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Lecture notes, cheat sheets
General hygiene. Lecture notes: briefly, the most important
Directory / Lecture notes, cheat sheets Table of contents
LECTURE #1. Environment and health History of the development of hygienic science Hygienic knowledge based on life observations originated in ancient times. The first hygienic treatises that have come down to us ("About a healthy lifestyle", "About water, air and localities") belong to the great physician of Ancient Greece, Hippocrates (460-377 BC). The first city water pipes, hospitals were built in Ancient Rome. Until now, not only known, but also of a certain scientific interest "Treatise on hygiene (elimination of any damage to the human body by correcting various errors in the regime)", written by the great Arab-Muslim scholar, born in Central Asia, Avicenna Abu Ali ibn Sina (980 -1037). The treatise outlines important issues of hygiene, suggests ways and means of treating and preventing diseases caused by sleep disturbance, nutrition, etc. However, hygienic science developed not only on the basis of empirical observations, but also, of course, taking into account new experimental data. Here it is necessary to recall the hygienic guidelines written by the Frenchman M. Levy (1844) and the English medical scientist E. Parkes. Max Pettenkofer (1865-1818) organized the first hygienic department at the medical faculty of the University of Munich in 1901. He not only investigated environmental factors (water, air, soil, food), but also created the first school of hygienists. From Ancient (Kyiv, Novgorod) Rus', empirical knowledge about hygiene also comes to us. Suffice it to recall the well-known treatise on the life of the Russian family - "Domostroy", which outlines the basics of proper food storage, paid attention to cleanliness and tidiness. Peter I did a lot to protect the health of the population and prevent the spread of diseases in Russia, by issuing a number of decrees on the sanitary condition of cities, on the mandatory notification of cases of infectious diseases, etc. Many Russian doctors pointed out the special importance of preventive measures in preventing high morbidity: N. I. Pirogov, S. P. Botkin, N. G. Zakharyin, M. Ya. Mudrov. N. I. Pirogov wrote: "I believe in hygiene. This is where the true progress of our science lies. The future belongs to preventive medicine." In an act speech delivered in 1873, another well-known Russian clinician, Professor G.N. Zakharyin, said: “The more mature the practical doctor, the more he understands the power of hygiene and the relative weakness of treatment, therapy ... The most successful therapy is possible only with condition of hygiene. Only hygiene can victoriously argue with the ailments of the masses. We consider hygiene one of the most important, if not the most important, subject of the activity of a practical doctor. " In Russia, hygiene as a course of forensic science (forensic medicine) begins to be taught at the Medical and Surgical Academy (St. Petersburg) right from its opening, that is, from 1798. At first, the course is called "Medical Police", and since 1835 "Medical Police and hygiene." An independent department of hygiene at the academy and the first in Russia was opened in 1871 under the guidance of Privatdozent Alexei Petrovich Dobroslavin (1842-1889). A.P. Dobroslavin organized an experimental laboratory at the department, created the first Russian school of hygienists, he wrote the first Russian textbooks on hygiene. The Moscow School of Hygienists was founded by Fedor Fedorovich Erisman (1842-1915). In 1881, F. F. Erisman was elected Privatdozent of the Hygiene Department of the Medical Faculty of Moscow University. He worked a lot in the field of hygiene of children and adolescents (Erisman's universal desk is still known), social hygiene, laid the foundation for studying the influence of environmental factors on the health of the younger generation, and proved that physical development can act as an indicator of the sanitary well-being of the child population. In the Soviet period, such scientists as professors Grigory Vitalyevich Khlopin, Fedor Grigorievich Krotkov, Alexei Nikolaevich Sysin, Alexei Alekseevich Minkh, Gennady Ivanovich Sidorenko and many others did a lot for the development of domestic hygiene. Subject, content of hygiene, place and importance of hygiene in the activities of a practitioner The philological origin of hygiene is associated in Greek mythology with the goddess of health (Hygieinos) - the daughter of Aesculapius. Hygiene - the goddess of health - a symbol of health. Hygiene - medical, preventive discipline. It studies the patterns of influence of environmental factors on the body in order to prevent diseases and improve the environment itself. Environmental factors are also studied by other disciplines. The peculiarity of hygiene is that it studies the influence of environmental factors on human health. The task of hygiene as a science is to weaken the effect of negative factors and strengthen the effect of positive factors by carrying out hygienic measures. In particular, it has now been established that fluorine in the composition of drinking water has a certain effect on the development and formation of teeth. For example, concentrations of fluorine in water less than 0,7 mg/l and especially at the level of 0,5 mg/l lead to the development of caries. The water of the Volga, widely used for water consumption in the cities of the Volga region, contains fluorine at the level of 0,2 mg/l. This level of fluoride in drinking water leads to massive development of caries. 80%, and in some places - 90% of the population of the Volga cities suffer from caries. Along with such a well-known negative factor of fluorine deficiency in drinking water, its excessive concentration (above 1,5 mg/l) leads to the development of fluorosis. Fluorosis is a disease, the development of which is associated with the action of fluorine on the body as a protoplasmic poison. In particular, a high concentration of fluoride leads to changes in the formation and development of teeth. Along with the skeletal form, there is the so-called dental form of fluorosis. The optimal level of fluorine, which ensures the prevention of caries and excludes its toxic effect, is in the range from 0,7 to 1,5 mg/l. Such a range of doses of fluorine in drinking water is established taking into account regional characteristics and some other aspects. Thus, a distinctive feature of hygiene is the rationing of factors, which we have considered using the example of fluorine. The subjects of hygiene are the environment and health. What are they? The environment is a set of elements of a physical, chemical, biological, psychological, economic, cultural and ethnic nature that make up a single, continuously changing ecological system (ecosystem). The definition of health most adequate to modern conditions is given by the experts of the World Health Organization. Health is a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity. Over the past XNUMXth century the main funds invested in health care were mainly used to solve problems that had already arisen, and not to prevent their occurrence. The emphasis was on cure, or at any rate on the reduction of ill health, on therapeutic help, rather than on the promotion of health and the prevention of disease. There should be a reorientation of priorities. More attention should be paid to the preventive direction of the development of medicine. It is well known that hygiene arose from the needs of clinical medicine. First of all, representatives of clinical medicine spoke out for the development of hygiene, such prominent scientists as M. Ya. Mudrov, N. G. Zakharyin, N. I. Pirogov, S. P. Botkin. Zakharyin's statement is well-known: "The more mature the practitioner, the more he understands the power of hygiene and the relative weakness of treatment - therapy." The very success of therapy is possible only if hygiene is observed. The task of hygiene is to make the development of man the most perfect, life - strong, and death - the most remote. Knowledge of hygiene is necessary in the practice of doctors of various profiles: medical, pediatric and dental. It is well known that the development of various pathologies is influenced by environmental factors. If these factors are not taken into account, the effectiveness of the treatment is reduced. For example, in the field of pathology of diseases of the oral cavity, the influence of a professional factor is known. Working with certain chemicals can enhance the development of the pathological process in the oral cavity, caries, and other diseases. The development of caries is significantly influenced by such a factor as the nature of nutrition (alimentary). It is well known that tooth decay is more likely to develop in those who consume more refined carbohydrates. Currently, a significant number of diseases are known in medicine that have an environmental factor in their genesis. The course of a number of diseases is influenced by housing conditions, the consumption of water of one or another mineral composition. Working conditions contribute to the development of certain diseases, can aggravate the course of cardiovascular pathology, have a negative impact on the development of pathology of the respiratory system. I must say that there are diseases that are caused by the impact on the body of a professional factor. These diseases are called occupational diseases. The doctor needs knowledge of the impact of one or another factor on the body: the alimentary factor, the nature of the water, its composition, quality. When carrying out this or that treatment using pharmacological preparations, the nature of nutrition should be taken into account, since it can weaken or enhance the effect of the drug (just like drinking water can enhance the effect or, conversely, weaken the effectiveness of the ongoing drug treatment). The development of hygiene goes in two directions. On the one hand, the process of its so-called differentiation is noted. The differentiation process is associated with the separation from general hygiene of its independent branches, such as social hygiene, communal hygiene, food hygiene, occupational hygiene, hygiene of children and adolescents, radiation hygiene, military hygiene, hygiene and toxicology of polymeric materials, space hygiene, aviation hygiene. On the other hand, the development of hygiene is also moving along the path of integration. Hygiene develops in close contact with clinical areas of medicine, therapy, pediatrics, obstetrics and gynecology and other branches. At present, such a course has emerged from hygiene as valeology - a science that studies the patterns of formation of a high level of health. Much attention has always been paid to the patterns of the formation of the pathological process, but insufficient attention has been paid to problems associated with the conditions, factors and patterns that determine the conditions for the formation of a high level of health. Hygiene methodology Hygiene methodology - its section, part of hygiene, dealing with the use of its methodological techniques to study the patterns of interaction between the organism and the environment. Hygiene methodology is associated with the development of hygienic standards, guidelines, sanitary norms and rules. In hygiene, there are so-called specific classical hygiene methods. These include the method of sanitary inspection, the method of sanitary description and the method of sanitary observation. In hygiene, various methods are widely used related to the assessment of factors acting on a person. Such methods are physical, chemical, which assess the physical and chemical state of the environment. In hygiene, toxicological methods are widely used, aimed at assessing the nature of the toxic effect on the body of certain chemicals. Physiological methods are widely used, not without reason hygiene is called applied physiology. Biochemical, genetic, clinical and epidemiological research methods are widely used to assess the impact of factors on certain body systems. To generalize the results obtained, statistical methods are widely used with the involvement of modern technologies. Methods for studying the influence of environmental factors in natural conditions. This direction is called natural experiment. What is associated with the study of the state of health of certain groups of the population living under the influence of various environmental factors. Under natural conditions, it is possible to study the influence of working conditions on the health of workers. They also study the influence of the factors of the educational process on the growing body of the child. Clinical and hygienic studies are being carried out to develop the maximum permissible concentrations of harmful chemicals in the working area. Thus, clinical and hygienic studies and laboratory experiment complement each other and constitute a single approach to hygienic studies of the environment and human health. Environment and health The subject of hygiene is the environment and health. Extremely complex processes take place in the environment (ecosystem), biosphere. Some of these processes are associated with the action of factors aimed at ensuring the constancy of the quality of the environment (water, soil, atmospheric air). These are stabilizing factors. Other factors (and they can be of a natural nature or associated with human activities, the so-called anthropogenic factors) lead to a violation of the natural balance, harmony in nature. These are destabilizing factors. In ecology, there is the concept of anthropogenic exchange. Anthropogenic exchange has natural resources as an input, industrial and household waste as an output. Ecological anthropogenic exchange is extremely imperfect. It has an open, open character and is devoid of the cycle of life that is inherent in the biosphere as a whole. To characterize anthropogenic exchange, there is an indicator - its efficiency, showing the amount of natural resources used for the benefit of man. The value of efficiency today is 2%, i.e. 98% is an unused natural resource, and, moreover, this is the part of the resources that acts as waste - environmental pollutants. Among these pollutants, there are substances that have a pronounced destabilizing effect, the so-called destabilizing factors. These include halogen-containing components, rare and heavy metals, substances with an ionizing effect, and other factors. In general, these factors by the nature of the action can be classified as physical or chemical. Chemical compounds are a serious danger. The action of individual chemicals can lead to the development of destabilizing, destructive processes, which lead to an increasing effect. This process is out of human control. It exceeds the effect of natural stabilizing factors, as a result of which the development of spontaneously uncontrollable, growing destabilizing phenomena is noted. Substances and factors that have such an effect are called superecotoxicants. Chemicals assigned to this class are rare and heavy metals, ionizing radiation, halogen-containing components. All of them have a special effect on the human body, expressed in damage to cell membranes, in the development of disturbances in the enzyme systems of the body, disturbances in homeostasis, leading to destructive phenomena in the human body. Ecotoxicants are characterized by high stability in the environment and stability. They can accumulate in environmental objects. The stability and ability of chemicals to accumulate in the environment ensure their migration, which is extremely dangerous for humans and their environment. There is a close interaction between the human body and the environment. The problem of the unity of the organism and the environment is the most important problem. It must be said that a certain form of balance develops between the environment and the organism. This balance of the environment and the body is formed as a result of the most important mechanisms of the physiological response of the body to the effects of various factors and is carried out through the work of the central nervous system. This form of balance is the so-called dynamic stereotype, i.e., if the factor acts constantly, is of a repetitive nature, the body develops stereotyped reactions. The emergence of new factors leads to the destruction of this balance. The so-called excessive factors pose a particularly serious danger in this respect. They lead to a violation of the dynamic stereotype. Changes in the dynamic stereotype are associated with a significant violation of the functions of the body: neuropsychic, stressful condition, extreme factor. The task of hygiene is to find ways and methods of forming a new stereotype. This can be achieved by appropriate changes in the external environment, as well as by improving the mechanisms of adaptation of the body. The diagram, developed by Academician of the Russian Academy of Medical Sciences, Professor Yu. L. Lisitsin, according to experts from the World Health Organization, presents the factors that determine the level of somatic health of a person. The determining factor of somatic (general) health, according to experts from the World Health Organization, is style, or, as we say, lifestyle. It determines the somatic state of human health by 53%. 17% of a person's somatic health is determined by the quality of the environment, 20% is due to hereditary factors, and only 10% of somatic health is determined by the level and availability of medical care to the population. Thus, 70% of the level of human health depends on those moments that are directly related to hygiene. This is a healthy lifestyle of a person, the quality of the environment. The environment has an impact on the main indicators of the health of the population (life expectancy, birth rates, levels of physical development, morbidity and mortality). Moreover, there are a number of diseases that are pronounced in nature, depending on environmental conditions. These are environmentally driven diseases. These include, in particular, a disease called "chronic fatigue syndrome". This disease is based on a membrane-damaging effect and the effect of chemical pollutants and ionizing radiation on enzyme systems. The adverse effect of chemicals leads to a sharp decrease in immunobiological parameters. Mass surveys of large cities show a sharp change in the immune homeostasis of residents. A change in immunity indicators by 50% is noted among residents of Moscow. A situation arises that indicates the so-called secondary nonspecific immunodeficiency associated with the impact on the body of a number of adverse factors, including chemicals. Assessment of the level of health of the population living in various environmental conditions, currently makes us talk about the existence of environmentally caused foci of diseases. These diseases are associated with pollution of the urban environment with rare and heavy metals, to which the children's body is primarily sensitive. Therefore, the study of the impact of urban environmental factors on the body of the population, especially children, is an urgent task of hygienic science. Hygiene is preventive medicine. What is meant by prevention? There are concepts of primary and secondary prevention. Let's start with the concept of the so-called secondary prevention. Secondary prevention is understood as a set of measures aimed at localizing and weakening the pathological process through active medical examination, anti-relapse therapy, spa treatment and therapeutic nutrition, i.e. secondary prevention is the activity that is carried out by practitioners. Hygiene is primary prevention. The basis of primary prevention is the elimination of the causes and factors leading to the occurrence of pathological processes, and diseases in general, by improving the natural, industrial, and household environment; formation of a healthy lifestyle aimed at increasing the body's resistance and strengthening health. Prevention should be understood not only as the prevention of diseases and the implementation of recreational activities aimed at protecting the health of the population, but the whole set of state, public and medical measures aimed at creating the most favorable living conditions for a person that fully meets his physiological needs. Hygiene is a preventive discipline, and the basis of preventive measures is hygienic regulation. Hygienic regulation What is meant by hygienic standards? A hygienic standard is a strict range of parameters of environmental factors that is optimal and harmless for maintaining normal life and health of a person, the human population and future generations. Sanitary rules, norms, hygienic standards are normative acts that establish criteria for the safety and harmlessness of environmental factors for a person in his life. Sanitary rules are obligatory for observance by all state bodies and public associations, enterprises and other economic entities, organizations, institutions, regardless of their subordination and form of ownership, by officials and citizens. Hygienic standards for chemicals are set in the form of maximum allowable concentrations (MACs). For physical factors, they are set in the form of permissible exposure levels (MPL). For chemicals, MPCs are set in the atmospheric air of populated areas in the form of maximum one-time and average daily maximum allowable concentrations. MPCs for harmful chemicals in the water of reservoirs and drinking water are established. MPCs are set for the content of harmful chemicals in the soil. In foodstuffs, hazardous chemicals are regulated in the form of acceptable residues (RTA). For chemicals, the maximum allowable amounts in water are set in milligrams per 1 dm3, or 1 l, for air - in milligrams per 1 m3 air, food products - in milligrams per 1 kg of product mass. MPCs characterize safe levels of exposure to harmful chemicals in certain environmental objects. The remote controls for the impact of physical factors are also set. In particular, there is an idea of the optimal and permissible parameters of the microclimate, i.e., temperature, humidity, air velocity, etc. The optimal permissible amounts of nutrients are established, and their rationing takes place taking into account physiological needs. There are so-called physiological norms of need for proteins, fats, carbohydrates, minerals, vitamins. When establishing MPCs for harmful chemicals in the environment, certain principles of hygienic regulation are observed, which include: 1) the principle of stages; 2) the principle of threshold. The phasing in rationing is that the work on rationing is carried out in a strictly defined sequence associated with the implementation of the corresponding stage of research. For chemicals, the first stage of these studies is the analytical stage. The analytical stage includes an assessment of the physicochemical properties: data on the structure of the chemical, its parameters - melting point, boiling point, solubility in water, other solvents. To conduct analytical studies, it is necessary to have specific methods of determination. The second mandatory stage of hygienic research in establishing MPC is toxicometry, i.e., the determination of the main parameters of toxicity. Toximetry includes conducting studies to determine the parameters of acute toxicity (acute toxicometry or, more simply, acute experiments). This is followed by a subacute experiment and a chronic sanitary-toxicological experiment. The main and main task of the acute experiment is to determine the average lethal concentrations and doses of LD50 or CL50. Setting up acute experiments allows us to assess the degree of danger of chemicals, the nature of the direction of action, the vulnerability of certain systems and functions of the body. Acute experiments allow the most reasonable approach to setting up subacute and chronic sanitary-toxicological experiments. The staged normalization also makes it possible, in some cases, to reduce the amount of research conducted, using the so-called principle of normalization by analogy, i.e., the study of the indicators of the evaluated toxic substance by physical and chemical properties makes it possible to find out the presence of so-called analogous substances and carry out normalization using the principle of similarity. This approach is called - rationing by analogy. For substances with similar properties, i.e., the regulation of which is carried out by analogy, it is mandatory to establish the parameters of acute toxicity. The presence of acute toxicity parameters also makes it possible to reduce the amount of research and save a significant amount of material resources, as well as the time spent on the experiment. An important stage of toxicometric studies is the subacute sanitary-toxicological experiment. A subacute experiment makes it possible to reveal the presence of cumulative properties from the standpoint of a qualitative and quantitative assessment of this stage of action. In the subacute experiment, the most vulnerable systems of the body are also identified, which allows an objective approach to the formulation of the main stage of toxicometry, associated with the determination of toxic parameters in a chronic experiment. The subacute experiment tests a large array of toxicology tests that assess the effects of a chemical on the cardiovascular system, nervous system, gastrointestinal tract, excretory systems, and other bodily functions and systems. The most important principle of hygienic regulation is the study of the threshold nature of the action of the normalized factor. According to the threshold level of exposure in a chronic experiment, the lowest concentration that causes changes in the body of a laboratory animal is determined. Based on the results of a chronic sanitary-toxicological experiment, MPCs are established for substances, primarily those with a pronounced toxic effect. When rationing harmful chemicals in the aquatic environment, the mandatory stages of the study are the study of the effect of the substance on the organoleptic properties of water and the sanitary regime of water bodies, i.e., to establish the MPC of chemicals in water bodies, additional research stages are introduced. At all these stages of studying the effects of harmful chemicals, exposure thresholds, threshold doses and concentrations are necessarily established. The limiting sign of harmfulness is determined by threshold concentrations, i.e., the lowest concentration is established in which the effect of a harmful chemical is primarily manifested either on the organoleptic properties of water, or on the sanitary regime of a reservoir, or when assessing toxic properties. When establishing the MPC of harmful chemicals in the water of reservoirs, a limiting sign is identified, either organoleptic, or according to the sanitary regime, or toxicological. According to the limiting sign of harmfulness, taking into account the lowest threshold concentration, MPC is set. Thus, the defining principles of rationing are the principles of threshold and phasing. The established principles of rationing of chemicals and levels of exposure to physical factors form the basis of the current sanitary legislation. MPCs allow, on the one hand, to control the content of harmful chemicals in the environment, on the other hand, to create a so-called system for monitoring the content of harmful chemicals, that is, to monitor them in the environment. MPCs are also used in the design of industrial enterprises; MPCs are laid down in projects for the construction of industrial and other enterprises. The structure of the sanitary service The activities of the sanitary and epidemiological service in the Russian Federation are determined by the Law of the Russian Federation "On the sanitary and epidemiological welfare of the population". Occurring in 2004-2005 changes in the country also affected the structure of the sanitary service. The Ministry of Health and Social Development of the Russian Federation transformed the Centers for State Sanitary and Epidemiological Surveillance (TSGSEN) into territorial departments of the Federal Service for Surveillance in the Field of Consumer Rights Protection and Human Welfare (TU) and federal public health institutions "Centers for Hygiene and Epidemiology" (FGU). The main tasks Territorial Administration of Rospotrebnadzor (TU) are: 1) state supervision and control over the fulfillment of the requirements of the legislation of the Russian Federation in the field of ensuring the sanitary and epidemiological welfare of the population in the field of consumer protection; 2) prevention of harmful effects of environmental factors on humans; 3) prevention of infectious and mass non-infectious diseases (poisoning) of the population. Functions Territorial administration: 1) state supervision and control over the fulfillment of the requirements of the Russian Federation in ensuring the sanitary and epidemiological well-being of the population in the field of consumer protection; 2) sanitary and epidemiological supervision during the development, construction, reconstruction, liquidation of urban planning, industrial construction; for the production, sale of products, for the operation of water supply systems, medical institutions; 3) organization and conduct of social and hygienic monitoring; 4) issuance of a sanitary-epidemiological conclusion on programs, methods, modes of education, training; 5) carrying out anti-epidemic measures, attesting the decreed contingent and exercising their control; 6) control of laboratory research and testing; 7) conducting sanitary and quarantine control. The main task of federal state health care institutions is to conduct sanitary and epidemiological examinations, investigations, examinations, studies, tests, toxicological, hygienic and other examinations. The Chief State Sanitary Doctor - the head of the Territorial Institution and the head of the Federal State Health Institution on a regional scale is appointed and dismissed by the Minister of Health and Social Development of the Russian Federation on the proposal of the Head of the Federal Service (Chief State Sanitary Doctor of the Russian Federation). Financing of expenses for the maintenance of territorial health care institutions is carried out at the expense of the federal budget. Sanitary supervision in Russia is carried out in the form of two forms. In the form of preventive sanitary supervision and current sanitary supervision. Preventive sanitary supervision provides for the development of measures related to the introduction of health-improving, preventive measures at the stage of developing projects for industrial and civil facilities, the construction of communal facilities, the development of new technologies, the introduction of new food and industrial products, children's toys. Of particular note is the active rather than contemplative role of the sanitary service in all of the above activities. In other words, prevention, preventive sanitary supervision should always go ahead of a person, and not follow him. This is the most important role of preventive sanitary supervision. Preventive sanitary supervision on the example of the construction of certain objects ends at the stage of its acceptance. It begins with the approval of the project, control over the progress of construction and acceptance. The most important point in the implementation of preventive sanitary supervision of objects under construction is the control over the progress of hidden work. After the acceptance of the object, the current sanitary supervision begins. Current sanitary supervision covers almost all areas of activity of various institutions, facilities on the territory of a particular settlement, district, region and in general throughout Russia. Sanitary and epidemiological supervision bodies exercise control over the activities of industrial enterprises, communal facilities, kindergartens, schools, medical and preventive and other institutions. The Sanitary and Epidemiological Service is endowed with great rights to supervise the activities of certain institutions and organizations. The sanitary service monitors the implementation of sanitary rules by certain institutions, enterprises and objects. Sanitary rules are mandatory for all state and public organizations and other economic organizations, regardless of their subordination and form of ownership, as well as officials and citizens. The Sanitary Service exercises control aimed at preventing sanitary offenses. Sanitary offenses are unlawful, guilty intentional or negligent actions or omissions that infringe on the rights of citizens and the interests of society, associated with non-compliance with the sanitary legislation of the Russian Federation, including various sanitary rules and norms. Hygienic standards, developed sanitary norms and rules ensure the effective implementation of preventive and current sanitary and epidemiological supervision, effective implementation of measures to improve the environment and improve public health. LECTURE No. 2. The role and importance of water in human life Physiological and hygienic value of water Water - the most important factor in the formation of the internal environment of the body and at the same time one of the factors of the external environment. Where there is no water, there is no life. All the processes characteristic of living organisms that inhabit our Earth take place in water. Lack of water (dehydration) leads to disruption of all body functions and even death. Reducing the amount of water by 10% causes irreversible changes. Tissue metabolism, vital processes occur in the aquatic environment. Water participates in the processes of assimilation and dissimilation, in the processes of resorption and diffusion, sorption and desorption, regulates the nature of osmotic relations in tissues and cells. Water regulates the acid-base balance, maintains pH. Buffer systems are active only in those conditions where there is water. Water is a general indicator of the activity of physiological systems, the background and environment in which all vital processes take place. It is no coincidence that in the human body the water content approaches 60% of the total body weight. It has been established that aging processes are associated with the loss of water by cells. It should be noted that hydrolysis reactions, as well as all redox reactions, proceed actively only in aqueous solutions. Water takes an active part in the so-called water-salt exchange. The processes of digestion and respiration proceed normally in the case of a sufficient amount of water in the body. The role of water is also great in the excretory function of the body, which contributes to the normal functioning of the genitourinary system. The role of water in the processes of thermoregulation of the body is also great. It is involved, in particular, in one of the most important processes - the process of sweating. It should be noted that mineral substances enter the body with water, moreover, in such a form when they are absorbed almost completely. The role of water as a source of mineral salts is now generally recognized. This is the so-called pharmacological value of water. Mineral salts in water are in the form of ions, which is favorable for their absorption by the body. Macro- and microelements in food products are in the form of complex compounds, which, even under the influence of gastrointestinal juice, do not dissociate well and therefore are less absorbed. Water is a universal solvent. It dissolves all physiologically active substances. Water is a liquid phase that has a certain physical and chemical structure, which determines its ability as a solvent. Living organisms that consume water with different structures develop and grow in different ways. Therefore, the structure of water can be considered as the most important biological factor. The structure of water can change during its desalination. The structure of water is largely influenced by the ionic composition of water. The water molecule is not a neutral compound, but an electrically active one. It has two active electrical centers that create an electric field around them. The structure of the water molecule is characterized by two features: 1) high polarity; 2) a peculiar arrangement of atoms in space. According to modern concepts, a water molecule is a dipole, that is, it has 2 centers of gravity. One is the center of gravity of positive charges, the other is negative. In space, these centers do not coincide, they are asymmetric, i.e. the water molecule has two poles that create a force field around the molecule, the water molecule is polar. In an electrostatic field, the spatial arrangement of water molecules (the structure of water) determines the biological properties of water in the body. Water molecules can exist in the following forms: 1) in the form of a single water molecule, it is a monohydrol, or simply a hydrol (H2ABOUT)1; 2) in the form of a double water molecule - this is a dihydrol (H2ABOUT)2; 3) in the form of a triple water molecule - trihydrol (H2ABOUT)3. The aggregate state of water depends on the presence of these forms. Ice usually consists of trihydrols, which have the largest volume. The vapor state of water is represented by monohydrols, since a significant thermal movement of molecules at a temperature of 100 ° C disrupts their association. In the liquid state, water is a mixture of hydrol, dihydrol and trihydrol. The ratio between them is determined by temperature. The formation of di- and trihydrol occurs due to the attraction of water molecules (hydrols) to each other. Depending on the dynamic balance between the forms, certain types of water are distinguished. 1. Water associated with living tissues - structural (ice-like, or perfect water), represented by quasi-crystals, trihydrols. This water is highly biologically active. Its freezing temperature is -20 °C. The body receives such water only with natural products. 