Soil, its hygienic and ecological significance. Soil as an environmental factor, its epidemiological role. The concept of soil contamination and self-cleaning, indicators of its sanitary state
The soil - integral object of the ecological system.
Along with sunlight, water and air, she is the most important component of the human environment and all biota on Earth.
Role of soil
1. Soil plays a leading role in the cycle of substances in nature.
It represents a huge natural laboratory, in which the most diverse and complex processes are continuously running
Destruction and synthesis inorganic and organic matter ,
Photochemical reactions.
2. Live and die in the soil pathogenic bacteria, viruses, protozoa and helminth eggs.
3. She is one of main routes of transmission
Infectious and non-infectious diseases,
Helminthiasis.
4. Soil can directly or indirectly affect the human body:
- toxic,
- allergenic,
- carcinogenic,
- mutagenic
5. Lack or excess of trace elements in the soil causes endemic diseases.
6. Closely related to the soil quantity and quality of products of plant and animal origin, i.e.... our food.
7. The soil significantly affects the climate of the area.
Therefore, you need to knowprocessesflowing in the soil, and theirpatternsto properly exercisepreventionadverse effect of soil on public health.
The soil - natural education, irreplaceable natural resource, the surface layer of the earth's crust containing minerals and organic matter.
Organic part of the soil consists of the remains of plants, animals, microorganisms.
Soil thickness ranges from several centimeters up to 2 m and more.
Even in ancient times, Hippocrates distinguished between "healthy" and "unhealthy" soils.
Ø Healthy areas were considered elevated, dry and sunny.
Ø K unhealthy included low-lying, cold, flooded, damp, with frequent fogs.
The soil consists of
1. parent rock (mineral compounds);
2. humus (humus);
3. living organisms;
4. air;
For a hygienic assessment of the degree of soil contamination as a control, it is very important to know it. natural composition.
The mineral composition of the soil includes almost all elements of D.I. Mendeleev. But of greatest interest are fluorine, iodine, manganese, selenium, since their increased or decreased content in the soil affects the formationnatural geochemical provinces, playing poles in emergence endemic diseases (fluorosis, caries, endemic goiter, etc.).
Humus soil – this is a fertile layer.
The destructive effect of water, wind and anthropogenic factors on the soil, the demolition of the most fertile upper layer or erosion is called soil erosion... Erosion causes great harm, since the soil has a number of properties that are disturbed by erosive changes in the soil.
Hygienic value of the composition and properties of the soil:
1. Is filter, traps solid suspensions.
2. Is medium for the accumulation of nutrients for plants.
3. Clay and humus adsorb harmful substances, preventing them from entering the groundwater.
4. The soil is capable of regeneration.
Filterability and the ability of the soil to regeneration defines her buffering capacity in relation to anthropogenic influences.
More than 90 types of soils.
However, 7 types are most common:
Tundra,
Sod-podzolic,
Gray forest,
Chernozems,
Chestnut,
Serozem,
Red earth.
The largest area is sod-podzolic soils.
Hygienists conditionally divide everything soil according to their purpose into 3 types:
1) natural soil outside populated areas;
2) artificially created soil of populated areas, mixed with waste of the population and industrial waste;
3) artificial soil coverings: asphalt, crushed stone, concreted, etc.
From a hygienic point of view, it is important classification soils on mechanical composition , on which its properties such as
Filtration capacity,
Air permeability, etc.
Soil layers
1. Of all soil layers, hygienists are primarily interested in the surface, arable layer (horizon).
This is, on average, a layer of soil 25 cm thick, which is processed when growing plants.
The hygienic value of this layerwhat exactly of it soil contaminants can enter agricultural plants, surface water bodies, atmospheric air, etc..
2. In addition to the surface layer, the soil layers that lie before the groundwater, in which the following occurs:
- neutralization of organic waste and waste water,
- shaping the quality of groundwater and soil air;
In these layers are laid sewerage and water supply networks and are laid foundations of residential and industrial buildings.
3. Soil layers in which there issoil water formation, got the nameHoffmann zones.
All of them five:
1) zone evaporation;
2) zone filtration;
3) zone capillary rise;
4) aquifer;
5) waterproof layer.
1) The thickness of the layer of the evaporation zone in central Europe is not more than 1 m.
This layer is very rich in organic matter, plant roots nest in it.
2) Water, having passed the evaporation zone, is filtered through the lower soil layer - the filtration (passage) zone. This is a powerful layer of soil... Each cubic meter of this soil layer can retain 150-350 liters of water. All atmospheric precipitation that fell on this area during the year can be retained in this layer..
3) After the passage area is filled with an amount of water exceeding its absorption capacity, excess water will be filtered into the layers below until it meets waterproof layer, practically impermeable to water. Such a waterproof layer can be rock (for example, granite, limestone, oily clay).
4) Filtering water lingers on this layer, accumulates and forms a zone of soil or groundwater, or the so-called aquifer.
5) From it, part of the water will rise upward, due to capillarity, to a height determined by the size of the pores of this soil layer. A zone of capillarity of the rise of soil waters is formed.
Soil properties.
1. Porosity - total pore volume in soil per unit volume, expressed as a percentage... How higher porosity, themes below filtration soil capacity... Porosity sandy soil is 40%, peat 82 %. In homogeneous soil the more pores how coarser granularity.
- the largest pores available in stony ground,
- very small - in clay,
- the smallest - in peat.
In addition to the natural porosity of the soil, it can contain channels and cracks artificially formed by animals and humans.
With a soil porosity of 60-65% in it optimal conditions for processes are created self-cleaning from biological and chemical pollution.
At higher porosity soil self-cleaning processes are getting worse. Soil of this type is rated as unsatisfactory.
2. Soil air permeability - the ability of the soil to pass air through its thickness.
Air permeability of the soil
Is increasing with growthbarometric pressure
And decreases with increase in thickness soil layer and its moisture .
Soil air movement and exchange it with atmospheric air occur constantly under the influence:
Differences in their temperatures
Fluctuations in atmospheric pressure
And the water level.
Soil permeabilityfor air and relatedenriching it with oxygen have great hygienic value, associated with biochemical oxidation processes flowing in the soil and
freeing her from organic pollution.
Healthy soil must be coarse-grained and dry , since damp and fine-grained soils are very poorly ventilated, and therefore, self-cleaning processes go wrong in them.
3. Water permeability, or filtration capacity of the soil, - it is the ability of the soil to absorb and pass water coming from the surface.
I. Phase one water permeability - absorption, when free pores are sequentially filled with water. With an excess of moisture, its absorption continues until the soil is completely saturated.
II. Second phase - filtration- characterized the movement of water in the soil pores under the influence of gravity when the soil is completely saturated with water.
Soil water permeability has a decisive influence on soil water formation and the accumulation of their reserves in the bowels of the Earth. This is directly related to the supply of water to the population from underground sources.
4. Soil moisture - this is the amount of water that the soil is able to retain in its depths by sorption and capillary forces.
The moisture capacity is the greater, the smaller pore size and the greater their volume.
The highest moisture capacity is possessed by peatlands (up to 500-700%).
Moisture capacity expressed in percentage to weight of dry soil.
Hygienic valuemoisture capacity of the soildue to the fact that
High moisture content causes dampness of the soil and buildings located on it,
- reduces the permeability of the soil to air and water
AND interferes with wastewater treatment.
Such soils belong to unhealthy, raw and cold.
5. Soil capillarity is the ability of the soil to lift water through the capillaries from the lower horizons to the upper ones.
Coarse-grained soils raise the water faster, but not to a great height.
The high capillarity of the soil can be the reason dampness of buildings.
Hygienic assessmentdegree of soil pollution inorganic compounds based on a comparison of the quantitative content of this element in the soil with its MPC:
For mercury - 2.1 mg / kg,
Chromium - 0.05 mg / kg,
Lead 20 mg / kg,
Manganese - 1500 mg / kg,
Arsenic - 45 mg / kg
Organic matter soil presented:
- actually organic(humic acids, fulvic acids, etc.), synthesized by soil microorganisms called humus,
AND organic substances alien to the soil entering the soil from the outside.
Soil pollution
Huge reserves are concentrated in humic substances carbon.
2-3 times increase in the carbon content of organic compounds indicates possible soil contamination.
Attitude carbon humus To vegetable carbon bears the name- coefficient of humification.
O degree of soil pollution also evidenced by the content:
Organic nitrogen
And the value of the sanitary number, or the number of N.I. Khlebnikov, how attitude humus nitrogen To total organic nitrogen.
In clean soil, the sanitary number is close to 1.
The lower the sanitary number, the dirtier the soil.
Sanitary and bacteriological examination of the soil consists of:
From the determination of the total number of microorganisms in it per 1 g,
The number of thermophiles per 1 g,
If-titer,
Titra-perfringens,
And in some cases, also the presence of staphylococcus and pathogenic microbes.
Highly sensitive to fresh faecal contamination is the detection of viable helminth eggs in the soil (in 1 kg).
The main sanitary and entomological indicator of soil pollution is the number of larvae and pupae of flies per unit area of soil(0.25 m 2).
Hygienic diagnostics of the soil can be carried out according to the indicators of the chemical composition of the soil air and according to the so-called complex parameters.
Ø An increased content of organic nitrogen and carbon without an increase in the amount of ammonia nitrogen, a low col-titer and a large number of helminth eggs indicate fresh fecal contamination of the soil in the absence of organic matter mineralization.
