of organophosphorus and organochlorine pesticides. Prevention of possible poisoning.

Pesticides are an important factor in the productivity of crop production, but at the same time they can have various side effects on the environment: possible contamination of plants, soil, water, air with residues of preparations; accumulation and transfer of persistent pesticides through food chains; disruption of the normal functioning of certain species of living organisms; development of stable populations of pests, etc. To prevent the undesirable effects of pesticides on nature, a systematic study of the behavior of pesticides and metabolites in various environmental objects is carried out. Based on these data, recommendations for the safe use of drugs are developed. Pesticides enter the atmospheric air directly when they are applied by any means using ground or aviation equipment. The largest amounts of pesticides enter the air during dusting, the use of aerosols, and aerial spraying, especially under high temperature conditions. Aerosols and dust particles are carried over considerable distances by air currents. Therefore, in our country the use of pesticides by dusting is limited. The use of aerial spraying, small-droplet ultra-low-volume spraying is recommended to be carried out at lower temperatures in the morning and evening, and aerosols - at night. Chemical compounds released into the atmosphere do not remain there permanently. Some of them end up in the soil, the other part undergoes photochemical decomposition and hydrolysis with the formation of simple non-toxic substances. Most pesticides in the atmosphere are destroyed relatively quickly, but persistent compounds such as DDT, arsenates, and mercury preparations are destroyed slowly and can accumulate, especially in the soil.
Soil is an important component of the biosphere. It concentrates a huge number of different living organisms, the products of their vital activity and death. Soil is a universal biological adsorbent and neutralizer of various organic compounds. Pesticides that enter the soil can cause the death of soil-dwelling harmful insects (larvae of click beetles, darkling beetles, ground beetles, beetles, cutworms, etc.), nematodes, pathogens, and weed seedlings. At the same time, they can also have a negative effect on the beneficial components of soil fauna, which help improve the structure and properties of the soil. Less dangerous for soil fauna are unstable, quickly decomposing pesticides. The duration of preservation of pesticides in the soil depends on their properties, rate of application, form of preparation, type, humidity, temperature and physical properties of the soil, composition of soil microflora, characteristics of soil cultivation, etc. It has been established that organochlorine pesticides remain in the soil longer than organophosphorus ones , although within each of these groups the duration of persistence of insecticides may vary. Various soil microorganisms, for which pesticides are often a source of carbon, have a great influence on the persistence of chemical compounds in the soil. The higher the soil temperature, the faster the decomposition of drugs occurs, both under the influence of chemical factors (hydrolysis, oxidation) and under the influence of microorganisms and other soil inhabitants. Based on the rate of decomposition in soil, pesticides are conventionally divided into: very persistent (more than 18 months), persistent (up to 12 months), moderately persistent (more than 3 months), and low-resistant (less than 1 month).
The use of very persistent pesticides (DDT, heptachlor, polychlorpinene, arsenic compounds, etc.) in agriculture is not permitted. The use of less persistent drugs (HCCH, Sevin, Thiodan) is strictly regulated.
Great importance is attached to water protection measures to prevent pollution of seas, rivers, lakes, inland water bodies, soil and groundwater by harmful pesticide residues. Pesticides enter open water bodies during aerial and ground processing of agricultural land and forests, with soil and rainwater, and during direct treatment against vectors of human and animal diseases.
When pesticides are used correctly in agriculture, a minimal amount of them enters water bodies. Only very persistent pesticides (DDT) can accumulate in certain types of aquatic organisms. Their concentration occurs not only in phytoplankton and invertebrate organisms, but also in some species of fish. Depending on the type of organism, the concentration of persistent pesticides can vary within fairly wide limits. Along with accumulation, pesticides are gradually decomposed by phytoplankton. Different pesticides are degraded by phyto- and zooplankton at different rates. Based on the rate of destruction in the aquatic environment, pesticides are conventionally divided into the following five groups: with a duration of biological activity of more than 24 months, up to 24 months, 12 months, 6 months and 3 months. Almost all drugs used in agriculture in aqueous solution are quite easily hydrolyzed to form low-toxic products, and the rate of hydrolysis is higher at higher water temperatures. Organophosphorus preparations hydrolyze especially quickly.
The most dangerous pollution of water bodies is with organochlorine insecticides that are persistent and highly toxic to fish.

Organochlorine compounds.

Substances in this group include DDT, hexachlorocyclohexane (HCCH), hexachlorane, aldrin etc. Most are solids, highly soluble in fats.

Organochlorine substances enter the body arrive by inhalation, through the skin and orally. Stand out kidneys and through the gastrointestinal tract. Substances have pronounced cumulative properties and accumulate in parenchymal organs and lipid-containing tissues.

Organochlorine compounds are lipidotropic, capable of penetrating into cells and blocking the function of respiratory enzymes, as a result of which the processes of oxidation and phosphorylation in internal organs and nervous tissue are disrupted.

At acute poisoning in mild cases, weakness, headache, and nausea are observed. In severe cases, damage to the nervous system (encephalopolyneuritis), liver (hepatitis), kidneys (nephropathy), respiratory system (bronchitis, pneumonia) occurs, and an increase in body temperature is observed.

