water supply sources"

Student assignment:

1. Familiarize yourself with regulatory documents in the field of water supply hygiene and methods of laboratory water analysis.

2. Having received a water sample, write down its passport data.

3. Conduct organoleptic and physicochemical studies of the quality of drinking water and compare the obtained data with standard values.

4. Make a conclusion about the quality of drinking water and the conditions for using water supply sources based on the results of water analysis and inspection of the water source.

5. Solve a situational problem of assessing the quality of drinking water and choosing a source of water supply.

Working method:

Determination of organoleptic properties of water

The smell of water indicates the presence of polluting chemicals and saturation of water with gases. The smell is determined at temperatures of 20 0 C and 60 0 C. A flask with a capacity of 150-200 ml is filled with water to 2/3 of the volume. Covering it with a watch glass, shake it vigorously and then, quickly opening it, determine the smell of the water. Qualitatively, the smell is characterized as “chlorine”, “earthy”, “putrefactive”, “swampy”, “petroleum”, “pharmacy”, “undefined”, etc. .d. The odor is assessed quantitatively on a five-point scale (Table 34).

Table 34. Scale of intensity of odor and taste of drinking water

Smell	Description of odor intensity	Points
None	No smell or taste is noticeable
Very weak	It is felt only by an experienced analyst when water is heated to 60 0 C
Weak	It is felt, if you pay attention to it, even when the water is heated to 60 0 C
Perceptible	It is felt without heating and is significantly noticeable when water is heated to 60 0 C
Distinct	Attracts attention and makes water unpleasant to drink without heating
Very strong	Harsh and unpleasant, water undrinkable

With a centralized water supply system, the odor of drinking water is allowed to be no more than 2 points at 20 0 C and 60 0 C and ≤ 2-3 points - with a non-centralized (local) water supply system.

Taste of water determined only if it is certain that it is safe. The oral cavity is rinsed with 10 ml of the test water and, without swallowing it, the taste (“salty”, “bitter”, “sour”, “sweet”) and taste (“fishy”, “metallic”, “uncertain”, etc.) are determined. .). The intensity of the taste is assessed on the same scale.

Water clarity depends on the content of suspended solids. Transparency is determined by the height of the water column through which text printed in standard Snellen font can be read. The water to be tested is shaken and poured to the top into a special glass cylinder with a flat bottom and an outlet valve at the bottom, which is fitted with a rubber tip with a clamp. Place a cylinder of water over the Snellen font at a distance of 4 cm from the bottom of the cylinder and try to read the text through the thickness of the column of water in the cylinder. If the font cannot be read, then using a clamp on the rubber tip of the cylinder, gradually pour water into an empty vessel and note the height of the water column in the cylinder at which the letters of the font are distinguishable. Drinking water must have a transparency of at least 30 cm.

The degree of water transparency can also be characterized by its reciprocal value - turbidity. Turbidity is determined quantitatively using a special device - a turbidity meter, in which the water being tested must be compared with a standard solution prepared from infusor soil or kaolin in distilled water. Water turbidity is expressed in milligrams of suspended matter per liter of water. A turbidity of 1.5 mg/l for coalin is equal to a transparency of 30 cm; with a transparency of 15 cm, the turbidity is 3 mg/l.

Water color caused by the presence of substances dissolved in water.

The color of water is determined qualitatively by comparing the color of filtered water (100 ml) with the color of an equal volume of distilled water. Cylinders with samples are examined over a white sheet of paper, characterizing the water being tested as “colorless,” “faint yellow,” “brownish,” etc.

Quantitative determination of color is carried out by comparing the color intensity of the test water with a standard scale, which allows it to be expressed in conventional units - degrees of color.

The color scale represents a set of 100 ml cylinders filled with a standard solution of various dilutions. A platinum-cobalt or chrome-cobalt scale with a maximum color of 500 0 is used as a reference solution. To prepare the scale, take a series of colorimetric cylinders with a capacity of 100 ml and pour into them the basic solution and distilled water with 1 ml of chemically pure sulfuric acid (specific gravity 1.84) per 1 liter of water in the quantities given in the table. 35.

To quantitatively determine color in degrees, it is necessary to pour 100 ml of the test water into a colorimetric cylinder and compare its color with the color of the standards when viewed from top to bottom through a column of water on a white background. Determine the degree of color of the water being tested by selecting a cylinder that has an identical color intensity.

A hygienic conclusion about the quality of the water sample under study is made based on comparison with hygienic standards: the color of drinking water is allowed no more than 20 0 (in agreement with the sanitary and epidemiological authorities, no more than 35 0 is allowed) with a centralized water supply system and no more than 30 0 with a non-centralized water supply system. The color of water can be determined using a photoelectrocolorimeter.

Table 35. Scale for determining the color of water

Quality control of water resources and wastewater plays a huge role in ensuring personal (the country's population) safety. What methods of water analysis are used today? What do the results obtained from the study indicate?

To be able to regulate and control the quality of drinking resources, specialists use laboratory methods of water analysis, based on identifying the physical and chemical characteristics of the tested sample. How important are water and wastewater research processes? They are of extreme importance because they help prevent environmental pollution and environmental degradation. But their main task is to stop the development of a huge number of diseases among the population who come into contact with and drink poor-quality water every day. In our independent laboratory you can order research of various classes of liquids at a low price. We guarantee the reliability of the results and the use of the most modern techniques.

What methods of water analysis exist today?

The control procedure and water treatment processes in residential and country houses, manufacturing and industrial enterprises begin with measures to identify and calculate the amount of components and compounds contained in consumed (used) water. Modern methods of water analysis make it possible to identify with high accuracy the substance in the composition of the sample and its volume per unit mass. All tests are carried out in laboratory conditions using special equipment, chemical reagents and drugs.