2. Fresh melt water - 70% ice-like water. It has medicinal properties, improves adaptogenic properties, but quickly (after 12 hours) loses its biological properties to stimulate biochemical reactions in the body. 3. Free, or ordinary, water. Its freezing point is 0 °C. Dehydration The water content in the human body is 60% of its weight. The body constantly loses oxidative water in various ways: 1) with air through the lungs (1 m3 air contains an average of 8-9 g of water); 2) through the kidneys and skin. In general, a person loses up to 4 liters of water per day. Natural water losses must be compensated by the introduction of a certain amount of water from outside. If the losses are not equivalent to the introduction, dehydration occurs in the body. A lack of even 10% of water can significantly worsen the condition, and an increase in the degree of dehydration to 20% can lead to impaired vital functions and death. Dehydration is more dangerous for the body than fasting. A person can live without food for 1 month, and without water - up to 3 days. The regulation of water metabolism is carried out with the help of the central nervous system (CNS) and is administered by the food center and the thirst center. At the heart of the feeling of thirst lies, apparently, a change in the physicochemical composition of the blood and tissues, in which osmotic pressure is disturbed due to their depletion of water, which leads to excitation of the central nervous system. An important role in the regulation of water metabolism is played by the endocrine glands, especially the pituitary gland. The relationship between water and salt metabolism is called water-salt metabolism. Water consumption standards are determined by: 1) water quality; 2) the nature of the water supply; 3) the state of the body; 4) the nature of the environment, and primarily the temperature and humidity conditions; 5) the nature of the work. Water consumption rates are made up of the physiological needs of the body (2,5-5 liters per day for the administration of physiological functions) to maintain life and water necessary for household and communal purposes. The latest norms reflect the sanitary level of the settlement. In a dry and hot climate, when performing intensive physical work, physiological norms increase to 8-10 liters per day, in rural areas (with decentralized water supply) - up to 30-40 liters. Water consumption rates at an industrial enterprise depend on the ambient temperature of production. They are especially great in hot shops. If the amount of heat generated is 20 kcal per 1 m3 per hour, then the norms of water consumption per shift will be 45 liters (including showering). According to sanitary standards, water consumption norms are regulated as follows: 1) in the presence of running water and the absence of baths - 125-160 liters per day per person; 2) in the presence of water supply and baths - 160-250 l; 3) in the presence of plumbing, baths, hot water - 250-350 l; 4) in the conditions of use of water columns - 30-50 l. Today, in large modern cities, water intake per capita per day is 450 liters or more. So, in Moscow, the highest level of water consumption is up to 700 liters. In London - 170 liters, Paris - 160 liters, Brussels - 85 liters. Water is a social factor. The social conditions of life and the level of morbidity depend on the quantity and quality of water. According to WHO, up to 500 million diseases per year that occur on Earth are associated with water quality and water consumption. Factors that shape water quality can be divided into 3 large groups: 1) factors that determine the organoleptic properties of water; 2) factors that determine the chemical properties of water; 3) factors that determine the epidemiological danger of water. Factors that determine the organoleptic properties of water The organoleptic properties of water are formed by natural and anthropogenic factors. Odor, taste, color and turbidity are important characteristics of drinking water quality. The reasons for the appearance of odors, taste, color and turbidity of water are very diverse. For surface sources, this is primarily soil pollution coming with the flow of atmospheric water. The smell and taste can be associated with the flowering of water and the subsequent decomposition of vegetation at the bottom of the reservoir. The taste of water is determined by its chemical composition, the ratio of individual components and the amount of these components in absolute terms. This is especially true for highly mineralized groundwater due to the high content of chlorides, sodium sulfates, less often calcium and magnesium. So, sodium chloride causes the salty taste of water, calcium is astringent, and magnesium is bitter. The taste of water is also determined by the gas composition: 1/3 of the total gas composition is oxygen, 2/3 is nitrogen. There is a very small amount of carbon dioxide in water, but its role is great. Carbon dioxide can be present in water in various forms: 1) dissolved in water to form carbonic acid CO2 + H2O=H2CO3; 2) dissociated carbonic acid H2CO3 =H+HCO3 = 2H + CO3 to form the bicarbonate ion HCO3 and CO3 - carbonate ion. This balance between different forms of carbonic acid is determined by pH. In an acidic environment, at pH = 4, free carbon dioxide is present - CO2. At pH = 7-8, the HCO ion is present3 (moderately alkaline). At pH = 10, the CO ion is present3 (alkaline environment). All these components determine the taste of water to varying degrees. For surface sources, the main cause of odors, tastes, color and turbidity are soil pollution coming from atmospheric water runoff. An unpleasant taste of water is characteristic of widespread highly mineralized waters (especially in the south and southeast of the country), mainly due to the increased concentration of sodium chlorides and sulfates, less often calcium and magnesium. The color (color) of natural waters often depends on the presence of humic substances of soil, plant and plankton origin. The construction of large reservoirs with active processes of plankton development contributes to the appearance of unpleasant odors, tastes and colors in the water. Humic substances are harmless to humans, but worsen the organoleptic properties of water. They are difficult to remove from water, and besides, they have a high sorption capacity. The role of water in human pathology The relationship between the incidence of the population and the nature of water consumption has long been noted. Already in antiquity, some signs of water dangerous to health were known. However, only in the middle of the XIX century. epidemiological observations and bacteriological discoveries of Pasteur and Koch made it possible to establish that water may contain certain pathogenic microorganisms and contribute to the emergence and spread of diseases among the population. Among the factors that determine the occurrence of water infections, we can distinguish: 1) anthropogenic water pollution (priority in pollution); 2) release of the pathogen from the body and entry into the reservoir; 3) stability in the aquatic environment of bacteria and viruses; 4) entry of microorganisms and viruses with water into the human body. water infections Water infections are characterized by: 1) a sudden rise in the incidence; 2) maintaining a high level of morbidity; 3) rapid fall of the epidemic wave (after elimination of the pathological factor). Cholera, typhoid fever, paratyphoid, dysentery, leptospirosis, tularemia (contamination of drinking water with rodent secretions), brucellosis are transmitted by water. The possibility of a water factor in the transmission of Salmonella infections is not excluded. Among viral diseases, these are intestinal viruses, enteroviruses. They enter the water with fecal matter and other human excreta. In the aquatic environment, you can find: 1) infectious hepatitis virus; 2) polio virus; 3) adenoviruses; 4) Coxsackie virus; 5) pool conjunctivitis virus; 6) influenza virus; 7) ECHO virus. The literature describes cases of infection with tuberculosis when using infected water. Diseases caused by animal parasites can be transmitted by water: amoebiasis, helminthiases, giardiasis. Amoebiasis. The dysenteric amoeba, common in the tropics and in Central Asia, has a pathogenic value. The vegetative forms of the amoeba die quickly, but the cysts are resistant to water. Moreover, conventional doses of chlorination are ineffective against amoeba cysts. Helminth eggs and Giardia cysts enter water bodies with human excretions, and they enter the body when drinking, with contaminated water. It is generally recognized that the possibility of eliminating the danger of water epidemics and thereby reducing the incidence of intestinal infections in the population are associated with progress in the field of water supply to the population. Therefore, a properly organized water supply is not only an important general sanitary measure, but also an effective specific measure against the spread of intestinal infections among the population. Thus, the successful elimination of the Eltor cholera outbreak in the USSR (1970) was largely due to the fact that the predominant part of the urban population was protected from the danger of its spread by water due to normal centralized water supply. Chemical composition of water The factors that determine the chemical composition of water are chemicals that can be conditionally divided into: 1) bioelements (iodine, fluorine, zinc, copper, cobalt); 2) chemical elements harmful to health (lead, mercury, selenium, arsenic, nitrates, uranium, synthetic surfactants, pesticides, radioactive substances, carcinogens); 3) indifferent or even useful chemicals (calcium, magnesium, manganese, iron, carbonates, bicarbonates, chlorides). The chemical composition of water is a possible cause of non-infectious diseases. We will analyze the basics of rationing the indicators of the safety of the chemical composition of drinking water further. Indifferent chemicals in water Hardware divalent or trivalent is found in all natural water sources. Iron is an essential component of animal organisms. It is used to build vital respiratory and oxidative enzymes (hemoglobin, catalase). An adult receives tens of milligrams of iron per day, so the amount of iron supplied with water does not have significant physiological significance. However, the presence of iron in the form of high concentrations is undesirable for aesthetic and domestic reasons. Iron gives water turbidity, yellow-brown color, bitterish-metallic taste, leaves rust spots. A large amount of iron in the water contributes to the development of iron bacteria, which, when they die, accumulates a dense sediment inside the pipes. In groundwater, ferrous iron is more often found. If the water is pumped, then, combining on the surface with oxygen in the air, iron becomes trivalent, and the water becomes brown. Thus, the iron content in drinking water is limited by the effect on turbidity and color. Permissible concentration according to the standard is no more than 0,3 mg/l, for underground sources no more than 1,0 mg/l. Manganese in underground waters it is contained in the form of bicarbonates, highly soluble in water. In the presence of atmospheric oxygen, it turns into manganese hydroxide and precipitates, which enhances the color and turbidity of the water. In the practice of centralized water supply, the need to limit the manganese content in drinking water is associated with a deterioration in organoleptic properties. Not more than 0,1 mg/l is normalized. Aluminum contained in drinking water that has undergone processing - clarification in the process of coagulation with aluminum sulfate. Excess concentrations of aluminum give the water an unpleasant, astringent taste. The residual content of aluminum in drinking water (not more than 0,2 mg per liter) does not cause deterioration of the organoleptic properties of water (turbidity and taste). Calcium and its salts cause water hardness. The hardness of drinking water is an essential criterion by which the population evaluates the quality of water. In hard water, vegetables and meat are poorly digested, since calcium salts and food proteins form insoluble compounds that are poorly absorbed. Laundry is difficult to wash, scale (insoluble sediment) is formed in the heaters. Experimental studies have shown that with drinking water with a hardness of 20 mg. eq/l, the frequency and weight of stone formation were significantly greater than with water with a hardness of 10 mg. equiv/l. The effect of water with a hardness of 7 mg. equiv per l for the development of urolithiasis was not found. All this makes it possible to consider the accepted standard of hardness in drinking water as reasonable - 7 mg eq per liter. Bioelements Copper found in low concentrations in natural groundwater and is a true biomicroelement. The need for it (mainly for hematopoiesis) of an adult is small - 2-3 g per day. It is covered mainly by the daily food ration. In high concentrations (3-5 mg/l) copper has an effect on taste (astringent). The standard on this basis is not more than 1 mg / l. in water. Zinc It is found as a trace element in natural ground waters. It is found in high concentrations in water bodies polluted by industrial wastewater. Chronic zinc poisoning is unknown. Zinc salts in high concentrations irritate the gastrointestinal tract, but the value of zinc compounds in water is determined by their effect on organoleptic properties. At 30 mg/l, water acquires a milky color, and an unpleasant metallic taste disappears at 3 mg/l, so the zinc content in water is normalized to no more than 3 mg/l. The chemical composition of water as a cause of non-infectious diseases The development of medical science has made it possible to expand the understanding of the characteristics of the chemical (salt and microelement) composition of water, its biological role and possible harmful effects on public health. Mineral salts (macro- and microelements) take part in mineral metabolism and the life of the body, affect the growth and development of the body, hematopoiesis, reproduction, are part of enzymes, hormones and vitamins. Iodine, fluorine, copper, zinc, bromine, manganese, aluminum, chromium, nickel, cobalt, lead, mercury, etc. have been found in the human body. In nature, trace elements are constantly dispersed (due to meteorological factors, water, vital activity of organisms). This leads to their uneven distribution (lack or excess) in the soil and water of different geographic regions, which leads to a change in flora and fauna and the emergence of biogeochemical provinces. Of the diseases associated with the unfavorable chemical composition of water, endemic goiter is primarily distinguished. This disease is widespread in the territory of the Russian Federation. The causes of the disease are the absolute deficiency of iodine in the external environment and the social and hygienic conditions of the population. The daily requirement for iodine is 120-125 mcg. In areas where this disease is not typical, the intake of iodine into the body comes from plant foods (70 micrograms of iodine), from animal foods (40 micrograms), from air (5 micrograms) and from water (5 micrograms). Iodine in drinking water plays the role of an indicator of the general level of this element in the external environment. Goiter is common in rural areas, where the population eats exclusively food products of local origin, and there is little iodine in the soil. Residents of Moscow and St. Petersburg also use water with a low iodine content (2 micrograms), but there are no epidemics here, since the population eats imported products from other regions, which ensures a favorable balance of iodine. The main preventive measures against endemic goiter are a balanced diet, salt iodization, the addition of copper, manganese, cobalt, iodine to the diet. Carbohydrate foods and vegetable proteins should also predominate, as they normalize the function of the thyroid gland. Endemic fluorosis is a disease that appears in the indigenous population of certain regions of Russia, Ukraine and others, an early symptom of which is tooth damage in the form of enamel spotting. It is generally accepted that spotting is not a consequence of the local action of fluorine. Fluorine, getting into the blood, has a general tactic effect, primarily causing the destruction of dentin. Drinking water is the main source of fluorine intake into the body, which determines the decisive importance of fluorine in drinking water in the development of endemic fluorosis. The daily diet provides 0,8 mg of fluorine, and the fluorine content in drinking water is often 2-3 mg/l. There is a clear relationship between the severity of enamel damage and the amount of fluoride in drinking water. Of certain importance for the development of fluorosis are past infection, insufficient content of milk and vegetables in the diet. The disease is also determined by the socio-cultural conditions of the population. For the first time this disease was registered in India, but fluorosis was rare among the British and the local aristocracy, although the fluorine content in the water was at the level of 2-3 mg / l. Among the Indians, who eked out a half-starved existence, enamel spotting was already detected in those areas where the fluorine content was even 1,5 mg per 1 liter. Preventive measures against the action of fluorine can be considered: 1) the use of water with a high content of mineral salts; 2) the use of food and liquids with a high content of calcium (vegetables and dairy products), since calcium binds fluorine and converts it into an insoluble complex Ca + F = CaF2; 3) the protective role of vitamins; 4) ultraviolet irradiation; 5) defluorination of water. Fluorosis is a common disease of the whole organism, although it is most clearly manifested in the defeat of the teeth. However, with fluorosis, there are: 1) violation (inhibition) of phosphorus-calcium metabolism; 2) violation (inhibition) of the action of intracellular enzymes (phosphatase); 3) violation of the immunobiological activity of the body. The following stages of fluorosis are distinguished: 1 - the appearance of chalky spots; 2 - the appearance of age spots; 3 and 4 - the appearance of defects and erosion of the enamel (destruction of the dentin). The content of fluorine in water is normalized by the standard, since water with a small - 0,5-0,7 mg / l - fluorine content is harmful, as dental caries develops. Rationing is carried out by climatic regions, depending on the level of water consumption. In the 1st-2nd region - 1,5 mg / l, in the 3rd - 1,2 mg / l, in the 4th - 0,7 mg / l. Caries affects 80-90% of the total population. It is a potential source of infection and intoxication. Caries leads to indigestion and chronic diseases of the stomach, heart and joints. Convincing proof of the anti-caries action of fluorine is the practice of water fluoridation. With a fluorine content of 1,5 mg/l, the incidence of caries is the lowest. In Norilsk, after 7 years of water fluoridation in children of 7 years of age, the incidence of caries was 43% less. Individuals who consume fluoridated water throughout their lives have a 60-70% lower incidence of caries. On the island of New Guinea, people do not know caries, since the fluorine content in drinking water is optimal. A number of chemicals cause microchemical pollution, or water intoxication. So, they distinguish a group of atherogenic elements (these are copper, cadmium, lead), the excess of which has an adverse effect on the cardiovascular system. Moreover, lead in children crosses the blood-brain barriers, causing brain damage. Lead displaces calcium from bone tissue. Mercury causes Minamata disease (pronounced embryotoxic effect). Cadmium causes Itai-Itai disease (impaired lipid metabolism). Metals that are dangerous in terms of embryotoxic action form a gonadotoxic series, which looks like this: mercury - cadmium - thallium - silver - barium - chromium - nickel - zinc. arsenic has a pronounced ability to accumulate in the body, its chronic action is associated with effects on the peripheral nervous system and the development of polyneuritis. Bor has a pronounced gonadotoxic effect. Violates the sexual activity of men and the ovarian-menstrual cycle in women. Boron is rich in natural underground waters of Western Siberia. A number of synthetic materials used in water supply can cause intoxication. These are primarily synthetic pipes, polyethylene, phenol-formaldehydes, coagulants and flocculants (PAA), resins and membranes used in desalination. Pesticides, carcinogens, nitrosamines that enter the water are hazardous to health. surfactant (synthetic surfactants) are stable in water and slightly toxic, but have an allergenic effect, and also contribute to better absorption of carcinogens and pesticides. When using water containing elevated concentrations of nitrates, infants develop water-nitrate methemoglobinemia. A mild form of the disease can also occur in adults. This disease is characterized by indigestion in children (dyspepsia), a decrease in the acidity of gastric juice. In this regard, in the upper intestines, nitrates are reduced to nitrites NO2. Nitrates enter drinking water due to the widespread chemicalization of agriculture, the use of nitrogenous fertilizers. In children, gastric juice pH = 3, which contributes to the reduction of nitrates to nitrites and the formation of methemoglobin. In addition, children lack the enzymes that restore methemoglobin to hemoglobin. The intake of nitrates with infant formula prepared with contaminated water is very dangerous. Salt composition is a factor that constantly and for a long time affects the health of the population. This is a low intensity factor. The influence of chloride, chloride-sulfate and hydrocarbonate types of waters on: 1) water-salt exchange; 2) purine metabolism; 3) decrease in secretory and increase in motor activity of the digestive organs; 4) urination; 5) hematopoiesis; 6) cardiovascular diseases (hypertension and atherosclerosis). Increased salt composition of water affects unsatisfactory organoleptic properties, which leads to a decrease in "water appetite" and limit its consumption. Increased hardness (15-20 mg eq/l) is one of the factors in the development of urolithiasis; and leads to the development of endemic urolithiasis; It is difficult to use water of increased hardness for economic, domestic purposes, irrigation; With prolonged use of highly mineralized chloride waters, there is an increased hydrophobicity of tissues, their ability to retain water, tension in the pituitary-adrenal system; The use of chloride-class water with a total mineralization level of more than 1 g / l causes hypertensive conditions.! The influence of water with low salinity (desalinated, distilled) causes: 1) violation of water-salt metabolism (decrease in the exchange of chlorine in tissues); 2) a change in the functional state of the pituitary-adrenal system, the tension of protective and adaptive reactions; 3) lagging growth and weight gain of the body. The minimum allowable level of total salinity of desalinated water must be at least 100 mg/l. LECTURE No. 3. Hygienic issues of the organization of domestic and drinking water supply Hygienic characteristics of sources of centralized domestic drinking water supply To ensure a high level of drinking water quality, a number of mandatory conditions must be met, such as: 1) appropriate water quality of the centralized water supply source; 2) creation of a favorable sanitary situation around the sources and the water supply system (pipeline). Drinking water can only meet the high requirements after it has been reliably processed and conditioned. Underground and surface sources of water supply can be used as sources of water supply. Underground sources have a number of advantages: 1) they are protected to a certain extent from anthropogenic pollution; 2) they are characterized by high stability of bacterial and chemical composition. The following factors influence the formation of water quality in groundwater and interstratal waters: 1) climate; 2) geomorphological structures; 3) nature of vegetation (lithological structures). In the northern zones, bicarbonate-sodium waters rich in organic matter predominate, they occur very superficially, their mineralization is low. Sulfate, chloride and calcium waters appear closer to the south. These waters lie deep and are characterized by highly reliable bacteriological indicators. Underground water sources, depending on the depth of occurrence and relationship to rocks, are divided into: 1) soil; 2) ground; 3) interstratal. Soil water sources lie shallow (2-3 m), actually lie near the surface. They are abundant in spring, dry up in summer, and freeze in winter. As sources of water supply, these waters are of no interest. The quality of water is determined by the pollution of atmospheric precipitation. The amount of these waters is relatively small, organoleptic properties are unsatisfactory. 2. Groundwater - located in the 1st aquifer from the surface (from 10-15 m to several tens of meters). These horizons are fed mainly by precipitation filtration. The diet is not constant. Atmospheric precipitation is filtered through a large thickness of soil, therefore, in bacterial terms, these waters are cleaner than soil waters, but they are not always reliable. Groundwater has a more or less stable chemical composition, may contain a significant amount of ferrous iron, which, when the water rises to the top, turns into trivalent (brown flakes). Groundwater can be used for decentralized, local water supply, since their capacity is small. Interstratal waters lie deep in the aquifer, lying (up to 100 m) between two waterproof layers, one of which is the lower one - a waterproof bed, and the upper one - a waterproof roof. Therefore, they are reliably isolated from precipitation and groundwater. This predetermines the properties of water, in particular its bacterial composition. These waters can fill the entire space between layers (usually clay) and experience hydrostatic pressure. These are the so-called pressure, or artesian, waters. The quality of artesian waters in terms of physical and organoleptic properties is quite satisfactory. Such waters are also reliable in bacterial terms, they have a stable chemical composition. In such waters, as mentioned above, hydrogen sulfide (the result of the action of microbes on iron sulfide compounds) and ammonia are often found, there is little oxygen in them, and there are no humic substances. Classification of waters by chemical composition (hydrochemical classes of waters) as follows. 1. Bicarbonate waters (northern regions of the country): anion HCO¯3 and Ca cations++, mg++Na+. Hardness = 3-4 mg. equiv/l. 2. Sulfate: SO anion4-, cations Ca++Na+. 3. Chloride: anion Cl-, cations Ca++Na+. Surface sources of water supply - rivers, lakes, ponds, reservoirs, canals. They are widely used for water supply of large cities because of the huge amount of water in them (debit). At the same time, this leaves a certain imprint on them. In the northern regions (the zone of excessive moisture), the waters are weakly mineralized. Peat soils predominate here, which enrich the waters with humic substances. In the southern regions, the soil enriches the water with salts. Mineralization is up to 23 g/l. Surface sources when moving from north to south are characterized by: 1) increase in total mineralization; 2) water class change from HCO3 (bicarbonate) to SO4 (sulfate) and Cl (chloride). Surface sources are subject to significant anthropogenic pollution. The level of pollution with organic substances is estimated by high oxidizability. The oxygen regime of water bodies is disturbed. The species composition of the microflora is sharply narrowed. The level of BOD increases When choosing a source of water supply, you need to focus on the level and state of self-purification processes. If the water is clean and the self-purification process proceeds under favorable conditions, then BOD = 3 mg/l. Selection of the source of domestic and drinking water supply Naturally, when choosing a source, not only the qualitative side of the water itself is taken into account, but also the power of the sources themselves. When choosing sources, it is necessary first of all to focus on such sources, the water of which is close in composition to the requirements of SanPiN 2.1.4.1074-01 "Drinking water". In the absence or impossibility of using such sources due to the insufficiency of their flow rate or for technical and environmental reasons, in accordance with the requirements of SanPiN 2.1.4.1074-01, it is necessary to come to other sources in the following order: interstratal free water, groundwater, open reservoirs. Conditions for choosing a water source: 1) source water should not have a composition that cannot be changed and improved by modern processing methods, or the possibility of purification is limited according to technical and economic indicators; 2) the intensity of pollution should correspond to the effectiveness of water treatment methods; 3) the totality of natural and local conditions should ensure the reliability of the water source in the sanatorium respect. Sanitary protection zones (SPZ) of water sources Experience shows that, despite the existing water treatment system, it is extremely important to take measures to prevent significant pollution of water sources. For this purpose, special SSOs are established. Under the ZSO understand the territory specially allocated around the source, on which the established regime must be observed, in order to protect the water source and water supply facilities and the surrounding area from pollution. According to the legislation, this zone is divided into 3 zones: 1) high security belt; 2) belt of restrictions; 3) observation belt. WSS of surface water bodies First belt (strict regime belt) - the area where the place of water intake and the main water supply facilities are located. This includes the water area adjacent to the water intake for at least 200 m upstream and at least 100 m downstream of the water intake. A paramilitary guard is posted here. Residence and temporary stay of unauthorized persons, as well as construction are prohibited. The boundaries of the 1st belt of small surface sources usually include the opposite coast with a strip of 150-200 m. With a reservoir width of less than 100 m, the belt includes the entire water area and the opposite coast - 50 m. With a width of more than 100 m, the 1st belt includes a strip of water area to the fairway (up to 100 m). When water is withdrawn from a lake or reservoir, the shoreline is included in the 1st belt at least 100 m from the water intake in all directions. The water area of the 1st belt should be marked with buoys. Second Belt (zone of restrictions) - a territory, the use of which for industry, agriculture and construction is either completely unacceptable, or is permitted under certain conditions. Here, the discharge of all sewage and mass bathing are limited. For open water sources, the length of the belt upstream is determined by the distance above which the influx of pollutants does not affect the quality of the water at the point of intake. Thus, the upper point of this boundary is determined by the time during which the pollution that has entered here, when approaching the water intake, is eliminated as a result of self-purification processes. This time is set at 3-5 days. Since the processes of self-purification in winter are significantly slowed down, the WSS of the 2nd belt should be removed from the water intake so that the run of water from the upper boundary of the zone to the water intake provides a period of bacterial self-purification of at least 5 days. Approximately this distance for large rivers is upstream 20-30 km, for medium - 30-60 km. The lower boundary of the 2nd belt is set at least 250 m from the water intake, taking into account the wind reverse water flow. The observation belt is the 3rd belt, which includes all settlements that have a connection with a given source of water supply. ZSO for underground sources ZSO underground sources are installed around water wells, since the protection of impermeable rocks is not always reliable. A change in the composition of groundwater can take place during intensive water intake from a well, when, according to the laws of hydrodynamics, low pressure zones are created around the well, which can create water leakage. Changes in the composition of groundwater may also be due to the influence of external surface pollution. However, its manifestation should be expected after a long period of time, since the filtration rate is usually not more than 0,1 m per day. On the territory of the strict regime zone of an underground water source, all main water supply facilities should be located: wells and cappings, pumping units and water treatment equipment. The restriction zone is set taking into account the power of the well and the nature of the soil. This zone for groundwater is set with a radius of 50 m and an area of 1 ha, for interstratal water - 30 m and an area of 0,25 ha. Source water quality requirements Hygienic requirements for the quality of water from open water sources are set out in SanPiN 2.1.5.980-00 "Hygienic requirements for the protection of surface waters". The document establishes hygienic requirements for water quality in water bodies for two categories of water use. The first is when the source is used to draw water used for drinking, domestic and water supply of food industry enterprises. The second is for recreational water use, when the facility is used for swimming, sports and recreation. Water quality standards 1. Organoleptic properties. The smell of water should not exceed 2 points, the concentration of hydrogen ions (pH) should not go beyond 6,5-8,5 for both categories of water use. Coloring for the first category should not be detected in a column 20 cm high, for the second - 10 cm. The concentration of suspended solids during the discharge of wastewater in the control solution should not increase by more than 0,25 mg / dm compared to natural conditions3 for the 1st category and more than 0,75 mg / dm3 for the 2nd category of reservoirs. Floating impurities should not be detected. 2. The content of toxic chemicals should not exceed the maximum allowable concentrations and approximate allowable levels of substances in water bodies, regardless of the category of water use (GN 2.1.5.689-98, GN 2.1.5.690-98 with additions). If two or more substances of the 1st and 2nd hazard classes with a unidirectional mechanism of toxic action are present in the water of a water body, the sum of the ratios of the concentrations of each of them to their MPC should not exceed 1: (C1 / MPC1) + (C2 / MPC2) + … (Cn / MPCn) ≤ 1, where C1, …, FROMn - concentration of substances; MPC1, …, MPCn - MPC of the same substances. 3. Indicators characterizing the microbiological safety of water. Thermotolerant coliform bacteria in both categories of water use should not exceed 100 CFU/100 ml, and coliphages - 10 PFU/100 ml. The indicator of total coliform bacteria for the 1st category of water use should be no more than 1000 CFU / 100 ml, for the 2nd - no more than 500 CFU / ml. There should be no viable helminth eggs, cysts of pathogenic intestinal protozoa teniid oncospheres in 25 liters of water samples of both categories, as well as pathogens of intestinal infections. Despite the almost continuous flow of various pollutants into open water bodies, in most of them there is no progressive deterioration in water quality. This is because physicochemical and biological processes lead to self-purification of water bodies from suspended particles, organic substances and microorganisms. Waste water is diluted. Suspended substances, helminth eggs, microorganisms are partially precipitated, the water is clarified. Organic substances dissolved in water are mineralized due to the vital activity of microorganisms inhabiting water bodies. The processes of biochemical oxidation end with nitrification with the formation of final products - nitrates, carbonates, sulfates. For the biochemical oxidation of organic substances, the presence of dissolved oxygen in water is necessary, the reserves of which, as they are consumed, are restored due to diffusion from the atmosphere. In the process of self-purification, saprophytes and pathogenic microorganisms die off. They die due to the depletion of water with nutrients, the bactericidal action of sunlight, bacteriophages secreted by saprophytes. BOD is a valuable indicator of the degree of water pollution with organic substances and the intensity of self-purification processes. BOD is the amount of oxygen required for the complete biochemical oxidation of all substances contained in 1 liter of water at a temperature of 20 °C. The greater the water pollution, the greater its BOD. Since the determination of BOD is long (up to 20 days), in sanitary practice, BOD is often determined.5, i.e. oxygen consumption of 1 liter of water for 5 days. In the 1st category of water use BOD5 should be less than 2 mg O2/ dm3, in the 2nd category of water bodies - 4 mg O2/ dm3. Soluble oxygen should not be less than 4 mg/dm3 for both categories of reservoirs. Chemical oxygen consumption should not exceed 15 mg O2/ dm3 for the 1st category and 30 O2/ dm3 for the 2nd category of water use of the reservoir. The hygienic requirements for the quality of water from sources of non-centralized water supply (underground sources intended to meet drinking and household needs, using water intake devices without a distribution network) are set out in SanPiN 2.1.4.1175-02 "Hygienic requirements for the quality of water of non-centralized water supply. Sanitary protection sources". Water quality standards 1. Organoleptic indicators. Smell and taste no more than 2-3 points. Color not more than 30°. Turbidity is not more than 2,6-3,5 UMF (turbidity units according to formazin) or 1,5-2,0 mg/l (according to koalin). 2. The content of toxic chemicals of inorganic and organic nature must not exceed the maximum allowable concentrations. 3. Indicators characterizing the microbiological safety of water. Common coliform bacteria in 100 ml of water should be absent. In their absence, an additional determination of glucose-positive coliform bacteria (BCG) is carried out with an oxidase test. TMC (total microbial count) should not exceed 100 microbes in 1 ml. Thermotolerant coliform bacteria and coliphages should be absent in 100 ml of the test water. LECTURE No. 4. Hygienic regulation of drinking water quality Requirements for the quality of drinking water of centralized domestic drinking water supply and justification of drinking water quality standards Currently, on the territory of the Russian Federation, the requirements for the quality of water for centralized domestic and drinking water supply are regulated by the state standard - sanitary rules and norms of the Russian Federation or SanPiN RF 2.1.4.1074-01. SanPiN is a normative act that establishes the criteria for the safety and harmlessness for humans of water from centralized drinking water supply systems. SanPiN applies to water supplied by water supply systems and intended for public consumption for drinking and domestic purposes, for use in the processing of food raw materials, production, transportation and storage of food products. Moreover, SanPiN regulates the very conduct of water quality control of centralized domestic drinking water supply. According to the requirements of SanPiN, drinking water must be safe in epidemiological and radiation terms, harmless in chemical composition and have favorable organoleptic properties. At the same time, the quality of drinking water must comply with hygienic standards both before it enters the distribution network, and at any subsequent point of water intake. Indicators of sanitary and epidemiological safety of water The most common and widespread type of hazard associated with drinking water is caused by contamination with sewage, other wastes or human and animal faeces. Fecal contamination of drinking water can introduce a number of different enteric pathogens (bacterial, viral and parasitic) into the water. Intestinal pathogenic diseases are widespread throughout the world. Among the pathogens found in contaminated drinking water, strains of Salmonella, Shigella, enteropathogenic Escherichia coli, Vibrio cholerae, Yersinia, enterocolitics, campylobacteriosis are found. These organisms cause diseases ranging from mild gastritis to severe and sometimes fatal forms of dysentery, cholera, and typhoid fever. Other organisms that are naturally present in the environment and are not considered pathogenic agents can sometimes cause opportunistic diseases (i.e., diseases caused by opportunistic microorganisms - Klebsiela, Pseudomonas, etc.). Such infections most often occur in people with impaired immune systems (local or general immunity). At the same time, the drinking water used by them can cause a variety of infections, including lesions of the skin, mucous membranes of the eyes, ear, and nasopharynx. For various waterborne pathogens, there is a wide range of levels of the minimum infectious dose required for the development of infection. So, for Salmonella, the route of infection of which is mainly with food, and not with water, a single amount of the pathogen is necessary for the development of the disease. For Shigella, which is also rarely waterborne, that's hundreds of cells. For the water route of transmission of infection by pathogens enteropathogenic Escherichia coli or Vibrio cholerae, billions of cells are needed for the development of the disease. However, the availability of centralized water supply is not always sufficient to prevent isolated cases of diseases if there are violations of a sanitary and hygienic nature. Despite the fact that today there are developed methods for the detection of many pathogenic agents, they remain quite laborious, lengthy and expensive. In this regard, monitoring of each pathogenic microorganism in water is considered inappropriate. A more logical approach is to identify organisms commonly found in the faeces of humans and other warm-blooded animals as indicators of faecal contamination, as well as indicators of the effectiveness of water purification and disinfection processes. The detection of such organisms indicates the presence of faeces and hence the possible presence of enteric pathogens. Conversely, the absence of fecal microorganisms indicates that pathogenic agents are probably absent. Thus, the search for such organisms - indicators of faecal contamination - provides a means of monitoring water quality. Of great importance is also the supervision of bacteriological indicators of the quality of untreated water, not only in assessing the degree of contamination, but also in choosing the source of water supply and the best method of water purification. Bacteriological examination is the most sensitive test for detecting fresh and therefore potentially dangerous faecal contamination, thus providing a hygienic assessment of water quality with sufficient sensitivity and specificity that cannot be obtained by chemical analysis. It is important that testing be carried out regularly and frequently enough, as contamination may be intermittent and may not be detected by analysis of single samples. You should also be aware that bacteriological analysis can only indicate the possibility or absence of contamination at the time of the study. Organisms as indicators of faecal contamination The use of typical enteric organisms as indicators of faecal contamination (rather than the pathogens themselves) is a well-established principle for monitoring and assessing the microbiological safety of water supplies. Ideally, the detection of such indicator bacteria should indicate the possible presence of all pathogenic agents associated with such contamination. Indicator microorganisms should be easily isolated from the water, identified and quantified. At the same time, they must survive longer in the aquatic environment than pathogenic agents, and must be more resistant to the disinfecting effect of chlorine than pathogenic ones. Virtually no single organism can meet all of these criteria, although many of them occur in the case of coliform organisms, especially E. coli, an important indicator of water pollution by human and animal faeces. Other organisms that meet some of these requirements, although not to the same extent as coliforms, can also be used as additional indicators of faecal contamination in some cases. Coliform organisms used as indicators of faecal contamination include common coliforms, including E. coli, fecal streptococci, sulfite-reducing spore-bearing clostridia, especially clostridium perfringens. There are other anaerobic bacteria (for example, bifidobacteria) found in large quantities in feces. However, routine methods for their detection are too complicated and lengthy. Therefore, specialists in the field of aquatic bacteriology settled on simple, affordable and reliable methods for the quantitative detection of indicator coliform microorganisms, using the titration method (serial dilutions) or the membrane filter method. Coliforms have long been considered useful microbial indicators of drinking water quality, mainly because they are easy to detect and quantify. These are gram-negative rods, they have the ability to ferment lactose at 35-37 ° C (general coliforms) and at 44-44,5 ° C (thermotolerant coliforms) to acid and gas, oxidase-negative, do not form spores and include E. coli species, citrobacter , Enterobacter, Klebsiella. Common coliform bacteria General coliform bacteria according to SanPiN should be absent in 100 ml of drinking water. Common coliform bacteria should not be present in treated drinking water supplied to the consumer, and their presence indicates insufficient treatment or secondary contamination after treatment. In this sense, the coliform test can be used as an indicator of the cleaning efficiency. It is known that cysts of some parasites are more resistant to disinfection than coliform organisms. In this regard, the absence of coliform organisms in surface waters does not always indicate that they do not contain Giardia cysts, amoebas and other parasites. Thermotolerant fecal coliforms According to SanPiN, thermotolerant fecal coliforms should be absent in 100 ml of the studied drinking water. Thermotolerant faecal coliforms are microorganisms capable of fermenting lactose at 44°C or 44,5°C and include the genus Escherichia and, to a lesser extent, individual strains of Citrobacter, Enterobacter and Klebsiella. Of these organisms, only E. coli is specifically of fecal origin, and it is always present in large quantities in human and animal feces and is rarely found in water and soil that have not been subjected to fecal contamination. It is believed that the detection and identification of E. coli provides sufficient information to establish the faecal nature of the contamination. Secondary growth of faecal coliforms in the distribution network is unlikely unless sufficient nutrients are present (BOD greater than 14 mg/l), water temperature is above 13°C and there is no free residual chlorine. This test cuts off the saprophytic microflora. Other indicators of faecal contamination In doubtful cases, especially when the presence of coliform organisms is detected in the absence of faecal coliforms and E. coli, other indicator microorganisms can be used to confirm the faecal nature of the contamination. These secondary indicator organisms include faecal streptococci and sulfiding clostridia, especially Clostridium perfringens. Fecal streptococci The presence of fecal streptococci in water usually indicates faecal contamination. This term refers to those streptococci commonly found in human and animal feces. These strains rarely grow