For chronic poisoning Characterized by functional disorders of nervous activity (asthenovegetative syndrome), changes in the function of the liver, kidneys, cardiovascular system, endocrine system, and gastrointestinal tract. When contacted with the skin, organochlorine compounds cause occupational dermatitis.

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 insecticide compounds 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 likely assumption is that the toxic effect is caused by a disruption of both the substances themselves and their breakdown products, enzymatic processes.The latter is justified because aldrin and dieldrin (as well as their isomers) have much in their effect similar 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, the use of lower concentrations - 0.25-0.5 percent (Garner) is quite sufficient.

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, drowsiness, complete lack of appetite, gradual exhaustion, and reluctance to move. These symptoms may remain until death or may be replaced 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 given 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, which can be used to determine the presence of very small quantities of insecticides.

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 fur 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

Substances in this group include DDT, hexachlorocyclohexane (HCCH), hexachlorane, aldrin etc. Most are solids, highly soluble in fats.

Organophosphorus compounds.

TO organophosphorus compounds (OPCs) include karbofos, chlorophos, thiophos, metaphos etc. FOS are poorly soluble in water and highly soluble in fats.

Prevention.

1. Technological activities - mechanization and automation of work with pesticides. Manual spraying of plants with pesticides is prohibited.

2. Strict compliance with the rules storage, transportation and use of pesticides.

5. Hygienic standardization. The concentration of pesticides in warehouses and when working with them should not exceed the maximum permissible concentration.

7. Familiarization of workers with the toxic properties of chemicals and ways to safely work with them.

97. Environmental protection when using agrochemicals in agriculture.

No new pesticide can be used in agricultural practice without special permission from the Russian Ministry of Health.

The level of atmospheric air pollution with pesticides depends on their physical and chemical properties, state of aggregation, and method of application. The greatest contamination is observed when plants are processed by the aviation method using aerosols. Therefore, fields located closer than 1 km from populated areas are not allowed to be processed using this method. In these cases, ground equipment should be used, with the exception of aerosol generators, and moderate and low-hazard drugs should be used.

Within the boundaries of a populated area and within a radius of 1 km around it, according to sanitary rules, it is not allowed to treat plants with persistent and highly dangerous pesticides, as well as substances that have an unpleasant odor, such as metaphos, chlorine mixture. Chemical treatment of green spaces in this case should be carried out at dawn, before sunrise. It is prohibited to treat plantings with any pesticides on the territory of hospitals, schools, children's and health institutions, and sports grounds.

The sanitary and epidemiological station and residents must be notified about the upcoming treatment of green spaces with pesticides in a populated area and near it, since people are not allowed to stay in the treated area.

Plant products and feed grown in areas treated with persistent pesticides, the residual amount of which exceeds the maximum permissible, may be allowed for food and livestock feed in each specific case by sanitary and veterinary control authorities.

To prevent the penetration of pesticides into a reservoir when treating fields, forests, and meadows with them, it is necessary to maintain a sanitary protection zone equal to 300 m from the treated areas to the reservoir. The size of this zone can be increased depending on the terrain, the nature and intensity of the grass cover. If it is necessary to treat plants in the zone itself, it is necessary to use unstable, low- and moderately hazardous preparations using ground-based equipment.

The use of pesticides in the first zone of the sanitary protection zone of household and drinking water pipelines is not allowed. In the territory of the second zone, it is allowed to use pesticides that do not have cumulative properties. It is not allowed to wash containers that contained pesticides, or to discharge pesticide-contaminated waters and residues of unused preparations into these bodies of water.

98. Basics of personal hygiene. Skin and oral hygiene.

Personal hygiene concerns not only individual issues, but also social ones. It includes the following sections:

1. Human body hygiene, oral hygiene, skin hygiene, cosmetic issues;

2. Hygiene of sleep and rest - principles of proper alternation of work and rest, optimal daily regimen;

3. Hygienic rules of rational nutrition and giving up bad habits;

4. Hygiene of clothing and shoes.

the main task personal hygiene as a science - the study of the influence of working and living conditions on people's health in order to prevent diseases and ensure optimal human living conditions for maintaining health and longevity.

Studies have shown that the number of bacterial cultures applied to clean skin decreases by 85% after 10 minutes. The conclusion is simple: clean skin has bactericidal properties, dirty skin loses them largely. Exposed areas of the body are more susceptible to contamination. There are especially many harmful microorganisms under the nails, so taking care of them is very important. Trim them often and keep them clean.

Fixed assets personal hygiene for skin care - water and soap. It is better if the water is soft and the soap is toilet soap. Don't forget to take into account the characteristics of your skin. It can be normal, dry or oily. It is highly recommended to shower after work and before bed. The water temperature should be slightly higher than normal body temperature - 37-38 degrees.

Personal hygiene includes washing in a bath or sauna using a washcloth at least once a week. After washing, be sure to change your underwear.

Feet should be washed daily with cool water and soap. Cold water reduces sweating.

It is advisable to wash your hair in soft water. To soften it, add 1 teaspoon of baking soda to 5 liters of water. Dry and normal hair should be washed once every 10 days, and oily hair - once a week. Suitable water temperature is 50-55 degrees. It would be a good idea to rinse your hair with a strong infusion of chamomile.