Ø A similar situation, but with the appearance of ammonia nitrogen, indicates the beginning of the process of mineralization.
Ø The simultaneous presence of organic nitrogen and carbon, ammonia nitrogen, nitrites, nitrates and chlorides indicates long-term soil pollution and the presence of intensive mineralization of organic products.
Ø Detection of nitrogen, nitrates, chlorides and low titer perfringens characterize long-standing soil contamination without the addition of fresh soil.
Hygienic value soil moisture is that all chemicals, as well as biological contaminants of the soil (helminth eggs, protozoa bacteria, viruses) can move in it only with soil moisture. In addition, all chemical and biological processes occurring in the soil, including its self-purification from organic compounds, are carried out in aqueous solutions.
Hygienic soil diagnostics is required first of all when choosing:
Land plots for the construction of residential and public facilities,
Water lines,
Places for facilities for neutralization and disposal of household waste,
And also for hygienic diagnostics of the state of the territory of populated areas.
It includes:
Sanitary and topographic survey of the site,
Physical and mechanical analysis,
Sanitary-bacteriological, virological, helminthological, entomological, sanitary-toxicological and radiometric studies.
The endemic significance of the soil
Soil is an element of the Earth's biosphere that forms chemical composition foodstuffs consumed by humans, drinking water and atmospheric air.
Ø Plants grown in alkaline soils, with high content selenium can cause emergence"Alkaline disease" of livestock (selenium toxicosis),poisoning people.
Ø A link has been established between the level of arsenic in soils and the incidence of stomach cancer,
At present, in addition to natural soil regions endemic for one or another chemical element, there have appeared artificial biogeochemical regions and provinces as a result of human economic activity and the introduction of waste.
All soil contaminants can be divided into
Chemical
And biological (viruses, bacteria, protozoa, helminth eggs).
Chemical pollutants are divided into two groups:
1) chemical substances introduced into the soil in a systematic, purposeful, organized way (mineral fertilizers, plant growth stimulants, pesticides, etc.);
2) chemicals that enter the soil by accident with man-made liquid, solid and gaseous waste(household and industrial waste, exhaust gases, etc.).
The danger of compounds of both the first and second groups is determined by their –
Toxicity
Mutagenic,
Allergenic types of exposure, dangerous to human health.
So, for example,
Ø Soil contamination with fluorine from industrial emissions leads to the occurrence of leaf necrosis in grapes and apricot trees, and then the development of fluorosis in people eating fruits of plants.
Ø With an increased content of mercury, an increase in the incidence of diseasesnervous and endocrine system, genitourinary organs; in men, decreased fertility (the ability to produce offspring);
Ø As a result of the intake of lead from the soil into the human body, changes are observed on the part of the hematopoietic and reproductive systems, as well as malignant neoplasms.
Soil as a factor in the transmission of infectious diseases
There are not many infectious agents in clean, uncontaminated soil.
These are mainly pathogens:
- wound infections(tetanus, gas gangrene),
- botulism,
- anthrax.
it spore-forming microorganisms that are long-term (20-25 years) persist in soil.
Contaminated soil can play the role of a factor in the transmission of infections to humans, such as:
Dysentery, typhoid fever,
Giardiasis, leptospirosis, viral hepatitis, etc.,
the survival time of pathogens of which can fluctuate up to several months.
Soil plays a specific role in the transmission helminths whipworms, roundworms.
Ascaris eggs can remain viable in soil for up to 7-10 years.
Soil contaminated organic matter , serves as a habitat for rodents that are sources of such dangerous infections, how rabies, plague.
Contaminated soil is a favorable place for development flies "House flies", which are active carriers of pathogens intestinal infections and other infectious diseases.
Soil as a natural environment for waste disposal
The soil is the life support system of the Earth, an element of the biosphere in which detoxification occurs - neutralization, destruction, transformation into non-toxic compounds, the bulk of organic substances entering it.
1. The organic matter in the soil in the form of proteins, fats, carbohydrates and their metabolic products undergoes decomposition up to the formation of inorganic substances - the process of mineralization.
2. Parallel to this process, the process is taking place in the soil. synthesis from organic substances,waste of new complex soil organic matter. This substance is called humus, and the process of its synthesis is called humification.
Both processes mineralization and humification , aimed at restoring the original state of the soil, received the name soil self-cleaning processes.
Simultaneously with oxidative processes in the soil, reduction processes also take place.... The degree of the regenerative action of bacteria, in addition to their biochemical characteristics, depends on the composition of the medium, its reaction, and other conditions. The denitrification process is accompanied by the formation of gases.
Sanitary protection of soil
Undersanitary protection of soilunderstand a set of measures aimed at limiting the entry of various contaminants into the soil to values that do not violate the self-cleaning processes in the soil, do not cause the accumulation of harmful substances in plants in quantities hazardous to human health, and do not lead to air, surface and groundwater pollution.
Events can be divided into several groups.
1. Legislative, organizational, administrative measures, which is understood as a system of legally documented measures aimed at preventing soil pollution, ensuring the rational use of land resources in the interests of preserving and strengthening the health of the population.
2. Planning activities which include:
The correctness of the allotment of the site for the construction of structures
Neutralization and disposal of waste
And the observance of sanitary protection zones around them.
3. Technological measures, aimed at creating waste-free and low-waste technological production schemes.
4. Sanitary measures for the collection, removal, decontamination and disposal of waste(sanitary cleaning of populated areas).
Under sanitary cleaning of populated areas imply a set of measures for the collection, disposal, neutralization and destruction of solid waste generated in populated areas in order to preserve the health of the population and general improvement.
Waste is divided into 2 groups: liquid and solid.
Liquid include:
Sewage from the restrooms
Slop (from cooking, washing dishes),
Waste water (domestic, industrial, atmospheric, from sidewalk washing).
To solid:
Garbage (brownie)
Street estimate
Catering waste
Waste from industrial and trade enterprises
Waste and waste of animal origin (animal carcasses, manure)
Slag from boiler houses
Construction garbage
Distinguish 3 systems waste disposal:
1) floatable (sewage);
2) export (in non-canalized settlements). This method of solid waste disposal is called cleaning, and liquid waste - sewage;
3) mixed (in partially sewerage points). Collection of solid household waste can be carried out using garbage chutes (in residential buildings), waste bins (stationary), containers (removable). For garbage disposal use special garbage trucks... An innovation is the use of pipelines for waste disposal (pneumatic waste disposal).
All waste must be subject to neutralization to avoid the spread of infections.
Neutralization methods should meet the following requirements:
1. Epidemiological waste safety, especially medical ones.
2. Rapidity waste disposal.
3. Prevention of development fly larvae and creating an enabling environment for rodent development.
4. Rapid transformation organic substances into compounds that do not decay and do not pollute the air.
5. Protection of ground and surface waters from pollution.
6. Maximum and safe use of useful waste.
Everything solid waste may be subject
Utilization (processing into organic fertilizers, biofuels, etc.) and
Liquidation (landfill, sea discharge, incineration).
By technology neutralization methods are divided into:
1) biothermal - improved landfills, plowing fields, sewage fields;
2) thermal - combustion in special furnaces at a temperature of 900-1000 ° C, pyrolysis with the production of combustible gas and oil-like oils at a temperature of 1640 ° C and oxygen deficiency);
3) chemical (hydrochloric or sulfuric acid at high temperatures in order to obtain ethyl alcohol);
4) mechanical - pressing into building blocks.
The most widespread are biochemical and thermal methods.
The best is the biothermal method, which is often used as composting.
To form compost, a flat area is tamped with clay and surrounded by a clay roller 10-15 cm high and a groove, the width of the area is 1.52 m, the length is arbitrary. Composting material (peat, earth) is placed on the site with a layer of 10-15 cm, then a layer of garbage up to 15 cm is laid, covered with a layer of composting material. Then a layer of garbage is added again, covered with it, etc., until the height of the compost reaches 1.5 m. The compost is covered with straw mats.
Due to the vital activity of thermophilic microorganisms in the compost, biochemical processes and the garbage heats up to 50-70C, organic matter mineralized , and pathogenic microbes, helminth eggs and fly larvae perish.
The compost is shoveled every 1-2 months and periodically moisturize.
The ripening process lasts 12 months.
Ripe compost - loose, free-flowing mass of dark earthy color.
The benefits of composting include
The environment is not polluted,
Pathogenic microbes die
The result is a valuable fertilizer.
Collection of liquid household waste
Collection of liquid household waste ( feces, urine, slop) is carried out in toilets (closets).
Toilets can be canalized (water closet - toilet bowl and cistern) and non-canalized (backlash closets).
Sewerage - a system of structures that receives, transports wastewater through a network of underground pipelines outside the village.
In the absence of a sewerage system, removal is carried out by tank trucks to drainage stations.
Exists 2 ways to neutralize liquid household waste:
1) sanitation fields, on which it is produced as neutralization of sewage and sowing of agricultural crops;
2) plowing fields, where sewage is neutralized without sowing crops.
Industrial waste are divided into recyclable - are not destroyed and are used as fuel, fertilizers and non-recyclable(must be destroyed).
For this, methods are used:
Thermal ( incineration of waste at temperature 1000-1200 C);
Burial at landfills ( liquid - in steel and concrete boxes; pasty- in pits with bottom and sidewall insulation).
Waste water is the water discharged by a piping or duct system after being used in a household or production activities human.