in contaminated water and may be somewhat more resistant to disinfection than coliforms. The ratio of fecal coliforms to fecal streptococcus more than 3 : 1 is typical for human feces, and less than 0,7 : 1 for animal feces. This can be useful in identifying the source of faecal contamination in the case of heavily contaminated sources. Fecal streptococci can also be used to validate questionable coliform test results, especially in the absence of fecal coliforms. Fecal streptococci may also be useful in monitoring the quality of water in a distribution system following a repair to a water main. Sulfite-reducing clostridia These anaerobic spore-forming organisms, the most characteristic of which is Clostridium perfringens, are commonly found in faeces, although in much lower numbers than E. coli. Clostridial spores survive longer in the aquatic environment than coliform organisms, and they are resistant to decontamination at inadequate concentrations of this agent, contact time, or pH values. Thus, their persistence in the water subjected to disinfection may indicate defects in purification and the duration of fecal contamination. According to SanPiN, spores of sulfite-reducing clostridia should be absent when examining 20 ml of drinking water. Total microbial count The total microbial count reflects the total level of bacteria in the water, and not just those that form colonies visible to the naked eye on nutrient media under certain cultivation conditions. These data are of little value for the detection of faecal contamination and should not be considered an important indicator in assessing the safety of drinking water systems, although a sudden increase in the number of colonies in the analysis of water from a groundwater source can be an early signal of contamination of the aquifer. The total microbial count is useful in assessing the effectiveness of water treatment processes, especially coagulation, filtration and disinfection, with the main task being to keep their numbers in the water as low as possible. The total microbial count can also be used to assess the cleanliness and integrity of the distribution network and the suitability of water for food and beverage production, where microbial counts should be low to minimize the risk of spoilage. The value of this method lies in the possibility of comparing the results when examining regularly taken samples from the same water supply to detect deviations. The total microbial count, i.e. the number of bacterial colonies in 1 ml of drinking water, should not exceed 50. Virological indicators of water quality Viruses of particular concern for waterborne transmission of infectious diseases are mainly those that multiply in the gut and are shed in large numbers (tens of billions per gram of feces) in the faeces of infected people. Although viruses do not replicate outside the body, enteroviruses have the ability to survive in the external environment for several days and months. Especially a lot of enteroviruses in wastewater. During water intake at water treatment facilities, up to 1 viral particles per 43 liter are found in water. The high survival rate of viruses in water and an insignificant infectious dose for humans lead to epidemic outbreaks of viral hepatitis and gastroenteritis, but through water sources, not drinking water. However, this possibility remains potentially. The question of quantifying the permissible content of viruses in water is very complex. The determination of viruses in water, especially drinking water, is also difficult, since there is a risk of accidental contamination of water during sampling. In the Russian Federation, according to SanPiN, the assessment of viral contamination (determination of the content of coliphages) is carried out by counting the number of plaque-forming units created by the coliphage. Direct detection of viruses is very difficult. Coliphages are present together with intestinal viruses. The number of phages is usually greater than the number of viral particles. Coliphages and viruses are very close in size, which is important for the filtration process. According to SanPiN, there should be no plaque-forming units in 100 ml of a sample. Simplest Of all the known protozoa, pathogenic for humans, transmitted through water, can be the causative agents of amoebiasis (amebic dysentery), giardiasis and balantidiasis (ciliates). However, through drinking water, the occurrence of these infections rarely occurs, only when sewage enters it. The most dangerous person is the source-carrier of the reservoir of lamblia cysts. Getting into sewage and drinking water, and then back into the human body, they can cause giardiasis, which occurs with chronic diarrhea. Possible fatal outcome. According to the accepted standard, Giardia cysts should not be observed in drinking water with a volume of 50 liters. Should be absent in drinking water and helminths, as well as their eggs and larvae. Harmlessness of water in relation to pollution, standardized by sanitary and toxicological indicators or by chemical composition The safety and danger of water in relation to sanitary and toxicological indicators of the chemical composition is determined by: 1) the content of harmful chemicals most commonly found in natural waters on the territory of the Russian Federation; 2) the content of harmful substances formed in the process of its water treatment in the water supply system; 3) the content of harmful chemicals entering the sources as a result of human activities. There are a number of chemicals whose presence in drinking water at concentrations above a certain level can pose some health hazard. Their allowable levels should be determined based on the daily water intake (2,5 liters) of a person weighing 70 kg. All chemicals determined in drinking water not only have an established MPC, but also belong to a certain hazard class. MPC is understood as the maximum concentration at which the substance does not have a direct or indirect effect on the state of human health (when exposed to the body throughout life) and does not worsen the conditions of hygienic water consumption. The limiting sign of the harmfulness of a chemical substance in water, according to which the standard (MAC) is established, can be "sanitary-toxicological", or "organoleptic". For a number of substances in tap water, there are TACs (indicative allowable levels) of substances in tap water, developed on the basis of calculation or experimental methods for predicting accuracy. Hazard classes of substances are divided into: 1 class - extremely dangerous; Class 2 - highly dangerous; 3 class - dangerous; Class 4 - moderately dangerous. The harmlessness of the chemical composition of drinking water is determined by the absence of substances hazardous to human health in it in concentrations exceeding the MPC. If several chemicals are found in drinking water, normalized according to the toxicological sign of harmfulness and belonging to the 1st and 2nd (extremely and highly dangerous) hazard classes, excluding RS, the sum of the ratios of the detected concentrations of each of them to their maximum allowable content (MAC) should not be more than 1 for each group of substances characterized by a more or less unidirectional effect on the body. The calculation is carried out according to the formula: (C1fact / FROM1extra) + (C2fact / FROM2extra) + … + (Cnfact / FROMnextra) ≤ 1, where C1, FROM2, FROMn- concentrations of individual chemicals; Сfact - actual concentrations; Сextra - permissible concentrations. Harmful substances formed during water treatment are presented in Table 1 (see Appendix). Particular attention should be paid to the stage of chlorination in the process of water treatment. Along with disinfection, chlorination can also lead to the saturation of organic substances with chlorine with the formation of helogenesis products. These transformation products, in some cases, can be more toxic than the initial ones present at the level of the maximum concentration limit of chemicals. Table 1. The content of harmful substances formed during its water treatment in the water supply system.  When disinfecting water with free chlorine, the time of contact with water should be no more than 30 minutes, with bound chlorine - no more than 60 minutes. The total concentration of free and combined chlorine should not exceed 1,2 mg/l. The control of the residual ozone content is carried out after the displacement chamber, providing a contact time of at least 12 minutes. Indicators of radioactive contamination of drinking water The safety of water in terms of RW contamination is determined by the MPC of the total volumetric activity of α- and β-emitters, and if the MPC is exceeded by these indicators, by assessing the compliance of the content of individual radionuclides with radiation safety standards (NRB): the total activity of α-emitters should be no more than 0,1, 1,0 Bq/l (becquerel) β-emitters not more than XNUMX Bq/l. Organoleptic indicators of drinking water quality Organoleptic indicators provide an aesthetic need, indicate the effectiveness of cleaning, may underlie the causes of serious diseases associated with chronic dehydration (water-salt balance). According to the SNiP for drinking water, the smell and taste should not exceed 2 points, i.e. it is a faint smell and taste, detected by the consumer only if you point to it or focus on it. The scale of normalized indicators is as follows: 0 - not felt; 1 - not determined by the consumer, but detected by an experienced researcher; 3 - noticeable, causes disapproval of the consumer; 4 - distinct, the water is not suitable for drinking; 5 - very strong smell or taste. The color of drinking water should be no more than 20 °. Turbidity should not exceed 2,6 NMF or 1,5 mg/L. LECTURE No. 5. Problems of atmospheric air hygiene. Structure, chemical composition of the atmosphere History and modern problems of atmospheric air hygiene Atmospheric air hygiene is a section of communal hygiene. She deals with the consideration of questions about the composition of the earth's atmosphere, natural impurities to it and pollution by its products of human activity, the hygienic significance of each of these elements, standards for air purity and measures for its sanitary protection. The atmosphere is the gaseous envelope of the earth. The mixture of gases that make up the atmosphere is called air. The subject of atmospheric air hygiene is only the air of open spaces. The question of the air in residential and public premises is considered in other sections of communal hygiene, and the question of the air in working premises is one of the subjects of industrial hygiene. The idea that air is essential for human life existed long before the advent of scientific medicine and hygiene. We find statements on this issue in the most ancient writings on medicine, including those of Avicenna and Hippocrates. After the emergence of scientific hygiene, which dates back to the middle of the XNUMXth century, the issues of atmospheric air hygiene received a strictly scientific development. They have found their presentation in all the major hygiene manuals, both here and abroad. This issue was given much attention by such prominent hygienists as F. F. Erisman, G. V. Khlopin, Pettenkofer. It must be said that this section of hygiene had a rudimentary character for a long time. It dealt primarily with the question of the normal composition of the atmosphere and natural impurities to it. Atmospheric air hygiene received rapid development in the XNUMXth century. due to the growing pollution of the atmosphere by emissions from industrial enterprises. The problem of smoke has become one of the topical hygiene problems of the city. Thus, the atmosphere is an environmental factor that has a constant, direct and indirect effect on the human body and its living conditions. Currently, atmospheric air hygiene defines a number of topical problems, such as: 1) hygiene and toxicology of natural pollution, especially rare and heavy metals; 2) air pollution by synthetic products: highly stable substances such as dichlorodiphenyltrichloroethane (DDT), derivatives of fluorine, chloromethane - freons, freons; 3) air pollution by products of microbiological synthesis. Atmosphere as an environmental factor. Its structure, composition and characteristics As a result of the interaction of organisms with each other and the environment, ecosystems are formed in the biosphere, which are interconnected by the exchange of substances and energy. An important role in this process belongs to the atmosphere, which is an integral part of ecosystems. Atmospheric air has a constant and continuous effect on the body. This impact can be direct or indirect. It is associated with the specific physical and chemical properties of atmospheric air, which is a vital environment. The atmosphere regulates the Earth's climate, many phenomena occur in the atmosphere. The atmosphere transmits thermal radiation, retains heat, is a source of moisture, a sound propagation medium, and a source of oxygen respiration. The atmosphere is an environment that perceives gaseous metabolic products, affects the processes of heat transfer and thermoregulation. A sharp change in the quality of the air environment can adversely affect the health of the population, morbidity, fertility, physical development, performance indicators, etc. So, the Earth is surrounded by a gas shell (atmosphere). Speaking about its structure, one should pay attention to the physical approach to assessing the structure. Although there are other approaches, for example physiological, but the physical one is universal. We will consider it. According to its structure, the atmosphere, taking into account the distance from the Earth's surface, is divided into the troposphere, stratosphere, mesosphere, ionosphere, exosphere. The troposphere is the densest air layers adjacent to the earth's surface. Its thickness over different latitudes of the globe is not the same: in the middle latitudes it is 10-12 km, at the poles - 7-10 km and over the equator - 16-18 km. The troposphere is characterized by vertical convection currents of air, the relative constancy of the chemical composition of air masses, the instability of physical properties: fluctuations in air temperature, humidity, pressure, etc. These phenomena are due to the fact that the Sun heats the soil surface, from which the lower layers of air heat up. As a result, the air temperature decreases with increasing altitude, which in turn leads to vertical movement of air, condensation of water vapor, the formation of clouds and precipitation. With the rise to a height, the air temperature decreases by an average of 0,6 ° C for every 100 m of altitude. The state of the troposphere reflects all processes occurring on the earth's surface. Therefore, dust, soot, various toxic substances, microorganisms are constantly present in the troposphere, which is especially noticeable in large industrial centers. Above the troposphere is the stratosphere. It is characterized by a significant rarefaction of the air, negligible humidity, and an almost complete absence of clouds and dust of terrestrial origin. Here there is a horizontal movement of air masses, and the pollution that has fallen into the stratosphere spreads over vast distances. In the stratosphere, under the influence of cosmic radiation and short-wave radiation from the Sun, air gas molecules, including oxygen, are ionized and form ozone molecules. 60% of atmospheric ozone is located in the layer from 16 to 32 km, and its maximum concentration is determined at the level of 25 km. The air layers lying above the stratosphere (80-100 km) make up the mesosphere, which contains only 5% of the mass of the entire atmosphere. This is followed by the ionosphere, the upper boundary of which is subject to fluctuations depending on the time of day and year within 500-1000 km. In the ionosphere, the air is highly ionized, and the degree of ionization and air temperature increase with altitude. The layer of the atmosphere lying above the ionosphere and extending to a height of 3000 km constitutes the exosphere, the density of which is almost the same as that of the airless space ocean. The rarefaction is even higher in the magnetosphere, which includes radiation belts. According to the latest data, the height of the magnetosphere ranges from 2000 to 50 km; a height of 000 km above the Earth's surface can be taken as the upper boundary of the earth's atmosphere. This is the thickness of the gaseous shell that envelops our planet. The total mass of the atmosphere is 5000 trillion tons. 80% of this mass is concentrated in the troposphere. Chemical composition of air The air sphere that makes up the earth's atmosphere is a mixture of gases. Dry atmospheric air contains 20,95% oxygen, 78,09% nitrogen, 0,03% carbon dioxide. In addition, atmospheric air contains argon, helium, neon, krypton, hydrogen, xenon and other gases. Small amounts of ozone, nitric oxide, iodine, methane, and water vapor are present in the atmospheric air. In addition to the constant components of the atmosphere, it contains a variety of pollution introduced into the atmosphere by human production activities. An important component of atmospheric air is oxygen, the amount of which in the earth's atmosphere is about 1,18 × 1015 m. The constant content of oxygen is maintained due to the continuous processes of its exchange in nature. Oxygen is consumed during the respiration of humans and animals, is spent on maintaining the processes of combustion and oxidation, and enters the atmosphere due to the processes of plant photosynthesis. Land plants and phytoplankton of the oceans fully restore the natural loss of oxygen. They annually emit 0,5 × 106 million tons of oxygen. The source of oxygen formation is also the photochemical decomposition of water vapor in the upper atmosphere under the influence of solar UV radiation. This process played a major role in the generation of oxygen before the emergence of life on Earth. In the future, the main role in this regard passed to plants. As a result of intensive mixing of air masses, the concentration of oxygen in the air of industrial cities and rural areas remains almost constant. The biological activity of oxygen depends on its partial pressure. Due to the difference in partial pressure, oxygen enters the body and is transported to the cells. With a drop in the partial pressure of oxygen, hypoxia can develop, which is observed when ascending to a height. The critical level is the partial pressure of oxygen below 110 mmHg. Art. The drop in the partial pressure of oxygen below 50-60 mm Hg. Art. usually incompatible with life. At the same time, an increase in the partial pressure of oxygen to 600 mm Hg. Art. (hyperoxia) also leads to the development of pathological processes in the body, a decrease in the vital capacity of the lungs, the development of pulmonary edema and pneumonia. Under the influence of short-wave UV radiation with a wavelength of less than 200 nm, oxygen molecules dissociate to form atomic oxygen. The newly formed oxygen atoms attach to a neutral molecule, forming ozone. Simultaneously with the formation of ozone, its decay occurs. The general biological significance of ozone is great; it absorbs short-wave UV radiation from the Sun, which has a detrimental effect on biological objects. At the same time, ozone absorbs long-wave infrared radiation coming from the Earth, and thus prevents excessive cooling of its surface. Ozone concentrations are unevenly distributed along the height. Its greatest amount is noted at the level of 20-30 km from the Earth's surface. As we approach the Earth's surface, ozone concentrations decrease due to a decrease in the intensity of UV radiation and the weakening of ozone synthesis processes. Ozone concentrations are not constant and range from 20 × 10-6 up to 60 × 10-6%. Its total mass in the atmosphere is 3,5 billion tons. It has been noted that the concentration of ozone in spring is higher than in autumn. Ozone has oxidizing properties, therefore, its concentration in the polluted air of cities is lower than in the air of rural areas. In this regard, ozone remains an important indicator of air purity. Nitrogen in quantitative content is the most significant component of atmospheric air. It is an inert gas. Life is impossible in a nitrogen atmosphere. Air nitrogen is assimilated by nitrogen-fixing soil bacteria, blue-green algae, under the influence of electrical discharges it turns into nitrogen oxides, which, falling out with atmospheric precipitation, enrich the soil with salts of nitrous and nitric acids. Salts of nitric acid are used for protein synthesis. Nitrogen is also released into the atmosphere. Free nitrogen is formed during the combustion of wood, coal, oil, a small amount of it is formed during the decomposition of organic compounds. Thus, in nature there is a continuous cycle of nitrogen, as a result of which atmospheric nitrogen is converted into organic compounds, restored and released into the atmosphere, then again bound by biological objects. Nitrogen is needed as an oxygen diluent, since breathing pure oxygen leads to irreversible changes in the body. However, an increase in the nitrogen content in the inhaled air contributes to the onset of hypoxia due to a decrease in the partial pressure of oxygen. With an increase in the partial pressure of nitrogen in the air to 93%, death occurs. An important component of atmospheric air is carbon dioxide - carbon dioxide (CO2). In nature, CO2 is in the free and bound states in the amount of 146 billion tons, of which only 1,8% of its total amount is contained in the atmospheric air. Its main mass (up to 70%) is in a dissolved state in the water of the seas and oceans. Some mineral compounds, limestones and dolomites contain about 22% of the total amount of CO2. The rest of the amount falls on the animal and plant world, coal, oil and humus. Under natural conditions, there are continuous processes of release and absorption of CO2. It is released into the atmosphere due to the respiration of humans and animals, the processes of combustion, decay and fermentation, during the industrial firing of limestones and dolomites. At the same time, processes of assimilation of carbon dioxide are going on in nature, which is absorbed by plants in the process of photosynthesis. The processes of formation and assimilation of CO2 interrelated, due to which the content of CO2 in atmospheric air is relatively constant and amounts to 0,03%. Recently, there has been an increase in its concentration in the air of industrial cities as a result of the intensity of pollution by fuel combustion products. Therefore, the average annual content of CO2 in the air of cities can increase up to 0,037%. The literature discusses the role of CO2 in creating a greenhouse effect, leading to an increase in surface air temperature. WITH2 plays a significant role in the life of humans and animals, being a physiological causative agent of the respiratory center. When CO is inhaled2 in high concentrations, there is a violation of redox processes in the body. With an increase in its content in the inhaled air up to 4%, headache, tinnitus, palpitations, an excited state are noted, at 8% death occurs. LECTURE No. 6. Atmospheric pollution, their hygienic characteristics Atmospheric pollution and their classification. Sources of atmospheric pollution. Impact of atmospheric pollution on a healthy population Pollution of the environment, and especially air, by emissions from industrial enterprises, road transport has been a growing concern in many countries in recent years. Millions of tons of pollution are emitted into the atmospheric air annually: 300 million tons - CO; 150 Mt - SO2, 100 million tons - suspended solids. According to UN experts, about 100 million tons of sulfur compounds alone are emitted annually into the atmosphere of Europe, the USA, and Canada. A significant part of these emissions, combined with water vapor in the atmosphere, then falls to the ground in the form of so-called acid rain. Moreover, these emissions, harmful both for humans and for nature, can travel in air streams over vast distances. For example, it has been established that emissions from industrial enterprises in Germany and England are transported over distances of more than 1000 km and fall on the territory of the Scandinavian countries. Under atmospheric pollution, we conditionally understand those impurities in the atmospheric air that are formed not as a result of natural processes, but as a result of human activity. In the course of its production activity, human society subjects natural bodies to special processing - mechanical, physical, chemical, biological, as a result of which a large number of various substances in the state of gases, vapors or heterogeneous dispersed systems - dust, smoke, fog enter the atmospheric air. etc. Atmospheric pollution is divided into 2 groups: 1) earthly; 2) extraterrestrial. Terrestrial are divided into natural and artificial. Natural pollution is represented by continental and marine. Marine - this is sea dust and other secretions of the oceans. Continental pollution is divided into substances of organic and inorganic nature. Inorganic are represented by products of volcanic activity and formed in the process of soil corrosion. Organic pollution can be of animal and vegetable origin. Organic contaminants of plant origin are pollen, products of plant grinding. However, artificial pollution of anthropogenic origin has now become a priority. They are divided into radioactive and non-radioactive. Radioactive can enter the atmospheric air during their extraction, transportation and processing. Nuclear explosions are also a source of pollution. Accidents at nuclear power plants, as we know, can lead to disaster. But these questions are considered by radiation hygiene. Non-radioactive, or other, pollution is the topic of today's lecture. They are currently an environmental problem. Vehicle exhaust gases, which make up about half of atmospheric pollution of anthropogenic origin, are formed from engine and crankcase emissions, wear products of mechanical parts, tires and road surfaces. The global fleet of vehicles includes many hundreds of millions of vehicles that burn a huge amount of fuel - valuable oil products and at the same time cause significant harm to the environment. The composition of exhaust gases, in addition to nitrogen, oxygen, carbon dioxide and water, includes such harmful components: carbon monoxide, hydrocarbons, nitrogen and sulfur oxides, as well as particulate matter. The composition of exhaust gases depends on the type of fuel used, additives and oils, engine operation modes, its technical condition, vehicle driving conditions, etc. The toxicity of exhaust gases of carburetor engines is mainly determined by the content of carbon monoxide and nitrogen oxides, and diesel engines - nitrogen oxides and soot . Among the harmful components are also solid emissions containing lead and soot, on the surface of which cyclic hydrocarbons are adsorbed, some of which have carcinogenic properties. The patterns of distribution of solid emissions in the environment differ from the patterns of distribution of gaseous products. Large fractions (> 1 mm), settling near the center of emission on the surface of soil and plants, accumulate in the upper soil layer, small particles (< 1 mm) form aerosols and spread by air masses over long distances. Moving at a speed of 80-90 km / h, the average car turns as much oxygen into carbon dioxide as 300-350 people. But it's not only that. The annual exhaust of one car is an average of 800 kg of carbon monoxide, 40 kg of nitrogen oxides and more than 200 kg of various hydrocarbons. In this set, carbon monoxide is the most insidious. Passenger car with a 50 hp engine. With. emits 60 liters of carbon monoxide per minute into the atmosphere. The toxicity of carbon monoxide is due to its high affinity for hemoglobin, 300 times greater than that of oxygen. Under normal conditions, human blood contains an average of 0,5% carboxyhemoglobin. The content of carboxyhemoglobin more than 2% is considered harmful to human health. There is chronic and acute carbon monoxide poisoning. Acute poisoning is often noted in motorists' garages. The action of carbon monoxide is enhanced in the presence of hydrocarbons in exhaust gases, which are also carcinogens (cyclic hydrocarbons, 3,4 - benzpyrene), aliphatic hydrocarbons have an irritating effect on mucous membranes (tear smog). The content of hydrocarbons at the intersections at traffic lights is 3 times higher than in the middle of the block. Under conditions of high pressure and temperature (as occurs in internal combustion engines), nitrogen oxides (NO)n are formed. They are methemoglobin formers and have an irritating effect. Under the influence of UV radiation (NO)n undergo photochemical transformations. A passenger car emits about 10 g of nitrogen oxides per kilometer. Oxides of nitrogen and ozone - oxidizing agents, reacting with organic substances of the atmosphere, form photooxidants - PAN (peroxyacyl nitrates) - white smog. Smog appears on sunny days, in the afternoon, with a large congestion of cars, when the PAN concentration reaches 0,21 mg/l. PANs have methemoglobin-forming activity. Children and the elderly are the first to suffer. In some countries, under such circumstances, it is recommended to use devices for respiratory protection. When using leaded gasoline, the car engine releases lead compounds. Lead is especially dangerous because it can accumulate both in the external environment and in the human body. In chronic lead poisoning, it accumulates in the bones as tribasic phosphate. Under certain conditions (trauma, stress, nervous shock, infection, etc.), lead is mobilized from its depot: it passes into a soluble dibasic salt and appears in high concentrations in the blood, causing severe poisoning. The main symptoms of chronic lead poisoning are lead rim on the gums (combining with acetic acid), lead skin color (golden-gray color), basophilic granularity of erythrocytes, hematoporphyrin in the urine, increased excretion of lead in the urine, changes in the central nervous system and gastrointestinal -intestinal tract (lead colitis). 1 liter of gasoline may contain about 1 g of tetraethyl lead, which breaks down and is released as lead compounds. There is no lead in emissions from diesel vehicles. Lead accumulates in roadside dust, plants, mushrooms, etc. The level of gas contamination of highways and adjacent territories depends on the intensity of car traffic, the width and topography of the street, wind speed, the share of freight transport, buses in the general flow, and other factors. The second place in terms of emissions into the atmosphere is occupied by industrial enterprises. Among them, ferrous and non-ferrous metallurgy enterprises, thermal power plants, petrochemical enterprises, waste incineration - polymers are of the greatest importance. Thus, the technology of combustion and combustion of especially solid and liquid fuels poses a particular danger to the atmosphere. For several centuries, problems associated with air pollution by fuel combustion products have increased, the greatest manifestation of which has become the thick yellow fogs inherent in the landscapes of London and other large urban agglomerations. The event that attracted world attention was the infamous London fog in December 1952, which lasted several days and claimed 4000 lives, as it had an extremely high concentration of smoke, sulfur dioxide and other pollution. The most dangerous pollutants for the entire population (as opposed to professional groups) are smoke and sulfur dioxide, which are formed as a result of the combustion of coal and oil during production processes or in heating systems. The term "smoke" mainly refers to carbonaceous compounds produced by the incomplete combustion of fuels, the main source of which until recently was coal. An important factor in air pollution in the city is sulfur dioxide, which is formed during the combustion of any fuel, although the sulfur content in it depends on its type. High-sulfur coals or fuel oils produce emissions that are particularly rich in sulphurous gas. Millions of tons of sulfur oxides released into the atmosphere turn the rainfall into a weak (and sometimes not very weak) solution of acids - "acid" rain. It has been established that acid rain reduces the resistance of the human body to colds, accelerates the corrosion of structures made of steel, nickel, copper, destroys sandstone, marble and limestone, causing irreparable damage to buildings, cultural and ancient monuments. Enterprises of the metallurgical, chemical and cement industries emit into the atmosphere a huge amount of dust, sulfur dioxide and other harmful gases released during various technical production processes. Ferrous metallurgy, the processes of smelting pig iron and processing it into steel are accompanied by the emission of various gases into the atmosphere. Dust emission per 1 ton of pig iron is 4,5 kg, sulfur dioxide - 2,7 kg and manganese 0,1-0,6 kg. Together with blast-furnace gas, compounds of arsenic, phosphorus, antimony, lead, mercury vapor and rare metals, hydrogen cyanide and resinous substances are also emitted into the atmosphere in small quantities. Sinter plants are sources of air pollution with sulfur dioxide. Air pollution with dust during coal coking is associated with the preparation of the charge and its loading into coke ovens, with the unloading of coke. Non-ferrous metallurgy is a source of air pollution with dust and gases. Emissions from non-ferrous metallurgy contain toxic dust-like substances, arsenic, lead and others, which makes them especially dangerous. During the production of metallic aluminum by electrolysis, a significant amount of gaseous and dust-like fluorine compounds is released into the atmospheric air with exhaust gases. Upon receipt of 1 ton of aluminum, depending on the type and power of electrolysis, 38-47 kg of fluorine is consumed, while about 65% of it enters the atmospheric air. Emissions from the oil producing and oil refining industries contain large amounts of hydrocarbons, hydrogen sulfide and other gases. The emission of harmful substances into the atmosphere at oil refineries occurs mainly due to insufficient sealing of equipment. As a result of air pollution, the morbidity of the population, especially the extreme age groups, increases, and mortality increases. The so-called nonspecific resistance syndrome is noted, when immunobiological resistance decreases, metabolic reactions are perverted, enzyme systems are disrupted - enzyme disorganization occurs associated with damage to membrane structures, mitochondria, lysosomes, microsomes. The pathogenetic aspect of the influence of atmospheric air pollution has been established - the systemic membrane-damaging effect of the main cellular structures. Understanding this process allows you to determine the system of preventive measures. It should be noted that chemical pollution of atmospheric air increases the body's sensitivity to the effects of adverse factors, including infection, especially in children with poor nutrition. Patterns of behavior of atmospheric pollution in the surface layer The behavior of atmospheric pollutants in the surface layer depends on various factors: the magnitude of emissions, wind direction and speed, temperature gradient, barometric pressure, air humidity, distance to the emission source and pipe height, terrain, as well as the physicochemical properties of pollutants. The change in air temperature for every 100 m of altitude, expressed in degrees, is called the vertical temperature gradient, its value mainly fluctuates with air temperature. In summer, the temperature gradient fluctuates within 1 °C, in the cold season it drops to tenths of a degree, and in January and February it drops to negative values. This latter phenomenon, i.e., the perversion of the temperature gradient as the air temperature rises, is called temperature inversion. The higher the temperature gradient, the stronger the vertical currents and the mixing of smoke with air. In other words, the opening angle of the smoke plume increases with increasing temperature gradient. With a temperature inversion, the smoke cannot rise up and is distributed in the surface layer. The highest concentrations of contaminants are observed at low temperatures. The area of distribution of winter inversions coincides with the area of distribution of anticyclones; therefore, high concentrations of smoke are usually observed in anticyclonic weather. In addition to temperature inversion, the anticyclone is characterized by low wind speeds, which also leads to an increase in the concentration of pollutants in the atmosphere. Anticyclones are known to arise in areas of high barometric pressures. This should explain the correlation between atmospheric pollution and barometric pressure height. Humidity also contributes to an increase in the concentration of pollutants in the atmospheric air, but this does not matter for all gases. Thus, the concentration of chlorine decreases with increasing humidity. With regard to the physicochemical properties of contaminants, the particular danger of compounds with high persistence (DDT, freons) should be noted. Along with air pollution, self-cleaning processes take place in nature, but they occur extremely slowly. Air self-purification is facilitated by physical, physicochemical and chemical processes occurring in the atmosphere: dilution, sedimentation, precipitation, the role of green spaces, chemical neutralization, etc. More effective measures are taken as a result of the sanitary protection of atmospheric air. LECTURE No. 7. Sanitary protection of atmospheric air Hygienic regulation of harmful substances in the atmospheric air. The concept of maximum permissible concentrations of harmful substances in the atmospheric air, their rationale The development of science and technology and the sharp rise in industrial production associated with it lead, as we noted in previous lectures, to environmental pollution and, first of all, to air pollution. Thousands of chemicals (and their number is constantly growing) are used and produced by industry. Many of them do not decompose into simpler harmless products, but accumulate in the atmosphere and transform into even more toxic products. A large number of compounds, especially products of incomplete combustion, enter the atmosphere, are included in the processes occurring in it, and, like a boomerang, return to a person, penetrating through the respiratory tract. To effectively address a number of problems related to environmental protection, extensive international cooperation is needed. This, in particular, applies to the problem of the spread of atmospheric pollution over long distances, because air masses know no boundaries. Currently, there are two approaches to the method of sanitary protection of atmospheric air. 1. Achieving the best practical results from events. Their basis is a perfect production technology. This is the most effective, but at the same time expensive approach. 