99. Hygiene of clothing and footwear, characteristics and properties of materials for the manufacture of clothing and footwear.

Cloth serves to regulate heat transfer from the body, is protection from adverse meteorological conditions, external pollution, and mechanical damage. Clothing remains one of the important means of human adaptation to environmental conditions.

Due to the various physiological characteristics of the body, the nature of the work performed and environmental conditions, several types of clothing are distinguished:

■ household clothing manufactured taking into account seasonal and climatic characteristics (winter, summer, clothing for mid-latitudes, north, south);

■ children's clothing, which, being lightweight, loose-fitting and made from soft fabrics, provides high thermal protection in the cold season and does not lead to overheating in the summer;

■ professional clothing, designed taking into account working conditions, protecting a person from exposure to occupational hazards. There are many types of professional clothing; This is a mandatory element of personal protective equipment for workers. Clothing is often crucial in reducing the impact of an unfavorable occupational factor on the body;

■ sportswear designed for various sports. Currently, great importance is attached to the design of sportswear, especially in high-speed sports, where reducing the friction of air flows on the athlete’s body helps improve athletic performance. In addition, fabrics for sportswear must be elastic, with good hygroscopicity and breathability;

■ military clothing of a special cut from a certain range of fabrics. The hygienic requirements for the fabrics and cut of military clothing are especially high, since a military man’s clothing is his home. Fabrics must have good hygroscopicity, breathability, retain heat well, dry quickly when wet, be wear-resistant, dust-resistant, and easy to wash. When worn, the fabric should not discolor or deform. Even a completely wet set of clothing for a soldier should not weigh more than 7 kg, otherwise heavy clothing will reduce performance. There are casual, dress and work military clothes. In addition, there are sets of seasonal clothing. The cut of military clothing is different and depends on the type of troops (clothing for sailors, infantrymen, paratroopers). Formal clothing has various finishing details that give the costume solemnity and elegance;

■ hospital clothing, consisting primarily of underwear, pajamas and a gown. Such clothing should be light, easy to clean from dirt, easy to disinfect, and is usually made from cotton fabrics. The cut and appearance of hospital clothing require further improvement. Currently, it is possible to produce disposable hospital clothing from paper of a special composition.

Clothing fabrics are made from plant, animal and artificial fibers. Clothing in general consists of several layers and has different thicknesses. The average thickness of clothing varies depending on the time of year. For example, summer clothing has a thickness of 3.3-3.4 mm, autumn clothing - 5.6-6.0 mm, winter clothing - from 12 to 26 mm. The weight of men's summer clothing is 2.5-3 kg, winter - 6-7 kg.

Regardless of the type, purpose, cut and shape, clothing must correspond to weather conditions, the state of the body and the work being performed, weigh no more than 10% of the person’s body weight, have a cut that does not impede blood circulation, does not restrict breathing and movement and does not cause displacement of internal organs, and is easy to clean from dust and dirt, be durable.

Clothing plays a big role in the processes of heat exchange between the body and the environment. It provides a microclimate that, under different environmental conditions, allows the body to remain in normal thermal conditions. The microclimate of the space under clothing is the main parameter when choosing a suit, since ultimately the microclimate under clothing largely determines a person’s thermal well-being. Under underwear microclimate one should understand the complex characteristics of the physical factors of the air layer adjacent to the surface of the skin and directly affecting the physiological state of the person catcher. This individual microenvironment is in particularly close interaction with the body, changes under the influence of its vital activity and, in turn, continuously influences the body; The state of the body's thermoregulation depends on the characteristics of the underwear microclimate.

The microclimate under clothing is characterized by temperature, air humidity and carbon dioxide content.

Temperature of the under-clothes area ranges from 30.5 to 34.6 °C at an ambient temperature of 9-22 °C. In a temperate climate, the temperature of the under-clothing space decreases as it moves away from the body, and at high ambient temperatures it decreases as it approaches the body due to heating of the clothing surface by the sun's rays.

Relative humidity Under clothing air in the middle climate zone is usually less than the humidity of the surrounding air and increases with increasing air temperature. So, for example, at an ambient temperature of 17 °C, the humidity of the underlying air is about 60%; when the ambient air temperature rises to 24 °C, the air humidity in the underlying space decreases to 40%. When the ambient temperature rises to 30-32 °C, when a person actively sweats, the humidity of the air under clothing increases to 90-95%.

Air The underclothing space contains about 1.5-2.3% carbon dioxide, its source is the skin. At an ambient temperature of 24-25 °C, 255 mg of carbon dioxide is released into the underwear space in 1 hour. In contaminated clothing, on the surface of the skin, especially when moistened and the temperature rises, intense decomposition of sweat and organic substances occurs with a significant increase in the carbon dioxide content in the air of the under-clothes space. If in a loose-fitting dress made of chintz or satin, the carbon dioxide content in the air of the underwear space does not exceed 0.7%, then narrow And tight clothes from the same tissue amount of carbon dioxide reaches 0.9%, and in warm clothes consisting of 3-4 layers, it increases to 1.6%.

The properties of clothing largely depend on properties of fabrics. Fabrics must have thermal conductivity in accordance with climatic conditions, sufficient breathability, hygroscopicity and moisture capacity, low gas absorption, and not have irritating properties. Fabrics should

to be soft, elastic and at the same time durable, not to change its hygienic properties during wear.