Wastewater is divided into
- urban(washed, household, from hospitals, baths, laundries),
- showers(rain, thawed),
- agricultural.
The scheme for draining water after use in everyday life is as follows:
Through sanitary devices (sinks, bathtubs, toilets), water flows through the internal sewerage system to the external network within the microdistrict.
Intra-quarter networks are connected by street sewerage network into sewerage pools,
From which wastewater is discharged to the treatment plant by collectors.
Depending on the relationship between domestic and storm sewers, the following systems are distinguished:
1) separate - consists of two networks: household, storm;
2) semi-divided - consists of two networks, united by a common collector;
3) general-purpose water - domestic and storm water is discharged through one network to treatment facilities.
Wastewater treatment stages.
1. Mechanical cleaning (up to 50% efficiency), for which are used
- lattice holding large debris;
- grit traps for settling heavy particles;
- sedimentation tanks for sedimentation of undissolved suspended solids.
2. Biological treatment, the main purpose of which is decay and mineralization of organic matter. To do this, use: filtration fields, irrigation fields; biofilters(crushed stone, slag); bioponds(in which a mixture of waste water and activated sludge flows).
3. Disinfection of waste water.
Use bleach... Efficiency is assessed by coli-index(no more than 1000) and residual chlorine(not less than 1-1.5 mg / l).
Soil microflora
The soil is the main reservoir and natural habitat for microorganisms that take part in the processes of soil formation and purification, as well as the cycle of substances in nature.
The vital activity of microorganisms in the soil, their qualitative and quantitative composition is determined by soil conditions: the presence of nutrients, humidity, aeration, the reaction of the environment, temperature, etc.
The type of soil has a great influence on both the total number and the ratio of individual systematic groups of microorganisms.
Differing in physical and chemical properties, the soil is a different environment for the life of microorganisms. There are more of them in moist and cultivated soil, less in forest soil, in sands.
The microflora is most abundant in the upper soil horizon with a depth of 2.5-15 cm. In this layer, the main biochemical processes of the transformation of organic matter, caused by the vital activity of microorganisms, take place.
At a depth of 4-5 m, the number of microorganisms is significantly reduced, as the amount of nutrients decreases and the aeration conditions deteriorate.
The following groups of microorganisms are distinguished in the composition of the soil microflora
Bacteria ammonifiers that cause rotting of animal corpses, plant residues, decomposition of urea with the formation of ammonia and other products: aerobic bacteria - B. subtilis, B. mesentericus, Serratia marcescens; bacteria of the genus Proteus; mushrooms of the genus Aspergillus, Mucor, Penicillium; anaerobes - C. sporogenes, C. putrificum; urobacteria - Urobacillus pasteuri, Sarcina urea, which break down urea;
Nitrifying bacteria: Nitrobacter and Nitrosomonas (Nitrosomonas oxidize ammonia to nitrous acid, forming nitrites, Nitrobacter converts nitrous acid to nitric acid and nitrates);
Nitrogen-fixing bacteria: assimilate free oxygen from the air and, in the course of their life, synthesize proteins and other organic nitrogen compounds used by plants from molecular nitrogen;
Bacteria participating in the cycle of sulfur, iron, phosphorus and other elements - sulfur bacteria, iron bacteria, etc. (sulfur bacteria oxidize hydrogen sulfide to sulfuric acid, iron bacteria oxidize iron compounds to iron oxide hydrate, phosphorus bacteria contribute to the formation of easily soluble phosphorus compounds);
Bacteria that break down fiber, causing fermentation (lactic acid, alcohol, butyric acid, acetic acid, protionic, etc.).
With human and animal secretions, with fecal and household waste water pathogenic and opportunistic microorganisms (causative agents of fungal diseases, botulism, tetanus, gas gangrene, anthrax, brucellosis, leptospirosis, intestinal infections, etc.) can enter the soil.
Sanitary and bacteriological study of soil
When examining the soil, a complete or short analysis can be carried out.
A complete sanitary and bacteriological analysis of the soil is carried out:
For a detailed and deep characterization of the sanitary state of the soil;
To determine the suitability of the soil when placing housing, recreational facilities, childcare facilities and water supply facilities;
For epidemiological research.
Brief analysis It is recommended for the implementation of current sanitary supervision and includes the determination of the total number of saprophytic bacteria, BGKP (coli-titer and coli-index), clostridium (perfringens titer), thermophilic bacteria, nitrifying.
The complete sanitary-bacteriological analysis includes additionally: determination of actinomycetes, fungi, salmonella, shigella, tetanus pathogens, botulism, brucellosis, anthrax.
Determination of the total number of saprophytic bacteria
Microbial number of soil - the total number of microorganisms contained in 1 g of soil.
Determination of coliform bacteria
Coli-index - the number of viable E. coli in 1 g of soil.
Soil-titer is the smallest amount of soil in which viable E is found. coli.
Determination of perfringens titer
Soil perfringens titer is the smallest amount of soil by weight, expressed in grams, in which a viable C cell is found. perfringens.
Determination of perfringens titer is an important criterion for the sanitary assessment of the soil and its self-cleaning. The perfringens titer makes it possible to judge the age of faecal contamination.
Determination of thermophilic bacteria
The number of bacteria per gram of soil.
Sanitary and microbiological assessment of soil
It is produced according to a set of indicators.
For the sanitary assessment of the soil, it is necessary to use the indicators in Table 1.
Table 1
Scheme of the sanitary state of the soil according to microbiological indicators
1.The reason for the development of methemoglobinemia in humans can be the introduction into the soil:
a) potash fertilizers
b) phosphorus fertilizers
c) nitrogen fertilizers
d) pesticides
2. If contaminated soil gets into a person's wound, it can cause the development of:
a) cholera
b) salmanelosis
c) gas gangrene
d) tetanus
3.Indicators of the sanitary condition of the soil are:
a) sanitary number
b) if-titer
c) titer of anaerobes
d) the number of helminth eggs in a gram of soil
e) the number of earthworms per square meter of soil
4. The following pathogens cannot remain viable in the soil for a long time:
a) Bac.anthracis
c) Cl.perfringens
d) Cl.Botulinum
5. "Healthy soil" should be:
a) coarse-grained, wet, with high porosity
b) coarse-grained, dry, with low porosity
c) fine-grained, dry, with low porosity
d) fine-grained, wet, with high porosity
6. Soil has a big impact on:
a) microclimate of the area
b) micro-relief of the area
c) construction and improvement of populated areas
d) vegetation development
7. Transmission of pathogens of intestinal diseases to humans from the soil occurs:
a) through foodstuffs
b) through damaged skin
c) with water from underground sources
d) from surface waters
8.Select the appropriate indicators of standards typical for clean soil:
9. The transmission factor of which infectious diseases is soil:
a) tuberculosis
c) typhoid fever
d) dysentery
e) diphtheria
f) anthrax
10. An increased content of nitrates in the soil with a low amount of chlorides indicates:
a) about long-standing soil pollution
b) about recent soil pollution
c) about constant soil pollution
d) on periodic soil pollution
11. Find the logically correct endings of the statements:
12. Select the appropriate characteristics:
13. Find the right conclusions:
14. Find the right conclusions.
(according to K.D. Pyatkin)
The danger of infection, of course, also exists through direct human contact with the soil. In such cases, diseases of tetanus, gas gangrene, the causative agents of which are among the spore-bearing anaerobes and are permanent inhabitants of the soil, are possible. Tetanus spores are most often found in garden and vegetable garden soil fertilized with manure, as well as in other places contaminated with animal excrement. In case of various traumatic injuries of the skin, together with soil particles and dust, tetanus spores enter the damaged tissues and can cause a serious illness, releasing a potent toxin.In order to prevent it, it is necessary to immediately inject tetanus serum even with minor injuries, scratches and abrasions contaminated with soil and dust.
Athletes should be well aware of this, since during athletics, football and other sports, damage to the skin is possible. In the classroom in gyms with dirty floors there is also a risk of skin lesions.
Soil contaminated with the secretions of anthrax-infected animals or their carcasses may contain anthrax spores that persist for years. Once in the human body, they germinate and most often cause the skin form of the disease, less often the pulmonary and intestinal.
The importance of soil is especially great as a specific factor in the transmission of a number of helminthic diseases, the so-called geohelminthiasis (ascariasis, hookworm infection, etc.).
Bacterial soil contamination in settlements should be taken into account when choosing sites for the construction of outdoor sports facilities. Often it is necessary to remove the surface layer of the soil and replace it with a new one that meets not only sports and technical, but also sanitary and epidemiological requirements. In rural settlements, it is strictly forbidden to set aside sports grounds for places that were previously used for keeping livestock.
A rational system for the removal and disposal of sewage and waste plays a decisive role in preventing soil pollution in cities and towns.
Chemical and radioactive contamination of soil
In connection with the growth of chemicalization of agriculture, the issue of soil contamination with chemical agents used to fertilize the soil and to combat pests and diseases of agricultural plants and weeds has acquired a topical hygienic importance. Chemical substances used as mineral fertilizers, as a rule, have insignificant toxicity. However, on a soil oversaturated with fertilizers, root crops grow, containing excessive concentrations of nitrates, which cause various serious disorders of human health.
Pesticides used to combat pests and diseases of plants and increase yields are, in most cases, potent toxic substances, sometimes with carcinogenic and other harmful properties. Their negative effect on the human body can manifest itself not only through direct contact with them during work, but also as a result of their accumulation in the soil, penetration from it into underground waters, into plants, and with them into the body of animals and then with products of plant and of animal origin - into the human body. Pesticides cause various acute and chronic poisoning.