2. Air quality management. Its essence lies in hygienic regulation, which is currently the basis for the protection of atmospheric air. This approach has several concepts. One concept is to ration harmful components in raw materials and is unsuccessful, as it does not provide a level of safe concentrations in the atmospheric air. The other one is the establishment of the maximum permissible emission (MAE) for each enterprise and, on the basis of MPE, the stabilization of the maximum permissible concentrations (MAC) of pollution. This is one of the most effective means of air protection today. MPCs are concentrations that do not have a direct or indirect harmful and unpleasant effect on a person, do not reduce his ability to work, do not negatively affect his well-being and mood. However, it should be borne in mind that not only exceeding the MPE, but even observing its value cannot always be considered as optimal. The currently established MPC values, as a rule, ensure the safety of the environment for health based on today's scientific knowledge. The analysis of changes in MPC values in recent years indicates their relativity - they were revised in most cases downward. Thus, the idea of their complete harmlessness should be considered conditional. The basic principles of hygienic regulation of harmful substances in the atmospheric air were formulated by V. A. Ryazanov. MPC according to the standards should be: 1) below the threshold for acute and chronic effects on humans, animals and vegetation; 2) below the threshold of odor and irritant effect on the mucous membranes of the eyes and respiratory tract; 3) significantly below the MPC adopted for the air of industrial premises. It is necessary to take into account information about the incidence and complaints of the population in the area of influence of emissions that should not affect the domestic and sanitary conditions of life, and should not cause addiction to the body. MPC serves as a scale by which one judges how much existing pollution exceeds the permissible limit. They make it possible to justify the need for certain measures for the sanitary protection of atmospheric air and to check the effectiveness of these measures. Rationing is based on the principles of threshold and phasing. MPCs of pollution in the atmospheric air are set according to two indicators - maximum one-time (MPC m. R.) and average daily - MPC s. With. (24 hours). The most important average daily concentrations, the excess of which indicates a possible adverse toxic effect of regulated substances. Maximum single concentrations are set for substances that have a predominantly irritating or reflex effect. While in most foreign countries, to establish the standard, epidemiological data on the impact of atmospheric air pollution on public health are mainly taken into account, in our country the experimental approach dominates. Conducting an experiment under precisely specified conditions not only provides greater accuracy of the data obtained, but also allows you to set control indicators without waiting for the appearance of adverse effects on public health. At the first stage of the experiment, the threshold concentrations of the reflex action are studied - the odor threshold and, in some cases, the threshold of irritating action. These studies are carried out with volunteers at special installations that ensure the supply of strictly dosed concentrations of chemical compounds into the breathing zone. As a result of statistical processing of the obtained results, a threshold value is set. These materials are then used to substantiate the maximum single MPC. At the second stage of research, the resorptive effect of the compounds is studied under conditions of long-term exposure to experimental animals (usually outbred white rats) in order to establish the average daily maximum concentration limit. The chronic experiment in special seed chambers lasts at least 4 months. Animals must be in the cells around the clock. An important point is the choice of the studied concentrations. Three concentrations are usually chosen: the first is at the level of the odor threshold, the second is 3-5 times higher and the third is 3-5 times lower. If the test substance is odorless, then the concentrations for the toxicological experiment are calculated according to formulas based on regulated hygienic, toxicometric indicators or on physicochemical parameters and structural features of the substance. During the experiment, tests are selected that are adequate to the mechanism of action of the studied compound, as well as integral tests that characterize the manifestation of protective-adaptive reactions. MPCs of atmospheric pollution are set according to the limiting indicator - according to the level of concentration, which turned out to be the lowest when using various tests. As threshold concentrations are taken that cause odor, irritant action, specific manifestations, or some other reactions that can be considered as protective and adaptive. Much attention is paid to the possibility of long-term consequences (embryotropic, gonadotropic, carcinogenic, mutagenic, etc.). Methods of express regulation of atmospheric pollution have now become widely used. The results of a short-term experiment (1 month) are analyzed graphically on a double logarithmic grid, along the ordinate - the time of onset of effects, along the abscissa - concentration values are plotted. Direct dependencies "concentration - time", obtained by the most reliable tests, may have different angles of inclination to the abscissa axis (concentration). Threshold concentrations are set according to the direct relationship "concentration - time" by extrapolating them to a four-month period of chronic experiment. Thus, time-differentiated MPC values can be established, including average annual values corresponding to MPC s. With. The MPCs and indicative safe levels (SHL) of pollutants in the atmospheric air of populated areas developed in Russia are mandatory as an element of sanitary legislation and are used in design and sanitary supervision. Measures for the sanitary protection of atmospheric air Atmospheric air protection measures are divided into: 1) technological; 2) planning; 3) sanitary; 4) legislative. Technological and sanitary. This group includes activities that can be carried out at the enterprise itself in order to reduce emissions and reduce the concentration of dust and gases in the air (the so-called waste-free technologies). This includes, above all, the rationalization of coal combustion. It is known that thick black smoke is produced by incomplete combustion of fuel. It is in these cases that elements of coal, soot, and unburned hydrocarbons are emitted into the atmospheric air in large quantities. It is possible to reduce the amount of coal by rationalizing the arrangement of furnaces and improving their operation. Reducing air pollution with dust and sulfur dioxide can be achieved by enriching coal before burning: removing rock that gives a lot of dust, as well as pyrites containing sulfur. Sanitary and technical measures are associated with the use of cleaning devices. These are dust settling chambers, filters, moisturizing cleaning technologies, and electrofiltration. The device of high pipes (100 m and above) contributes to a more intensive dispersion of gases. The correct calculation and justification of the height of the pipe are essential in protecting the surface layers of the atmosphere from pollution. Transport - the ultimate goal is the creation of an environmentally friendly car. Currently, much attention is paid to the development of toxicity reduction devices - neutralizers, which are equipped with modern cars. The method of catalytic conversion of combustion products is that the exhaust gases are cleaned by coming into contact with the catalyst. At the same time, afterburning of the products of incomplete combustion contained in the exhaust of cars takes place. Many cities already use unleaded gasoline. The use of gas as a fuel for cars is also an effective measure in relation to the protection of atmospheric air. Electric car, solar energy, hydrogen car is the future of the automotive industry. Planning measures are based on the principle of functional zoning of settlements: industrial zones, residential zones, etc. This allows you to concentrate dangerous enterprises, taking into account aeroclimatic conditions and justify the installation of mandatory gaps between enterprises and residential buildings - sanitary protection zones of a certain width. In some cases, sanitary protection zones are 10-20 km. The sanitary protection zone or any part of it cannot be considered as a reserve territory of the enterprise and used to expand the industrial area. The territory of the sanitary protection zone should be landscaped. The sizes of sanitary protection zones are determined in accordance with the sanitary classification of various types of industries and facilities that pollute the atmospheric air with their emissions. Sanitary design standards establish 5 classes of sanitary protection zones: I class - 1000 m; II class - 500 m; III class - 300 m; IV class - 100 m; V class - 50 m. With regard to the protection of the atmosphere of cities from vehicle emissions, planning activities are carried out by constructing ring roads, overpasses, green waves, and excluding crossroads. The principle of district planning is also a preventive measure - it is the rational placement of waste disposal systems, airports and other communication systems on the territory of cities on the scale of the region, region, etc. This is the greening of the city, the creation of a master plan for the development of the city. Of particular importance are legislative measures that determine the responsibility of various organizations for the protection of atmospheric air. At present, when addressing issues of atmospheric air protection, they are guided by the Constitution of the Russian Federation (adopted on December 12, 1993), "Fundamentals of the legislation of the Russian Federation on protecting the health of citizens", Federal laws "On the sanitary and epidemiological welfare of the population" and "On the protection of atmospheric air" . Legislative measures include the establishment of MPC and SHEL for pollutants in the atmospheric air. At present, 656 MPCs and 1519 OBUVs have been established in Russia for substances polluting the atmospheric air. Measures aimed at preventing the adverse effects of atmospheric air pollution on public health and establishing mandatory hygienic requirements for ensuring the quality of atmospheric air in populated areas and compliance with hygienic standards in the placement, design, construction, reconstruction (technical re-equipment) and operation of facilities, as well as in the development of all stages of urban planning documentation are carried out purposefully on the basis of SanPiN 2.1.6.1032-01 "Hygienic requirements for ensuring the quality of atmospheric air in populated areas". LECTURE No. 8. Food ecology The main directions and problems of food ecology There are several directions in food ecology. One of these areas is associated with solving the problems of hunger on our planet. According to the Food Committee and the UN World Health Organization, an average of 10 million people die of starvation every year on the planet. The solution to the problem of hunger on our planet is carried out by: 1) by increasing the area under crops; 2) by intensifying agricultural production; 3) by using chemical, biological and other means of combating pests and diseases of agricultural crops. Solving the problems of hunger associated with an increase in acreage has certain consequences. During the plowing of virgin lands in Kazakhstan on the territory of the USSR, in the USA, Canada, in the first years there was an intensive growth of weeds (in particular, wheatgrass). This dramatically affected the cultivation of agricultural crops. To combat wheatgrass, a special plowing system was used - a deep plowing system, which had negative consequences. This way of cultivating agricultural land leads to soil erosion, dust storms and further environmental consequences. In the Zavolzhsky steppes on virgin lands, irrigation and drainage works were widely deployed, irrigation systems were created, which led to the formation of new agrobiogeocenoses. It must be said that land reclamation work dramatically changed the ecology of the Trans-Volga water ecosystems, led to a change in hydrodynamic processes in groundwater and had certain environmental consequences associated with the peculiarity of the distribution of certain pollutants in the external environment. Another area of food ecology is related to the fact that food products in difficult environmental conditions are themselves the object of pollution and exposure to harmful chemicals - pesticides and pesticides. Another area of nutritional ecology is the study of the influence of the alimentary factor, food products on the body's resistance. One of the most urgent problems of our time in the field of food hygiene is the use of food additives. Rational nutrition is a nutritional factor in modern environmental conditions Rational nutrition is of current importance in modern environmental conditions. The tasks of nutrition in conditions of intense chemical pollution are to prevent the accumulation of harmful chemicals in the human body. Rational nutrition should ensure the weakening of the negative effects of chemicals and other harmful factors on the body, on the predominantly affected organs and systems. Rational nutrition in difficult environmental conditions should help increase the protective and adaptive capabilities of the human body. Particularly relevant are the issues of nutrition for people living in urban areas, exposed to heavy metals, electromagnetic radiation, experiencing heavy physical exertion, and being in stressful situations for a long time. The population living in areas of environmental risk, as well as the part of the population that is affected by negative factors in production conditions, should receive special nutrition or therapeutic and preventive nutrition. This food must meet certain requirements. 1. It must contain an additional amount of vitamins. In this case, we are not talking about a large number of vitamins, but about 2-3 vitamins, and first of all it is ascorbic acid, that is, vitamin C, vitamin A and thiamine. 2. Nutrition should contain a complex of amino acids, such as cysteine and methionine, tyrosine and phenylalanine, tryptophan. 3. Nutrition should ensure the formation in the body of such compounds that have great biological activity. First of all, it is vitamin B12, choline, pyridoxine. 4. Nutrition in risk areas and therapeutic and preventive nutrition should be enriched with pectin substances, which contain methoxyl groups, which cause a gel-forming effect and have great sorption properties, and which help to eliminate heavy metals, radioactive substances, autotoxins and other toxic compounds from the body. 5. In modern conditions, alkalizing diets are widely used, diets due to the inclusion of vegetables, fruits, and dairy products in them. A large role in such nutrition is played by elevated concentrations of magnesium. It has been established that magnesium contributes to an increase in the body's resistance to the effects of substances with carcinogenic properties. It should be noted that not all foods have magnesium anticarcinogenic properties, but only those of its forms and compounds that are contained in beans. The population living in difficult environmental conditions, in urban conglomerates, needs to enrich their diets with pectin substances. A sufficient level of pectins, their delivery to the body, is associated with a daily consumption of about two apples. A high level of pectin content is found in beets and citrus fruits. Under production conditions, the rations of workers are enriched with beet or citrus pectins. The population living in areas of ecological risk is recommended to widely use products containing a large amount of such an amino acid as methionine. This amino acid is involved in the processes of transmethylation and provides detoxification function of the liver. Methionine is found in sufficient quantities in dairy and sour-milk products and cottage cheese. But when prescribing dairy products, it is necessary to take into account the peculiarities of the digestive system of the human body, milk tolerance; whether the use of cottage cheese is indicated. In general, the daily intake of milk should be approximately 500 ml under optimal conditions, cottage cheese and sour-milk products - about 100 g. It is advisable to enrich the diets of people exposed to the negative effects of environmental factors with products that contain alginates in their composition. Alginates, like pectins, are able to remove autotoxins, toxic chemicals from the body. Alginates are found in marine products and, in particular, in algae belonging to the spirulina species. Spirulina supplements in the diet cleanse the body of toxic substances, regulate the metabolism of cholesterol and carbohydrates, normalize the intestinal microflora and significantly increase the body's resistance to various negative environmental factors. It must be said that the action of spirulina is carried out at the level of cellular metabolism and has a positive effect on detoxification processes. When exposed to radionuclides such as cesium, strontium-90, on the human body, especially on that part of the population that is in the zone of influence after the Chernobyl disaster (where cesium is mainly concentrated), it is recommended to include ferrocin (Prussian blue) in the diet for about 1 g per day. In this case, there is a decrease in the absorption of cesium by 2 times. Strontium-90 is adsorbed by barium sulphate - polysulmin, but it can only be taken once. In conditions of exposure to production factors, workers should be prescribed therapeutic and preventive nutrition. The nutrition of the population living in large industrial centers, exposed to external factors of various nature and suffering from various diseases, must be individual in nature and largely meet the requirements of dietary nutrition, especially at home. Therefore, the population should be familiar with the basic requirements and provisions of dietary nutrition at home. Hygienic problems of application and use of food additives Modern nutrition is associated with the widespread use of nutritional supplements. Food additives are substances deliberately added to foodstuffs in small quantities in order to improve their appearance, taste, aroma, texture or to make them more stable during storage. These are fat antioxidants, preservatives, antibiotics, etc. There are substances that can be formed in products as a result of special methods of processing and obtaining them using smoking, ionizing radiation, ultrasound, and the use of endocrine preparations when fattening animals and birds. The problem of nutritional supplements is extremely complex and is associated with the consumption of small amounts of substances for a long time, more than the lifespan of one generation. In this case, there may be a delay of substances in the body, their accumulation, which is important in relation to microelements. There may be a cumulative effect, and above all carcinogens. Dyes have carcinogenic properties, in particular naphthol yellow C, which until 1961 was used in many countries of the world to tint a number of food products. Among food additives, there are substances that have a carcinogenic and mutagenic effect. These include polycyclic hydrocarbons of smoke smoke, food dyes - naphthol yellow and a number of other azo dyes, polymeric compounds - wax, resins, paraffin, pesticides, amarin, steroid group hormones, radioisotopes. Food additives can have a cocarcinogenic effect, i.e. have properties that, under appropriate conditions, can enhance the effect of active carcinogens. Some emulsifiers have such properties - saponins, fatty acid esters, detergents. The relationship of cocarcinogenic, carcinogenic and mutagenic effects has not been fully established. Carcinogenic and mutagenic effects do not always coincide. Among food additives, substances with the most pronounced mutagenic effect are distinguished. These include: phenols, heavy metals, arsenic, almost all alcohols, protein breakdown products, antibiotics, purines, peroxides, lactones. In addition to the direct effect, additives can also have an indirect effect resulting from the destruction of vitamins, proteins, binding of food components (in particular, binding to sulfuric anhydride, the transformation of food components into toxic compounds, and then a violation of food digestion, the antitrypsinogenic effect of soy flour), at the same time digestibility worsens, there is a change in the intestinal flora. Food additives are handled by the World Health Organization, the UN Food and Agriculture Commission. In Russia, there are sanitary rules, special guidelines, instructions. There is such a principle: "everything that is not allowed is prohibited." Additives are strictly regulated by standards, specifications and special instructions. In Russia, the use of food additives is sharply limited, 3 artificial dyes are allowed for use, and in other countries (Belgium; Denmark, etc.) there is no list of permitted dyes at all. We do not allow the introduction of food additives in order to mask technological defects or spoilage of food products. For infants in our country, products are prepared without the use of food additives. State standards regulate the permissible content of food additives. Food additives are used in a variety of ways: dyes for coloring; preservatives prevent food spoilage; antioxidants, antioxidants, acidifying and alkalizing substances, emulsifiers, substances that improve the quality of food products are used. Of the artificially synthesized food dyes, only 3 are allowed to be used: tatrazine - yellow dye, indigo carmine - blue and amaranth - red dye. For them, a permissible daily dose has been established: for amaranth - up to 1,5 mg, tatrazine - from 0 to 7,5 mg per 1 kg. In our country, the quality of food products is regulated by a special standard, microbiological requirements and sanitary standards for the quality of food raw materials and food products. This standard gives a description of all food additives, all technologies that are associated with the production of certain food products. In particular, a list of various chemical compounds used in the production of sugar is given. For the treatment of infusion juices and syrups, these are hydrosulfide, calcium hydroxide, carbon dioxide, surfactants, defoamers, sorbents, ion-exchange resins, such as KU-2-8 and AV-16, AV-17-8C and others, activated carbon. For filtration, perlite, fabric filter are used, for tinting - ultramarine and indigo carmine. In the production of confectionery products, gelling agents, agar, or furapiran, peptin, gelatin are used. Also used are emulsifiers - phosphatides, lecithin, foaming agents - a decoction of a soap root, glycyrrhizin, chemical baking powder - sodium oxides, ammonium carbonate, food acids - citric, lactic, tartaric, etc. Recently, much attention has been paid to substances that are formed during the processing of food products and can adversely affect the health of the population. A special position is occupied by the so-called trans-fatty acids (TIFA). TIFA play a significant role in the development of diseases of the cardiovascular system. The problem of TIZHK is connected mainly with the production of margarines and their use. Margarines are usually made using hydrogenation, for which hydrogen is driven through vegetable oils at a high temperature. In such a melted crucible, some fatty acid molecules "break down", becoming trans-isomers. Normally, fatty acid molecules are cis isomers. The essence of the difference between them lies in the spatial arrangement. For biological molecules, this is fatal. For example, the trans isomers that make up an enzyme can make it inoperative. It is believed that transisomers worsen the quality of breast milk of lactating women, increase the risk of having children with low weight, increase the risk of developing diabetes, impair immunity, impair sperm quality, disrupt the activity of the cytochrome oxidase enzyme, which plays a role in the neutralization of carcinogens, and disrupt prostaglandin metabolism. Therefore, it is necessary to be wary of margarines and those products that are prepared with their use (potato chips, etc.). Natural products (meat, milk) contain TIFA no more than 2%, and in confectionery (crackers) TIFA can contain from 30 to 50% of the total fat. Donuts contain 35%, potato chips 40%, French fries - about 40% FAFA. Pesticides and nitrates in food hygiene The problem of pesticides or pesticides and nitrates is very urgent. Pesticides are synthetic chemicals of varying degrees of toxicity used in agriculture to protect plants from weeds, pests and diseases, and to stimulate their growth. It should be noted that modern agricultural production is impossible without the use of pesticides. The use of pesticides leads to a 40% increase in yield. However, the introduction of persistent pesticides into the soil can lead to their circulation and accumulation in the human body. Pesticides are widely used in Central Asia, and their application to the soil is 54 kg per 1 ha, while in the USA it is only 1 kg per 1 ha. Irrational use of pesticides leads to their accumulation in consumer products. The tasks of hygienic science in the field of nutrition are the regulation of residual amounts of pesticides in food products, the control of their content, as well as the development of preventive measures to prevent chronic intoxication with pesticides and other pesticides. For the hygienic characteristics of pesticides, their classification is important. They are classified by chemical structure, by application, by toxicological and hygienic parameters. According to the chemical structure, pesticides are divided into organochlorine, organophosphorus, carbamate derivatives, organomercury, cyanide, sulfur, arsenic, and copper preparations. By application, they are distinguished: herbicides - for weed control, bactericides - for the destruction of microorganisms, for the destruction of insects - insecticides, for the destruction of ticks - acaricides, for the destruction of roundworms - nematicides, for the destruction of leaves before harvesting - defoliants, fungi - fungicides, etc. d. By toxicity pesticides are classified into potent, high, medium and low toxicity. The main criterion of toxicity is the average lethal concentration (LD50) per 1 kg of animal weight. The most dangerous are pesticides with an LD50 of less than 50 mg per kg of body weight. Pesticides with LD50 from 50 to 200 mg per 1 kg of body weight are classified as highly toxic, from 200 to 1000 mg per 1 kg as moderately toxic, and pesticides with an average lethal concentration of more than 1000 mg per kg are classified as low-toxic substances. The most important criterion for pesticides is their ability to accumulate, that is, the ability to accumulate in tissues and organs. The main indicator of this ability is the cumulation coefficient. Supercumulative pesticides include those with a cumulative coefficient of less than 1, pesticides with pronounced cumulative properties have a cumulative coefficient from 1 to 3, and those with low cumulative properties - more than 5. Extremely important in the evaluation of pesticides is their stability index. In terms of stability pesticides are subdivided: very persistent - they remain in the soil for more than 2 years; moderately persistent - up to 6 months; low-resistant - up to 1 month. The problem of assessing the transformation of pesticides both in the environment and in the human body is very important. Some pesticides, various chemical compounds under the influence of environmental factors or microorganisms, being destroyed, turn into more toxic and dangerous compounds. According to the nature of their action and according to the cumulation criteria, organophosphorus pesticides belong to the functional group, i.e. they affect functional processes, in particular, cause a violation of synoptic transmission, affecting the activity of cholinesterase. Organochlorine compounds are characterized by the influence on the structural formations of certain systems, organs, tissues, i.e. they are structural poisons. If we compare these two large groups of pesticides according to the mechanism of action, then preference should be given to organophosphates. In sanitary and toxicological terms, pesticides that have a complex of the following properties are of great danger: 1) high toxicity of the drug; 2) high stability in the environment; 3) long-term storage in soil, water, food (dichlorophenyltrichloroethane is stored in soil for up to 10 years or more); 4) high toxicity of substances formed as a result of decay, destruction of the drug under the influence of biological and other factors that cause the transformation, destruction and transformation of pesticides; 5) pronounced cumulative property of the drug, its ability to accumulate in the body, systems and tissues. DDT is a highly cumulative poison; in the living tissue of people who do not have direct contact with pesticides, its concentration can reach 5 mg or more per 1 kg of weight; 6) methods of excretion from the body. The greatest danger is represented by pesticides that accumulate in milk; 7) pesticides capable of forming stable oil emulsions are highly dangerous. In hygienic measures to prevent the adverse effects of pesticides on the human body, it is important to take into account the allowable residual amounts of the tolerant dose in products, taking into account the allowable daily dose. To control the intake of pesticides, the products in the diet are taken into account, as well as the intake of pesticides with water and through the air. For a number of pesticides, the approach to them is such that they should not be found at all in baby food, milk, should not be excreted with the milk of lactating animals and lactating women. The requirements for pesticides are that they should have maximum selectivity, would not have the ability to accumulate. Measures to prevent poisoning by pesticides include: 1) complete exclusion of the residual content of pesticides that are stable in the environment and have pronounced cumulative properties; 2) tolerance in food products of the residual content of pesticides and their metabolites in quantities that do not have an adverse effect; 3) the use in agriculture in the production of food products of pesticides with a short half-life and the release of the edible part of the product from residual quantities of pesticides by the time of their commercial ripeness and harvest; 4) control over the strict observance of instructions for the use of pesticides and compliance with waiting periods that ensure the release of products from residual quantities; 5) monitoring the content of pesticide residues in food products and preventing exceeding the established permissible residues. (Residual amounts of pesticides are not allowed in the criteria for medical and biological food safety, in standards, etc.) Nitrates are a very important hygiene problem. Nitrates in foodstuffs can accumulate as a result of their cultivation. Vegetable crops pose a particularly serious danger in this regard. Plant foods provide 70% of all nitrates. 10% of nitrate intake is associated with the consumption of animal food and 20% - with the consumption of water. Only 0,1% of nitrates is associated with pulmonary intake. According to the content of nitrates in them, food products can be divided into 3 groups. The first group includes food products containing up to 10 mg of nitrates per 1 kg of weight - milk, cheese, fish, meat, eggs, white sugar, wine. The second group - products in which the content of nitrates is from 50 to 2000 mg per 1 kg - tea, brown sugar. The third group includes products enriched with nitrate ions during their processing - sausages and semi-finished meat products, cheese. Sausage can contain up to 700 mg of nitrates per 1 kg. The intake of nitrates in the human body is associated with their danger to biotransformation. This phenomenon can take place in several directions - nitrates, having recovered in the human body to nitrites, interact with blood hemoglobin in the blood, and methemoglobin is formed, which leads to methemoglobinemia. It should be noted that such conditions are observed in premature infants who are bottle-fed due to the characteristics of enzymatic systems and intestinal microflora. The life-threatening value of the formation of methemoglobin is 3,0-3,7 g%, i.e. already higher concentrations can lead to death. Especially dangerous is the defeat of hemoglobin in the fetus in the womb (the so-called germinal methemoglobinemia), which is of great importance in the pathology of newborns. The biotransformation of nitrates can also follow a different path. Entering the stomach, nitrates interact with food proteins, and nitrosamines are formed, which have pronounced carcinogenic properties. Nitrates are rightfully blamed for the significant increase in pathologies such as stomach cancer. Nitrates do not accumulate in the body, they are excreted in the urine and feces. The only possible source of intake associated with their accumulation in the human body is saliva. In saliva, nitrates accumulate, and the recovery process is underway: 20% of nitrates are restored in saliva. The content of nitrates is very significant in parsley, celery, early kaput, as well as those plant products that were grown indoors. It should be noted that in potatoes 25% of all nitrates are contained in the core, i.e. more than in other parts of it, in carrots the same is in the core and stem. In beets, the content of nitrates differs in their content in the root system; in cucumbers, their content increases from top to bottom. The tail part of the cucumber contains 25% nitrates. Celery leaves contain 50% (more than stalks). In cabbage, nitrates accumulate mainly in the stalk and in the leaves. In the prevention of the negative effects of nitrates, food processing technology is of great importance. When boiled, nitrates go into the decoction. It is possible to remove nitrates by mechanical treatment, taking into account their distribution in food products. For potatoes, the most effective way to extract nitrates is soaking, saline solutions help to reduce the nitrate content. Nitrates are removed by 93% when boiling vegetables. The negative effects of nitrates can be prevented by neutralizing them. Ascorbic and folic acids possess such properties. A change in the pH of the environment in the stomach of a child more than 4 prevents the biotransformation of nitrates. In children, the acidity of the contents of the stomach approaches neutral, and the transformation of nitrates becomes dangerous at pH = 5. When normalizing the total load of nitrates on the body, their intake with food, water and air is taken into account. The total load for an adult per 1 kg of weight is 4,8 mg, i.e., based on the average body weight of an adult, the daily load is 300-325 mg. For children, the daily load should not exceed 150 mg. In everyday life, it is necessary to follow hygiene recommendations and remember that the use of aluminum utensils in the culinary processing of food greatly increases the toxicity of toxic substances. In modern ecological conditions, nutrition should be adequate. There is a certain relationship between the state of human health and the propensity to consume any particular food. It is especially important to study the nutrition of people living in extreme climatic conditions. For example, in the diet of the Eskimos, animal products and marine products predominate. In this regard, it is necessary to take into account the peculiarities of the enzymatic processes of the population, depending on the nature of the diet, since their digestive system is adapted to a certain set of products. In some peoples of Europe and Asia, 19% of the population has milk intolerance. In the Middle East, milk intolerance is 10%. Adequate nutrition in modern conditions is based on the following principles: 1) the use of protective components in food products, compounds that improve the neutralizing function of the liver; the use of food components that have the ability to influence microorganisms and viruses, anti-carcinogens; 2) the inclusion of dietary fiber and an increase in their content up to 20 g per day; 3) optimization of the quantitative and qualitative relationship of nutrients; Nutrition should correspond to the state of health and high working capacity, contribute to the removal of old age and a high life expectancy. Nutrition should provide the body's defenses against the influence of adverse environmental factors, neuropsychic overload, ensure the prevention of diseases of the gastrointestinal tract, cardiovascular system, and metabolic diseases. LECTURE No. 9. Hygienic foundations of rational nutrition Nutrition and health. Alimentary diseases The nutritional factor (nutrition) and health are closely related. Experts of the World Health Organization (WHO) in order to draw the attention of international organizations, government officials to nutrition problems, to the decisive influence of nutrition on the level of planetary health, specially spend decades, years dedicated to nutrition and even special decades. WHO pays special attention to this issue in underdeveloped countries and developing countries. WHO experts travel to African and Latin American countries to organize special sessions with the medical personnel of these countries and directly with the population on rational nutrition. These decades, WHO nutrition events, are held under the motto "Healthy food - good health!" This provision, put forward by WHO, has not lost its relevance today. Nutrition, or nutritional factor, largely determines the most important functions of the body. The nature of nutrition in modern conditions is especially important. This is due to a number of factors, primarily high neuropsychic stress and stress. It is important to note that the nature of stress has clearly changed in recent years. Today, stress is constant. Their influence is of such a nature that the concept of "whispering of neurons" has appeared. The second factor that forms the problems of nutrition in modern conditions is physical inactivity (absence or low level of physical activity). The third factor influencing nutrition in modern conditions is environmental pollution. The level of environmental pollution provides the basis for nutritional problems. This problem can be considered in several planes. On the one hand, nutrition is a way to reduce the impact of negative environmental factors on health. On the other hand, in conditions of intense environmental pollution, food itself becomes the object of pollutants. Nutrition is a social factor, as it affects the interests of the population of the entire planet. According to WHO experts, about 500 million people are starving in the world. About 150 million people are starving in Africa. Approximately 50 million people die each year worldwide from various causes, including approximately 39 million in developing countries. About 10 million people die of hunger every year. 100 million children in dependent countries suffer from hunger. The UN and its committees (in particular, WHO, FAO - the UN Agriculture and Food Commission) constantly pay attention to nutrition problems. At present, a clear relationship between the nature of nutrition and health indicators has been established. Nutrition has an impact on the most important indicators of public health: 1) fertility and life expectancy; 2) state of health and physical development; 3) the level of performance; 4) morbidity and mortality. The study of the nature of the nutrition of centenarians indicates that the most important condition for this longevity was a diet with high-grade foods. The nature of nutrition is directly related to morbidity and mortality rates in countries such as Africa, Latin America, and Southeast Asia. The nature of nutrition determines the features of the formation and development of a number of diseases. In particular, nutrition and disease are undoubtedly related to the nature of nutrition. Violation of the nature of nutrition largely determines the development of early atherosclerosis, coronary insufficiency, hypertension, diseases of the gastrointestinal tract. Violation of the diet contributes to the emergence of cancer. The nature of nutrition affects fat and cholesterol metabolism and contributes to the early development of diseases of the cardiovascular system and other organs. The problem is overnutrition, which leads to the development of obesity. Finally, there are a number of diseases associated with malnutrition (nutritional diseases). These include primarily protein deficiency. Protein-calorie deficiency can manifest itself in the form of alimentary insanity. A severe form of protein-calorie malnutrition is kwashiorkor. Nutritional diseases include endemic goiter, alimentary anemia, rickets, obesity and other diseases. A more detailed description of alimentary diseases can be presented as follows. The literature provides the most detailed coverage of protein-calorie deficiency - a complex of pathological conditions associated with insufficient intake of protein, calories, and, as a rule, with a concurrent infection. Most often, this pathology occurs in infants and young children. Protein-calorie deficiency includes a whole range of pathological conditions - from alimentary insanity to kwashiorkor. Alimentary insanity is a condition characterized by muscle atrophy, lack of subcutaneous fat and very low body weight. All this is the result of eating low-calorie foods for a long time, as well as a lack of proteins and other nutrients in it. Infectious diseases are of great importance. The most severe form of protein-calorie malnutrition is kwashiorkor disease. This is a severe clinical syndrome, the main cause of which is the lack of amino acids necessary for protein synthesis. Clinically, kwashiorkor is characterized by growth retardation, edema, muscle atrophy, dermatoses, hair color changes, liver enlargement, diarrhea, psychomotor impairments such as apathy, and a distressed appearance. Kwashiorkor is characterized by the detection of low levels of argenin in the blood serum. Most often, this syndrome occurs in children aged 1 to 3 years. During the period of breastfeeding or during the period of its termination, the condition is aggravated by infection, which increases the breakdown of protein or reduces its intake into the body. In tropical Africa, all forms of protein-calorie deficiency are noted - from alimentary insanity to kwashiorkor. However, in developing countries, protein-calorie deficiency with a clinic of alimentary insanity is more common than kwashiorkor. Growing urbanization with deteriorating living conditions leads to alimentary insanity. Insanity is characteristic of the slums of overcrowded cities, and kwashiorkor is a disease characteristic of the countryside, of villages. Protein-calorie deficiency most often affects children aged 2 years, older than 4 years and more much less frequently. The impact of protein-calorie malnutrition persists into later life. Recovery of impaired functions is slow and incomplete. And growth and mental development are delayed for many years. With the end of infancy, the symptoms of the disease change. The symptoms of insanity, in which the main role is played by a lack of calories, are shifting towards a deficiency caused by protein and calorie deficiencies. In the second year, infections matter, especially measles and whooping cough, which lead to the breakdown of protein and exacerbate protein-caloric deficiencies and, in particular, deficiencies in amino acids. Classic kwashiorkor occurs in children who, after full and prolonged breastfeeding, were gradually or suddenly transferred to an unlimited diet of foods rich in starch and poor in proteins, as is often the case in tropical Africa in children in the last months of the second and during the third year of life. Child mortality from protein-calorie deficiency is quite high. Kwashiorkor is the basis of the pathology of protein-calorie deficiency. A manifestation of protein-calorie deficiency is a mental disorder and disorders of mental and physical development. The defeat of the psyche is characterized by the development of insanity, there is a decrease in body weight, a change in constitutional signs (large belly). The most important in the treatment of kwashiorkor is a balanced diet. Endemic goiter also belongs to alimentary diseases. Endemic goiter (cretinism) - an alimentary disease associated with a lack of iodine intake - is the main cause of endemic goiter. The intake of other microelements is also important: copper, nickel, cobalt, unbalanced diet, its protein and fat deficiency. According to WHO experts, about 200 million people suffer from endemic goiter on the planet. It has now been established that in the area where the population receives food that provides iodine intake at the level of 100-200 mcg per day, endemic goiter is not observed. Endemic goiter is common in areas where there is a low level of iodine in soil, water, plant and animal products. In the daily balance, the main intake of iodine is provided by products of plant origin. 