Good breathability is important for summer clothing; on the contrary, clothing for working in the wind at low air temperatures should have minimal breathability. Good absorption of water vapor is a necessary property of linen fabrics, completely unacceptable for the clothing of people working in an atmosphere of high humidity or with constant wetting of clothes with water (dying shop workers, sailors, fishermen, etc.).

When hygienically assessing clothing fabrics, their relationship to air, water, thermal properties and ability to retain or transmit ultraviolet rays are examined.

Breathability fabrics are of great importance for ventilation of the underwear space. It depends on the number and volume of pores in the fabric, the nature of the fabric processing.

Airtight clothing creates difficulties in ventilating the space under clothing, which quickly becomes saturated with water vapor, which disrupts the evaporation of sweat and creates the preconditions for a person to overheat.

It is very important that the fabrics maintain sufficient breathability even when wet, that is, after wetting by rain or getting wet from sweat. Wet clothing makes it difficult for outside air to reach the surface of the body, in the space underneath moisture and carbon dioxide accumulate, which reduces the protective and thermal properties of the skin.

An important indicator of the hygienic properties of fabrics is their relationship to water. Water in tissues can be in the form of vapor or liquid droplets. In the first case we talk about hygroscopicity, in the second - about moisture capacity fabrics.

Hygroscopicity means the ability of tissues to absorb water in the form of water vapor from the air - to absorb vaporous secretions from human skin. The hygroscopicity of fabrics varies. If the hygroscopicity of linen is taken as one, then the hygroscopicity of chintz will be 0.97, cloth - 1.59, silk - 1.37, suede - 3.13.

Wet clothing quickly removes heat from the body and thereby creates the preconditions for hypothermia. In this case, the evaporation time matters. Thus, flannel and cloth evaporate water more slowly, which means that the heat transfer of woolen clothing due to evaporation will be less than that of silk or linen. In this regard, wet clothes made of silk, cotton or linen, even at a fairly high air temperature, cause a feeling of chilliness. Flannel or wool clothing worn over the top significantly softens these sensations.

Are of great importance thermal properties fabrics. Heat loss through clothing is determined by the thermal conductivity properties of the fabric, and also depends on the saturation of the fabric with moisture. The degree of influence of clothing fabrics on the overall heat loss serves as an indicator of its thermal properties. This assessment is carried out by determining the thermal conductivity of fabrics.

Under thermal conductivity understand the amount of heat in calories passing through 1 cm 2 of fabric in 1 s when its thickness is 1 cm and the temperature difference on opposite surfaces is 1 ° C. The thermal conductivity of the fabric depends on the size of the pores in the material, and it is not so much the large spaces between the fibers that matter, but the small ones - the so-called capillary pores. The thermal conductivity of worn or repeatedly washed fabric increases, as there are fewer capillary pores and the number of larger spaces increases.

Due to different ambient air humidity, the pores of clothing contain more or less water. This changes thermal conductivity, since wet fabric conducts heat better than dry fabric. When completely wet, the thermal conductivity of wool increases by 100%, silk by 40% and cotton fabrics by 16%.

The ratio of tissues to radiant energy- the ability to retain, transmit and reflect both the integral flux of solar radiation and the most biologically active infrared and ultraviolet rays. The absorption of visible and thermal rays by fabrics largely depends on their color, and not on the material. All undyed fabrics absorb visible rays equally, but dark fabrics absorb more heat than light ones.

In hot climates, it is better to make underwear from cotton dyed fabrics (red, green), which provide better retention of sunlight and less heat access to the skin.

One of the significant features of fabrics is their permeability to ultraviolet rays. It is important as an element in the prevention of ultraviolet deficiency, which often occurs in residents of large industrial cities with intense air pollution. Of particular importance is the transparency of materials in relation to ultraviolet rays for residents of northern regions, where increasing the area of exposed parts of the body is not always possible due to harsh climatic conditions.

The ability of materials to transmit ultraviolet rays turned out to be uneven. Of the synthetic fabrics, nylon and nylon are the most permeable to ultraviolet rays - they transmit 50-70% of ultraviolet rays. Fabrics made of acetate fiber transmit ultraviolet rays much worse (0.1-1.8%). Dense fabrics - wool, satin do not transmit ultraviolet rays well, but chintz and cambric are much better.

Silk fabrics of rare weave, both undyed (white) and dyed in light colors (yellow, light green, blue), are more transparent to ultraviolet rays than materials with a higher specific density, thickness, as well as dark and saturated colors (black, lilac , red).

Ultra-violet rays, having passed through polymer-based tissues, retain their biological properties and, above all, antirachitic activity, as well as a stimulating effect on the phagocytic function of blood leukocytes. High bactericidal effectiveness against Escherichia coli and Staphylococcus aureus is also maintained. Irradiation with ultraviolet rays through nylon fabrics leads to the death of 97.0-99.9% of bacteria within 5 minutes.

Under the influence of wear, clothing fabric changes its properties due to wear and contamination.

Chemical fibers are divided into artificial and synthetic. Artificial fibers are represented by cellulose and its acetate, viscose and triacetate esters. Synthetic fibers are lavsan, cashmilon, chlorine, vinyl, etc.