In order to prevent their adverse effects on the human body in Russian Federation the list and doses allowed for use in agriculture pesticides (hexochlorane, metaphos, etc.) and developed rules for their use.
The soil, as already noted, can be exposed to radioactive contamination. Subsequently, radioactive isotopes enter plants, and through them - into the body of herbivorous animals.
Hygienic rationale for the choice of soils for sports facilities
Mechanical, physical and Chemical properties soils are important for physical culture and sports. Even in ancient times, people understood the advantages of a non-swampy, dry and elevated area over a low-lying, swampy and damp area. The water, thermal and air regimes of the soil have a great influence on the state of health of a person and people involved in sports and physical culture. The high standing of soil water causes dampness in sports facilities, high air humidity and, therefore, affects the microclimate of the area. The thermal properties of the surface layer of air depend on the thermal regime of the soil.
At the same time, the soil (a complex of physical and chemical properties and structure - the lithosphere) is involved in creating not only vital conditions external environment(biosphere), but also the dispersed environment of the atmosphere. As a result of air movement, soil trace elements are dispersed in the external environment. They are of vital importance for the normal functioning of the human body, and especially physical culture and sports activity. When choosing a construction site for a sports facility, it is necessary to be guided by the basic hygienic requirements for the soil of a sports site:
The site should not be flooded with rain or melt water;
The soil must be dry;
Groundwater should be at a depth of at least 0.7 m;
For the construction of sports facilities, coarse-grained soil is most preferable;
The soil must be epidemically and toxicologically safe.
Control questions and tasks
1 What is soil?
2 Indicate the main properties of the soil.
3 Indicate the composition and physical properties of the soil
4 What types of soil do you know?
5 Give the hygienic characterization of the soil
6 What is the epidemiological significance of soil?
7 What hygiene requirements applied to the soil in the planning and construction of sports facilities?
Chapter 6 HYGIENE OF HARDENING
Hardening is one of the most powerful and effective health-improving means of physical education. It allows not only to maintain and improve health, but also to increase efficiency.
Under hardening it is understood an increase in resistance - adaptation of the human body to the action of various unfavorable climatic factors (cold, heat, solar radiation) due to the use of a complex of systematized and purposeful measures.
Hardening is organized for a professional (production) purpose (preparation for work in certain climatic conditions in the north, south, in the mountains); for the purpose of general health promotion; increasing mental and physical performance; increasing the resistance of the human body to the action of adverse factors the environment.
Physiological basics of hardening
Hardening is based on training the central and peripheral links of the thermoregulatory apparatus, improving the mechanisms that regulate the return and generation of heat. The constant systematic and purposeful strictly dosed effect of irritating factors leads to the development of adaptive reactions that reduce the body's sensitivity to their action. This increases the resistance of the human body to changing environmental factors. The leading role in this belongs to the human central nervous system.
In the process of onto- and phylogenesis in the human body, certain physiological and biochemical mechanisms have been developed that ensure its resistance to the effects of a complex of unfavorable meteorological factors. The human body is able to effectively adapt to changes in meteorological and temperature conditions, to withstand even significant fluctuations in air temperature, while maintaining the thermal equilibrium of the body.
The body's heat balance is achieved as a result of complex thermoregulatory processes. On the one hand, there is an optimal dynamic fluctuation in the volume and intensity of heat production due to changes in the intensity of redox processes that provide the formation of thermal energy, on the other hand, a simultaneous restructuring of the body's heat exchange through its heat transfer to the external environment.
At low temperatures in the human body, the mechanisms of heat production are enhanced, while the diameter of the vessels of the skin decreases, the redistribution of blood flow between the skin and internal organs.
The range of functional capabilities of human thermoregulation mechanisms can be significantly expanded after applying a complex of targeted, systematic hardening procedures.
The mechanism of the healing action of hardening at the subcellular level is identical to the mechanism of action of physical training: a deficiency of ATP and creatine phosphate is created and the phosphorylation potential increases. The genetic apparatus of cells is activated, the production of mitochondria - the energy "factories" of the cell, increases.
The energy capacity of the cell (the power of mitochondria), the production of ATP per unit of tissue mass increase, its deficiency is eliminated, therefore, adaptation to cold, hypoxia and physical activity develops.
As a result of hardening, not only thermoregulation is improved, but also some changes occur in the morphological structure and physicochemical properties of various tissues of the body. Repeated temperature irritations cause thickening of the epidermis, a decrease in the water content in the skin, hardening of biological calloids, etc. This increases the body's resistance to unfavorable meteorological factors in the external environment.
Activation of energy processes contributes to the normalization of fat and carbohydrate metabolism and plays a positive role in the prevention of atherosclerosis, hypertension, diabetes and obesity.
When hardened, immune mechanisms are sharply activated. Through the central nervous system and its subcortical formations (hypothalamus), the functional state of the pituitary gland, the endocrine gland, which controls the action of all endocrine glands, is activated. The main role in enhancing immunity during hardening procedures is the effect of the pituitary gland on the thymus (thymus) gland and adrenal glands. The functioning of the main immune mechanisms - lymphocytes and antibodies - depends on this gland, as a result of which the body's resistance to various infections caused by bacteria and viruses is significantly increased, control over the appearance of foreign malignant cells is improved, their destruction occurs, which creates an obstacle to the development of oncological diseases.
The functioning of the adrenal cortex is accompanied by an increase in the formation of its hormone - cortisone. This enhances the action of immune mechanisms, reduces the possibility of allergic reactions and diseases, increases the body's adaptive abilities to stressful influences and, in particular, to such as excessive physical exertion, climatic factors, mental irritants, excessive neuro-emotional stress.
Thus, cold hardening strengthens health, increases mental and physical performance, resistance to infectious, allergic, malignant diseases, atherosclerosis, obesity, diabetes. For athletes, hardening allows them to quickly adapt to training loads, achieving a more effective impact. The danger of an adverse effect on the body of physical and mental overstrain decreases, the risk of a decrease in immune defense at the peak of sports form decreases.
The result depends on the type of hardening factor (air, water, sun), the method of its application (rubdown, bathing, shower, swimming), physical activity during this period, the intensity and duration of the procedures, the level of hardening. The local action of the procedures is especially important, for example, hardening of the nasopharynx, legs, chest for the prevention of upper respiratory tract infections.
The intensity of the procedures should increase gradually, since the body quickly adapts to hardening activities. Therefore, their use should be systematic, daily or even twice a day.
If hardening is irrational, acute and chronic diseases of the upper respiratory tract (runny nose, sinusitis, bronchitis, tonsillitis, pneumonia), kidneys (nephritis), joints (arthritis) may develop. This most often occurs when the principle of the correspondence of the strength of the stimulus to the age-sex functional capabilities and individual characteristics of the organism is violated.
Hygienic principles of hardening
The principle of complexity. The greatest health-improving effect of hardening is possible only with the simultaneous targeted use of a complex of various hardening agents (sun, air, water).
The principle comes from the physiological nature of hardening. The physiological effects on the body of each agent used are complementary during the hardening process, which expands the range of compensatory-adaptive reactions of the body and enhances the health-improving effect of hardening.
The principle of systematicity. A hardening agent will have a healing effect only if it is applied regularly, without long interruptions. Multiple and systematic short-term thermal effects with a gradual increase in the strength of irritation lead to the formation of a stable adaptation of the human body to a specific stimulus. Reflex responses change significantly during the hardening process, and some of them fade away, and instead of them new ones appear that have a greater adaptive effect. In the establishment of new functional relationships between the organism and the environment, the leading role is played by the formation of conditioned reflex neural connections, which ensure the effective adaptability of the organism to changing temperature conditions. Hardening procedures must be applied day after day, and not from case to case, since the trace reactions that occur after individual procedures are not properly fixed. With forced long breaks, hardening is resumed with weaker procedures compared to those that were used the previous time.
The principle of gradualness: a stepwise increase in the strength of the influencing stimuli. For example, when starting water procedures, you need to start with cool water and gradually move on to colder water.
The principle of optimal dosing of procedures. The correct dosage is the one that most closely matches the functional characteristics and capabilities of a particular person, including his state of health. Therefore, all procedures and methods of hardening are strictly age-related. When choosing a hardening agent, the main thing is the strength of the stimulus, and not the duration of its exposure. In this regard, hardening sessions should not be excessively increased.
Quenching at low temperatures
Physiological bases of cold hardening. The main hygienic value of various ambient temperatures lies in their effect on the heat exchange between the body and the environment: high temperatures make it difficult to recover, while low temperatures, on the contrary, increase it. Thanks to the perfection of thermoregulatory mechanisms, integrated and controlled by the central nervous system, a person is able to adapt to various temperature conditions and can tolerate even significant deviations from optimal temperatures for a short time.
Changes in the external temperature activate the physiological mechanisms of heat generation and its release into the environment: a person, on the one hand, changes the conditions for heat loss, and on the other, he effectively adapts to the external temperature, changing the amount of heat generated.
The change in the value of heat production is explained by chemical thermoregulation. At low air temperatures (starting from + 15 ° С), the decomposition of nutrients in the body, which serve as a source of thermal potential energy, increases, while at high temperatures (above + 25 ° С) it decreases. The activation of metabolism at low temperatures also occurs due to the involuntary contraction of the muscles (muscle tremors).