50% of the total intake of iodine in the body is provided by food of plant origin. Most often, endemic goiter is common in mountainous and foothill areas. Its distribution in flat areas is an exception. In areas with high endemicity, physical and mental development disorders are noted. This can be observed in the population in the early periods of life as a result of inhibition of the functions of the gland and a decrease in secretion production. The result of this is a violation of the psyche in the form of cretinism, idiocy. WHO provides data (review) for 120 countries on the prevalence of endemic goiter. Classical endemic areas associated with the spread of goiter are the high mountain valleys of the Alps, the Pyrenees. The prevalence of endemic goiter is noted in the population on the slopes of the Himalayas and along the Cordillera. This pathology is also widely observed in the Great Lakes basin (between Canada and the USA). A number of food products exacerbate the development of endemic goiter. In particular, substances contained in ordinary cabbage have such an effect. It has a goiter effect. A number of chemicals also have a goiter effect, which should be taken into account in the prevention of this disease. The prevalence of endemic goiter is noted in the beekeeping mountainous regions of India. Here, with the population affected by more than 30%, there is a mass birth rate of children suffering from mental illness, a mass birth of children with manifestations of idiocy. It is also noted that in families where parents suffer from endemic goiter or receive insufficient amounts of iodine, children are born with congenital deafness. Thus, the problem of endemic goiter should be considered in all its aspects and manifestations. Endemic goiter is common in the Saratov region. Endemic goiter is widespread among rural residents of the right-bank region of the Khvalynsky, Bazarno-Karabulaksky, Volsky and some other regions. It must be said that one of the preventive measures to reduce the incidence of endemic goiter is rational nutrition. And the most important part of this rational nutrition is the intake of iodine. Professor L.I. Elk Academician R.A. Gabovich and others who dealt with the problem of endemic goiter proposed to provide the population with iodized salt for prophylactic purposes. The population provided with such salt is largely protected from low levels of iodine intake from food products, mainly of plant origin. Scientists-hygienists in the field of food hygiene have proposed special diets to prevent endemic goiter. In particular, such diets were developed at the Department of Hygiene of the Ural Medical University. In these diets, sea products were obligatory - fish products, sea kale, which is distinguished by a fairly high content of iodine. Also, a high-grade animal protein and a sufficient level of PUFA and other biologically active food substances in the diet have a positive effect on reducing the incidence of endemic goiter. Nutritional anemia The WHO Scientific Group defined nutritional anemia as a condition in which the hemoglobin content in the blood is below normal due to a deficiency in one or more important nutrients, regardless of the cause of this deficiency. Anemia exists if the hemoglobin level is below the figure given here, based on 1 g or 1 ml of venous blood. Children aged 6 months to 6 years - 11 g per 100 ml of venous blood, children from 6 years to 14-12 g / 100 ml, adult men - 13 g / 100 ml of venous blood, women (not pregnant) - 12 g / 100 ml of venous blood and pregnant women - 11 g / 100 ml of venous blood. Anemia is widespread in African countries. In Kenya, 80% of the population has signs of iron deficiency. At the beginning of the last century, anemia was considered the most common pathology among agricultural workers and tea plantations in India. 14% of men and women suffer from a severe form of anemia, i.e., the hemoglobin content is noted in amounts of less than 8 g per 100 ml of venous blood. Anemia mainly affects women. Prevention of anemia is a balanced diet, the consumption of foods containing a sufficient amount of iron. These products include: veal liver, the content of which is iron at the level of 13,3 mg per 100 g of the product, raw beef - 3,5 mg per 100 g, chicken egg - 2,7 mg per 100 g, spinach - 3,0 mg per 100 g of product. Less than 1,0 mg contain carrots, potatoes, tomatoes, cabbage, apples. At the same time, the content of ionized biologically active iron in these products is of great importance. Nutritional diseases characterized by malnutrition include beriberi. These include xerophthalmia associated with insufficient content or impaired metabolism of vitamin A. Clinical manifestations are expressed by clouding of the cornea of the eye and the development of blindness, disorders of the skin. Rational nutrition, the use of foods rich in vitamin A, are the basis for the prevention of xerophthalmia. These include milk, egg yolk, and plant foods rich in provitamin A or β-carotene. However, it should be remembered that the ratio of vitamin A and β-carotene must be strictly defined. The activity of β-carotene is determined against the background of sufficient intake of vitamin A in the body. In the total daily balance of intake, vitamin A itself should account for at least 1/3 of the total need for this vitamin. The diseases associated with malnutrition also include rickets associated with insufficient intake of vitamin D. Vitamin deficiency is also associated with insufficient intake of vitamins C, group B and others. Obesity is one of the diseases of overnutrition. Obesity is a nutritional disease of a social nature. Every third person in developed countries suffers from this pathology. Obesity is a cause of disability and reduced life expectancy. People who are overweight tend to have a life expectancy 10% lower than people who have an ideal body weight. Obesity contributes to the development of other pathologies: neuroendocrine diseases (diabetes), cardiovascular diseases. A moderate degree of obesity is a risk factor for the onset of diabetes mellitus (persons suffering from this form of pathology are 4 times more likely to have diabetes mellitus). In severe forms of obesity, the incidence of diabetes mellitus is 30 times higher. Obesity is not only a risk factor for diabetes and cardiovascular disease, but also a risk factor for infectious diseases. Obese people are 11 times more likely to develop an infectious pathology. Balanced diet. The main provisions of the theory of rational balanced nutrition Nutrition is the basic biological need of man and the oldest essential connection of a living organism with the surrounding nature. Rational and complete nutrition in quantitative and qualitative terms, along with other conditions of the social environment, ensures the optimal development of the human body, its physical and mental performance, endurance and wide adaptive capabilities. A complete diet with an optimal content of nutrients has a beneficial effect on the immunobiological status of the body and increases its resistance to infectious agents and toxic substances. The modern concept of rational and nutritious nutrition has been formed on the basis of many years of research by foreign and domestic scientists. Rational, healthy nutrition is nutrition that satisfies the body's needs for essential nutrients - proteins, fats, carbohydrates, vitamins and minerals. Currently, there are a number of theories of nutrition. In our country and throughout the world, the theory of rational, balanced nutrition has become widespread. In accordance with the theory of a rational balanced diet, a healthy diet must meet certain requirements. Nutrition should be balanced in chemical composition in relation to the main nutrients - proteins, fats, carbohydrates, minerals and vitamins. This ratio of essential nutrients has been called the principle of first-order nutritional balance. The ratio of irreplaceable essential substances is also important. For proteins, this is the ratio of essential amino acids, for fats - a balanced ratio of fatty acids (marginal and unsaturated), for carbohydrates - this is the ratio of simple and complex carbohydrates, for vitamins - the ratio of various forms of provitamins and vitamins proper, the optimal ratio of macro- and microelements. This position was called in the theory of rational and balanced nutrition the principle of balanced nutrition of the second order. The third position of the theory of rational nutrition is the idea of a rational diet, determined by the number of meals, the intervals between them, eating at a strictly defined time and the correct distribution of food for its individual meals. The fourth position in the theory of rational nutrition is determined by the digestibility or digestibility of diets, i.e. nutrition should, according to the method of culinary processing, according to the food set of products, correspond to the digestive capacity of the gastrointestinal tract, depending on age, individual characteristics, the state of the enzyme systems of the gastrointestinal tract on all stages of food digestion: cavitary, parietal and intracellular. Nutrition should be balanced in digestibility and digestibility. The first position of the theory of rational and balanced nutrition - the optimal ratio of chemicals in the diet - is closely related to the concept of a balanced megacalorie. A megacalorie - a million small calories, a thousand kilocalories - large calories, must be strictly balanced in terms of the content of proteins, fats and carbohydrates in it. To the greatest extent, the body's energy needs are provided by carbohydrates, then fats, and finally proteins. If the total energy value of the diet is taken as 100%, then proteins account for 12%, fats - 33%, carbohydrates - 55% of calories. Or, if in absolute terms, then in 1000 kcal there should be 120 kcal from protein, 333 kcal from fat and 548 kcal from carbohydrates. If we take proteins proteins 120 kcal per unit, then the ratio of calories of proteins, fats and carbohydrates within a megacalorie will be expressed as: 1: 2,7: 4,6. It is known that the calorie content of 1 g of protein is 4 kcal, 1 g of fat - 9 kcal and 1 g of carbohydrates - 4 kcal. Thus, 120 kcal will be provided by 30 g of proteins, 333 kcal of fat will be provided by 37 g of fat and 543 kcal of carbohydrates will be provided by 137 g of carbohydrates. If we take 30 g of protein proteins as a unit, then by weight the ratio of proteins, fats and carbohydrates within a balanced megacalorie will be expressed as 1: 1,2: 4,6. This position of the optimal ratio of the main nutrients of proteins, fats and carbohydrates, taking into account the minimum calorie content of the diet, is called the principle of first-order nutritional balance. The ratio of essential, irreplaceable nutrients in the diet is also important. It is primarily about a balanced, optimal ratio of essential amino acids. This is ensured by a certain ratio of proteins of plant and animal origin. The optimal ratio of essential amino acids is determined by the ratio of 3 essential amino acids that limit the protein usefulness of the diet: tryptophan, methionine and lysine. The ratio of these essential amino acids to tryptophan should be 1 : 3 : 3. The optimal ratio should be other essential substances that are part of fats, carbohydrates, minerals and vitamins. This optimal ratio of essential, indispensable nutrients of a nutritional nature has been called the second-order nutritional balance principle. The idea of a balanced megacalorie is also associated with a certain correspondence between caloric content and the intake of vitamins and other food components into the body. So, in particular, vitamin C, taking into account the calorie content of the diet per 1 μcal, should be contained in the diet at the rate of 25 mg per 1 μcal. Thus, if energy consumption is 3 Mcal, or 3000 kcal, then the daily requirement for vitamin C should be 75 mg. The same approach exists in relation to providing the body with B vitamins and other ingredients of the diet. An important provision of the theory of rational and balanced nutrition is the second provision that the energy value of the diet in most cases should correspond to the energy expenditure of a person. In children, pregnant women, nursing mothers, emaciated convalescents, it should exceed energy expenditure. Part of the nutrients is spent on plastic processes. The energy consumption of the human body depends mainly on the profession and nature of labor activity, housework, lifestyle, as well as on age, body weight, gender, physical condition, and the impact of various environmental factors. Energy costs for individuals of a homogeneous team are determined as follows: they consist of the main exchange (for an adult, it is approximately equal to 4,18 kJ, or 1 kcal per 1 kg of body weight per hour). The second element of unregulated energy consumption of the basal metabolism is the energy consumption spent on the assimilation of food - a specific dynamic action. The specific dynamic action of food of a mixed nature leads to an increase in basal metabolism by 10%. The sum of basal metabolism and energy expenditure associated with the specific dynamic action of food constitute an unregulated part of a person's daily energy expenditure. When determining the total energy consumption of a person, it is necessary to add to this unregulated part the energy expenditure of the body for the work performed during the day, related to labor activity, i.e. production, office and household work. For this purpose, the timing of the activities of groups of people of a given team is carried out, or a calculation is made using data on energy costs for various types of labor activity. There are direct and indirect methods for determining energy costs. The most widely used method for determining energy costs in modern conditions is to determine them according to special tables compiled on the basis of data on energy costs obtained by studying gas exchange. It is very important to note that energy expenditure is the basis of physiological nutritional norms, taking into account age aspects, taking into account the state of the human body, gender, climate, and living conditions. The most important provision of rational nutrition is its balance according to the regimen. The diet provides for the frequency of meals depending on age, nature of work activity and health status, in particular the functional state of the gastrointestinal tract, the state of its enzymatic systems. The time between separate meals matters. The diet provides timely delivery to the body of energy sources and nutrients needed by the human body. The diet creates optimal conditions for the activity of the gastrointestinal tract, associated with its motility, peristalsis and the release and formation of certain enzymes, secrets. Physiological nutritional norms The physiological norms of nutrition are based on differentiated approaches depending on professional activity, i.e., energy expenditure, age, gender, physiological state and climatic conditions of residence. Physiological nutritional norms are based on the energy expenditure of the population. According to energy expenditure, the entire able-bodied population is divided into 5 groups. 5 groups of labor intensity The first group includes mainly mental workers, business leaders, engineering and technical workers, medical workers, except for surgeons, nurses and nurses. This group also includes educators and teachers. The energy expenditure of this group ranges from 2550 to 2800 kcal. This group is divided into three age subgroups. There are groups of 18-29 years old, 30-39 years old and 40-59 years old. The second group of the population in terms of labor intensity is represented by workers engaged in light physical labor. These are engineering and technical workers, whose work is associated with some physical effort, workers in the radio-electronic, watch industry, communications and telegraph, service industries serving automated processes, agronomists, livestock specialists, nurses and nurses. The energy costs of the second group are 2750-3000 kcal. This group, like the first, is divided into 3 age categories. The third group of the population in terms of labor intensity is represented by workers engaged in medium-heavy work. These are locksmiths, turners, adjusters, chemists, drivers of vehicles, water workers, textile workers, railway workers, surgeons, printers, foremen of tractor and field farming teams, grocery store sellers, etc. The energy expenditure of this group is 2950-3200 kcal. The fourth group includes workers of heavy physical labor - machine operators, agricultural workers, workers in the gas and oil industries, metallurgists and foundry workers, workers in the woodworking industry, carpenters and others. For them, energy costs are 3350-3700 kcal. The fifth group - workers engaged in especially hard physical labor: workers of underground mines, chippers, masons, fellers, steelworkers, diggers, loaders, concrete workers, whose labor is not mechanized, etc. This group includes only male representatives, since it is prohibited by law women's work with such labor intensity. This is especially hard physical labor, because the energy costs here are in the range from 3900 to 4300 kcal. There are physiological norms for children's nutrition. In general, for the adult working-age population, protein requirements average 100-120 g ± 10%. The same needs of an adult organism for fats - from 80 to 150 g and the need for carbohydrates - 350-600 g per day. Depending on energy expenditure and working conditions, physiological nutritional norms provide for the necessary level of providing the body with vitamins, mineral salts, macro- and microelements. The need for children and adolescents in the required calories of the diet is determined by the following indicators. The nutritional value of the diet of children aged 7 to 10 is 2300 kcal, 11-13 year old boys - 2700 kcal, girls - 2450 kcal, boys and girls 17 years old, respectively, 2900 and 2600 kcal. There are recommended daily requirements for proteins, fats and carbohydrates for children and adolescents in different age groups. For children aged 7-10 years, the need for proteins is 70 g, fats - 79 g (of which vegetable - 15 g) and carbohydrates - 330 g. For boys and girls 11-13 years old, respectively, in proteins - 93 g (55 grams of animal origin), fats - 93 (19 g of plant origin) and carbohydrates - 370 g. For girls 11-13 years old - proteins - 85 g (51 g of animal origin), fats - 85 g (17 g of plant origin) and carbohydrates - 340 g. For boys aged 14-17, protein requirements approach the needs of the adult population and amount to 100 g (of which animal proteins are 60 g), in fats - 100 g (of which vegetable origin is 20 g) and carbohydrates - 400 g. For girls aged 14-17 years, the need for proteins is 90 g (54 g of animal origin), fats - 90 g (18 g of plant origin), carbohydrates - 360 g per day. There is a special provision on the rational nutrition of persons engaged in physical education and sports. Of particular importance is nutrition for people with various diseases - clinical nutrition. For persons employed in certain industries, where certain professionally harmful physical and chemical factors are affected, therapeutic and preventive nutrition is used. In general, the issue of nutrition should be addressed individually. Everyone should receive individual rational nutrition, taking into account the state of health. In the world there is a concept of the nutritional status of a person. This is a state of health based on nutrition. LECTURE No. 10. The importance of proteins and fats in human nutrition The biological role of proteins Protein, being the most important component of nutrition, providing the plastic and energy needs of the body, is rightly called a protein, showing its first role in nutrition. The role of proteins in human nutrition cannot be overestimated. Life itself is one of the modes of existence of protein bodies. The biological role of proteins Protein can be attributed to vital nutrients, without which life, growth and development of the body are impossible. The sufficiency of protein in the diet and its high quality make it possible to create optimal conditions for the internal environment for the normal functioning of the body, its development and high performance. Protein is the main component of the diet, which determines the nature of nutrition. Against the background of a high level of protein, the most complete manifestation in the body of the biological properties of other nutritional components is noted. Proteins provide the structure and catalytic functions of enzymes and hormones, perform protective functions, participate in the formation of many important protein structures: immune bodies, specific γ-globulins, blood protein properdin, which plays a known role in creating natural immunity, participate in the formation of tissue proteins, such as like myosin and actin, which provide muscle contractions, globin, which is part of the hemoglobin of red blood cells and performs the most important function of respiration. The protein that forms visual purple (rhodopsin) of the retina of the eye ensures normal perception of light, etc. It should be noted that proteins determine the activity of many biologically active substances: vitamins, as well as phospholipids responsible for cholesterol metabolism. Proteins determine the activity of those vitamins, the endogenous synthesis of which is carried out from amino acids. For example, from tryptophan - vitamin PP (nicotinic acid), the exchange of methionine is associated with the synthesis of vitamin U (methylmethionine sulfonium). It has been established that protein deficiency can lead to deficiency of vitamin C and bioflavonoids (vitamin P). Violation of the synthesis of choline (a group of vitamin-like substances) in the liver leads to fatty infiltration of the liver. With great physical exertion, as well as with insufficient intake of fats and carbohydrates, proteins are involved in the energy metabolism of the body. Dietary proteins determine such conditions as alimentary dystrophy, insanity, kwashiorkor. Kwashiorkor means "weaned child". They get sick children weaned and transferred to a carbohydrate diet with a sharp lack of animal protein. Kwashiorkor causes both persistent irreversible constitutional changes and personality changes. The most severe consequences in the state of health, often for life, are left by such a type of malnutrition as alimentary dystrophy, which most often occurs with a negative energy balance, when energy processes include not only food chemicals that come with food, but also their own, structural body proteins. In alimentary dystrophy, edematous and non-edematous forms are distinguished with or without symptoms of vitamin deficiency. It may seem that nutritional diseases occur only when there is insufficient intake of protein in the body. It's not exactly like that! With excessive intake of protein in children of the first three months of life, symptoms of dehydration, hyperthermia and metabolic acidosis appear, which dramatically increases the load on the kidneys. This usually occurs when non-adapted milk mixtures, non-humanized types of milk are used during artificial feeding. Metabolic disorders in the body can also appear with an imbalance in the amino acid composition of incoming proteins. Replaceable and irreplaceable amino acids, the value and need for them Currently, 80 amino acids are known, the most important in nutrition are 30, which are most commonly found in foods and are most often consumed by humans. These include the following. 1. Aliphatic amino acids: a) monoamino monocarboxylic - glycine, alanine, isoleucine, leucine, valine; b) oxymonoaminocarboxylic - serine, threonine; c) monoaminodicarboxylic - aspartic, glutamine; d) amides of monoaminodicarboxylic acids - asparagine, glutamine; e) diaminomonocarboxylic - arginine, lysine; e) sulfur-containing - histine, cysteine, methionine. 2. Aromatic amino acids: phenylalanine, tyrosine. 3. Heterocyclic amino acids: tryptophan, histidine, proline, hydroxyproline. The most important in nutrition are essential amino acids, which cannot be synthesized in the body and come only from the outside - with food. These include 8 amino acids: methionine, lysine, tryptophan, threonine, phenylalanine, valine, leucine, isoleucine. This group also includes amino acids that are not synthesized in the child's body or are synthesized in insufficient quantities. The first is histidine. The subject of discussion is also the question of the indispensability of glycine, cystine in childhood, and in premature babies also glycine and tyrosine. The biological activity of the hormones ACTH, insulin, as well as coenzyme A and glutathione is determined by the presence of cystine SH groups in their composition. In newborns, due to a lack of cystenase, the transition of methionine to cystine is limited. In the body of an adult, tyrosine is easily formed from phenylalanine, and cystine from methionine, but there is no reverse substitution. Thus, we can assume that the number of essential amino acids is 11-12. An incoming protein is considered complete if it contains all the essential amino acids in a balanced state. By their chemical composition, proteins of milk, meat, fish, eggs approach such proteins, the digestibility of which is about 90%. Proteins of plant origin (flour, cereals, legumes) do not contain a complete set of essential amino acids and therefore belong to the category of inferior ones. In particular, they contain an insufficient amount of lysine. The assimilation of such proteins is, according to some reports, 60%. To study the biological value of proteins, two groups of methods are used: biological and chemical. The basis of biological is the assessment of the growth rate and the degree of utilization of food proteins by the body. These methods are labor intensive and expensive. The chemical method of column chromatography allows you to quickly and objectively determine the content of amino acids in food proteins. Based on these data, the biological value of proteins is determined by comparing the amino acid composition of the studied protein with a reference amino acid scale of a hypothetical ideal protein or aminograms of high-quality standard proteins. This methodical technique was called the amino acid SCORA = the ratio of the amount of AA in mg per 1 g of the studied protein to the amount of AA in mg per 1 g of ideal protein, multiplied by 100%. Animal proteins have the highest biological value, vegetable proteins are limited in a number of essential amino acids, primarily in lysine, and in wheat and rice, also in threonine. Proteins of cow's milk differ from breast proteins in the deficiency of sulfur-containing amino acids (methionine, cystine). According to the WHO, the protein of breast milk and eggs approaches the "ideal protein". An important indicator of the quality of food protein is also the degree of its digestibility. According to the degree of digestion by proteolytic enzymes, food proteins are arranged as follows: 1) fish and milk proteins; 2) meat proteins; 3) proteins of bread and cereals. Fish proteins are better absorbed due to the absence of connective tissue protein in their composition. The protein value of meat is estimated by the ratio between tryptophan and hydroxyproline. For high quality meat, this ratio is 5,8. Each amino acid from the essential group plays a specific role. Their deficiency or excess leads to any changes in the body. The biological role of essential amino acids Histidine plays an important role in the formation of hemoglobin in the blood. The lack of histidine leads to a decrease in the level of hemoglobin in the blood. When decarboxylated, histidine is converted to histamine, a substance that is of great importance in the expansion of the vascular wall and its permeability, affects the secretion of gastric digestive juice. The lack of histidine, as well as the excess, impairs conditioned reflex activity. Valine - the physiological role of this NAC is not clear enough. With insufficient intake in laboratory animals, disorders of coordination of movements, hyperesthesia are noted. Isoleucine, along with leucine, is part of all body proteins (with the exception of hemoglobin). The blood plasma contains 0,89 mg% of isoleucine. The absence of isoleucine in food leads to a negative nitrogen balance, to a slowdown in growth and development. Lysine is one of the most important essential amino acids. It is included in the triad of amino acids, especially taken into account when determining the overall usefulness of nutrition: tryptophan, lysine, methionine. The optimal ratio of these amino acids is: 1 : 3 : 2 or 1 : 3 : 3, if we take methionine + cystine (sulfur-containing amino acids). The lack of lysine in food leads to circulatory disorders, a decrease in the number of red blood cells and a decrease in hemoglobin in them. There is also a violation of the nitrogen balance, muscle wasting, a violation of bone calcification. There are also a number of changes in the liver and lungs. The need for lysine is 3-5 g per day. Significant amounts of lysine are found in cottage cheese, meat, and fish. Methionine plays an important role in the processes of methylation and transmethylation. This is the main donor of methyl groups, which are used by the body to synthesize choline (vitamin B). Methionine belongs to lipotropic substances. It influences the metabolism of fats and phospholipids in the liver and thus plays an important role in the prevention and treatment of atherosclerosis. Methionine has been linked to vitamin B metabolism12 and folic acid, which stimulate the separation of methionine methyl groups, thus ensuring the synthesis of choline in the body. Methionine is of great importance for the function of the adrenal glands and is necessary for the synthesis of adrenaline. The daily requirement for methionine is about 3 g. The main source of methionine should be considered milk and dairy products: 100 g of casein contains 3 g of methionine. Tryptophan, like threonine, is a growth factor and maintenance of nitrogen balance. Participates in the formation of serum proteins and hemoglobin. Tryptophan is essential for the synthesis of nicotinic acid. It has been established that about 50 mg of niacin is formed from 1 mg of tryptophan, and therefore 1 mg of niacin or 60 mg of tryptophan can be taken as a single "niacin equivalent". The daily requirement for nicotinic acid is on average determined in the amount of 14-28 niacin equivalents, and per balanced megacalorie - 6,6 niacin equivalents. The body's need for tryptophan is 1 g per day. Tryptophan is unevenly distributed in foods. So, for example, 100 g of meat is equivalent in tryptophan content to 500 ml of milk. Legumes should be distinguished from vegetable products. There is very little tryptophan in corn, so in areas where corn is a traditional source of nutrition, preventive examinations should be carried out to determine the body's supply of vitamin PP. Phenylalanine is associated with thyroid and adrenal function. It provides the nucleus for the synthesis of thyroxine, the main amino acid that forms the protein of the thyroid gland. From phenylalanine, tyrosine and then adrenaline can be synthesized. However, reverse synthesis from tyrosine-phenylalanine does not occur. There are NAC balance standards developed taking into account age data. For an adult (g / day): tryptophan - 1, leucine 4-6, isoleucine 3-4, valine 3-4, threonine 2-3, lysine 3-5, methionine 2-4, phenylalanine 2-4, histidine 1,5 ,2-XNUMX. Replaceable amino acids The body's need for non-essential amino acids is satisfied mainly through endogenous synthesis, or reutilization. Due to recycling, 2/3 of the body's own proteins are formed. The approximate daily requirement of an adult for the main non-essential amino acids is as follows (g / day): arginine - 6, cystine - 2-3, tyrosine - 3-4, alanine - 3, serine - 3, glutamic acid - 16, aspiraginic acid - 6, proline - 5, glucocol (glycine) - 3. Non-essential amino acids perform very important functions in the body, and some of them (arginine, cystine, tyrosine, glutamic acid) play a physiological role no less than irreplaceable (essential) amino acids. Some aspects of the use of non-essential amino acids in the food industry, such as glutamic acid, are of interest. In the largest quantities, it is found only in fresh foods. As food products are stored or preserved, glutamic acid in them is destroyed, and the products lose their characteristic aromas and taste. In industry, the sodium salt of glutamic acid is more commonly used. In Japan, monosodium glutamate is called "Ajino motto" - the essence of taste. Food products are sprayed with a 1,5-5% sodium glutamate solution, and they retain a fresh aroma for a long time. Since monosodium glutamate has antioxidant properties, food products can be stored for longer periods. The need for proteins depends on age, gender, nature of work, climatic and national characteristics, etc. Studies have shown that the nitrogen balance in the body of an adult is maintained with the intake of at least 55-60 g of protein, but this value does not take into account stressful situations illness, intense physical activity. In this regard, in our country, the optimal need for an adult in protein is 90-100 g / day. At the same time, in the diet due to protein, an average of 11-13% of its total energy value should be provided, and in percentage terms, protein of animal origin should be at least 55%. American and Swedish scientists have established ultra-minimal protein intake rates based on the endogenous breakdown of tissue proteins with protein-free diets: 20-25 g / day. However, such norms, with constant use, do not satisfy the needs of the human body and do not ensure normal performance, since during the breakdown of tissue proteins, the resulting amino acids, which are subsequently used for protein resynthesis, cannot provide a proper replacement for the animal protein that comes with food, and this leads to a negative nitrogen balance. The energy requirement of people in the first group of labor intensity (the group of mental labor) is 2500 kcal. 13% of this value is 325 kcal. Thus, the protein requirement for students is approximately 80 g (325 kcal: 4 kcal = 81,25 g) of protein. In children, the need for protein is determined by age norms. The amount of protein due to the predominance of plastic processes in the body per 1 kg of body weight is increased. On average, this value is 4 g / kg for children from 1 to 3 years of age, 3,5-4 g / kg for children 3-7 years old, 3 g / kg for children 8-10 years old and children over 11 years old - 2,5-2 g/kg, while the average for adults is 1,2-1,5 g/kg per day. The importance of fats in a healthy diet Fats are among the main nutrients and are an essential component in a balanced diet. The physiological significance of fat is very diverse. Fats are a source of energy that surpasses the energy of all other nutrients. When burning 1 g of fat, 9 kcal is formed, while when burning 1 g of carbohydrates or proteins, 4 kcal each. Fats are involved in plastic processes, being a structural part of cells and their membrane systems. Fats are solvents for vitamins A, E, D and contribute to their absorption. A number of biologically valuable substances come with fats: phospholipids (lecithin), polyunsaturated fatty acids, sterols and tocopherols and other biologically active substances. Fat improves the taste of food, and also increases its nutritional value. Insufficient intake of fat leads to disturbances in the central nervous system, weakening of immunobiological mechanisms, degenerative dysfunctions of the skin, kidneys, organ of vision, etc. In the composition of fat and its accompanying substances, essential, vital, irreplaceable components, including lipotropic, anti-atherosclerotic action (PUFA, lecithin, vitamins A, E, etc.) were identified. Fat affects the permeability of the cell wall, the state of its internal elements, which contributes to protein conservation. In general, the intensity and nature of many processes occurring in the body related to the metabolism and absorption of nutrients depend on the level of balance of fat with other nutrients. By chemical composition, fats are complex complexes of organic compounds, the main structural components of which are glycerol and fatty acids. The specific gravity of glycerol in the composition of fat is insignificant and amounts to 10%. Fatty acids are essential for determining the properties of fats. They are divided into limiting (saturated) and unsaturated (unsaturated). Fat composition Limit (saturated) fatty acids more commonly found in animal fats. High molecular weight saturated acids (stearic, arachidic, palmitic) have a solid consistency, low molecular weight (butyric, caproic, etc.) - liquid. The melting point also depends on the molar mass: the higher the molar mass of saturated fatty acids, the higher their melting point. In terms of biological properties, saturated fatty acids are inferior to unsaturated ones. Limiting (saturated) fatty acids are associated with ideas about their negative effect on fat metabolism, on the function and condition of the liver, as well as the development of atherosclerosis (due to the intake of cholesterol). Unsaturated (unsaturated) fatty acids are widely present in all dietary fats, especially in vegetable oils. The most common in the composition of dietary fats are unsaturated acids with one, two and three double unsaturated bonds. This determines their ability to enter into oxidation and addition reactions. Hydrogen addition reactions (saturation) are used in the food industry to produce margarine. The easy oxidizability of unsaturated fatty acids leads to the accumulation of oxidized products and their subsequent spoilage. A typical representative of unsaturated fatty acids with one bond is oleic acid, which is found in almost all animal and vegetable fats. It plays an important role in the normalization of fat and cholesterol metabolism. Polyunsaturated (essential) fatty acids PUFAs are fatty acids containing several double bonds. Linoleic has two double bonds, linolenic has three, and arachidonic has four double bonds. Highly unsaturated PUFAs are considered by some researchers as vitamin F. PUFAs take part as structural elements of biologically highly active complexes - phospholipids and lipoproteins. PUFA is a necessary element in the formation of cell membranes, myelin sheaths, connective tissue, etc. The synthesis of fatty acids necessary for the structural lipids of the body occurs mainly due to food PUFAs. The biological role of linolenic acid is that it precedes the biosynthesis of arachidonic acid in the body. The latter, in turn, precedes the formation of prostaglandins - tissue hormones. An important role of PUFAs in cholesterol metabolism has been established. With PUFA deficiency, cholesterol is esterified with saturated fatty acids, which contributes to the formation of an atherosclerotic process. With a lack of PUFAs, growth intensity and resistance to adverse external and internal factors decrease, reproductive function is inhibited, and a tendency to thrombosis of the coronary vessels appears. PUFAs have a normalizing effect on the cell wall of blood vessels, increasing its elasticity and reducing permeability. PUFAs are essential non-synthesized substances, but the conversion of some fatty acids into others is possible. The biologically optimal formula for the balance of fatty acids in fat can be the following ratio: 10% PUFA, 30% saturated fatty acids and 60% monounsaturated (oleic) acid. The daily requirement for PUFA with a balanced diet is 2-6 g, which is provided by 25-30 g of vegetable oil. Phospholipids are biologically active substances that are part of the structure of cell membranes and are involved in the transport of fat in the body. In the phospholipid molecule, glycerol is esterified with unsaturated fatty acids and phosphoric acid. A typical representative of phospholipids in food products is lecithin, although cephalin and sphingomyelin have similar biological effects. Phospholipids are present in the nervous tissue, brain tissue, heart, liver. Phospholipids are synthesized in the body in the liver and kidneys. Lecithin is involved in the regulation of cholesterol metabolism, contributing to its breakdown and excretion from the body. Normally, its content in the blood is 150-200 mg%, and the lecithin / cholesterol ratio is 0,9-1,4. The need for phospholipids for an adult is 5 g per day and is satisfied by endogenous phospholipids formed from precursors of complete degradation. Phospholipids are especially important in the nutrition of the elderly, as they have a pronounced lipotropic, anti-atherosclerotic effect. Sterols - hydroaromatic alcohols of a complex structure, belonging to the group of unsaponifiable substances of a neutral nature. The content in animal fats - zoosterols - 0,2-0,5 g per 100 g of product, in vegetable fats - photosterols - 6,0-17,0 g per 100 g of product. Phytosterols play an important role in the normalization of cholesterol and fat metabolism. Their representatives are sitosterols, which form insoluble, non-absorbable complexes with cholesterol. The main source of β-sitosterol used for therapeutic and prophylactic purposes in atherosclerosis is corn oil (400 mg per 100 g of oil), cottonseed (400 mg), soybean, peanut, olive (300 mg each) and sunflower oil (200 mg) . Cholesterol is the most important zoosterol. Of the food products, most of it is in the brain - 4%, although it is widely represented in all food products of animal origin. Cholesterol ensures the retention of moisture by the cell and gives it the necessary turgor. Participates in the formation of a number of hormones, including sex hormones, participates in the synthesis of bile, and also neutralizes poisons: hemolytic, parasitic, bacterial. Cholesterol is also considered as a factor involved in the formation and development of atherosclerosis. However, there are studies highlighting the increased consumption of animal fats rich in solid, saturated fatty acids. The main biosynthesis of cholesterol occurs in the liver and depends on the nature of the incoming fat. With the intake of saturated fatty acids, cholesterol biosynthesis in the liver increases and, conversely, with the intake of PUFAs, it decreases. The composition of fats also includes vitamins A, D, E, as well as pigments, some of which have biological activity (carotene, gossypol, etc.). The need for fat regulation The daily requirement of an adult for fats is 80-100 g / day, including vegetable oil - 25-30 g, PUFA - 3-6 g, cholesterol - 1 g, phospholipids - 5 g. In food, fat should provide 33% of the daily energy value of the diet. This is for the middle zone of the country, in the northern climatic zone this value is 38-40%, and in the southern - 27-28%. LECTURE No. 11. The importance of carbohydrates and minerals in human nutrition Importance of carbohydrates in nutrition Carbohydrates are the main component of the diet. Carbohydrates provide at least 55% of daily calories. (Recall the ratio of key nutrients in terms of calories in a balanced diet - proteins, fats and carbohydrates - 120 kcal: 333 kcal: 548 kcal - 12%: 33%: 55% - 1: 2,7: 4,6). The main purpose of carbohydrates is to compensate for energy costs. Carbohydrates are a source of energy for all types of physical work. When burning 1 g of carbohydrates, 4 kcal is formed. This is less than that of fats (9 kcal). However, in a balanced diet there is a predominance of carbohydrates: 1: 1,2: 4,6; 30 g : 37 g : 137 g. At the same time, the average daily requirement for carbohydrates is 400-500 g. Carbohydrates as an energy source have the ability to be oxidized in the body both aerobically and anaerobically. Carbohydrates are part of the cells and tissues of the body, and thus, to some extent, participate in plastic processes. Despite the constant consumption of carbohydrates by cells and tissues for energy purposes, the content of these substances in them is maintained at a constant