In terms of physical-chemical and physical-mechanical properties, chemical fibers are significantly superior to natural ones.

Synthetic fibers are highly elastic, have significant resistance to repeated deformation, and are resistant to abrasion. Unlike natural fibers, chemical fibers are resistant to acids, alkalis, oxidizing agents and other reagents, as well as mold and moths.

Fabrics made from chemical fibers have antimicrobial properties. Thus, microorganisms survive significantly less on chlorine underwear after experienced wear than on underwear made from natural fabrics. New fibers have been created that inhibit the growth of staphylococcal flora and E. coli.

Fabrics made from chemical fibers also have higher breathability than materials made from natural fibers of the same structure. The air permeability of lavsan, nylon and chlorine fabrics is higher than that of cotton.

Shoes (leather) should contribute to the formation of the arch of the foot, prevent the development of flat feet - have a wide raised toe and a high heel. 10 mm, dense heel, providing heel fixation. The fingertips should not reach 10 mm from the toe. For teenagers and adults, it is possible to use synthetic materials in clothes and shoes, for example. artificial fur, waterproof and windproof fabrics for outerwear, leather substitutes for shoes. Shoes intended for constant wear must be light, true to size and have a heel no higher than 3–4 cm. Inconsistency with the shape of the foot, wearing tight, narrow shoes with high heels leads to deformation of the bones and joints of the foot, spine, pelvis, and shortening calf muscles, sprains and ankle sprains. Sneakers that are popular among teenagers should have insoles and lining made of hygroscopic material, a thick elastic sole, and a durable upper with sealing inserts. They should be worn with wool or thick cotton socks.

Clothes must be washed regularly and dry cleaned; shoes - disinfect by placing paper soaked in formaldehyde inside. It is unacceptable to use other people's clothes and shoes.

100. Ionizing radiation, their types, properties and hygienic characteristics. Principles of protection when working with sources of ionizing radiation.

Ionizing radiation - in the most general sense - various types of microparticles and physical fields that can ionize matter.

· Alpha radiation is a stream of alpha particles - helium-4 nuclei. Alpha particles produced by radioactive decay can easily be stopped by a piece of paper.

· Beta radiation is a flow of electrons resulting from beta decay; To protect against beta particles with energies up to 1 MeV, an aluminum plate a few millimeters thick is sufficient.

· Gamma radiation has much greater penetrating power because it consists of high-energy photons that have no charge; heavy elements (lead, etc.) that absorb MeV photons in a layer several cm thick are effective for protection. The penetrating ability of all types of ionizing radiation depends on energy

There are two types of effects of ionizing radiation on the body: somatic And genetic . With a somatic effect, the consequences appear directly in the irradiated person, with a genetic effect - in his offspring. Somatic effects may be early or delayed. Early ones occur in the period from several minutes to 30-60 days after irradiation. These include redness and peeling of the skin, clouding of the lens of the eye, damage to the hematopoietic system, radiation sickness, and death. Long-term somatic effects appear several months or years after irradiation in the form of persistent skin changes, malignant neoplasms, decreased immunity, and shortened life expectancy.

When studying the effect of radiation on the body, the following features were identified:

The high efficiency of absorbed energy, even small amounts can cause profound biological changes in the body.
The presence of a latent (incubation) period for the manifestation of the effects of ionizing radiation.
The effects of small doses can be additive or cumulative.
Genetic effect - impact on offspring.
Various organs of a living organism have their own sensitivity to radiation.
Not every organism (person) generally reacts the same way to radiation.
Exposure depends on the frequency of exposure. With the same dose of radiation, the lesser the harmful effects, the more dispersed it is received over time.

Ionizing radiation can affect the body through both external (especially x-rays and gamma radiation) and internal (especially alpha particles) irradiation. Internal irradiation occurs when sources of ionizing radiation enter the body through the lungs, skin and digestive organs. Internal irradiation is more dangerous than external irradiation, since radiation sources that get inside expose unprotected internal organs to continuous irradiation.

Under the influence of ionizing radiation, water, which is an integral part of the human body, is split and ions with different charges are formed. The resulting free radicals and oxidants interact with the molecules of the organic matter of the tissue, oxidizing and destroying it. Metabolism is disrupted. Changes occur in the composition of the blood - the level of red blood cells, white blood cells, platelets and neutrophils decreases. Damage to the hematopoietic organs destroys the human immune system and leads to infectious complications.

101. Ionizing radiation: α-radiation, nature, characteristics, properties, path length in air. Protection from α-radiation.

Alpha radiation (alpha rays) is one of the types of ionizing radiation; is a stream of rapidly moving, highly energetic, positively charged particles (alpha particles).

The main source of alpha radiation are alpha emitters - radioactive isotopes that emit alpha particles during the decay process. A feature of alpha radiation is its low penetrating ability. The path of alpha particles in a substance (that is, the path along which they produce ionization) turns out to be very short (hundredths of a millimeter in biological media, 2.5-8 cm in air). However, along a short path, alpha particles create a large number of ions, that is, they cause a large linear ionization density. This provides a pronounced relative biological effectiveness, 10 times greater than when exposed to X-ray and gamma radiation. During external irradiation of the body, alpha particles can (with a sufficiently large absorbed dose of radiation) cause severe, although superficial (short range) burns; when ingested through the mouth, long-lived alpha emitters are carried throughout the body by the bloodstream and deposited in the organs of the reticuloendothelial system, etc., causing internal irradiation of the body.