Heat transfer occurs on the basis of physical thermoregulation. With temperature irritations of the skin thermoreceptors, the lumen of the peripheral vessels of the skin changes. If the temperature is low, they narrow, the blood moves into deep-lying tissues, to the internal organs, protecting them from cooling. At the same time, the temperature of the skin decreases, and the difference between it and the ambient temperature becomes smaller, which reduces the transfer of heat. If the air temperature is high, the blood vessels dilate, the blood flow to the periphery increases, the skin temperature rises and there is an increased heat release. Most of the heat is lost from the skin surface as a result of:
radiation to colder surrounding objects (about 45%);
convection, i.e. layer-by-layer heating of air adjacent to the body and usually in some motion (about 30%);
evaporation of moisture from the skin and mucous membranes of the respiratory tract (about 25%).
The rest of the heat is spent on warming food, inhaled air and is lost with secretions - up to 10%. At rest and thermal comfort, heat loss by convection is 15.3%, by radiation - 55.6%, by evaporation - 29.1%.
The given values of heat losses are approximate and typical for a state of rest at room temperature. At high or low ambient temperatures and during physical work, they change significantly. Starting from a temperature of + 30 ° С, heat transfer through radiation and convection decreases and evaporation increases, which becomes the only way of heat transfer at temperatures above +37 ° С. Heat dissipation by convection also occurs when it comes into contact with soil or other colder surfaces.
Thanks to the regulation of heat generation and heat transfer, the human body is able to maintain a constant body temperature with significant fluctuations in the ambient temperature, however, the limits of thermoregulation are far from unlimited.
Hardening is carried out when exposed to low ambient temperatures on the skin and mucous membranes of the upper respiratory tract.
The skin consists of two layers: the upper - the epidermis (epithelial cells with the outer layer of keratinized scales) and the lower - the dermis, which is a conglomeration of blood and lymphatic vessels, sweat glands, hair follicles, nerve receptors located in the supporting connective tissue.
In the body's reaction to the action of a temperature stimulus (air or water procedure), three phases are distinguished.
In the first phase (when cold air is inhaled), small arteries (arterioles) spasm in the skin and mucous membranes of the upper respiratory tract, blood supply and skin temperature decrease, thereby reducing heat transfer. Thus, a constant body temperature is maintained. In slightly hardened people, the first phase is more pronounced both in the degree of decrease in the temperature of the skin and mucous membranes, and in the duration of this reaction.
This feature of the body's reaction is used to determine the degree of hardening. A vessel with cold water (for example, 4 ° C) is applied to the skin and the degree of decrease in the local temperature at the point of contact and the duration of its recovery are determined.
The first phase of the reaction to cold serves as a trigger for the development of the second phase. Reflexively, through the neuroendocrine system, metabolism is enhanced, energy production by skeletal muscles, liver, internal organs, the blood supply increases, the blood vessels of the skin expand, the number of capillaries functioning in the skin increases.
In the second phase, the body maintains a constant body temperature through more intense heat production. These processes are especially important in the hardening mechanism.
When carrying out each hardening procedure, it is necessary to reach this phase and prevent the development of the third phase, since it appears due to overvoltage and disruption of regulatory and protective mechanisms and serves as a sign of an overdose of the hardening procedure. In this phase, the blood flow in the skin slows down, it acquires a bluish tint, "goose bumps" appear, the person feels an unpleasant chill.
The hardening effect is manifested in a more rapid onset and persistent retention of the second phase of the reaction. With hardening, the intensity of cold irritation increases. However, there is a specificity in the development of physiological mechanisms of hardening, depending on the strength of cold stimulation.
The body can adapt to the action of predominantly moderate but prolonged cooling factors (prolonged exposure to air with a moderate drop in temperature, prolonged swimming in moderately cold water) or to strong but relatively short-term cold factors (swimming in ice water - winter swimming).
The first type of hardening obviously plays more important role in preserving and improving human health, increasing its resistance to the action of infectious and non-infectious environmental factors. And not only because of the peculiarities of physiological reactions, but also because of the greater prevalence of these factors in everyday life and working conditions and due to the availability of hardening.
Air hardening hygiene standards
Air baths begin to be taken at a room temperature of +18 ... + 20 ° C, completely or partially exposing the body (up to panties, bathing suit). Starting with a 10-minute duration of the procedure, it is increased daily by 3-5 minutes and up to 30-50 minutes. Depending on the age and state of health, hardening is stopped at a temperature of +12 ... + 15 ° C. The criterion for the adequacy of the procedure to the functional capabilities of the body is the state of health. The appearance of a feeling of chills, "goose bumps" indicates an overdose of hardening procedures.
It is very effective to combine air hardening with simultaneous exercise (Tables 20, 21).
Moscow region
METHODOLOGICAL DEVELOPMENT
Topic: Soil, its physical and chemical properties, hygienic and ecological significance
MINISTRY OF HEALTH OF THE MOSCOW REGION
state budgetary educational institution
secondary vocational education
Moscow region
Kolomna Medical College
METHODOLOGICAL DEVELOPMENT
Discipline: Hygiene and human ecology.
Topic: Atmospheric air, its physical and chemical properties, hygienic and ecological significance
Development for teachers and self-training of students
Teacher: E.V. Klopkova
Theme: Soil, its physical and chemical properties, hygienic and ecological significance.
Activity type: The study new topic... Thematic control.
Methods and technologies for studying the topic:
Explanation of teaching material, use of ICT and problem-based learning
Control of knowledge of the topic
Independent work
Target:
Reveal the importance of soil as an element of the biosphere that determines environmental and hygienic conditions
Time spending: theory - 2 hours (1 lesson)
practice - 4 hours (2 lessons)
Location: hygiene cabinet
Equipment: computer, demonstration projector, multimedia manuals.
Students should know:
The role of soil in the spread of diseases. Content of anthropogenic chemicals in the soil. Soil protection ways.
Self-cleaning of the soil, indicators of soil pollution, collection and disposal of household waste.
Students should be able to:
To identify the causes of diseases, the factor of which is the soil.
Topic study plan
Methodological justification
The study of this topic takes 2 hours (1 lesson)
|
I lesson |
time |
methodological rationale |
|
1.Organizational part |
It is carried out with the aim of activating students, setting them up to study the topic. Give a certain direction to the lesson. |
|
|
2.The main part |
Explanation of educational material using a multimedia manual. |
|
|
3.The final part a) answers to questions b) the formulation of the main questions to control the level of knowledge. Formulation of the problem. |
In order to clarify the incomprehensible points of the material. It is given to prepare for thematic control and discussion of the problem. |
|
|
Summing up the results of the lesson |
Soil, its physical and chemical properties, hygienic and ecological significance.
1. Soil - as a factor of the external environment.
2. Composition and properties of the soil. The role of soil in human life. Soil-forming factors. Anthropogenic processes, the value of anthropogenic impurities.
3. Geochemical significance of the soil. Relationship of soil with the occurrence of endemic diseases. Ways of influence of soil pollution on humans.
4. Self-cleaning of the soil. Sanitary and hygienic indicators of soil pollution.
5. Soil as a factor in the spread of infectious diseases, helminths.
6.Sanitary protection of the soil. Requirements for the design and operation of the simplest facilities for the collection and disposal of household waste.
7. Cleaning systems.
Soil- called the upper layer of the earth's crust, formed by the main soil-forming factors, climate, vegetation, soil organisms.
In different climatic conditions, the soil is different in composition. Climate is a slow and constant factor affecting the soil. Vegetation sharply and in a short time affects soil formation. Soil organisms - bacteria, fungi, viruses, protozoa, worms, etc., influence the soil in a short time.
Soil as a factor of the external environment
Soil, as an integral part of the ecological system, along with sunlight, water, ambient temperature, is the most important component of the human environment.
The soil plays a leading role in the cycle of substances in nature. It is in constant interaction with other ecological systems, such as the atmosphere, hydrosphere, flora.
The soil is an important link in the pathway of food and toxic components entering the human body. It is a huge natural laboratory in which the most varied and complex processes of destruction and synthesis of inorganic and organic substances, photochemical reactions are continuously taking place. Soil is a food source that provides 95-97% of food resources for the world's population.
The soil significantly affects the climate of the area. Pathogenic bacteria, viruses, protozoa and helminth eggs live and die in it. It is one of the main routes of transmission of a number of infectious and non-infectious diseases, helminthiases. Soil can directly or indirectly have toxic, carcinogenic, mutagenic and other effects on the human body. Lack or excess of trace elements in the soil causes endemic diseases. Therefore, it is necessary to know the processes occurring in the soil and their regularities in order to correctly implement the prevention of the adverse effect of the soil on the health of the population.
The area of land resources of the world is 129 million km2, or 86.5% of the land area.
The fund of chernozem soils in Russia occupies approximately 120 million hectares, which is about 7% of the total area. About 80% of all agricultural products are produced on these arable lands.
Soil is a natural formation that lies between the atmosphere and the underlying rocks. The thickness of the soil ranges from a few centimeters to 2 m or more. The soil consists of parent rock (mineral compounds), dead organic matter, humus (humus), living organisms, air and water.
Several layers (or horizons) can be seen in a vertical section of the soil. The sequence of these horizons is called soil profile.