level, provided that they are sufficiently supplied with food. Carbohydrates are closely related to fat metabolism. During heavy physical exertion, when energy consumption is not covered by food carbohydrates and carbohydrate reserves of the body, sugar is formed from fat, which is located in the fat depot. However, the opposite effect is more often observed, i.e., the formation of new amounts of fat and the replenishment of body fat depots by them due to excessive intake of carbohydrates from food. At the same time, the conversion of carbohydrates does not follow the path of complete oxidation to water and carbon dioxide, but the path of transformation into fat. Excess consumption of carbohydrates is a widespread phenomenon that underlies the formation of overweight. Carbohydrate metabolism is closely related to protein metabolism. So, insufficient intake of carbohydrates with food during intense physical activity causes increased protein consumption. On the contrary, with limited protein norms, by introducing a sufficient amount of carbohydrates, it is possible to achieve a minimum expenditure of protein in the body. Some carbohydrates also have a pronounced biological activity, performing specialized functions. These are blood heteropolysaccharides that determine blood groups, heparin, which prevents the formation of blood clots, ascorbic acid, which has C-vitamin properties, marker specificity due to carbohydrate-containing components in enzymes, hormones, etc. The main source of carbohydrates in the diet are vegetable products, in which carbohydrates make up at least 75% of the dry matter. The value of animal products as sources of carbohydrates is small. The main animal carbohydrate - glycogen, which has the properties of starch, is found in animal tissues in small quantities. Another animal carbohydrate - lactose (milk sugar) - is found in milk in an amount of 5 g per 100 g of product (5%). In general, the digestibility of carbohydrates is quite high and amounts to 85-98%. So, the digestibility coefficient of vegetable carbohydrates is 85%, bread and cereals - 95%, milk - 98%, sugar - 99%. Chemical structure and classification of carbohydrates The very name "carbohydrates", proposed in 1844 by K. Schmidt, is based on the fact that in the chemical structure of these substances, carbon atoms are combined with oxygen and hydrogen atoms in the same ratios as in the composition of water. For example, the chemical formula for glucose is C6(n2ABOUT)6, sucrose C12(n2ABOUT)11, starch C5(n2ABOUT)n. Depending on the complexity of the structure, solubility, speed of absorption and use for glycogen formation, carbohydrates can be presented in the form of the following classification scheme: 1) simple carbohydrates (sugars): a) monosaccharides: glucose, fructose, galactose; b) disaccharides: sucrose, lactose, maltose; 2) complex carbohydrates: polysaccharides (starch, glycogen, pectin, fiber). Importance of simple and complex carbohydrates in nutrition Simple carbohydrates. Monosaccharides and disaccharides are characterized by easy solubility in water, rapid digestibility (absorbability) and pronounced sweet taste. Monosaccharides (glucose, fructose, galactose) are hexoses that have 6 carbon atoms, 12 hydrogen atoms and 6 oxygen atoms in their molecule. In food products, hexoses are in indigestible α- and β-forms. Under the action of pancreatic enzymes, hexoses are converted into an assimilable form. In the absence of a hormone (for example, insulin in diabetes), hexoses are not absorbed and are excreted in the urine. Glucose in the body quickly turns into glycogen, which is used to nourish the tissues of the brain, heart muscle, and maintain blood sugar. In this regard, glucose is used to maintain postoperative, debilitated and seriously ill patients. Fructose, having the same properties as glucose, is absorbed more slowly in the intestines and quickly leaves the bloodstream. Having a greater sweetness than glucose and sucrose, fructose allows you to reduce the consumption of sugars, and hence the calorie content of the diet. At the same time, less sugar passes into fat, which favorably affects fat and cholesterol metabolism. The use of fructose is the prevention of caries and putrefactive colitis of the intestine, it is used to feed children and the elderly. Galactose is not found in free form in foods, but is a product of the breakdown of lactose. The source of hexoses are fruits, berries and other plant foods. Disaccharides. Of these, sucrose (cane or beet sugar) and lactose (milk sugar) are important in nutrition. During hydrolysis, sucrose breaks down to glucose and fructose, and lactose breaks down to glucose and galactose. Maltose (malt sugar) is a breakdown product of starch and glycogen in the gastrointestinal tract. It is found in free form in honey, malt and beer. Most of the disaccharides consumed sugar - up to 40-45 kg per year, the excess of which affects the development of atherosclerosis, leads to hyperglycemia. Complex carbohydrates, or polysaccharides, are characterized by the complexity of the molecular structure and poor solubility in water. These include starch, glycogen, cellulose (fiber) and pectin. The last two polysaccharides are classified as dietary fiber. Starch. It accounts for up to 80% of the total amount of carbohydrates consumed in the human diet. Sources of starch are cereals, legumes and potatoes. Starch in the body goes through a whole stage of transformation of polysaccharides: first to dextrins (under the action of the enzymes amylase, diastase), then to maltose and the final product - glucose (under the action of the maltase enzyme). This process is relatively slow, which creates favorable conditions for the full use of starch. Therefore, at an average energy cost, the body is provided with sugar mainly due to food starch. With significant energy costs, it becomes necessary to introduce sugars, which are a source of rapid glycogen formation. The need for the parallel use of starch and sugar is allowed by the fact that the starch of food does not satisfy the body's need for a sense of taste. With average energy costs (2500-3000 kcal), the amount of sugar in the diet of an adult is 15% of the total amount of carbohydrates, for children and young men - 25%. The daily requirement of sugar is 50-80 g. A balanced intake of starch and sugar in the food provides favorable conditions for maintaining normal blood sugar levels. Glycogen (animal starch). It is present in animal tissue, in the liver up to 230% of the wet weight, in the muscles - up to 4%. It is used in the body for energy purposes. Its recovery occurs by resynthesis of glycogen at the expense of blood glucose. Pectins - colloidal polysaccharides, hemicellulose (gelling agent). There are two types of these substances: protopectins (water-insoluble compounds of pectin and cellulose) and pectins (soluble substances). Pectins are hydrolyzed to sugar and tetragalacturonic acid by the action of pectinase. At the same time, the methoxyl group (OCH) is cleaved from pectin3), and pectic acid and methyl alcohol are formed. The ability of pectin substances to transform in aqueous solutions in the presence of acid and sugar into a jelly-like, colloidal mass is widely used in the food industry. The raw material for pectins is the waste of apples, sunflowers and watermelons. Pectins have a beneficial effect on the processes of digestion. They have a detoxifying effect in case of lead poisoning, and are used in therapeutic and prophylactic nutrition. Cellulose (cellulose) in its structure is very close to polysaccharides. The human body almost does not produce enzymes that break down cellulose. In small quantities, these enzymes are secreted by bacteria in the lower digestive tract (caecum). Cellulose is broken down by the enzyme cellulase to form soluble compounds that actively remove cholesterol from the body. The more tender the fiber (potato), the more completely it breaks down. The value of fiber is: 1) in stimulating intestinal motility due to the sorption of water and an increase in the volume of feces; 2) the ability to remove cholesterol from the body due to the sorption of sterols and prevent their reabsorption; 3) in the normalization of intestinal microflora; 4) the ability to cause a feeling of satiety. The daily requirement of fiber and pectin is about 25 g. Recently, the role of dietary fiber (cellulose, pectin, gum, or gum and other ballast substances of plant origin) in nutrition has become more important. Refined foods (sugar, fine flour, juices) are completely free from dietary fiber, which are poorly digested and absorbed into the gastrointestinal tract. However, we should not forget that some types of dietary fiber retain water 5-30 times more than their own weight. As a result, the volume of feces increases significantly, their movement through the intestines and the emptying of the colon are accelerated. The latter is extremely useful for patients with hypomotor dyskinesia and constipation syndrome. Dietary fiber changes the composition of the intestinal microflora, increasing the total number of microbes while reducing the number of E. coli. An important property of food products with a high content of dietary fiber is their low calorie content with a significant volume of the product. However, excessive consumption of dietary fiber can lead to a decrease in the absorption of certain minerals (calcium, manganese, iron, copper, zinc). The main sources of dietary fiber are grain products, fruits and vegetables. Wholemeal rye bread, peas, legumes, oatmeal, cabbage, raspberries, black currants are characterized by the highest level of dietary fiber. Most dietary fiber in bran. Wheat bran contains 45-55% dietary fiber, of which 28% is hemicellulose, 9,8% cellulose, 2,2% pectin. 3/4 of all biologically active substances are contained in bran. Adding to the daily diet 2-3 tbsp. l. bran sufficiently enhances the motor-evacuation function of the colon, gallbladder, reduces the possibility of stone formation in the gallbladder, inhibits the increase in blood sugar after eating in diabetes mellitus. Gums are widely used in the food industry to impart viscosity to solutions. They are obtained from some plants and are used to crystallize sugar, making chewing gum. There is evidence that gums reduce the acidity of gastric juice and slow down gastric emptying in patients with duodenal ulcer. Gum increases the feeling of satiety, allows you to reduce the caloric content of the diet, which is important in the diet therapy of obesity. The total level of dietary fiber for the body is about 25 g per day. In some diseases (constipation, gallbladder dyskinesia, hypercholesterolemia, diabetes mellitus), it is necessary to increase the content of dietary fiber in the diet to 40-60 g per day. When building diets, it should be borne in mind that the consumption of foods rich in starch, as well as fruits and vegetables containing sugar, has an advantage over taking such a high-calorie product as sugar and confectionery, since with the first group of products a person receives not only carbohydrates, but and vitamins, and mineral salts, trace elements and dietary fiber. Sugar, on the other hand, is the carrier of "bare", or empty, calories and is characterized only by a high energy value. Therefore, the quota of sugar in the daily diet should not exceed 10-20% (50-100 g per day). The need and rationing of carbohydrates The need for carbohydrates is determined by the amount of energy costs, i.e., the nature of work, age, etc. The average need for carbohydrates for people not engaged in heavy physical labor is 400-500 g per day, including starch - 350-400 g, mono- and disaccharides - 50-100 g, dietary fiber (fiber and pectin) - 2 g. Carbohydrates should be rationed according to the energy value of the daily diet. For every megacalorie, there are 137 grams of carbohydrates. The main source of carbohydrates for children should be fruits, berries, juices, milk (lactose), sucrose. The amount of sugar in baby food should not exceed 20% of the total amount of carbohydrates. The sharp predominance of carbohydrates in the diet of a child disrupts metabolism and reduces the body's resistance to infections (possible growth retardation, general development, obesity). Minerals. Role and importance in human nutrition F. F. Erisman wrote: "Food that does not contain mineral salts and is satisfactory in other respects leads to a slow starvation, since depletion of the body with salts inevitably leads to malnutrition." Minerals are involved in all physiological processes: 1) plastic - the formation and construction of tissues, in the construction of the bones of the skeleton, where calcium and phosphorus are the main structural components (there is more than 1 kg of calcium and 530-550 g of phosphorus in the body); 2) maintaining acid-base balance (acidity of the serum is not more than 7,3-7,5), creating a concentration of hydrogen ions in tissue, cells, intercellular fluids, giving them certain osmotic properties; 3) in protein formation; 4) in the functions of the endocrine glands (and especially iodine); 5) in enzymatic processes (every fourth enzyme is a metalloenzyme); 6) in the neutralization of acids and the prevention of the development of acidosis; 7) normalization of water-salt metabolism; 8) maintaining the body's defenses. More than 70 chemical elements have been found in the human body, of which more than 33 are found in the blood. Acid-base balance changes under the influence of the nature of nutrition. The intake of calcium, magnesium, sodium with food (legumes, vegetables, fruits, berries, dairy products) increases the alkaline reaction and contributes to the development of alkalosis. The intake of chlorine ion, phosphorus, sulfur with food (meat and fish products, eggs, bread, cereals, flour) increases the acid reaction - acidosis. Even with a mixed diet in the body, there is a shift towards acidosis. Therefore, it is necessary to introduce fruits, vegetables and milk into the diet. In view of the foregoing, mineral substances are divided into substances: 1) alkaline action (cations) - sodium, calcium, magnesium, potassium; 2) acid action (anions) - phosphorus, sulfur, chlorine. Macro- and microelements, their role and significance Conventionally, all minerals are additionally divided according to the level of content in products (tens and hundreds of mg%) and high daily requirements into macro- (calcium, magnesium, phosphorus, potassium, sodium, chlorine, sulfur) and microelements (iodine, fluorine, nickel, cobalt , copper, iron, zinc, manganese, etc.). Calcium is a trace element involved in the formation of skeletal bones. It is the main structural component of bone. Calcium in the bones contains 99% of its total amount in the body. Calcium is a constant component of blood, cell and tissue juices. It is part of the egg. Calcium strengthens the protective functions of the body and increases resistance to external adverse factors. Calcium, being an element of alkaline action, prevents the development of acidosis. Calcium normalizes neuromuscular excitability (a decrease in calcium can lead to tetanic convulsions). In biological fluids (plasma, tissues), calcium is contained in an ionized state. Calcium metabolism is characterized by the fact that with its lack in food, it continues to be excreted from the body in large quantities due to reserves. A negative calcium balance is created in the body. In growing children, the skeleton is completely renewed in 1-2 years, in adults - in 10-12 years. In an adult, up to 700 mg of calcium is excreted from the bones per day and the same amount is deposited again. Calcium is a hard-to-digest element, since it is found in food products in a difficult or insoluble state. In the acidic contents of the stomach, pH = 1 (0,1 T acid), calcium passes into soluble compounds. But in the small intestine (acidity is sharply alkaline), calcium again turns into sparingly soluble compounds and is easily absorbed by the body again only under the influence of bile acids. The absorption of calcium depends on its ratio with other components: fat, magnesium and phosphorus. Good absorption of calcium is observed if there are 1 mg of dietary calcium per 10 g of fat. This is due to the fact that calcium forms compounds with fatty acids, which, interacting with bile acids, form a complex, well-assimilated compound. With an excess of fat in the diet, there is a lack of bile acids to convert the calcium salts of fatty acids into soluble states, and most of them are excreted in the feces. An excess of magnesium has a negative effect on the absorption of calcium, since its absorption also requires its combination with bile acids. Thus, the more magnesium enters the body, the less bile acids remain for calcium. Therefore, an increase in the amount of magnesium in the diet enhances the excretion of calcium from the body; in the daily diet of magnesium should contain half as much as calcium. The daily requirement for calcium is 800 mg, and magnesium - 400 mg. The phosphorus content affects the absorption of calcium. Calcium with phosphorus in the body forms a compound Ca3Ro4 - calcium salt of phosphoric acid. This compound, under the action of bile acids, is poorly soluble and absorbed, that is, a significant increase in phosphorus in food worsens the balance of calcium and leads to a decrease in calcium absorption and an increase in calcium excretion. Optimal absorption of calcium occurs when the ratio of calcium and phosphorus is 1:1,5 or 800:1200 mg. For children, this ratio of calcium and phosphorus looks like 1: 1. The process of ossification in a growing organism proceeds normally with the correct ratio of calcium and phosphorus. Since this ratio is often not optimal in the diet, special regulators are prescribed (for example, vitamin D, which promotes the absorption of calcium and its retention in the body). An important rachitogenic factor is also protein-vitamin (complete protein and vitamins A, B1 and B6) balance. Calcium absorption is promoted by food proteins, citric acid and lactose. Amino acids of proteins form well-soluble complexes with calcium. The mechanism of action of citric acid is similar. Lactose, fermented in the intestine, maintains the acidity value, which prevents the formation of insoluble phosphorus-calcium salts. The best source of calcium in human nutrition is milk and dairy products. 0,5 l of milk or 100 g of cheese provide the daily requirement for calcium. When compiling daily rations, it is necessary to take into account not so much the total amount of calcium as the conditions that ensure its optimal absorption. It is necessary to take into account the fact that water is also an important source of calcium. Here calcium is in the form of an ion and is absorbed by 90-100%. The daily requirement of calcium for all categories is 800 mg. Children under 1 year old - 250-600 mg, 1-7 years old - 800-1200 mg, 7-17 years old - 1200-1500 mg. Phosphorus is a vital element. The human body contains from 600 to 900 g of phosphorus. Phosphorus is involved in the processes of metabolism and synthesis of proteins, fats and carbohydrates, affects the activity of skeletal muscles and heart muscle. The metabolic functions of phosphorus are extremely important. Being a part of DNA and RNA, it takes part in the processes of coding, storage and use of genetic information. The importance of phosphorus in energy metabolism is due not only to the role of ATP, but also to the fact that all carbohydrate transformations (glycolysis, pentose cycles) occur not in a free, but in a phosphorylated form). Phosphorus plays an essential role in maintaining the acid-base state of blood plasma acidity in the range of 7,3-7,5. Phosphorus plays a leading role in the function of the central nervous system. Phosphoric acids are involved in the construction of enzymes, catalysts for the process of decomposition of food organic substances, creating conditions for the use of potential energy. The need for phosphorus increases with physical activity and with a lack of protein in the diet. Phosphorus absorption is related to calcium absorption, protein content in the diet, and other related factors. The ratio of phosphorus to proteins is 1:40. Phosphorus with proteins and polyunsaturated fatty acids form complex compounds with great biological activity. The absence of phytase in the human intestine makes it impossible to absorb the phosphorus of phytic acid, in the form of which a significant part of it is found in plant products. The absorption efficiency of phosphorus depends on their breakdown by intestinal phosphatases and is usually 40-70%. Phosphorus is excreted from the body with urine (up to 60%) and feces. Its excretion in the urine increases during fasting and after increased muscular work. The largest amount of phosphorus is found in dairy products, especially in cheeses (up to 600 mg%), as well as in eggs (470 mg% in the yolk). Some vegetable products are also distinguished by a high content of phosphorus (legumes - beans, peas - contain up to 300-500 mg). Good sources of phosphorus are meat, fish, caviar. The daily need for phosphorus is 1200 mg. Magnesium in the body contains up to 25 g. Its biological role has not been studied enough. However, its role in the process of carbohydrate and phosphorus metabolism is well known. Magnesium normalizes the excitability of the nervous system, has antispastic and vasodilating properties, stimulates intestinal motility, increases bile secretion, participates in the normalization of female specific functions, lowers cholesterol, has an antiblastogenic effect (in areas where magnesium is found in soil and water in large quantities, less mortality from cancer). Sources of magnesium are bread, cereals, peas, beans, buckwheat. It is low in milk, vegetables, fruits and eggs. The daily requirement for women is 500 mg, for men - 400 mg. Sulfur is a structural component of some amino acids (methionine, cystine), vitamins and insulin. It is found mainly in products of animal origin. The daily requirement for sulfur is 1 g for adults. The role of sodium chloride in the nutrition of a healthy and sick person is great. The human body contains about 250 g of sodium chloride. More than 50% of this amount is in the extracellular fluid and bone tissue, and only 10% is inside the soft tissue cells. Conversely, potassium ions are localized inside the cells. They are responsible for maintaining a constant volume of fluid in the body, the transport of amino acids, sugars, potassium, and the secretion of hydrochloric acid in the stomach. Sodium, chloride and potassium ions come with bread, cheese, meat, vegetables, concentrates and mineral water. Excreted in the urine (up to 95%). In this case, sodium ions are followed by chloride ions. Potassium-rich foods cause increased sodium excretion. Conversely, consuming large amounts of sodium causes the body to lose potassium. The excretion of sodium by the kidneys is regulated by the hormone aldosterone. Significant disturbances in the balance of sodium chloride can occur with damage to the adrenal glands, chronic kidney disease. The need for a daily diet of sodium chloride is 10-12 g, when working in hot shops, with heavy physical exertion - 20 g. A salt-free diet is prescribed for diseases of the cardiovascular system with circulatory disorders of II and III degrees, acute and chronic nephritis, hypertension II-III degrees. The daily requirement for sodium is 4000-6000 mg, for chlorine - 5000-7000 mg, for potassium - 2500-5000 mg. Biomicroelements are involved in hematopoiesis. Iron is an essential part of hemoglobin and myoglobin. 60% of iron is concentrated in hemoglobin. Another important side of iron is participation in oxidative processes, as it is part of enzymes: peroxidase, cytochrome oxidase, etc. Iron deficiency leads to iron deficiency anemia. The body of an adult contains up to 4 g of iron (2,5 g of them are in hemoglobin). Iron is deposited in the cells of the reticuloendothelial system (liver, spleen, bone marrow). The most iron-rich liver, blood sausages, legumes, buckwheat. The absorption of iron in the body is difficult due to its binding by phytic acid. Iron from meat products is well absorbed. Iron in an easily digestible form in plant foods is found in garlic, beets, apples, etc. The iron requirement is 10 mg for men and 18-20 mg per day for women. Copper is actively involved in the synthesis of hemoglobin, is part of cytochrome oxidase. Copper is necessary for the conversion of iron into an organic bound form, promotes the transfer of iron to the bone marrow. Copper has an insulin-like effect. Under the influence of taking 0,5-1 mg of copper in diabetic patients, the condition improves, hyperglycemia decreases, and glucosuria disappears. The connection of copper with the function of the thyroid gland has been established. With thyrotoxicosis, the copper content in the blood rises. The daily requirement for adults is 2-3 mg, for young children - 80 mcg / kg, for older children - 40 mcg / kg. The content of copper is highest in the liver, legumes, seafood, nuts. It is not found in dairy products. Cobalt is the third biomicroelement involved in hematopoiesis, which is manifested at a sufficiently high level of copper. Cobalt affects the activity of intestinal phosphatases, is the main material for the synthesis of vitamin B in the body12. The largest amount of cobalt is found in the pancreas and is involved in the formation of insulin. In natural food products, its content is low. In sufficient quantities, it is found in river and sea water, algae, fish. The daily requirement is 100-200 mcg. Biomicroelements associated with bone formation: manganese - 5-10 mg / day and strontium up to 5 mg / day. Biomicroelements associated with endemic diseases: iodine - 100-200 mcg / day (endemic goiter), fluorine - the maximum allowable coefficient in water is 1,2 mg / l, in food - 2,4-4,8 mg / kg of diet . LECTURE No. 12. Industrial hazards of a physical nature, occupational hazards caused by them, their prevention Hygienic characteristics of noise, its regulation and measures to prevent its negative impact on the body Noise is a random combination of sounds of different heights and loudness, causing an unpleasant subjective sensation and objective changes in organs and systems. Noise consists of individual sounds and has a physical characteristic. The wave propagation of sound is characterized by frequency (expressed in hertz) and strength, or intensity, i.e., the amount of energy carried by a sound wave for 1 s through 1 cm2 surface perpendicular to the direction of sound propagation. The strength of sound is measured in energy units, most often in ergs per second per 1 cm.2. Erg is equal to a force of 1 dyne, i.e., the force imparted to a mass, weighing 1 g, an acceleration of 1 cm2/from. Since there are no ways to directly determine the energy of sound vibrations, the pressure produced on the bodies on which they fall is measured. The unit of sound pressure is the bar, which corresponds to a force of 1 dyne per 1 cm.2 surface and equal to 1/1 of atmospheric pressure. Speech at normal volume creates a pressure of 000 bar. Perception of noise and sound A person is able to perceive vibrations with a frequency of 16 to 20 Hz as sound. With age, the sensitivity of the sound analyzer decreases, and in old age, vibrations with a frequency above 000-13 Hz do not cause an auditory sensation. Subjectively, the frequency, its increase is perceived as an increase in tone, pitch. Usually, the main tone is accompanied by a number of additional sounds (overtones) that arise due to the vibration of individual parts of the sounding body. The number and strength of overtones create a certain color, or timbre, of a complex sound, due to which it is possible to recognize the sounds of musical instruments or human voices. To evoke an auditory sensation, sounds must have a certain force. The smallest amount of sound that a person perceives is called the hearing threshold for that sound. The hearing thresholds for sounds with different frequencies are not the same. The lowest thresholds have sounds with a frequency of 500 to 4000 Hz. Outside this range, hearing thresholds increase, indicating a decrease in sensitivity. An increase in the physical strength of the sound is subjectively perceived as an increase in volume, but this occurs up to a certain limit, above which painful pressure is felt in the ears - the threshold of pain, or the threshold of touch. With a gradual increase in sound energy from the threshold of audibility to the pain threshold, features of auditory perception are revealed: the sensation of sound volume increases not in proportion to the growth of its sound energy, but much more slowly. So, in order to feel a barely noticeable increase in the volume of a sound, it is necessary to increase its physical strength by 26%. According to the Weber-Fechner law, the sensation grows in proportion not to the strength of the stimulus, but to the logarithm of its strength. Sounds of different frequencies with the same physical intensity are not felt by the ear as equally loud. High frequency sounds are perceived as louder than low frequency sounds. To quantify sound energy, a special logarithmic scale of sound intensity levels in bels or decibels has been proposed. In this scale, the force (10-9 erg/cm2 × sec, or 2 × 10-5 W / cm2/ s), approximately equal to the threshold of audibility of sound with a frequency of 1000 Hz, which in acoustics is taken as a standard sound. Each step of such a scale, called white, corresponds to a 10-fold change in sound intensity. A 100 times increase in sound intensity on a logarithmic scale is referred to as an increase in the sound intensity level by 2 bels. An increase in the level of sound strength by 3 bels corresponds to an increase in its absolute strength by 1000 times, etc. Thus, in order to determine the strength level of any sound or noise in bels, one should divide its absolute strength by the strength of the sound taken as the level of comparison, and calculate the decimal logarithm of this ratio.  where I1 - absolute strength; I0 - the strength of the comparison level sound. If we express in bela a huge range of sound intensity with a frequency of 1000 Hz from the threshold of hearing and (zero level) to the pain threshold, then the entire range on a logarithmic scale will be 14 Bel. Due to the fact that the hearing organ is able to distinguish between a sound increase of 0,1 bels, in practice, when measuring sounds, a decibel (dB) is used, that is, a unit 10 times smaller than a bel. Due to the peculiarity of the perception of the auditory analyzer, the sound of the same loudness will be perceived by a person from noise sources with different physical parameters. Thus, a sound of 50 dB and a frequency of 100 Hz will be perceived as equally loud as a sound of 20 dB and a frequency of 1000 Hz. In order to be able to compare sounds of various strengths with different frequency composition with respect to their loudness, a special loudness unit called "phon" has been introduced. At the same time, the unit of comparison is the sound of 1000 Hz, which is considered standard. In our example, a sound of 50 dB and a frequency of 100 Hz will be equal to 20 phons, since it corresponds to a sound of 20 dB and a frequency of 1000 Hz. The noise level that does not cause harmful effects on the ear of workers, or the so-called normal loudness limit at a frequency of 1000 Hz, corresponds to 75-80 phons. With an increase in the frequency of sound vibrations compared to the standard, the loudness limit must be reduced, since the harmful effect on the organ of hearing increases with increasing frequency of vibrations. If the tones that make up the noise are located continuously over a wide frequency range, then such noise is called continuous, or continuous. If at the same time the strength of the sounds that make up the noise is approximately the same, such noise is called white by analogy with "white light", characterized by a continuous spectrum. The definition and normalization of noise are usually carried out in a frequency band equal to an octave, half an octave or a third of an octave. An octave is a frequency range in which the upper frequency limit is twice the lower one (for example, 40-80, 80-160, etc.). To designate an octave, it is usually not the frequency range that is indicated, but the so-called geometric mean frequencies. So, for an octave of 40-80 Hz, the geometric mean frequency is 62 Hz, for an octave of 80-160 Hz - 125 Hz, etc. According to the spectral composition, all noise is divided into 3 classes. Class 1. Low-frequency (noises of low-speed units of non-impact action, noise penetrating through soundproof barriers). The highest levels in the spectrum are located below the frequency of 300 Hz, followed by a decrease (at least 5 dB per octave). Class 2. Mid-frequency noises (noises of the majority of machines, machine tools and units of non-impact action). The highest levels in the spectrum are located below the frequency of 800 Hz, and then again a decrease of at least 5 dB per octave. Class 3. High-frequency noises (ringing, hissing, whistling noises characteristic of impact units, air and gas flows, units operating at high speeds). The lowest noise level in the spectrum is located above 800 Hz. Distinguish noise: 1) broadband with a continuous spectrum of more than 1 octave; 2) tonal, when the noise intensity in a narrow frequency range sharply prevails over the rest of the frequencies. According to the distribution of sound energy in time, noise is divided into: 1) constants, the sound level of which during an 8-hour working day changes over time by no more than 5 dB; 2) intermittent, the sound level of which changes by more than 8 dB over an 5-hour working day. Intermittent noises are divided into: 1) fluctuating in time, the sound level of which continuously changes in time; 2) intermittent, the sound level of which changes stepwise (by 5 dB or more), and the duration of the intervals with a constant level is 1 s or more; 3) pulse, consisting of one or more signals with a duration of less than 1 s each, while the sound level changes by at least 7 dB. If, after exposure to noise of a particular tone, sensitivity to it decreases (the perception threshold rises) by no more than 10-15 dB, and its recovery occurs in no more than 2-3 minutes, one should think about adaptation. If the change in thresholds is significant, and the duration of recovery is delayed, this indicates the onset of fatigue. The main form of occupational pathology caused by intense noise is a persistent decrease in sensitivity to various tones and whispered speech (professional hearing loss and deafness). Effect of noise on the body The whole complex of disorders that develop in the body under the influence of noise can be combined into the so-called noise disease (Prof. E. Ts. Andreeva-Galanina). Noise disease is a general disease of the whole organism that develops as a result of exposure to noise, with a primary lesion of the central nervous system and the auditory analyzer. A characteristic feature of noise disease is that changes in the body proceed according to the type of astheno-vegetative and asthenoneurotic syndromes, the development of which is much ahead of the disturbances arising from the auditory function. Clinical manifestations in the body under the influence of noise are divided into specific changes in the organ of hearing and non-specific - in other organs and systems. Noise regulation Noise regulation is carried out taking into account its nature and working conditions, the purpose and purpose of the premises, associated harmful production factors. For hygienic assessment of noise, materials are used: SN 2.2.4 / 2.1.8.5622-96 "Noise at workplaces, in residential, public buildings and in residential areas." For constant noise, normalization is performed in octave bands with geometric mean frequencies of 31,5; 63; 125; 250; 500; 1000; 2000; 4000; 8000 Hz. For a rough estimate, it is allowed to measure in dBA. The advantage of measuring noise in dBA is that it allows you to determine the excess of permissible noise levels without spectral analysis of it in octave bands. At frequencies of 31,5 and 8000 Hz, the noise is normalized at the level of 86 and 38 dB, respectively. The equivalent sound level in dB(A) is 50 dB. For tonal and impulse noise, it is 5 dB less. For time-varying and intermittent noise, the maximum sound level should not exceed 110 dB, and for impulsive noise, the maximum sound level should not exceed 125 dB. In certain industries, in relation to professions, rationing is carried out taking into account the category of severity and intensity. At the same time, 4 degrees of severity and tension are distinguished, taking into account ergonomic criteria: 1) dynamic and static muscle load; 2) nervous load - tension of attention, density of signals or messages for 1 hour, emotional tension, shift; 3) the tension of the analyzer function - vision, the amount of RAM, that is, the number of elements to be memorized for 2 hours or more, intellectual tension, monotony of work. At low intensity, as well as light and medium severity of labor, noise is regulated at the level of 80 dB. With the same intensity (small), but with heavy and very heavy form of labor, it is 5 dB less. With moderately hard work, hard and very hard work, the noise is normalized by 10 dB less, respectively, i.e. 70, 60 and 50 dB. The degree of hearing loss is determined by the amount of hearing loss at speech frequencies, i.e. at frequencies of 500, 1000 and 2000 Hz and at the professional frequency of 4000 Hz. There are 3 levels of hearing loss: 1) slight decrease - at speech frequencies, hearing loss occurs by 10-20 dB, and at professional frequencies - by 60 ± 20 dB; 2) moderate decrease - at speech frequencies, hearing loss by 21-30 dB, and at professional frequencies - by 65 ± 20 dB; 3) a significant decrease - by 31 dB or more, respectively, and at professional frequencies by 70 ± 20 dB. Noise Prevention Measures Technical measures to combat noise are diverse: 1) changing the technology of processes and the design of machines that are a source of noise (replacing noisy processes with silent ones: riveting - by welding, forging and stamping - by pressure treatment); 2) careful fitting of parts, lubrication, replacement of metal parts with non-sound materials; 3) absorption of vibration of parts, the use of sound-absorbing pads, good insulation when installing machines on foundations; 4) installation of silencers to absorb the noise of the exhaust air, gas or steam; 5) soundproofing (soundproofing of cabins, use of casings, remote control). planning measures. 1. It is advisable to plan the placement of noisy industries at a certain distance from objects that must be protected from noise. For example, aviation motor test stations with a noise level of 130 dB should be located outside the city limits in compliance with the appropriate sanitary protection zone. Noisy workshops should be surrounded by trees that absorb noise. 2. Small rooms up to 40 m3, in which noisy equipment is located, it is recommended to line with sound-absorbing materials (acoustic plaster, tiles, etc.). Personal protective measures: antiphons or anti-noises: 1) internal - plugs and liners; 2) outdoor - headphones and helmets. The simplest design is a sterile cotton plug. More effective is a cap made of special ultra-thin UTV glass wool. Plugs can be made of soft casing, rubber and plastic. Their damping ability does not exceed 7-12 dB. The damping capacity of antinoise headphones VTSNICHOT-2 is, depending on the noise frequency: up to 500 Hz - 14 dB, up to 1000 Hz - 22 dB, in the range from 2000 to 4000 Hz - 47 dB. In industries where intense noise is observed, preliminary and periodic medical examinations of workers should be carried out with a mandatory hearing test with audiometers or tuning forks. Periodic medical examinations for ear sensitivity to noise should be performed every 3, 6, 12 months during the first three years, and then every 3 years to detect hearing loss. Persons found to have a significant hearing loss between two periodic examinations, namely an increase in thresholds of more than 20 dB, or a sharp deterioration in their general condition, should be transferred to quiet work. Vibration and its importance in occupational health It is widely used in various technological processes - vibrocompaction, pressing, molding, drilling, metal processing, in the operation of many machines and mechanisms. Vibration is a mechanical oscillatory movement in which a material body periodically passes through the same stable position after a certain period of time. No matter how complex the oscillatory motion is, its simple component is a harmonic or periodic oscillation, which is a regular sinusoid. Such vibrations are typical for rotary machines and tools. This fluctuation is characterized by: 1) amplitude - this is the maximum movement of an oscillating point from its stable position; 2) frequency is the number of complete oscillation cycles per unit time (Hz). The time it takes to complete one complete cycle of oscillation is called a period. The amplitude is expressed in centimeters or in fractions of it (millimeters or microns). A person is able to feel vibration in the range from fractions of a hertz to 8000 Hz. Vibration of a higher frequency is perceived as a thermal sensation. Vibration with an oscillation frequency of more than 16 Hz is also perceived as low-frequency noise. Oscillations can be damped. In this case, the amplitude of the oscillation is constantly decreasing due to the presence of resistance. Amplitude-variable vibration is typical for poorly adjusted motors, chaotic vibration (chaotic amplitude) - for poorly fixed parts. Vibration with an amplitude of less than 0,5 mm is damped by tissues, more than 33 mm - acts on systems and organs. The effect of vibration depends on the force with which the worker holds the tool (static stress enhances the effect of vibration). Low temperature also enhances the effect of vibration, causing additional vasospasm. According to the method of transmission to a person, vibration is divided into: 1) general (vibration of workplaces) - transmitted through the supporting surfaces to the human body; 2) local - through the hands when working with different tools (machines). The general vibration according to the source of occurrence is divided into: 1) transport (category 1), arising from the movement of vehicles on the terrain; 2) transport and technological (category 2), affecting a person at the workplace of machines with limited mobility and moving only on specially prepared surfaces of industrial premises, industrial sites and mine workings (excavators, industrial and construction cranes, filling machines for loading open-hearth furnaces, mining combines, track machines, concrete pavers, etc.); 3) technological (category 3), affecting a person at the workplace of stationary machines or transmitted to workplaces that do not have sources of vibration (metal and woodworking machines, forging and pressing equipment; foundry and electrical machines, stationary electrical installations; pumping units and fans, equipment for the building materials industry, installations for the chemical and petrochemical industries, etc.). Process vibration is divided into: 1) type A - at permanent workplaces of industrial premises; 2) type B - at workplaces of warehouses, canteens and other premises where there are no machines that generate vibration; 3) type B - at workplaces in the premises of plant management, design bureaus, laboratories, classrooms, in premises for mental workers. Regulation of vibration is carried out on the basis of SN 2.2.4/2.1/8.566-96, "Industrial vibration, vibration in the premises of residential and public buildings." Local vibration is classified according to the same principle as the general one, but its sources are different: 1) manual machines with motors (or manual mechanized tools), manual controls for machines and equipment; 2) hand tools without motors and machined parts. In the direction of action along the axes Local: z - axis close to the direction of application of force or the axis of the forearm; x - axis parallel to the axis of the covered handles; y - perpendicular to the z and x axes. General: z - vertical axis; x - horizontal axis (back and chest); y - horizontal axis (shoulder and shoulder). In terms of frequency. Table 2. Frequency composition of vibration.  