You can protect yourself from alpha rays by:

increasing the distance to radiation sources, because alpha particles have a short range;
use of special clothing and safety footwear, because the penetrating ability of alpha particles is low;
excluding sources of alpha particles from entering food, water, air and through mucous membranes, i.e. use of gas masks, masks, goggles, etc.

102. Ionizing radiation: β-radiation, nature, characteristics, properties, path length in air. Protection against β-radiation.

Beta radiation is a flow of electrons (β - radiation, or, most often, simply β radiation) or positrons (β + radiation) resulting from radioactive decay. Currently, about 900 beta radioactive isotopes are known.

The mass of beta particles is several tens of thousands of times less than the mass of alpha particles. Depending on the nature of the source of beta radiation, the speed of these particles can range from 0.3 to 0.99 times the speed of light. The energy of beta particles does not exceed several MeV, the path length in air is approximately 1800 cm, and in the soft tissues of the human body ~ 2.5 cm. The penetrating ability of beta particles is higher than that of alpha particles (due to lower mass and charge) . For example, to completely absorb a flux of beta particles with a maximum energy of 2 MeV, a protective layer of aluminum 3.5 mm thick is required. The ionizing ability of beta radiation is lower than that of alpha radiation: per 1 cm of travel of beta particles in the medium, several dozen pairs of charged ions are formed.

The following is used as protection against beta radiation:

fences (screens), taking into account the fact that an aluminum sheet several millimeters thick completely absorbs the flow of beta particles;
methods and methods that exclude sources of beta radiation from entering the body.

103. Ionizing radiation: γ-radiation, nature, characteristics, properties, path length in air. Protection against γ-radiation.

Gamma radiation (gamma rays, γ rays) is a type of electromagnetic radiation with an extremely short wavelength -< 5×10 −3 нм и, вследствие этого, ярко выраженными корпускулярными и слабо выраженными волновыми свойствами.

Gamma rays are high energy photons. The average range of a gamma quantum is about 100 m in air and 10-15 cm in biological tissue. Gamma radiation can also occur when fast charged particles decelerate in a medium (bremsstrahlung gamma radiation) or when they move in strong magnetic fields (synchrotron radiation).
Processes in outer space are also sources of gamma radiation. Cosmic gamma rays come from pulsars, radio galaxies, quasars, and supernovae.
Gamma radiation from nuclei is emitted during nuclear transitions from a state with higher energy to a state with lower energy, and the energy of the emitted gamma quantum, up to an insignificant recoil energy of the nucleus, is equal to the difference in the energies of these states (levels) of the nucleus.

Protection from X-rays and gamma radiation must be organized taking into account the fact that these types of radiation have a high penetrating ability. The following measures are most effective (usually used in combination):

increasing the distance to the radiation source;
reducing the time spent in the danger zone;
shielding the radiation source with high-density materials (lead, iron, concrete, etc.);
use of protective structures (anti-radiation shelters, basements, etc.) for the population;
use of personal protective equipment for the respiratory system, skin and mucous membranes;
Dosimetric monitoring of the external environment and food.

104. The concept of sealed sources of ionizing radiation. Principles of protection.

First of all, it should be noted that sources of ionizing radiation, depending on their relationship to radioactive substance are divided into:

1) Open

2) Closed

3) Generating AI

4) Mixed

Closed sources- these are sources, during normal operation of which radioactive substances do not enter the environment

These sources are widely used in practice. For example, they are used in shipyards, in medicine (X-ray machines, etc.), in flaw detectors, and in the chemical industry.

Dangers when working with sealed sources:

1) Penetrating radiation.

2) For powerful sources - the formation of general toxic substances (nitrogen oxides, etc.)

3) In emergency situations - environmental contamination with radioactive substances.

It must be said that when working with radiation sources, a person may be exposed to

1. External exposure

2. Internal exposure(when a radioactive substance enters the body and irradiation occurs from the inside)

When working with sealed sources of ionizing radiation, as stated in the definition, there is no release of radioactive substances into the environment and therefore they cannot enter the human body.

MINISTRY OF HOUSING AND COMMUNAL SERVICES OF THE RSFSR

ORDER OF THE RED BANNER OF LABOR
ACADEMY OF UTILITIES named after. K.D. PAMFILOVA

MANAGEMENT
FOR DRINKING WATER PREPARATION TECHNOLOGY,
PROVIDING
COMPLIANCE WITH HYGIENIC REQUIREMENTS
IN RELATION TO ORGANOCHLORINE COMPOUNDS

Department of Scientific and Technical Information of AKH

Moscow 1989

The hygienic aspects and causes of contamination of drinking water with toxic volatile organochlorine compounds are considered. Technological methods for purifying and disinfecting water that prevent the formation of organochlorine compounds and methods for their removal are presented. The methodology for choosing one or another method is outlined depending on the quality of the source water and the technology for its processing.