The top (or arable) soil layer contains plant roots, fungi, microorganisms, many different soil insects and animals. In this horizon, the main circulation of organic matter takes place. All unused organic material from different trophic levels is recycled again and decomposes here, first to humus, and ultimately to inorganic compounds.
The parent rock is a complex of mineral compounds consisting mainly of sand, clay, lime and silt, including salts of silicon, magnesium, aluminum, etc. Depending on the ratio of sand and clay, all soils are divided into sandy, sandy loam, clayey and loamy. More than 90 types of soils are found on the territory of Russia. Taking into account the size of the particles, stony (more than 3 mm), sand (0.2-3 mm), clay (0.001-0.01 mm), colloidal fraction of humus are distinguished - humus. Coarse-grained soils, as a rule, have good air and water permeability, while fine-grained soils are characterized by significant water capacity, high hygroscopicity and capillarity. From a hygienic point of view, the most favorable is the soil, which has a high air and water permeability, since these properties contribute to the processes of self-cleaning, ensuring the normal thermal regime of the surface layer of the atmosphere.
Hygienic value of the composition and properties of the soil
From a hygienic point of view, it is important to know the basic properties of the soil in order to be able to conclude whether this or that soil will be healthy or unhealthy. These include porosity, air and water permeability, moisture capacity, capillarity, temperature, soil organisms.
Porosity- total pore volume per unit volume of soil, expressed as a percentage. Its filtration capacity depends on this property: the higher the porosity of the soil, the lower this capacity. With a porosity of 60-65%, the best conditions for self-cleaning processes are created.
Air permeability- the ability of the soil to pass air. It depends on the size of the pores of the soil, increases with an increase in atmospheric pressure and decreases with an increase in the thickness of the soil layer and its moisture content.
High air permeability is a favorable hygienic property, as it promotes soil aeration, i.e. saturation with oxygen necessary for the oxidation of organic substances.
Water permeability (filtration capacity) - the ability of the soil to absorb and transmit water, which comes mainly from precipitation. This property is important for the formation of soil water and its reserves in underground layers.
Moisture capacity- the amount of moisture that the soil is able to hold with the help of sorption and capillary forces. The smaller the pores and the larger their total volume, the larger it is. The hygienic value of this property lies in the fact that high moisture capacity contributes to soil dampness, a decrease in air and water permeability, and impairs self-cleaning processes. Soils with this property are considered damp, cold and therefore unhealthy.
Capillarity- the ability of the soil to lift water through capillaries from deep layers to the upper ones. The more small pores in the soil, the more capillary it is and the higher the water rises through it.
Soil temperature affects the temperature of the surface layer of the atmosphere, the thermal regime of the premises of the 1st floor and basements, as well as the vital activity of soil microorganisms and self-cleaning processes.
The degree of heating of the soil by the sun depends on the geographic location of the area, its relief, season, day and the nature of the soil. The slopes facing southerly heat up more and more quickly, the dark color of the soil contributes to the absorption of heat, and the light color - its reflection, dry soils warm up faster than moist soils. Daily fluctuations in air temperature are reflected to a depth of no more than 1 m.However, in severe frosts, the soil can freeze to a depth of 1-2 m, which must be taken into account in construction practice when laying water and sewer pipes, laying the foundations of buildings.
In the cold climate of the northern regions, the soil never thaws at a certain depth, forming a layer of permafrost.
Soil organisms... The natural inhabitants of the soil are various representatives of soil flora and fauna, the number of which is variable and depends on the composition of the soil, its temperature regime, insolation, mechanical processing and other factors. The soil flora includes fungi, algae, bacteria and viruses. The fauna is represented by unicellular organisms, protozoa, nematodes, ticks, larvae and pupae of flies, earthworms, mammals (moles, mice, rats, etc.).
Soil organisms have a direct and indirect effect on the state of the soil, contributing to the processes of self-purification and increasing fertility.
Soil has a huge impact on the properties and composition of groundwater and water in open reservoirs. It always contains a certain amount of moisture that came with atmospheric precipitation or that rose through capillaries from the underlying layers of the earth, as well as formed as a result of the absorption of water vapor from the atmospheric air. Water is essential for the existence of living organisms and the growth of plants. The hygienic value of soil water is great and varied. It serves as a universal solvent for organic and mineral compounds, as a vehicle for the delivery of chemicals to plants. Soil moisture significantly affects the thermal properties of the soil, increasing its heat capacity and thermal conductivity. Groundwater is formed from soil water. The chemical and bacterial composition of drinking water is largely determined by the composition and properties of the soil.
The amount of soil air is determined by the properties and nature of the soil. Soil air is constantly exchanged with atmospheric air. Soils always contain an increased amount of carbon dioxide compared to atmospheric air (up to 8%), the oxygen content in the soil decreases to 14%. With limited access of air, putrefactive processes develop in the thickness of the waste with the release of fetid gases and vapors (hydrogen sulfide, ammonia, hydrogen fluoride and others), capable of toxic effects on the human body in appropriate concentrations.
Geochemical significance of soil
The earth's crust (soil) contains more than 60 different chemical elements. The absence or excess of one or another element leads to the appearance of endemic diseases (biogeochemical endemia).
The standard for the quality of the natural chemical composition of the soil is the soil of the Kursk Chernozem Reserve.
Under the guidance of Professor V.V. Kovalsky, the staff of the biogeochemical laboratory of the Institute of Geochemistry and Analytical Chemistry of the Russian Academy of Sciences carried out a large amount of important work to study the content and distribution of micro- and macroelements in 130 regions of the country, compiled a general map and an atlas. A new scientific direction has emerged - geochemical ecology of endemic diseases.
Geochemical ecology of endemic diseases studies the influence of micro- and macroelements on the human body. Studies have shown that diseases common in different regions are directly related to the peculiarities of the chemical composition of the soil and food products produced in these territories. Trace elements enter the human body according to the scheme: soil-plant-animal organism, human. A deficiency or excess of trace elements in the soil leads to a deficiency or excess of them not only in herbivores, but also in carnivores and humans. This entails a violation of the intermediate metabolism and the occurrence of endemic (from the Greek. Endemos - local) diseases.
In particular, it was found that a lack of copper and cobalt leads to anemia, hepatitis, osteodystrophy, and a high lead content leads to the occurrence of gingivitis. Lack of fluoride contributes to tooth damage, and high levels of molybdenum and copper cause gout.
Thyroid disease is widely known, caused by the low content of cobalt, copper, chromium, molybdenum, manganese, and iodine in the soil. Scientists associate another serious illness - Kashin-Beck disease (Uvskaya disease) - with an increased strontium content in the soil, an excess intake of phosphorus and manganese with water, as well as a low calcium content in drinking water.
The reason for the influence of trace elements on the spread of diseases is that they have high biological activity and are involved in many life processes.
Self-cleaning and soil pollution
The soil cover belongs to a self-regulating biological system, which is the most important part of the biosphere as a whole. The soil, especially its upper layers, is constantly polluted with all kinds of waste hazardous to human health, and if it did not have the ability to neutralize them, life on Earth would become impossible.
The natural process of freeing the soil from organic compounds and pathogenic microorganisms contained in the sewage that has got into the soil is called self-cleaning.
Self-cleaning of the soil begins with a partial retention of bacteria, viruses and helminth eggs in its thickness and gradually leads to a decrease in their number when passing through the soil layers. At the same time, under the influence of complex processes with the use of mechanical, physicochemical, biological and biochemical absorption capacity of the soil, sewage gradually discolor, lose its bad smell.
The soil converts epidemiologically dangerous organic substances into inorganic minerals, humus, gases and water by processes of mineralization, nitrification and humification.
The decomposition and mineralization of organic matter in the soil occurs under aerobic and anaerobic conditions.
Aerobic processes proceed with an abundance of oxygen in the presence of aerobic microorganisms, in this case, organic matter decomposes and oxidizes without the formation of foul-smelling gases.
Anaerobic processes take place in an anoxic environment with the participation of anaerobic putrefactive bacteria, accompanied by the release of ammonia and hydrogen sulfide.
From a hygienic point of view, an aerobic process of decomposition of organic matter is preferable.
The self-cleaning capacity of the soil is not unlimited and it should be loaded with waste only to those limits that do not impede a sufficient access of oxygen.
As a result economic activity humans, a huge amount of chemicals enters the soil directly or indirectly, which significantly change its chemical composition. The degree of soil pollution is most intense in the area of non-ferrous metallurgy enterprises (450 times higher than the background), instrumentation (300 times) and ferrous metallurgy (250 times) and less intense near machine-building and chemical enterprises... Highways pose a particular environmental hazard. In the United States, a study of a 50-meter-wide strip along the sides of a highway showed that earthworms are dramatically enriched in lead, zinc, nickel and cadmium due to soil contamination. Birds that eat these worms die from heavy metal poisoning.
All chemicals that enter the soil can be divided into 2 groups:
a) chemical substances introduced into the soil in a planned, expedient, organized manner: mineral fertilizers, pesticides, soil structure-forming agents,
growth stimulants;
b) chemicals that get into the soil accidentally with man-made liquid, solid and gaseous waste.
Geographically, this is associated with specific types of industry. Such territories suffer from an excess of certain chemicals that are included in the human biological cycle.
The main criterion for assessing soil pollution by chemical substances is the maximum permissible concentration (MPC) or roughly permissible concentration (APC) of chemicals in the soil. Assessment of the degree of danger of soil pollution by chemical substances is carried out for each substance.