By temporal characteristics 1. Constant (vibration velocity changes up to 6 dB for more than 1 min). 2. Non-constant (the value of the vibration velocity changes by more than 6 dB for a time greater than or equal to 1 min): 1) oscillating vibration - the level of vibration velocity continuously changes in time; 2) intermittent - the operator's contact with vibration is interrupted during operation (the duration of the intervals when contact with vibration takes place for more than 1 s); 3) impulse - consists of one or more impacts, each with a duration of less than 1 s. The effect of vibration on the body The vibration transmitted to the human body, regardless of the place of contact, spreads throughout the body. The skin of the palmar surface of the terminal phalanges of the fingers has the highest vibration sensitivity. The greatest sensitivity is observed to vibration with frequencies of 100-250 Hz, and in the daytime the sensitivity is more pronounced than in the morning and evening. The vibrational factor serves as a source of many diseases, united in the domestic literature under the general name "vibration disease". Different forms of this disease differ significantly from each other both in the clinical picture, development and course, and in the mechanism of its occurrence and pathogenesis. There are 3 main forms of vibration disease: 1) peripheral, or local, vibration, due to the predominant effect of local vibration on the hands of workers; 2) cerebral form, or general vibration, caused by the predominant effect of the general vibration; 3) cerebral-peripheral, or intermediate, form, which is generated by the combined action of general and local vibration. The cerebral form occurs in workers during vibrocompaction of concrete, truck drivers, railway workers. Vibration disease of concrete workers is characterized by severity and tension. With it, changes in the nervous system, proceeding according to the type of severe vasoneurosis, come to the fore. It is taken as a cerebral form with simultaneous presence of local lesions, with similar symptoms and syndromes that are observed in vibration disease caused by the action of local vibration. There may be "vegetative crises" - dizziness, numbness, pain in the abdomen, heart, limbs. Patients suffer from insomnia, subfibrillation, impotence, loss of appetite, sudden weight loss, excessive irritability. Vibration transmitted from vehicles can lead to diseases of internal organs, the musculoskeletal system, functional changes in the vestibular apparatus, the development of solar pain, impaired secretory and motor function of the stomach, exacerbation of inflammatory processes in the pelvic organs, and impotence. There may be significant changes in the lumbar spine, radiculitis. With a vibration disease, metabolic processes can be disturbed, carbohydrate, protein, phosphorus metabolism suffers, the functional state of the thyroid gland changes. With local exposure to vibration, marbling of the skin appears, pain in the limbs, first at night, then a constant loss of all types of sensitivity. On the part of the muscular system, tunnelers and drillers often experience a spastic state of some muscle groups, convulsions, degeneration of muscle tissue, hypercalcification of muscle tissue, and as a result, its sclerosis occurs. In some cases, due to damage to peripheral motor fibers, atrophy of the small muscles of the hands and shoulder girdle develops, and muscle strength decreases. When working with vibratory instruments, changes in the osteoarticular apparatus often occur, the elasticity of articular cartilage decreases. Often develop aseptic chondroosteonecrosis, which affects the small bones of the wrist and the epiphyses of long bones. There are 4 stages of vibration disease. The 1st stage is characterized by subjective phenomena (nocturnal short pains in the extremities, paresthesia, hypothermia, moderate acrocyanosis). Stage 2: increased pain, persistent skin sensitivity disorders on all fingers and forearm, severe vasospasm, hyperhidrosis. Stage 3: loss of all types of sensitivity, a symptom of a "dead finger", a decrease in muscle strength, the development of osteoarticular lesions, functional disorders of the central nervous system of an asthenic and asthenoneurotic nature. Stage 4: changes in large coronary and cerebral vessels, progressive muscle atrophy of the arms and legs. Stages 1 and 2 are completely curable. At the 3rd stage after treatment, removal from work associated with vibration and cooling is necessary. Severe forms of the disease sharply limit the ability to work, are always an indication for the transfer of workers to disability III, and sometimes II groups. Preventing the adverse effects of vibration Among the measures aimed at eliminating the adverse effects of vibration, there are: 1) hygiene measures; 2) technical measures. With the help of technical measures it is possible to eliminate or significantly reduce the occurrence of vibrations. This is the rational design of hand tools. An example is vibration-proof pneumatic impact tools, various means of shock absorption and vibration isolation, the use of vibration-damping supports to protect hands during riveting. If it is not possible to completely eliminate vibration, it is necessary to limit its propagation. This is achieved by installing machines and machine tools on felt or cork foundations. The air gap around the foundation also prevents vibration transmission. Hygiene preventive measures 1. Rationing of vibration Table 3.  Table 4. Prevention of vibration disease.  2. Limiting the duration of exposure to vibration. Working with a vibrating tool no more than 2/3 of the working day, 10-15 minutes, a break after every hour of work. 3. Elimination of conditions conducive to the occurrence of vibration disease: the air temperature in the room is not less than 16 ° C at a humidity of 40-60% and an air velocity of 0,3 m/s. It is necessary to provide for local heating of workers at workplaces. The use of gloves with anti-vibration pads is recommended. 4. Increasing the body's resistance: the use of water procedures (warm baths of the limbs at a temperature of 35-36 ° C, daily industrial gymnastics, self-massage). Due to the increased destruction in the body when exposed to noise and vibration of water-soluble vitamins, foods that are a source of nutrients should be included in the diet. When choosing methods of technological processing of food products, one should prefer those that do not cause the appearance of substances that irritate the central nervous system. So, it is desirable to use stewing instead of roasting, to exclude smoked meats, etc. All workers exposed to vibration are subject to periodic medical examination once a year. LECTURE No. 13. The state of health of children and adolescents Assessment of the health status of children and adolescents. Health groups The state of health of the younger generation is an important indicator of the well-being of society and the state, reflecting not only the present situation, but also the forecast for the future. The steadily unfavorable trend of deterioration in the health of children has become so stable today that it creates a real threat to the national security of the country. There is a decrease in the birth rate, an increase in infant mortality, a significant decrease in the proportion of healthy children at birth, an increase in the number of disabled since childhood, patients with chronic pathology. An analysis of the current situation shows that the causes of such a catastrophic situation are socio-economic instability in society, the unfavorable sanitary condition of the children's environment (the conditions and mode of education, living conditions, etc.), the environmental situation, the reform of the education and healthcare system, low medical activity and sanitary literacy of the population, curtailment of preventive work, etc. Undoubtedly, the emerging and continuing trend towards the deterioration of children's health indicators will entail a deterioration in the health of the younger generation in all age groups, and will invariably affect the quality of labor resources and the reproduction of future generations. The concept of the health of children and adolescents should be understood as a state of complete socio-biological and mental well-being, harmonious, age-appropriate physical development, a normal level of functioning of all organs and systems of the body and the absence of diseases. However, the concept of "health" includes not only absolute and qualitative, but also quantitative signs, since there is also an assessment of the degree of health, i.e., the adaptive capabilities of the organism. According to the definition of V. Yu. Veltishchev, "Health is a state of vital activity corresponding to the biological age of the child, the harmonious unity of physical and intellectual characteristics, the formation of adaptive and compensatory reactions in the process of growth." In this regard, the definition of indicators and criteria for the health status of the child population is of particular relevance. Initially, the assessment of the health status of children during preventive examinations was carried out exclusively on the basis of "healthy" or "sick", that is, having a chronic disease. However, the rough division of children's populations into "healthy" and "sick" did not allow paying attention to the timely correction of premorbid deviations and, therefore, did not provide adequate preventive direction of examinations. To overcome these shortcomings, Professor S. M. Grombakh and co-authors (1982) developed the "Methodology for a comprehensive assessment of the health status of children and adolescents during mass medical examinations", which is valid until 2004. The creation of the methodology was based on a clear qualitative and quantitative complex characteristic of the state of health. To ensure a comprehensive approach to assessing the state of health, 4 basic criteria were proposed: 1) the presence or absence at the time of examination of chronic diseases; 2) the level of development achieved (physical and mental), the degree of its harmony; 3) the level of the functional state of the main body systems; 4) the degree of resistance of the body to adverse external influences. At present, based on the data obtained in recent years on the state of children's health, its characteristics, information on the course of diseases, as well as expanded diagnostic capabilities, it has been determined that certain changes and additions to the existing methodology should be made. In accordance with the Order of the Ministry of Health of the Russian Federation of December 30.12.2003, 621 No. 4, a comprehensive comprehensive assessment of the state of health, based on the XNUMX criteria proposed by M. S. Grombakh and allowing each child to be attributed to a certain health group, draws attention not only to the absence or presence of diseases , but also allows you to determine their prenosological and premorbid forms. In accordance with the stated health criteria and methodological approaches to their identification, children, depending on the state of health, can be assigned to the following health groups. Group I - healthy children with normal, age-appropriate physical and neuropsychic development, without functional and morphofunctional abnormalities. At present, according to the Research Institute of Hygiene of Children and Adolescents, the occupancy of the I health group on average in Russia does not exceed 10%, and in some regions of the country it reaches only 3-6%, which undoubtedly reflects the sanitary and epidemiological problems of the population. Group II - children who do not suffer from chronic diseases, but have functional or morphofunctional abnormalities, convalescents, especially those who have had severe and moderate infectious diseases, with a general delay in physical development without endocrine pathology, as well as children with a low level of body immunoresistance - often (4 times and more per year) and (or) long-term (more than 25 calendar days for one disease) sick. The data of the Research Institute of Hygiene for Children and Adolescents show that over the past 10 years in all age groups there has been a rapid increase in the number of functional disorders (1,5 times), and the occupancy of the second health group has increased on average from 20 to 35%. The presence of functional deviations, which so often determine the assignment of a child to the II group of health, have some patterns of occurrence in the state of health of children, depending on their age. For infants, the occurrence of functional abnormalities in the blood and allergic manifestations without an organic pronounced character is most often characteristic. For early age (up to 3 years) - in the digestive system. At preschool age, deviations occur in the largest number of body systems - nervous, respiratory, urinary, as well as the musculoskeletal system and ENT organs. At school age, the maximum number of deviations occurs in the cardiovascular system and the organ of vision (especially during periods of reduced adaptation to educational activities. Group III - children suffering from chronic diseases in remission (compensation). On average, in Russia there is a steady upward trend in the number of chronic diseases among children and adolescents. The occupancy of the III health group increases in children at preschool age and becomes strongly pronounced in the school period (half of schoolchildren 7-9 years old and more than 60% of high school students have chronic diseases), reaching 65-70%. The number of students with multiple diagnoses is on the rise. Schoolchildren 7-8 years old have an average of 2 diagnoses, 10-11 years old - 3 diagnoses, 16-17 years old - 3-4 diagnoses, and 20% of high school students have a history of 5 or more functional disorders and chronic diseases. Group IV - children suffering from chronic diseases in the stage of subcompensation. Group V - children suffering from chronic diseases in the stage of decompensation, children with disabilities. If there are several functional abnormalities and diseases in one child, the final assessment of the state of health is carried out according to the most severe of them. In the presence of several diseases, each of which serves as the basis for referring the patient to group III and reducing the functional capabilities of the body, the patient is referred to group IV. Of particular preventive importance is the allocation of health group II, since the functional capabilities of children and adolescents assigned to this group are reduced, and in the absence of medical control, adequate corrective and therapeutic measures, they have a high risk of chronic pathology. The main method that allows obtaining characteristics, on the basis of which a comprehensive assessment of the state of health is given, is a preventive medical examination. For children aged 3 years and older, the following periods of examinations are provided: 3 years (before entering a preschool educational institution), 5 years 6 months, or 6 years (one year before entering school), 8 years (after the end of the 1st school class), 10 years (when switching to subject education), 12 years, 14-15 years. The distribution of children by health groups is widely used in pediatrics and for a one-time assessment of the state of health in a team. The distribution of children into health groups is very important for: 1) characteristics of the health of the child population, obtaining statistical slices of health indicators and the number of relevant health groups; 2) comparative comparison of groups of children in different groups, educational institutions, different territories, in time; 3) assessing the effectiveness of preventive and curative work in children's medical institutions based on the transition of children from one health group to another; 4) identification and comparison of the effect of risk factors affecting the health of children and adolescents; 5) determining the need for specialized services and personnel. Criteria for determining, methods and principles for studying the health of the child population The health of the child population is made up of the health of individuals, but it is also considered as a characteristic of public health. Public health is not only a medical concept, but to a large extent a public, social and economic category, since the external social and natural environment is mediated through the specific living conditions of the population. In recent years, the direction associated with the use of a multilevel system for assessing the health status of the child population has been intensively developing. The main groups of statistical indicators used to characterize the public health of the contingent of children and adolescents are the following: 1) medical and demographic; 2) physical development; 3) distribution of children by health groups; 4) morbidity; 5) data on disability. The medical and demographic criteria characterizing the state of the child population include the following: 1) fertility - an indicator that characterizes the process of renewal of new generations, which is based on biological factors that affect the body's ability to reproduce offspring; 2) mortality - an indicator characterizing the intensity of the process of death of persons of a certain age and sex in a population; 3) natural population growth - a generalizing characteristic of population growth; can be expressed as an absolute number as the difference between the number of births and the number of deaths per year, or calculated as the difference between birth and death rates; 4) average life expectancy - an indicator that determines how many years, on average, a given generation of those born will have to live if, throughout the life of this generation, mortality rates remain the same as they are at the moment. The indicator of average life expectancy is calculated on the basis of age-specific mortality rates by constructing mortality tables; 5) infant mortality - an indicator that characterizes the mortality of live-born children from birth to the age of 1 year. The next indicator characterizing the state of the child population is physical development. Physical development is one of the objective and informative indicators of the health status of the child population, which is currently changing as sharply as other indicators (morbidity, mortality, etc.). Physical development is understood as a complex of morphological and functional properties and qualities of a growing organism, as well as the level of its biological maturation (biological age). An analysis of physical development makes it possible to judge the rate of biological maturation and the harmony of the morphofunctional status, both of an individual and of the child population as a whole. Physical development is an integral indicator (index) of the sanitary and hygienic well-being of the child population, since it largely depends on a variety of external and internal factors. There are 3 groups of main factors that determine the direction and degree of physical development: 1) endogenous factors (heredity, intrauterine effects, prematurity, birth defects, etc.); 2) natural and climatic factors of the habitat (climate, terrain, as well as atmospheric pollution, etc.); 3) socio-economic and socio-hygienic factors (degree of economic development, living conditions, life, nutrition, upbringing and education of children, cultural and educational level, hygiene skills, etc.). All of the above factors operate in unity and interdependence, however, since physical development is an indicator of the growth and formation of the body, it is subject not only to biological laws, but also to a greater extent depends on a complex set of social conditions that are of decisive importance. The social environment in which the child is located largely forms and changes his health, including determining the level and dynamics of physical development. Systematic monitoring of the growth and development of children and adolescents in Russia is an integral part of the state system of medical control of the health of the younger generation. The algorithm of such observation includes anthropometry, somatoscopy, physiometry and a standardized evaluation of the obtained data. The distribution of children by health groups is used as a clear characteristic of the health of the child population, as an indicator of sanitary well-being. According to the WHO, if more than 80% of children in the population under consideration belong to health groups II-III, this indicates that the population is not well. The definition of criteria that characterize and determine the distribution of children and adolescents by health groups is carried out taking into account the so-called defining signs of health, which were considered earlier. Morbidity is one of the most important criteria characterizing the health of the child population. In a broad sense, incidence refers to data on the prevalence, structure and dynamics of various diseases registered among the population as a whole or its individual groups (territorial, age, gender, etc.). When studying morbidity, it is necessary to use a single methodological basis, including the correct use of terms and their common understanding, a unified system of accounting, collection and analysis of information. The source of information on morbidity is data on seeking medical care, data on medical examinations, and data on causes of death. To study and characterize the incidence of children, 3 concepts are distinguished: the incidence itself, the prevalence of diseases and pathological susceptibility. Morbidity (primary morbidity) - the number of diseases not previously registered anywhere and first detected in a given calendar year. Prevalence (morbidity) - the total number of all existing diseases, both first detected in a given year and in previous years, for which the patient again sought medical help in a given calendar year. There are significant differences between these two concepts, which are necessary to know for a correct analysis of the results. Actually, the incidence is an indicator that is more sensitive to changes in environmental conditions in the studied calendar year. When analyzing this indicator over a number of years, one can get a more correct idea of the incidence and dynamics of morbidity, as well as the effectiveness of a complex of hygienic and therapeutic measures aimed at reducing it. The indicator of morbidity is more stable in relation to various environmental influences, and its increase does not mean negative changes in the state of health of the child population. This increase may be due to the improvement in the treatment of sick children and prolongation of their lives, which leads to the "accumulation" of contingents of children who are on dispensary records. The morbidity rate also makes it possible to establish the frequency of visits, to identify children who are ill for a long time and repeatedly, and who have never been ill in a calendar year. The number of frequently ill children during the year is determined as a percentage of the number of those examined. Often ill children are considered to be those who fell ill 4 times or more during the year. The number of long-term ill children during the year is determined as a percentage of the number of those examined. Children who are ill for more than 25 calendar days are considered to be long-term ill. The number of children who have never been ill for a year, as a percentage, of the total number of those examined is defined as the "health index". Pathological afflictions - a set of diseases identified during medical examinations, as well as morphological or functional abnormalities, premorbid forms and conditions that can later cause a disease, but by the time of the examination do not yet force their carrier to seek medical help. The increase in the prevalence of severe forms of pathology largely determines the increase in the frequency of childhood disability. 5. Disability in children (according to WHO) is a significant limitation of life, leading to social maladjustment due to a violation of the development and growth of the child, the ability to self-service, movement, orientation, control of one's behavior, learning, communication, work in the future. Over the past 5 years, the number of disabled children of all ages has increased by 170 thousand people, the prevalence of childhood disability is 200 per 10 child population. At the same time, more than 000% of the disabled are children of adolescence (65-10 years old inclusive). In the structure of the causes of childhood disability, the leading place is occupied by infectious and somatic diseases (17%). Factors affecting the health of children and adolescents In the process of ontogenesis, the period of childhood and adolescence, from 0 to 17 years old, is an extremely intense period of morphofunctional rearrangements, which should be taken into account when assessing the formation of health. At the same time, this age period is characterized by the influence of a whole range of social conditions and their frequent change (nursery, kindergarten, school, vocational training, work activity). The child population is exposed to a variety of environmental factors, many of which are considered risk factors for the development of adverse changes in the body. The determining role in the occurrence of deviations in the health status of children and adolescents is played by 3 groups of factors: 1) factors characterizing the genotype of a population ("genetic load"); 2) lifestyle; 3) the state of the environment. Social and environmental factors do not act in isolation, but in complex interaction with biological, including hereditary, factors. This causes the dependence of the incidence of children and adolescents both on the environment in which they are located, and on the genotype and biological patterns of growth and development. According to WHO, the contribution of social factors and lifestyle to the formation of health status is about 40%, environmental pollution factors - 30% (including natural and climatic conditions - 10%), biological factors - 20%, medical care - 10% . However, these values are averaged, do not take into account the age-related characteristics of the growth and development of children, the formation of pathology in certain periods of their lives, the prevalence of risk factors. The role of certain socio-genetic and medical-biological factors in the development of adverse changes in the state of health is different depending on the sex and age of the individual. Certain factors affect the health of children: 1) medical and biological risk factors for the period of pregnancy and childbirth of the mother: the age of the parents at the time of the birth of the child, chronic diseases in the parents, acute diseases in the mother during pregnancy, the use of various drugs during pregnancy, psychotrauma during pregnancy, complications of pregnancy (especially gestosis second half of pregnancy) and childbirth, etc.; 2) early childhood risk factors: birth weight, feeding patterns, deviations in health status in the first year of life, etc.; 3) risk factors that characterize the conditions and lifestyle of the child: housing conditions, income and level of education of parents (primarily mothers), smoking of parents, family composition, psychological climate in the family, attitude of parents to the implementation of preventive and therapeutic measures, etc. When evaluating the contribution of individual factors that make up the socio-hygienic group, it must be remembered that their role is different in different age groups. At the age of up to 1 year, among the social factors, the nature of the family and the education of the parents are of decisive importance. At the age of 1-4 years, the significance of these factors decreases, but still remains quite significant. However, already at this age, the role of housing conditions and family income, keeping animals and smoking relatives in the house increases. An important factor is the child's attendance at a preschool institution. It is most important in the age group of 1-4 years. At school age, the most important are the factors of the intra-housing, including the intra-school environment, which account for 12,5% in the primary grades, and by the end of school - 20,7%, i.e., they increase almost 2 times. At the same time, the contribution of social and hygienic factors for the same period of growth and development of the child decreases from 27,5% when entering school to 13,9% at the end of education. Among the biological factors in all age groups of children, the main factors that have the greatest impact on morbidity are maternal diseases during pregnancy and complications during pregnancy. Since the presence of complications in childbirth (premature, late, rapid delivery, birth weakness) can lead to a violation of the state of health in the future, this also allows us to regard them as risk factors. Of the factors of early childhood, natural feeding and hygienically correct child care are of particular importance. Each age is characterized by the predominance of certain risk factors, which determines the need for a differentiated approach to assessing the role and contribution of factors, planning and implementing preventive and health measures. It is most expedient to objectively study the factors affecting the health of children and adolescents with the help of special formalized maps, questionnaires, etc. LECTURE No. 14. Physical development of children and adolescents, methods for their assessment Physical development indicators For a complete picture of the state of health of the younger generation, in addition to morbidity, demographic data, it is also necessary to study the leading criterion for the health of the child's body - physical development. The term "physical development", on the one hand, denotes the process of formation and maturation of the child's body, on the other hand, the degree of this maturation at each given period of time, that is, it has at least two meanings. Proceeding from this, physical development is understood as a set of morphological, functional properties and qualities, as well as the level of biological development (biological age) of the organism, which characterizes the process of maturation of a child at a certain stage of life. The physical development of a growing organism is one of the main indicators of a child's health. The more significant violations in physical development, the greater the likelihood of disease. At the same time, obeying the laws, physical development depends on a number of factors of a socio-economic, biomedical and environmental nature. This allows us to consider the physical development since the study by F. F. Erisman of the physical development of children and working teenagers-textile workers of the Glukhovskaya manufactory of the Moscow province in 1878-1886. as an objective indicator of the sanitary and epidemiological well-being of the population. The study of physical development is carried out simultaneously with the study of the state of health during in-depth medical examinations conducted in children's and adolescent institutions. The study of the physical development of the child begins with the establishment of his calendar (chronological) age. For each examined child, the exact age at the time of the examination, expressed in years, months and days, should be determined. This is necessary due to the fact that the rate of change in indicators of physical development is not the same in different periods of a child's life, therefore, taking into account the changing pace of development, the age grouping is carried out at different intervals ("time step"). For children of the first year of life - every 1 month. For children from 1 to 3 years - every 3 months. For children from 3 to 7 years old - every 6 months. For children over 7 years old - every year. That is why, with age grouping, it would be wrong to count the number of full years lived, since in this case, for example, 8-year-old children would have to include those who have just turned 8 years old, and those who are 8 years and 6 months old from birth, and even those who are 8 years 11 months 20 days old. Therefore, a different method is used, according to which children aged 8 years and 7 months to 6 years and 8 months 5 days are classified as 29-year-old children, from 9 years 8 months to 6 years 9 months 5 days, etc. d. Further, the program of unified anthropometric studies includes the determination of a number of basic morphological and functional features from the whole variety. These include somatometric, somatoscopic and physiometric signs. Somatometry includes determining the length, body weight, chest circumference. Body length is a total indicator characterizing the state of plastic (growth) processes in the body; this is the most stable indicator of all indicators of physical development. Body weight indicates the development of the musculoskeletal system, subcutaneous fat, internal organs; unlike length, body weight is relatively labile and can change under the influence of even a short-term illness, changes in the daily routine, and malnutrition. The circumference of the chest characterizes its capacity and the development of the pectoral and spinal muscles, as well as the functional state of the organs of the chest cavity. Somatoscopy is carried out to obtain a general impression of the physical development of the subject: the type of body structure as a whole and its individual parts, their relationship, proportionality, the presence of functional or pathological abnormalities. Somatoscopic examination is very subjective, however, the use of unified methodological approaches (and in some cases, additional instrumental measurements) makes it possible to obtain the most objective data. Somatoscopy includes: 1) assessment of the state of the musculoskeletal system: determination of the shape of the skull, chest, legs, feet, spine, type of posture, muscle development; 2) determination of the degree of fat deposition; 3) assessment of the degree of puberty; 4) assessment of the condition of the skin; 5) assessment of the condition of the mucous membranes of the eyes and oral cavity; 6) examination of the teeth and drawing up a dental formula. Physiometry includes the definition of functional indicators. When studying physical development, the vital capacity of the lungs is measured (it is an indicator of the capacity of the lungs and the strength of the respiratory muscles) - spirometry, muscle strength of the hands (characterizes the degree of muscle development) and dead strength - dynamometry. Depending on the age of the children, the program of anthropometric research can and should change. The characteristics of the physical development of children of early and preschool age should be supplemented by data on the development of motor skills of speech, but exclude some functional studies (determination of the vital capacity of the lungs, muscle and back strength). When studying the physical development of adolescents, it is advisable to include a number of functional tests in the examination program to determine the state of the main body systems. In the future, the obtained data of anthropometric measurements are processed by the method of variation statistics, as a result of which the average height, weight, chest circumference are obtained - the standards of physical development used in the individual and group assessment of the physical development of children. To study, analyze and evaluate the physical development of large groups of children or individuals, 2 main methods of observation (collection of anthropometric material) are used. 1. Generalizing method (population cross-sectional method) - based on a one-time examination of the physical development of large groups of children of different ages. Each age group must consist of at least 100 people. The method is used on a large number of observations in order to obtain age-sex standards and evaluation tables used both for individual assessment of physical development and for environmental and hygienic assessment of the area where children live. The method allows you to monitor the dynamic changes in the physical development of children in a given region in connection with the state of health, physical education, living conditions, nutrition, etc. Anthropometric data collected by the generalizing method are used for the purpose of hygienic regulation in the development of furniture standards for preschool and educational institutions, equipment for workshops, gyms, for hygienic justification of the size of children's tools, clothes, shoes and other children's household items. 2. The individualizing method (longitudinal section) is based on a single examination of a particular child or in the dynamics of years, followed by an assessment of his biological level of development and the harmony of the morphofunctional status using the appropriate evaluation tables, making it possible to obtain sufficient saturation of each age and sex group by months or years of life with a relatively small number of observations. This technique allows you to determine the features of the physical formation of the body from month to month (or from year to year) of the observed group of children in a homogeneous population. The individualizing method does not contradict the generalizing method and is an essential addition to it both in studying the process of the child's general development and in clarifying the influence of environmental factors in the course of this development. To obtain average indicators of physical development, a survey of large groups of practically healthy children of various age and sex groups is carried out. The obtained average values are the standards of physical development of the corresponding groups of the child population. In order for the received data to be accepted as a standard, they must meet certain requirements. 1. Standards of physical development should be regional. 2. The statistical population must be representative, therefore, each age and sex group must be represented by at least 100 children (observation units). 3. The statistical population should be homogeneous by sex, age (taking into account heteromorphism, heterochrony and sexual dimorphism of physical development), ethnicity (since there are significant differences in the physical development of peoples and nations), place of residence (due to the possible influence of biogeochemical provinces physical development) and health status. 4. All cases of "heterogeneity" for health reasons should be excluded from the observation group: children with chronic diseases that occur with intoxication (tuberculosis, rheumatism, etc.), serious disorders in the activity of organs and systems of the body (congenital heart defects, consequences of poliomyelitis, bone tuberculosis, injuries of the nervous system and musculoskeletal system, etc.), endocrine diseases. When developing materials for examining young children, children with severe rickets, malnutrition, premature babies, and twins are excluded. 