The manual was developed by the Research Institute of Municipal Water Supply and Water Purification, AKH named after. K.D. Pamfilova (Candidate of Technical Sciences I.I. Demin, V.Z. Meltser, L.P. Alekseeva, L.N. Paskutskaya, Candidate of Chemical Sciences Ya.L. Khromchenko) and is intended for research specialists, design and production organizations working in the field of natural water purification, as well as for SES workers monitoring hygienic indicators of drinking water quality.

The manual is compiled on the basis of studies conducted in semi-production and production conditions with the participation of LNII AKH, NIKTIGH, UkrkommunNIIproekt, NIIOCG named after. A.N. Sysin and 1 MMI named after. THEM. Sechenov.

By decision of the Academic Council of the Research Institute of KVOV AKH, the original title of the work “Recommendations for improving the technology of water purification and disinfection in order to reduce organohalogen compounds in drinking water” was replaced with the present one.

I. GENERAL PROVISIONS

In the practice of preparing drinking water, one of the main treatment methods that ensures its reliable disinfection, as well as allows maintaining the sanitary condition of treatment facilities, is chlorination.

Research in recent years has shown that toxic volatile organohalogen compounds (VOCs) may be present in water. These are mainly compounds belonging to the group of trihalomethanes (THM): chloroform, dichlorobromomethane, dibromochloromethane, bromoform, etc., which have carcinogenic and mutagenic activity.

Hygienic studies conducted abroad and in our country have revealed a relationship between the incidence of cancer and the population’s consumption of chlorinated water containing organohalogen compounds.

A number of countries have established maximum permissible concentrations for the amount of THMs in drinking water (µg/l): in the USA and Japan - 100, in Germany and Hungary - 50, in Sweden - 25.

According to the results of studies conducted by the 1st Moscow Medical Institute. THEM. Sechenov, Research Institute of General and Communal Hygiene named after. A.N. Sysin and the Institute of Experimental and Clinical Oncology of the USSR Academy of Medical Sciences, 6 high-priority volatile organochlorine compounds (VOCs) were identified, and the USSR Ministry of Health approved the approximate safe levels of their exposure to humans (OSL) taking into account blastomogenic activity (the ability of substances to cause various types of cancer) ( table).

Table

High-priority chemical substances and their permissible concentrations in drinking water, mg/l

Compound	OBUV on toxicological grounds of harmfulness	OBUV taking into account blastomogenic activity
Chloroform		0,06
Carbon tetrachloride		0,006
1,2-dichloroethane		0,02
1,1-dichlorethylene		0,0006
Trichlorethylene		0,06
Tetrachlorethylene		0,02

The guide discusses the causes of contamination of drinking water with volatile organochlorine contaminants and the influence of the quality of source water on their final concentration. Technological methods for water purification and disinfection are outlined that make it possible to reduce the concentration of chemical substances to acceptable limits. A methodology is given for selecting the proposed methods depending on the quality of the source water and its processing technology.

The technological methods presented in the manual were developed on the basis of specially conducted research in laboratory and semi-production conditions and tested at existing waterworks.

There are two known possible sources of chemical substances getting into drinking water:

1) as a result of contamination of water supplies with industrial wastewater containing chemical substances. At the same time, surface water supply sources, as a rule, contain small amounts of chemical substances, since self-purification processes are actively taking place in open reservoirs; in addition, LCS are removed from water by surface aeration. Contents of LHS inunderground water sources can reach significant values, and their concentration increases with the arrival of new portions of pollution;

2) the formation of LCS during water treatment, as a result of the interaction of chlorine with organic substances present in the source water. Organic substances responsible for the formation of LCS include oxo compounds having one or more carbonyl groups located in the ortho-para position, as well as substances capable of forming carbonyl compounds during isomerization, oxidation or hydrolysis. These substances include primarily humus and petroleum products. In addition, the concentration of formed LCHs is significantly influenced by the content of plankton in the source water.

The main concentrations of LCS are formed at the stage of primary chlorination of water when chlorine is introduced into untreated water. Over 20 different chemical substances have been found in chlorinated water. The presence of THMs and carbon tetrachloride is most often noted. Moreover, the amount of chloroform is usually 1-3 orders of magnitude higher than the content of other chemical substances, and in most cases their concentration in drinking water is 2-8 times higher than the established standard.

The process of formation of LCS during water chlorination is complex and time-consuming. It is significantly influenced by the content of organic contaminants in the source water, the time of contact of water with chlorine, the dose of chlorine and the pH of the water (Fig.).

Numerous studies have established that volatile organochlorine compounds present in source water and formed during its chlorination do not linger in traditional-type structures. Their maximum concentration is observed in a clean water reservoir.

Currently, at existing waterworks, pre-chlorination is often carried out with very high doses of chlorine in order to combat plankton, reduce the color of water, intensify coagulation processes, etc. In this case, chlorine is sometimes introduced at points remote from water treatment facilities (ladles, channels, etc.). At many waterworks, chlorine is introduced only at the pre-chlorination stage; the dose of chlorine in this case reaches 15-20 mg/l. Such chlorination regimes create the most favorable conditions for the formation of LCS due to prolonged contact of organic substances present in water with high concentrations of chlorine.