Chemical substances of exogenous origin, when they accumulate in the soil, almost completely suppress the entire biocenosis of the soil, distort the self-purification processes.
The compensatory forces of the soil are sufficient only when the soil contamination is very small in terms of quantity. A sharp increase in the load on soil processes leads to inhibition of self-purification and a sharp change in soil biocenosis.
The sanitary state of the soil is assessed by a number of indicators, one of which is the sanitary number, or the Khlebnikov number, which represents the ratio of soil humus nitrogen to the total organic nitrogen of the soil. In clean soil, it is 0.98-1.0, and in highly polluted soil - 0.7 or less.
To assess soil contamination with microorganisms, special bacteriological indicators are used (coli-titer, titer of anaerobes, etc.).
Epidemiological significance of soil
The soil is a natural receiver of solid and liquid waste of human and animal life, which may contain pathogens of various diseases. Fortunately, most pathogens that enter clean, uncontaminated soil die more or less quickly. In soil contaminated with organic matter, they are able to save life
failure long enough.
For example, the causative agent of typhoid fever can survive in such soil for up to 12 months, cholera up to 4 months, dysentery up to 2, tuberculosis up to 7 months. Ascaris eggs remain viable in the soil for up to 1 year, and the larva in the egg goes through the soil cycle of development, becoming invasive. Therefore, roundworms, whipworms, pinworms and hookworms are called "geohelminths" in contrast to "biohelminths" (bovine and pork tapeworm, echinococcus, cat fluke), which require an intermediate host for development.
The causative agents of anaerobic infections and anthrax are considered to be long-term inhabitants of the soil, the spores of which in the soil remain viable for decades.
The epidemiological role of soil is the possibility of transmission of such infections as intestinal (typhoid fever, dysentery, cholera, etc.), anaerobic (tetanus, botulism, gas gangrene), dust (tuberculosis), viral (poliomyelitis, viral hepatitis A), zoonotic ( anthrax, glanders, brucellosis), geohelminthiasis (ascariasis, entero-biosis, ankylostomiasis, etc.).
Infection with these infections occurs by direct contact through a soil-contaminated wound surface (wound infections - tetanus and gas gangrene), hands contaminated with soil, and indirectly through soil-contaminated water, food, animals, insect vectors, mainly flies.
The soil serves as a medium for the development of the larvae of insects harmful to humans, such as fleas, flies, mosquitoes and horseflies. The presence of a large number of flies is a clear indicator of sanitary problems, as it indicates a violation of the deadlines for removing solid waste from settlement... The period of development of a fly from larva to sexually mature individual is from 4 to 7 days. Flies are very active carriers of pathogens, primarily intestinal infections.
Soil contaminated with organic matter contributes to the development of rodents, which are sources and carriers of pathogens of especially dangerous infections (rabies, tularemia, plague).
Sanitary protection of soil
Sanitary protection of the soil in populated areas is a set of measures aimed at preventing and eliminating such changes in the composition and properties of the soil, which can have a harmful effect on the health and well-being of people.
The Federal Law "On the Sanitary and Epidemiological Welfare of the Population" (1999) regulates the requirements for soils, maintenance of populated areas and industrial sites, as well as for the collection, use, disposal, transportation, storage and disposal of production and consumption waste.
Soil sanitary protection solves the following tasks:
Preservation of the natural properties of the soil, ensuring its fertility and the content of biomicroelements;
Prevention of soil pollution by toxic, carcinogenic and radioactive substances with emissions and wastes of industrial enterprises, pesticides and fertilizers used in agriculture;
Prevention of soil pollution by organic substances, pathogenic microorganisms and helminth eggs contained in sewage.
Considering all this, the cleaning of populated areas from solid and liquid wastes seems to be a very important sanitary and hygienic task.
Waste classification:
Solid waste;
Liquid waste.
Currently, the removal and disposal of liquid wastes does not present such an acute problem as the problem of disposal and disposal of solid waste.
Liquid waste in the presence of a sewer enters a closed network, thereby not polluting either the soil or the air. Removal of liquid waste by fusion through pipes is economically cheaper than removal.
Sanitary cleaning of solid waste is currently a very serious problem. The significance of this problem is determined by the fact that all over the world there is a process of increasing household waste per person. A huge amount of solid waste accumulates on the surface of the earth, polluting the soil.
Sanitary cleaning from solid waste implies a certain stage of implementation: waste collection, storage, removal to the place of neutralization. When organizing the collection of solid waste, it is necessary to know their qualitative and quantitative composition. The qualitative composition determines the possibility of processing waste by different methods. The qualitative composition of solid waste determines the epidemiological significance of waste. In the epidemiological study of solid waste, it should be borne in mind that municipal solid waste contains a large number of pathogenic bacteria and viruses.
Correct determination of the amount of solid waste will allow you to calculate the required number of waste bins. The calculation is based on the rate of garbage accumulation per year per person, which is 1000 liters. The volumetric weight of 1 m3 of waste is 0.2 t, i.e. 1 m3 weighs 200 kg.
Removal of solid household waste all over the world is carried out exclusively by road transport.
Solid waste disposal methods pose a significant problem for the treatment system. These methods can be divided into 2 groups:
Liquidation;
Recycling.
The choice of waste disposal method depends on its composition and collection method, as well as on the economic significance of its collection. In the world, the most popular are methods for neutralizing solid waste by incineration and composting of waste. The most expensive method for neutralizing solid waste is incineration (50% more expensive than composting). The most cost-effective method of disposal is composting, which is based on aerobic waste processing. A promising direction in the disposal of solid waste is the construction of composting plants - representing an industrial enterprise for the processing of garbage and solid waste. At these factories, the waste processing process is completed within 5 days.
In Russia, about 3-4% of the total amount of solid waste is composted.
The problems of sanitary protection of the soil are extremely urgent for our country, despite its vast territories.
I. Sanitary and chemical indicators:
Sanitary number - the ratio of humus to organic nitrogen (for clean soil, the norm is 1 or more)
II.Sanitary and bacteriological indicators
Coli titer - titer 1 cell per 1000
III. Sanitary and helminthological indicators
in clean soil - no helminth eggs
IV.San-entomological indicators
The presence of larvae and pupae of flies
Clean soil - no
Contaminated - more than 25 per S = 0.25m2
V. Alyulogical indicators
Soil bloom - presence of microscopic algae
1.Clean soil - yellow-green algae
2.Medium dirty - green
3.Lightly polluted - yellow-brown
4.Highly polluted - blue-green algae
Prevention of soil contamination
Cleaning of populated areas in cities.
The organization of cleaning is an indicator of the sanitary-hygienic level of the population.
I waste collection
Sewerage is required in all houses with internal water supply:
Centralized cleaning (or floatable)
Decentralized (or export)
Basic systems
Scheduled regular cleaning system with replaceable dishes
Scheduled regular system with non-replaceable dishes
Planned apartment cleaning system
To install garbage containers, there must be an asphalted area of 6 by 10 m, located at a distance of 20 meters from the nearest entrance and no more than 100 meters from the furthest.
II. Neutralization and disposal of waste
All methods are divided into 3 groups:
Group 1 - soil methods, these include:
a) organization of plowing fields
b) agricultural irrigation fields
c) agricultural greenhouses
Group 2 - biothermal methods, these include:
a) improved landfills
b) composting
Group 3 - mechanical methods, these include:
a) mechanical installations
b) incineration
c) waste recycling plants
Cleaning up rural settlements
I. Centralized treatment - small sewerage
Small treatment facilities are being set up
Small filtration fields
Small irrigation fields
Biological ponds
Composting plants
II.Local cleaning
Arranged for each individual structure.
Types: Areas of underground filtration, irrigation
Filter well system
Filter trenches with natural or artificial soil layers
Sand and gravel filters
Test control
8. Soil - the surface layer of the soil, transformed under the influence of climate factors (water, air, temperature fluctuations), living organisms and purposeful human activities. Consists of solid, liquid (soil solution), gaseous and living parts.
9. The soil provides a person with food, work, a healthy living environment. Disruption of self-purification processes caused by pollution can have an adverse effect on the health of people and animals: the spread of infectious and invasive diseases, deterioration in the quality of food, water sources, atmospheric air.
10. Soil pollution is the appearance in its composition or on the surface of substances that are not a natural component and are not characteristic of this type of soil or its local varieties.
11. Household and industrial waste ends up in the soil, so the essential role of soil in the spread of infectious diseases is understandable. In uncontaminated soil, pathogens do not find favorable conditions for the existence of conditions and die after a few hours or days. But when overloaded with pollution, as well as when processing disinfectants that are destructive for biocenoses, the ability of the soil to self-purify is suppressed, and pathogenic microorganisms can remain viable for a long time. A variety of pathogens of intestinal infections, tetanus, gas gangrene, botulism, anthrax, tuberculosis, pathogenic staphylococci, leptospira, hepatitis viruses, poliomyelitis and others can be found in soil with a reduced self-cleaning ability. In the soil, spores of anaerobes, causative agents of especially dangerous infections, can remain viable for decades. Infection with pathogens in the soil is possible through dust, through direct contact with contaminated soil particles, through vegetables grown on such soil, through rodents or flies and other insects, when contaminated soil gets into a wound, through contaminated water, etc.