5. After the formation of a homogeneous and representative statistical population, a single methodology for surveying, measuring, processing and analyzing data should be applied. There are no generally accepted standards of physical development. Different living conditions in different climatic and geographical zones, in cities and rural areas, ethnographic differences cause different levels of physical development of the child population. In addition, taking into account changes in physical development indicators over the years (acceleration and deceleration of physical development), regional standards should be updated every 5-10 years. Methods for assessing the physical development of children and adolescents When developing and choosing methods for assessing physical development, it is necessary, first of all, to take into account the main patterns of the physical development of a growing organism: 1) heteromorphism and heterochrony of development; 2) the presence of sexual dimorphism and acceleration; 3) the dependence of physical development on genetic and environmental factors. In addition, when developing scales for assessing indicators of physical development, it is necessary to take into account the features of the statistical distribution of these indicators. Therefore, the following requirements should be imposed on methods for assessing physical development: 1) taking into account the heterochrony and heteromorphism of the growth and development of the individual and sexual dimorphism; 2) interrelated assessment of indicators of physical development; 3) taking into account the possibilities of asymmetry in the distribution of indicators; 4) low labor intensity, no complex calculations. There are various ways of individual and group assessment of the physical development of the child population. Consider the methods of individual assessment of physical development. Method of sigma deviations The method of sigma deviations is widely used, when the developmental indicators of an individual are compared with the average of their signs for the corresponding age and sex group, the difference between them is expressed in sigma shares. The arithmetic mean of the main indicators of physical development and their sigma represent the so-called standards of physical development. Since its own standards are developed for each age and sex group, the method makes it possible to take into account the heteromorphism of physical development and sexual dimorphism. However, a significant drawback of the method is the isolated evaluation of features outside of their relationship. In addition, the use of parametric statistics methods for assessing anthropometric indicators that have asymmetry in distribution (body weight, chest circumference, arm muscle strength) can lead to distortion of the results. Method of percentile (centile, percentile) scales To assess the physical development of an individual, the method of non-parametric statistics is also used - the method of centile scales or channels, when, according to the results of mathematical processing, the entire series is divided into 100 parts. It is generally believed that values in the centile channel up to the 25th centile are rated as below average, from 25th to 75th centile - as average and above 75th centile - as above average. The use of this method makes it possible to avoid distortions in the results of assessing indicators that have asymmetry in distribution. However, like the method of sigmal deviations, the method of centile scales evaluates anthropometric features in isolation, without their relationship. Regression scale method For an interconnected assessment of indicators of physical development, it is proposed to use regression scales. When compiling regression scales for body length, the relationship between body length and body weight and chest circumference is determined by the method of pair correlation. Next, evaluation tables are built in which there is a consistent increase in the values of one of the signs (for example, weight) with a corresponding increase in another sign (for example, growth) with a direct connection and a similar sequential decrease in the values of the signs - with feedback, i.e. with an increase or a decrease in body length by 1 cm, body weight and chest circumference change by the regression coefficient (Ry/x). To assess the deviations of the actual values from the due ones, the partial sigma of the regression of body weight and chest circumference is used. This method is most widely used, as it makes it possible to identify individuals with harmonious and disharmonious physical development. Its advantage lies in the fact that it allows to give a comprehensive assessment of physical development on the basis of a set of signs in their relationship, since none of the signs, taken individually, can give an objective and complete assessment of physical development. However, the use of the parametric statistics method can lead to distortion of the results when assessing features that have asymmetry in distribution. In addition, body weight is estimated depending only on body length and the influence of latitudinal dimensions is not taken into account. Method for assessing the physical development of children according to a complex scheme Informative and including the determination of the level of biological development and the degree of harmony of the morphofunctional state is a complex scheme for assessing physical development, carried out in two stages. At the first stage of the study, the level of biological development (biological age) is established, which is understood as the totality of the morphological and functional characteristics of the organism, depending on the individual rate of growth and development. The biological age of the child is determined by indicators of standing body length, body length gains over the past year, the level of ossification of the skeleton ("bone age"), the timing of secondary dentition (the timing of eruption and change of milk teeth to permanent ones), changes in body proportions, and the degree of development of secondary sexual characteristics. , the date of the onset of the first menstruation in girls. For this, tables are used that present the average values of the indicators of the biological development of boys and girls by age. Using these tables and comparing the child's data with average age indicators, they determine whether the biological age corresponds to the calendar (passport), ahead or behind it. At the same time, the change in the information content of biological age indicators depending on the age of the child is taken into account. At the age of up to 1 year, the most informative indicators are the length of the body, the increase in body length over the past year, as well as "bone age" (the timing of the appearance of ossification nuclei of the skeleton of the upper and lower extremities). In early, preschool and primary school age, the leading indicators of biological development are: body length, annual gains, the total number of permanent teeth in the upper and lower jaws ("dental age"). As additional indicators at preschool age, the following can be used: changes in body proportions (the ratio of head circumference to body length, "Philippine test"). In middle school age, the leading indicators are body length, body length gain, the number of permanent teeth, in senior school age - body length gain and the degree of development of secondary sexual characteristics, the age of menstruation in girls. When determining the number of permanent teeth, teeth of all stages of eruption are taken into account - from a clear appearance of the cutting edge or chewing surface above the gum to a fully formed tooth. When conducting the "Philippine test" the child's right hand with a vertical position of the head is placed across the middle of the crown, while the fingers of the hand are extended in the direction of the left ear, the hand and hand are snug against the head. The "Philippine test" is considered positive if the fingertips reach the upper edge of the pinna. The ratio of the head circumference to the body length: the coefficient OG / DT × 100% - is defined as the quotient of dividing the head circumference by the body length, expressed as a percentage. To establish the degree of sexual development, it is determined: in girls - the development of hair in the axillary region (Axillaris-Ax), the development of pubic hair (Pubis-P), the development of the mammary glands (Mammae-Ma), the time of the appearance of the first menstruation (Menarche-Me); in boys, development of axillary hair, development of pubic hair, voice mutation (Vocalis-V), facial hair (Facialis-F), development of Adam's apple (Larings-L). At the second stage, the morphofunctional state is determined in terms of body weight, chest circumference in the respiratory pause, muscle strength of the hands and vital capacity of the lungs (VC). As an additional criterion for differentiating excess body weight and chest circumference of age-sex norms due to fat deposition or muscle development, measurement of the thickness of skin-fat folds is used. To determine the morphofunctional state of the body, regression scales are used - to assess body weight and chest circumference, centile scales - to assess VC and muscle strength of the arms and a table of thickness of skin-fat folds. First, the correspondence of body weight and chest circumference to body length is taken into account. To do this, on a regression scale, an indicator of the body length of the subject and the corresponding indicators of body weight and chest circumference are found. Then the difference between the actual and due indicators of body weight and chest circumference is calculated. The degree of increase and decrease in the actual indicator is expressed as a sigmal deviation, for which the resulting difference is divided by the corresponding regression sigma. Functional indicators (VC, muscle strength of the arms) are evaluated by comparing them with a centile scale for a given age and sex group. Averages are indicators that are in the range from 25 to 75 centiles, below average - indicators whose values are below the 25th centile, above average - above the 75th centile. The morphofunctional state can be defined as harmonious, disharmonious and sharply disharmonious. Harmonious, normal should be considered a state when body weight and chest circumference differ from the proper within one particular regression sigma (± 1 ***R= sigma), and functional indicators are within 25-75 centiles or exceed them. Harmoniously developed individuals should be classified as those whose body weight and chest circumference exceed the due by more than 1 **** R due to the development of muscles: the thickness of none of the skin-fat folds does not exceed the average; functional indicators in the range of 25-75 centiles or higher. A morphofunctional state is considered disharmonious when body weight and chest circumference are less than due by 1,1-2 ***** R and more than due by 1,1-2 **** R due to fat deposition (thickness of skin-fat folds exceeds averages); functional indicators less than 25 centiles. A morphofunctional state is considered sharply disharmonious when body weight and chest circumference are less than due by 2,1 ***** R and more than due by 2,1 **** R due to fat deposition (thickness of skin-fat folds exceeds average values) ; functional indicators less than 25 centiles. Thus, when assessing physical development according to a complex scheme, the general conclusion contains a conclusion about the correspondence of physical development to age and its harmony. LECTURE No. 15. Healthy lifestyle and personal hygiene issueswww In the system of measures to form and ensure a healthy lifestyle in modern conditions, personal hygiene of each person is of great importance. Personal hygiene is part of general hygiene. If general hygiene is aimed at improving the health of the entire population or the health of the population, then personal hygiene is aimed at strengthening individual health. However, personal hygiene is also of public importance. Failure to comply with the requirements of personal hygiene in everyday life can also have an adverse effect on the health of others (passive smoking, the spread of infectious diseases and helminth infections, etc.). The scope of personal hygiene includes hygiene of the body and oral cavity, physical culture, hardening, prevention of bad habits, hygiene of sexual life, rest and sleep, individual nutrition, hygiene of mental labor, hygiene of clothes and shoes, etc. Oral hygiene Keeping the body clean ensures the normal functioning of the skin. Through the skin, by radiation, evaporation and conduction, the body loses more than 80% of the generated heat, which is necessary to maintain thermal equilibrium. Under conditions of thermal comfort, 10-20 g of sweat per hour is released through the skin, with heavy exertion and in uncomfortable conditions up to 300-500 g or more. Every day, the skin of an adult produces up to 15-40 g of sebum, which includes various fatty acids, proteins and other compounds, and up to 15 g of keratinized plates are shed. Through the skin, a significant amount of volatile substances are released, which are included in the group of anthropogases and anthropotoxins, organic and inorganic salts, and enzymes. All this can contribute to the reproduction of bacteria and fungi on the body. On the skin of the hands is more than 90% of the total number of microorganisms that seed the surface of the body. Human skin performs a barrier role, participates in gas exchange, participates in providing the body with ergocalceferol. Clean skin has bactericidal properties - the number of microbial bodies applied to clean skin is reduced by more than 2% within 80 hours. Clean skin is 20 times more bactericidal than unwashed skin. Therefore, for sanitary purposes, it is necessary to wash hands and face in the morning and before going to bed, wash the feet in the evening and wash the whole body at least once a week. It is also necessary to wash the external genital organs, which is an indispensable element of a woman's daily personal hygiene. It is essential to wash your hands before eating. Hair is recommended to be washed about 1 time per week for dry skin and 1 time in 3-4 days for oily skin using detergents. Soaps are a type of water-soluble salts of higher fatty acids containing surfactants. They are obtained by neutralizing higher fatty acids or saponifying neutral fats with caustic alkalis (anhydrous sodium soaps are solid, potassium soaps are liquid). The degree of solubility of soap in water depends on the salts of which fatty acids it is. Salts of unsaturated fatty acids are more soluble than saturated ones. There are toilet, household, medical and technical soaps. Contacting with the epidermis, the alkali contained in the soap converts the protein part of the epidermis into easily soluble alkaline albuminates, which are removed when washed off. Therefore, frequent washing with soap of dry skin has an unfavorable effect on it, aggravating its dryness and itching, the formation of dandruff, and hair loss. The amount of free alkali in soaps is regulated, and in toilet soaps it should not exceed 0,05%. The addition of lanolin to the soap ("Baby", "Cosmetic") softens the irritating effect of alkali. The restoration of the acid reaction of the skin, which has a bactericidal effect, is facilitated by rinsing with compounds containing acetic acid. In the production process, toilet soaps, depending on their purpose and product group, include various dyes, fragrances, therapeutic and prophylactic and disinfectants. Hot soapy solutions (40-60 °C) remove 80-90% of the microflora from the infected surface. In recent decades, along with soaps for laundry and cleaning, synthetic detergents (SMC) are widely used, which are complex chemical compounds, the main components of which are surface-active substances (surfactants). In addition to them, the composition of SMS (in the form of powders, pastes, liquids) includes bleaches, perfume fragrances, soda ash and other chemicals. So, for example, SMS contains 20% of a mixture of detergents (alkylbenzenesulfonates, alkylsulfonates), 40% sodium tripolyphosphate, 26% sodium sulfate, 2% monoalkylamides, carboxymethylcellulose, bleaches, perfume fragrances. High bacteriostatic and bactericidal properties are possessed by the cationic active substances included in SMS - degmin, diocil, pyrogem, etc. The bactericidal activity of sulfonols and other anionic surfactants is lower than that of cationic surfactants, and they are usually used for disinfection in a mixture with other disinfectants. At concentrations greater than 1%, CMC can be irritating and allergenic. Do not use SMS to soften water. The main method of hygienic care of the oral cavity is a daily double brushing of the teeth. It is necessary for the timely removal of plaque, slows down the formation of tartar, eliminates bad breath, and reduces the number of microorganisms in the oral cavity. Toothbrushes and toothpastes are used for brushing teeth. The main components of tooth powders are purified chalk and various additives and fragrances. The cleansing and massaging properties of powders are high, but their disadvantage in comparison with pastes is the abrasive effect on tooth enamel. The advantage of pastes containing significantly less chalk than powders is the ability to create a variety of compositions. There are hygienic and treatment-and-prophylactic toothpastes. Various biologically active substances (vitamins, plant extracts, mineral salts, trace elements) are introduced into the composition of therapeutic and prophylactic toothpastes, which have an anti-inflammatory, fluorine-replacing effect. The process of brushing the teeth should last at least 3-4 minutes and include 300-500 paired movements along (mainly) and across. To assess the cleanliness of the teeth and the intensity of plaque on them, it is recommended to use the so-called hygiene index, which is determined as follows. With the help of potassium iodide solution (KJ - 2 g, crystalline iodine - 1 g, H2O - 4 ml), applied to the surface of the six lower frontal teeth, the intensity of their coloration is estimated in points: no coloration - 1 point, strong brown coloration - 5 points. The index is calculated by the formula: КWed = KP / P, where Kп - sum of points; n is the number of teeth. If KWed less than 1,5 points - the score is good, from 2,6 to 3,4 points - bad, more than 3,5 - very bad. Physical education One of the most important elements of personal hygiene and a healthy lifestyle is physical education. The simplest types of physical culture should be practiced by all healthy adults and children. For people suffering from chronic diseases, exercise must be adapted. However, physical activity should be individualized and based on the real state of health, age and fitness of a particular person. To address the issue of the degree of functional readiness for physical exercises and control for their implementation, various tests have been proposed. One of them is a 12-minute test by American sports physician K. Cooper. It is based on the fact that between the distance traveled (km) and oxygen consumption (ml / kg min) there is a relationship that reflects the functional readiness of a person. So, at the age of 30-39 years, readiness is considered poor, in which oxygen consumption is only 25 ml / (kg min), satisfactory - from 30 to 40, excellent - 38 ml / (kg min) and more. At the age of 17 to 52 years, the distance when overcoming it for 12 minutes, and oxygen consumption is characterized by the following dependence. Table 5.  Based on this dependence, Cooper proposed (Table 5) criteria based on determining the length of the distance that the subject is able to walk or run in 12 minutes, while maintaining good general health and not experiencing severe shortness of breath, heart palpitations and other unpleasant sensations. As a test, Academician A. Amosov proposed to evaluate the change in the initial heart rate after 20 squats at a slow pace, with arms extended forward and knees wide apart. If the pulse quickens by no more than 25% of the original, then the state of the circulatory organs is good, by 20-25% - satisfactory, by 75% or more - unsatisfactory. Another available test is the change in heart rate and general well-being during a normal walk up to the 4th floor. The condition is assessed as good if the pulse rate does not exceed 100-120 per minute, breathing is free, easy, there are no discomfort, shortness of breath. Slight shortness of breath characterizes the condition as satisfactory. If shortness of breath is expressed already on the 1rd floor, the pulse rate is more than 3 per 140 minute, weakness is noted, then the functional state is assessed as unsatisfactory. It is possible to evaluate the state of health during physical exercises by the pulse rate measured 1-2 minutes after the completion of the exercises. The heart rate should not go beyond the so-called control zone - within 75-85% of the control figure obtained by subtracting the number of years from the figure 220. For example, at the age of 40, the control figure is 220 - 40 \u180d 75; 180% of 135 is 85, 153% - 50 (at the age of 127,5, respectively, 144,5 and XNUMX). Physical activity does not exceed functional capabilities if the actual heart rate is within the limits typical for a given age. The most ancient, simple and accessible type of physical activity, which has no contraindications for almost the vast majority of people, is walking. Energy consumption when walking at a speed of 3 km / h is 195 kcal / h, at a speed of 5 km / h - 390 kcal / h. During the day, each adult can walk at least 8-10 thousand steps, which at a pace of 90 steps per minute is approximately 1-1,5 hours of walking, at least 2% of which should be in the fresh air. For unprepared beginners, a training walking program is recommended (according to Cooper) with a gradual increase in its distance and time (on the 75st week, about 1 km for 1,5 minutes, on the 15th - about 6 km in 2,5 minutes). The second most important element of physical culture is morning hygienic gymnastics (UGG). Unlike special types of gymnastics, UGG exercises are a complex of relatively simple, corrective, general developmental and strength movements that affect the main muscle groups of the body, without much physical stress. UGG is recommended after sleep, before water procedures, preferably in the fresh air. UGG energy consumption is small and amounts to 80-90 kcal, but its value is enormous, it contributes to effective physical and mental activity throughout the working day. Hardening In the narrow sense of the word, hardening is understood as an increase in the body's resistance to the effects of fluctuations in air and water temperature, air humidity, atmospheric pressure, solar radiation and other physical environmental factors. Hardening increases the adaptive capacity of the body not only to low and other climatic factors, but also to physical, chemical, biological, psychological adverse effects, reduces susceptibility to respiratory and other infectious diseases, increases efficiency, and contributes to the formation of positive psychophysiological emotions. The role of hardening is especially great for children and people in conditions of physical inactivity. When carrying out hardening procedures, it is necessary to take into account their basic principles: 1) gradualness (gradual increase in the intensity and duration of exposure to the hardening factor); 2) systematic (performing hardening procedures not sporadically, but regularly, according to a certain scheme); 3) complexity (a combination of the impact of several factors, such as air and water); 4) an individualized mode (the nature, intensity and mode of hardening, taking into account the individual characteristics of a person - his age, gender, state of health, etc.). Hardening can be started and carried out at any time of the year. The main hardening factors are water, air and solar radiation. air hardening The most common form of air conditioning is aerotherapy (air baths). There are warm (temperature from 30 to 25 ° C), cool (20-14 ° C) and cold (less than 14 ° C) air baths. When assessing the temperature regime, one should take into account the complex nature of the microclimate and focus on the effectively equivalent temperature and humidity of the air, the speed of its movement and the level of radiation. For greater efficiency, baths should be taken in the most naked form in the shade, on special sites (aerariums) that are not polluted by atmospheric emissions. An acceptable and effective form of hardening of the upper respiratory tract is sleeping in the winter in a room with an open window. It is expedient to combine hardening with air with physical exercises. There are 4 degrees of cold exposure to air - from weakly training (3-18 kcal / m2) to the maximum training hardening (6-72 kcal/m2 body surface). water hardening is a very powerful, effective and diverse form of hardening. Hardening with water is based on the high heat transfer of the human body, since water has a heat capacity that is much higher (10-20 times) than the heat capacity of air with the same temperature. For hardening, baths, bathing, showers, dousing, wiping, foot baths and other water procedures can be used. According to the temperature regime, the following types of procedures are distinguished: cold (less than 20 ° C), cool (20-30 ° C), indifferent (34-36 ° C), warm) 37-39 ° C), hot (over 40 ° C) . Very useful ordinary and - especially - a contrast shower. It is advisable to carry out it in an alternating, gradually changing temperature regime (from 35-20 ° C to 45-10 ° C), lasting 0,5-2 minutes. Douche can be used as an independent hardening procedure (reducing the temperature from 30 ° C to 15 ° C) with the obligatory subsequent rubbing of the body, which enhances the training effect on the vessels. clothing hygiene Clothing hygiene is an important part of personal hygiene. According to F. F. Erisman, clothing is a kind of protection ring against adverse natural conditions, mechanical influences, protects the surface of the body from pollution, excessive solar radiation, and other adverse factors in the domestic and industrial environment. Currently, the concept of a clothing package includes the following main components: underwear (1st layer), suits and dresses (2nd layer), outerwear (3rd layer). According to the purpose and nature of use, household, professional (overalls), sports, military, hospital, ritual, etc. Everyday clothing must meet the following basic hygiene requirements: 1) provide an optimal underwear microclimate and promote thermal comfort; 2) do not impede breathing, blood circulation and movement, do not displace or squeeze internal organs, do not disrupt the functions of the musculoskeletal system; 3) be strong enough, easy to clean from external and internal contaminants; 4) do not contain toxic chemical impurities released into the external environment, do not have physical and chemical properties that adversely affect the skin and the human body as a whole; 5) have a relatively small mass (up to 8-10% of a person's body weight). The most important indicator of the quality of clothing and its hygienic properties is the underwear microclimate. At an ambient temperature of 18-22 °C, the following parameters of the underwear microclimate are recommended: air temperature - 32,5-34,5 °C, relative humidity - 55-60%. The hygienic properties of clothing depend on a combination of a number of factors. The main ones are the type of fabric, the nature of its manufacture, the cut of clothes. For the manufacture of fabric, various fibers are used - natural, chemical, artificial and synthetic. Natural fibers can be organic (vegetable, animal) and inorganic. Vegetable (cellulose) organic fibers include cotton, linen, sisal, jute, hemp and others, organic fibers of animal origin (protein) - wool and silk. For the manufacture of some types of workwear, inorganic (mineral) fibers, such as asbestos, can be used. In recent years, chemical fibers have become increasingly important, which are also divided into organic and inorganic. The main group of fibers of chemical origin is organic. They can be artificial or synthetic. Artificial fibers include viscose, acetate, triacetate, casein, etc. They are obtained by chemical processing of cellulose and other raw materials of natural origin. Synthetic fibers are obtained by chemical synthesis from oil, coal, gas and other organic raw materials. By origin and chemical structure, heterocidal and carbocidal synthetic fibers are distinguished. Polyamide (kapron, nylon, perlon, xylon, etc.), polyester (lavsan, terylene, dacron), polyurethane are heterocidal, polyvinyl chloride (chlorin, vinol), polyvinyl alcohol (vinylon, curalon), polyacrylonitrile (nitron, orlon ). The hygienic advantages or disadvantages of certain tissues primarily depend on the physicochemical properties of the original fibers. The most important hygienic value of these properties are air, vapor permeability, moisture capacity, hygroscopicity, thermal conductivity. Air permeability characterizes the ability of a fabric to pass air through its pores, which determines the ventilation of the underwear space, convection heat transfer from the surface of the body. The breathability of a fabric depends on its structure, porosity, thickness and moisture content. Breathability is closely related to the ability of a fabric to absorb water. The faster the pores of the fabric are filled with moisture, the less air-conducting it becomes. When determining the degree of breathability, a pressure of 49 Pa (5 mm of water column) is considered standard. Air permeability of household fabrics ranges from 2 to 60 l/m2 at a pressure of 1 mm of water. Art. According to the degree of breathability, windproof fabrics are distinguished (breathability 3,57-25 l / m2) with low, medium, high and very high air permeability (over 1250,1 l/m2). Vapor permeability characterizes the ability of a fabric to pass water vapor through the pores. Absolute vapor permeability is characterized by the amount of water vapor (mg) passing through 1 cm 2 of fabric for 2 hour at a temperature of 20 ° C and a relative humidity of 60%. Relative vapor permeability - the percentage of the amount of water vapor that has passed through the fabric to the amount of water that has evaporated from an open vessel. For various fabrics, this indicator fluctuates from 15 to 60%. Evaporation of sweat from the surface of the body is one of the main methods of heat transfer. Under conditions of thermal comfort, 1-40 g of moisture evaporates from the skin surface within 50 hour. Sweating over 150 g/h is associated with thermal discomfort. Such discomfort also occurs when the steam pressure in the underwear space exceeds 2 GPa. Therefore, good vapor permeability of the fabric is one of the factors for ensuring thermal comfort. Removal of moisture through clothing is possible by diffusion of water vapor, evaporation from the surface of wet clothing, or evaporation of sweat condensate from the layers of this clothing. The most preferred way to remove moisture is the diffusion of water vapor (other ways increase thermal conductivity, reduce air permeability, reduce porosity). One of the most important properties of a fabric in terms of hygiene is its hygroscopicity, which characterizes the ability of fabric fibers to absorb water vapor from the air and from the surface of the body and retain them under certain conditions. Woolen fabrics (20% or more) have the highest hygroscopicity, which allows them to maintain high heat-shielding properties even when moistened. Synthetic fabrics have minimal hygroscopicity. An important characteristic of fabrics (especially used for the manufacture of underwear, shirts and dresses, towels) is their ability to absorb liquid moisture. This ability is assessed by tissue capillarity. The highest capillarity is in cotton and linen fabrics (110-120 mm/h and more). Under normal temperature and humidity conditions, cotton fabrics retain 7-9%, linen - 9-11%, woolen - 12-16%, acetate - 4-5%, viscose - 11-13%, nylon - 2-4%, lavsan - 1%, chlorine - less than 0,1% moisture. The heat-shielding properties of a fabric are determined by thermal conductivity, which depends on its porosity, thickness, the nature of the interlacing of fibers, etc. The thermal conductivity of fabrics characterizes thermal resistance, to determine which it is necessary to measure the heat flux and skin temperature. The density of the thermal cover is determined by the amount of heat lost from a unit of body surface per unit of time, convection and radiation at a temperature gradient on the outer and inner surfaces of the tissue equal to 1 °C, and is expressed in W/m2. As a unit of the heat-shielding ability of the fabric (the ability to reduce the heat flux density), the value clo (from the English clothes - "clothes") is adopted, which characterizes the thermal insulation of room clothing, equal to 0,18 ° C m /2 h / kcal. One unit of clo provides a state of thermal comfort if the heat production of a calmly sitting person is approximately 50 kcal/m2 h, and the surrounding microclimate is characterized by an air temperature of 21 ° C, a relative humidity of 50%, and an air velocity of 0,1 m/s. Wet tissue has a high heat capacity and therefore absorbs heat from the body much faster, contributing to its cooling and hypothermia. In addition to those listed, such properties of the fabric as the ability to transmit ultraviolet radiation, reflect visible radiation, and the time for evaporation of moisture from the surface of the body are of great hygienic importance. The degree of transparency of synthetic fabrics for UV radiation is 70%, for other fabrics this value is much less (0,1-0,2%). The main hygienic advantage of fabrics made from natural fibers is their high hygroscopicity and good air conductivity. That is why cotton and linen fabrics are used for the manufacture of linen and linen products. The hygienic advantages of woolen fabrics are especially great - their porosity is 75-85%, they have high hygroscopicity. Viscose, acetate and triacetate fabrics, obtained by chemical treatment of wood pulp, are characterized by a high ability to absorb water vapor on their surface, they have high moisture absorption. However, viscose fabrics are characterized by prolonged evaporation, which causes significant heat loss from the skin surface and can lead to hypothermia. Acetate fabrics are close to viscose in their properties. However, their hygroscopicity and moisture capacity are much lower than those of viscose, and electrostatic charges are formed when they are worn. Synthetic fabrics have attracted particular attention of hygienists in recent years. Currently, more than 50% of the types of clothing are made using them. These fabrics have a number of advantages: they have good mechanical strength, are resistant to abrasion, chemical and biological factors, have antibacterial properties, elasticity, etc. The disadvantages include low hygroscopicity and, as a result, sweat is not absorbed by the fibers, and accumulates in air pores, worsening air exchange and heat-shielding properties of the fabric. At high ambient temperatures, conditions are created for overheating of the body, and at low temperatures, for hypothermia. Synthetic fabrics absorb water 20-30 times less than wool. The higher the moisture permeability of the fabric, the worse its heat-shielding properties. In addition, synthetic fabrics are able to retain unpleasant odors and are less washable than natural ones. Possible destruction of fiber components due to their chemical instability and migration of chlorine compounds and other substances into the environment and underwear space. Migration, for example, of formaldehyde-containing substances continues for several months and is capable of creating a concentration several times higher than the MPC for atmospheric air. This can lead to skin-resorptive, irritant and allergenic effects. Electrostatic voltage when wearing clothes made of synthetic fabrics can be up to 4-5 kV / cm at a rate of not more than 250-300 V / cm. Synthetic fabrics should not be used for underwear for newborns, toddlers, preschoolers and primary school children. In the manufacture of sliders and tights, the addition of no more than 20% of synthetic and acetate fibers is allowed. The main hygienic requirements for tissues of various origins are presented in Table 6. Table 6. Hygienic requirements for various types of fabrics.  Hygiene requirements for the various components of the clothing package The components of the clothing package perform different functions, and therefore the hygienic requirements for the fabrics from which they are made are different. The first layer of the clothing package is underwear. The main physiological and hygienic purpose of this layer is the absorption of sweat and other skin secretions, good ventilation between the skin and linen. Therefore, the fabrics from which linen is made must have high hygroscopicity, be hydrophilic, air and vapor permeable. These requirements are best met by natural fabrics. The second layer of clothing (suits, dresses) should ensure the creation of an optimal microclimate under the clothes, help to remove fumes and air from the linen and correspond to the nature of the work performed. In hygienic terms, the most important requirement for the second layer of clothing is its high vapor permeability. For the manufacture of suits and other types of the second layer, you can use both natural fabrics and synthetic ones. The most appropriate are mixed fabrics (for example, lavsan mixed with wool), which have improved sorption properties, reduced electrification, high vapor permeability, low thermal conductivity, combined with good performance and appearance. The main functional purpose of the third layer (outerwear) is protection from cold, wind, adverse weather conditions. Fabrics for this layer should have low thermal conductivity, high wind resistance, moisture resistance (low hygroscopicity), and abrasion resistance. These requirements are met by natural or synthetic furs. It is advisable to use combinations of different fabrics (for example, combine the upper wind and moisture protective layer made of synthetic fabric with a heat-insulating lining made of a mixture of artificial and natural fur, wool). For the manufacture of therapeutic knitted underwear, chlorine staple fiber was previously widely used. Chlorine underwear has good heat-shielding properties and, thanks to the so-called triboelectric effect (accumulation of an electrostatic charge on the surface of the material as a result of its friction against the skin), has a beneficial effect on patients with rheumatism and sciatica. This underwear is highly hygroscopic and at the same time air and vapor permeable. The disadvantage of chlorinated laundry is its instability to washing at high temperatures. In this regard, medical underwear made of polyvinyl chloride has an advantage. Antimicrobial underwear has been developed and is being used. Nitrofuran preparations can be used as bactericidal agents for antimicrobial linen. Additional requirements apply to children's clothing. Due to a less perfect mechanism of thermoregulation, a much larger specific ratio of the body surface to a unit of its mass in children than in adults, more intense peripheral circulation (a large mass of blood flows in the peripheral capillaries), they cool more easily in the cold season and overheat in the summer. Therefore, children's clothing should have higher thermal insulation properties in winter and promote heat transfer in summer. At the same time, it is important that the clothes are not bulky, do not impede movement, do not cause disturbances in the musculoskeletal tissues and ligaments. Children's clothing should have a minimum number of scars, seams, cut should be free. Differences in natural and climatic conditions in Russia also determine the hygienic requirements for clothing. 16 zones with different requirements for the heat-shielding properties of clothing have been identified. So, for example, for the zone of mixed and broad-leaved forests of the middle zone of the European part of Russia, a comfortable state in the summer is provided by clothing with thermal protection of 0,1-1,5 clo, in winter - 3-5 clo, depending on the nature and severity of the work. Shoe hygiene According to the purpose, household, sports, special working, children's, military, medical, etc. shoes are distinguished. Footwear must comply with the following hygiene principles: 1) have low thermal conductivity, ensure the optimal microclimate of the shoe space, its ventilation; 2) be easy to use, do not disturb the blood supply, growth and formation of the musculoskeletal elements of the foot, do not impede freedom of movement when walking, physical education and work processes, protect the feet from adverse physical, chemical and biological effects; 3) do not release chemicals into the shoe space in concentrations that can, under real operating conditions, have an adverse effect (skin-irritating, resorptive, allergenic, etc.) on the skin of the foot and the body as a whole; 4) respond to the age and other physiological characteristics of the organism; 5) easy to clean and dry, keep the original configuration and hygienic properties for a long time. The hygienic properties of footwear depend on the material from which it is made, the size and configuration of the foot, design features and performance. Various natural and artificial materials are used to make shoes. The indicators by which the advantages or disadvantages of a particular material are judged coincide with those that characterize the hygienic properties of clothing fabrics - thermal conductivity, moisture absorption, air and vapor permeability. Materials made of genuine leather have good hygienic properties. They are elastic, moderately breathable, have low thermal conductivity, do not emit harmful chemicals into the shoe space. This is very important, because even with moderate physical activity, the foot of an adult can produce from 2 to 5 g of sweat per hour. The feet are most susceptible to cooling. The optimal temperature for maintaining a balance between heat generation and heat transfer inside the shoe is considered to be a temperature of 1-18 ° C, relative air humidity - 22-40%. BIBLIOGRAPHY 1. Guidelines for communal hygiene. Volume I / Under the editorship of Professor V. A. Ryazanov. M.: Medgiz. 1961. 2. Marzeev A. N., Zhabotinsky V. M. Communal hygiene. M.: Medgiz. 1979. 3. Pivovarov Yu. P. Hygiene and human ecology: a course of lectures. M.: VUNMTs of the Ministry of Health of the Russian Federation. 1999. 4. SanPiN 2.1.5.980-00 "Hygienic requirements for the protection of surface waters". 5. SanPiN 2.1.4.1175-02 "Hygienic requirements for the quality of non-centralized water supply. Sanitary protection of sources". 6. SanPiN 2.1.5.1059-01 "Hygienic requirements for the protection of groundwater from pollution". 7. SanPiN 2.1.4.1074-01 "Drinking water. Hygienic requirements for water quality in centralized drinking water supply systems. Quality control". 8. Methods of monitoring and managing the sanitary and epidemiological well-being of children and adolescents: A guide for students of medical and preventive faculties of higher medical educational institutions / N. D. Bobrishcheva-Pushkina, T. Yu. Vishnevskaya, V. R. Kuchma et al. / Under edited by prof. V. R. Kuchma M.: VUNMTs MZ RF, 1999. 606 p. 9. Methods for studying the physical development of children and adolescents in population monitoring: A guide for doctors / Ed.: A. A. Baranov, V. R. Kuchma, Yu. A., Yampolskaya et al., Ed. Academician of the Russian Academy of Medical Sciences A. A. Baranov and prof. V. R. Kuchma. M.: Union of Pediatricians of Russia, 1999. 226 p. 10. V. R. Kuchma. Kuchma, V.R., Raengulov, B.M., Skoblina, N.A., Physical development, state of health and lifestyle of children in the Arctic. M.: NTsZD RAMN, 1999. 200 p. 11. V. R. Kuchma. Guidelines for hygiene and health protection of schoolchildren / V. R. Kuchma, G. N. Serdyukovskaya, A. K. Demin. M.: Ros. Public Health Association, 2000. 152 p. 12. Assessment of the physical development and health status of children and adolescents, the study of medical and social causes of the formation of deviations in health: Methodological recommendations of the GK SEN RF No. 01-19 / 31-17 dated March 17.03.1996, 1996. M .: GK SEN, 55. XNUMX With. 13. SN 2.2.4 / 2.1.8.5622-96 "Noise at workplaces, in the premises of residential, public buildings and in residential areas." 14. SN 2.2.4/2.1.8.566-96 "Industrial vibration, vibration in premises of residential and public buildings". 15. G. I. Rumyantsev. Hygiene. M., 2000. 16. Yu. P. Pivovarov. Hygiene and human ecology. M., 1999. 17. Yu. P. Pivovarov. Guide to laboratory and practical exercises on hygiene and the basics of human ecology. M., 1998. Authors: Eliseev Yu.Yu., Lutsevich I.N., Zhukov A.V., Kleshchina Yu.V., Danilov A.N.
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