To prevent the formation of VHCs during water treatment, it is necessary to change the mode of preliminary chlorination of water, while the concentration of VHCs in drinking water can be reduced by 15-30%, depending on the method used.

Thus, when choosing a dose of chlorine, you should be guided only by considerations of water disinfection. The dose of pre-chlorination should not exceed 1-2 mg/l.

In case of high chlorine absorption of water, fractional chlorination should be carried out; in this case, the calculated dose of chlorine is not introduced immediately, but in small portions (partially before the structures I water purification stages, partly before filters).

Fractional chlorination is also advisable to use when transporting untreated water over long distances. A single dose of chlorine during fractional chlorination should not exceed 1-1.5 mg/l.

In order to reduce the time of contact of untreated water with chlorine, preliminary disinfection of water should be carried out directly at treatment facilities. To do this, chlorine is supplied to the water after drum screens or microfilters at the water inlets of the mixer or after the air separation chamber.

To quickly regulate the process of water chlorination and effectively use chlorine, it is necessary to have communications for transporting chlorine to water intake structures, to water intake wells of the 1st rise, to mixers, clarified and filtered water pipelines, to clean water reservoirs.

In addition, to prevent biological and bacterial fouling of structures (periodic washing of sedimentation tanks and filters with chlorinated water), mobile chlorination units can be used.

To eliminate the possibility of the formation of organochlorine compounds when preparing chlorine water, only purified water from the domestic drinking water supply should be used in chlorination plants.

3. Purification of water from dissolved organic substances before chlorination

Organic substances present in source water are the main sources of formation of LCS during water treatment. Preliminary purification of water from dissolved and colloidal organic contaminants before chlorination reduces the concentration of chemical substances in drinking water by 10-80%, depending on the depth of their removal.

Preliminary water purification by coagulation . Partial purification of water from organic contaminants by coagulation and clarification (chlorine is introduced into the treated water after I water purification stage) allows you to reduce the concentration of chemical substances in drinking water by 25-30%.

When carrying out complete preliminary water purification, including coagulation, clarification and filtration, the concentration of organic substances decreases by 40-60%; accordingly, the concentration of chemical substances formed during subsequent chlorination decreases.

In order to maximize the removal of organic substances, it is necessary to intensify water purification processes (use flocculants, thin-layer modules in settling facilities and illuminators with suspended sediment, new filter materials, etc.).

When using water purification technology without pre-chlorination, attention should be paid to meeting the requirements of GOST 2874-82 “Drinking water. Hygienic requirements and quality control" regarding the time of contact of water with chlorine during its disinfection, as well as the sanitary condition of structures, carrying out periodicchemical disinfection in accordance with the works [,].

It is also necessary to regularly remove sediment from structures I water purification stages.

Sorptive water purification . The use of powdered activated carbon (PAC) for water purification reduces the formation of VOCs by 10-40%. The efficiency of removing organic substances from water depends on the nature of the organic compounds and mainly on the dose of PAHs, which can vary widely (from 3 to 20 mg/l or more).

Water should be treated with PAHs before it is chlorinated and in accordance with the recommendations of SNiP 2.04.02-84.

The use of sorption filters loaded with granular activated carbon without preliminary chlorination of water makes it possible to remove up to 90% of dissolved organic substances from water and, accordingly, reduce the formation of volatile chemicals during the water treatment process. In order to increase the efficiency of sorption filters in relation to organic substances, they should be placed in the technological scheme of water purification after the stages of coagulation treatment and water clarification, i.e. after filters or contact clarifiers.

Pre-treatment of water with oxidizing agents (ozone, potassium permanganate, ultraviolet irradiation, etc.) increases the regeneration period of the filters.

Substances in this group include DDT, hexachlorocyclohexane (HCCH), hexachlorane, aldrin etc. Most are solids, highly soluble in fats.

Organophosphorus compounds.

TO organophosphorus compounds (OPCs) include karbofos, chlorophos, thiophos, metaphos etc. FOS are poorly soluble in water and highly soluble in fats.

Prevention.

1. Technological activities - mechanization and automation of work with pesticides. Manual spraying of plants with pesticides is prohibited.

2. Strict compliance with the rules storage, transportation and use of pesticides.

5. Hygienic standardization. The concentration of pesticides in warehouses and when working with them should not exceed the maximum permissible concentration.

7. Familiarization of workers with the toxic properties of chemicals and ways to safely work with them.

133. Environmental protection when using agrochemicals in agriculture.

No new pesticide can be used in agricultural practice without special permission from the Russian Ministry of Health.

134. Basics of personal hygiene. Skin and oral hygiene.

Personal hygiene concerns not only individual issues, but also social ones. It includes the following sections:

1. Human body hygiene, oral hygiene, skin hygiene, cosmetic issues;

2. Hygiene of sleep and rest - principles of proper alternation of work and rest, optimal daily regimen;

3. Hygienic rules of rational nutrition and giving up bad habits;

4. Hygiene of clothing and shoes.

Personal hygiene includes washing in a bath or sauna using a washcloth at least once a week. After washing, be sure to change your underwear.

Feet should be washed daily with cool water and soap. Cold water reduces sweating.

135. Hygiene of clothing and footwear, characteristics and properties of materials for the manufacture of clothing and footwear.