13. Soil, or earth, is a natural formation, the neck between the atmosphere and the underlying pores. The thickness of the soil ranges from a few centimes to 2 m or more. The soil is composed of maternal trawl compounds), dead organic matter; humus (humus) ;: organisms; air and water On a vertical section of the soil, you can see several layers, or gori-ev. The sequence of these horizons is called the soil pros. The top, or arable, soil layer contains plant roots, fungi, microorganisms, many different soil insects and animals. In this zone, the main circulation of organic substances takes place. All unused organic material from various trophic levels is again lysed and decomposed here, first to humus, and ultimately to organic compounds. Humus consists of lignin, fiber, protein complexes and other anic compounds. Humic acids, which are part of humu-, are high-molecular compounds formed from the decomposition of lignin, fiber, proteins, fats and carbohydrates. Humus helps to preserve water in the soil and maintains it in a loose state. The subsoil, located under the topsoil, contains inorganic compounds that were formed as a result of the decomposition of organic
14. l of substances. 1<Третий слой почвы - материнская порода, на основе которой образовалась чва. Этот слой состоит в основном из глины, песка, извести, ила, включаю-; соли кальция, магния, алюминия и другие макро- и микроэлементы. Считается, что тип почвы, образующийся в конкретном регионе, зависит от ямата данной территории, хотя растения, животные и материнская порода сят свой вклад в формирование почвы. Температура и осадки - это два магических фактора, которые оказывают наибольшее влияние на процесс жирования почвы. Процесс образования почвы идет очень медленно, за-в зонах умеренного климата тысячи лет. |!Гипы почв различаются определенными комбинациями почвенных гори-эв. В зависимости от соотношения песка и глины все почвы делятся на чые, супесчаные, глинистые, суглинистые. На территории России встреча-I более 90 видов почв, из них наиболее часто 7: тундровые; дерново-подзоли-г, серые лесные; черноземы; каштановые; сероземы; красноземы. уктура почвы зависит от взаиморасположения твердых минеральных и мческих компонентов и степени заполнения пор в ней воздухом комковатую. ^Почвенные вода и воздух определяют пористость, воздуха- и водопроницае-
15. b, moisture capacity, capillarity, thermal regime of the soil. Soil water. Soil has a tremendous impact on the properties and composition of water and open water bodies. The soil always contains this or the amount of moisture that came with atmospheric precipitation or lifted through the capillaries from the underlying layers of the earth, as well as the water vapor formed in the process of absorbing water vapor from the atmospheric air. Water is essential for the existence of living organisms and the growth of plants. Hygienic value: the soil water is large and varied. It serves as a universal solution for organic and mineral compounds, as a transport for dosage I chemical substances to plants. Soil moisture significantly affects the thermal properties of the soil, increasing its heat capacity and thermal conductivity. Groundwater is formed from soil water. The chemical and bacterial composition of drinking water is largely determined by the composition and properties of the soil.
16. Soil air. Its amount is determined by the property and nature of the soil. Soil air is constantly exchanged with ambient air. The soil air of even clean soils always contains an increased amount of carbon dioxide compared to the atmospheric one (up to 8%), the oxygen content decreases to 14%. With limited air access, putrefactive processes develop in the thickness of the waste with the release of fetid gases and vapors (hydrogen sulfide, ammonia, hydrogen fluoride, indole, skatole, methyl mercaptan), which are capable of toxic effects on the human body in appropriate concentrations. The hygienic value of soil air is determined by its composition and the conditions of human contact with it. There are known cases of soil air poisoning, for example, when digging wells, deep pits, laying underground structures. Soil air significantly affects the human body in recreation areas, populated areas, residential areas.
17. Porosity. Soil porosity should be understood as the total pore volume per unit volume of soil, expressed as a percentage. The higher the porosity, the lower the filtration capacity of the soil. So, the porosity of sandy soil is 40%, peat - 82%. With a porosity of 60-65%, optimal conditions are created in the soil for self-cleaning from biological and chemical pollutants. With a higher porosity, the self-cleaning process of the soil slows down. This type of soil is considered unsatisfactory.
18. Air permeability. Air permeability is understood as the ability of the soil to allow air to pass through. This property of the soil is primarily determined by the size of its pores. Air permeability increases with increasing barometric pressure and decreases with increasing layer thickness and soil moisture. The high permeability of the soil to air contributes to its enrichment with oxygen, which is of great hygienic importance, as it increases the biochemical processes of oxidation of organic substances.
19. Water permeability. Water permeability, or filtration capacity, is understood as the ability of the soil to absorb and pass water coming from the surface. This property of the soil has a decisive influence on the formation of soil waters and the accumulation of their reserves in the bowels of the earth. Soil water permeability is directly related to the supply of the population with water from underground sources.
20. Moisture capacity. The moisture capacity of the soil is understood as the amount of moisture that the soil is able to hold by sorption and capillary forces. The water capacity is the greater, the smaller the pores of the soil and the greater their total volume. and water, target the following structural types of soil: loose, cohesive (aggregate-fissured,
21. The hygienic value of this soil property is due to the fact that high moisture capacity creates the preconditions for dampness of the soil and buildings located on it, reduces the permeability of the soil to air and water and interferes with the purification of wastewater. Such soils are unhealthy, damp, and cold.
22. Soil capillarity. The capillarity of the soil is understood as its ability to lift water through the capillaries from the lower horizons to the upper ones. The less granular the soil, that is, the more finely porous it is, the greater its capillary capacity, the higher the water rises along it. The high capillarity of the soil can cause dampness in buildings.
23. Soil temperature. The temperature of the surface layer of the atmosphere, the thermal regime of the premises of the basements and the first floors of buildings largely depend on the temperature of the soil. At a depth of 1 m, the soil has no daily temperature fluctuations. At 8 m, the soil maintains its lowest temperature in May and the highest in December. This is important for storing food in basements, where it is cooler in summer and warmer in winter than on the surface. Soil temperature significantly affects the life of soil organisms and self-purification processes. Stony and dry soils with a slope facing south and southeast heat up faster.
24. Coarse-grained soils, as a rule, have good air and water permeability, fine-grained - significant water capacity, high hygroscopicity and capillarity. Hygienically, for housing and communal construction, you should choose areas with coarse-grained soil.
25. Soil organisms. Creatures living in the soil have both direct and indirect effects on it. Among them there are radiant fungi (actinomycetes), algae, bacteria, viruses that form the soil flora. In addition, the soil is inhabited by unicellular organisms, protozoa, nematodes, ticks, springtails, spiders, snails, beetles, larvae and pupae of flies, earthworms, and vertebrates representing the soil fauna. The number of organisms is subject to significant fluctuations due to the composition and chemical properties of the soil, temperature regime, solar radiation, aeration, mechanical soil cultivation, etc.
26. Soil is of great epidemiological importance. In it, pathogens of many infectious diseases, as well as eggs and larvae of helminths, can be found and transmitted to humans by direct contact and indirect (through dust, water, animals, food, drinks) (Fig. 6.2).
27. Pathogenic microorganisms enter the soil with physiological excretions of humans and animals, sewage, corpses, etc. Clean, uncontaminated soil is unfavorable for pathogenic non-spore microorganisms. In soil, especially contaminated with organic matter, they remain viable for a long time. So, in the soil, the bacteria typhoid-paraty-
29. Classification of waste
30. Liquid waste: Solid waste:
31. impurities (feces and urine); - street estimates;
32. slops (dirty water from prepared - house garbage;
33. lingering food, washing the body, dishes, - food leftovers;
34. floors, laundry); - kitchen, household and pro
35. industrial waste water and turf wastes;
36. Govyh enterprises, baths and laundries - - animal corpses, slaughterhouse waste;
37. ny, polluted meteoric waters. - manure.
38. Sanitary and epidemiological significance of liquid and solid waste
39. Physiological excretions of people and animals, slops, sewage make up the smallest part of waste, but their removal and disinfection are given priority due to their high epidemiological significance and unpleasant odor. Many wastes contain organic matter, water and provide a good breeding ground for microorganisms, among which there may be pathogenic bacteria (Table 6.4).
40. Waste plays an exceptional role in the spread of helminthic invasions. In cesspools, ascaris eggs last up to 6 months, in contaminated soil - up to 1 year. Household waste serves as a breeding ground and a reservoir for feeding flies. Carrying pathogenic microorganisms, flies can contaminate food and kitchen items. Flies are carriers of many infectious diseases, especially gastrointestinal diseases. Waste accumulations serve as a breeding ground and habitat for mice and rats, which are carriers of plague, tularemia, and leptospirosis.
41. Waste poses not only an epidemiological but also a toxicological hazard. More than 100 chemical compounds can be contained in solid household waste, including mercury, cadmium, lead, arsenic, thallium, Table 6.5. The main stages of the removal and disposal of liquid and solid waste
42. Self-cleaning soil- a complex physicochemical and biochemical process of converting pollutants into harmless to humans and animals, as well as to plants in contact with them. Such transformations occur in the soil environment itself, as well as during the transition of pollutants into air, water, and flora.
The effectiveness of self-cleaning depends on many factors, including the chemical composition and structure of the soil, its temperature and humidity regimes, the composition and characteristics of biocenoses, as well as the nature of soil cultivation and other agrotechnical measures. As a result of self-cleaning, the organic part of the pollution turns into minerals or humus (humus), pathogenic microorganisms and helminth eggs die off, and the number of microorganisms per unit of soil mass decreases. In the process of self-cleaning, some harmful chemical compounds (industrial poisons, pesticides, components of rocket fuels) are destroyed.
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