There are the following types of studies of wastewater and drinking water samples:

Chemical - gravimetric and volumetric methods of analysis are used.
Electrochemical - the procedure uses polarographic and potentiometric methods of analysis.
Optical - the sample is examined using photometric, luminescent and spectrometric techniques. They are considered the most effective, but due to the need to use very rare and complex equipment, they are also the least used and expensive. They are used for component-by-component testing of drinking, waste, and domestic and industrial waters.

The listed types of studies are designed to check the quality of liquids used for cooking, drinking and used for household needs. However, many methods of drinking water analysis are also suitable for establishing the degree of contamination of wastewater passing through treatment plants. Our laboratory carries out all existing types of liquid tests at an affordable cost. To submit water for analysis to a laboratory, we recommend purchasing special containers for its collection, storage and transportation.

What parameters are assessed by drinking water and wastewater analysis methods?

Content of natural substances in the sample and their concentrations. Mandatory test for samples taken from natural bodies of water: borehole, well, tap water.
The content in the sample of chemical elements and compounds that entered the sample as a result of water purification. These water control methods are applied to all types of samples: wastewater, domestic, industrial, drinking water;
The presence of bacteria and pathogenic microbes, viral microorganisms and rods in the sample. A test that examines drinking water and samples taken from surface sources: lakes, reservoirs, rivers, and so on. The presence of bacteria in liquids that a person comes into contact with (not drinking) can also cause a number of diseases.
Presence of odor. Organoleptic and sanitary-microbiological tests allow us to identify the “culprits” of the odor. They are microorganisms and their metabolic products. Important research on drinking and domestic water.
Degree of hardness, turbidity. Household and drinking samples must be analyzed.

The results obtained are compared with SanPiN standards, which stipulate the acceptable and normal presence of macro- and microelements, salts, natural substances and other things in water. If the quantitative values of impurities, minerals and salts fall within the range allowed by SanPiN, the tested sample can be considered suitable for drinking, household, and industrial purposes. Wastewater is assessed similarly. If their physicochemical and toxic composition complies with established standards, then the contaminated slurry purified by the system can be released into the environment. It will not cause pollution and poisoning of people. For each type of water, its own evaluation criteria and standards have been developed.

Water quality control should be carried out not only by enterprises, but also by people using tap, well and borehole water. Based on the test results, you can easily determine which filtration and purification systems will be most effective. From our independent company you can order any type of analysis of various classes of water at an affordable price.

Purpose of the lesson

Familiarity with the hygienic principles of regulating the quality of drinking water, the rules for choosing water supply sources, and the physical and organoleptic properties of water. Learn to analyze drinking water for compliance with the requirements of GOST 2874-82.

Tasks

Read the legislative documents: GOST 2874 - 82, GOST 2761 - 84 and rules for organizing sanitary protection zones for water pipelines and water supply sources.
Take water samples for research, become familiar with the rules for storing and transporting water, and laboratory documentation forms.
Determine the physical and organoleptic properties of the proposed water sample, determine the dry residue in it.
Give an opinion on the suitability of the water sample under study for household and drinking purposes.
Answer test questions and solve problems.

Water used by humans has physiological, sanitary-hygienic, economic and epidemiological significance. Drinking poor-quality water can cause infectious diseases, helminthiases, geo-endemic diseases, and diseases associated with pollution of water bodies with chemicals.

In the USSR, the basis for hygienic regulation of tap water is based on two standards: GOST 2874 - 82 “Drinking water. Hygienic requirements and quality control" and GOST 2761 - 84 "Sources of centralized domestic and drinking water supply. Hygienic, technical requirements and selection rules."

“Guide to practical exercises on methods
sanitary and hygienic research", L.G. Podunova

Purpose of the lesson: Introduction to methods of selection and analysis of wastewater in the SES laboratory. Tasks Take a sample of wastewater for research. Determine the physical and chemical properties of the collected water sample. Complete a laboratory test protocol. Answer test questions and solve problems. Wastewater is characterized by variable composition. Changes in the composition of industrial wastewater are associated with the progress of technological processes. TO…

Purpose of the lesson: To become familiar with the basic methods of improving the quality of drinking water. Master the methods of coagulation and chlorination of water. Tasks Determine the working dose of the coagulant for water coagulation. Determine the content of active chlorine in bleach. Determine the working dose of bleach. Determine residual chlorine in tap water. Submit your test results. Answer test questions and solve problems. "A Guide to Practical...

A single sampling of wastewater for research is usually not enough, so an average mixed sample is taken (per hour, shift, day) or serial samples according to a developed plan. Determine the daily maximum and minimum wastewater and the daily, weekly or annual change in water quality. During the technological process, agreed samples are taken at various places in the wastewater flow…

To improve the quality of drinking water, clarification, decolorization and disinfection are carried out. Clarification and decolorization are achieved by coagulation, sedimentation and filtration. To disinfect water, physical (boiling, UV irradiation) and chemical (chlorination, ozonation, etc.) methods are used. Selecting a coagulant dose To speed up the process of settling water during its purification and removing color, coagulants are added to the water - usually Al2(SOl4)3 *...

Temperature The water temperature is determined simultaneously with sampling with a mercury thermometer with a division value of 0.1 - 0.5 °C. Transparency Before analysis, the water is mixed and poured into a Snellen cylinder 30 cm high, 2.5 cm in diameter, graduated in centimeters. Before the study, a well-lit font is placed under the bottom of the cylinder at a distance of 4 cm from the bottom, shaken...

Equipment Glasses with a capacity of 200 cm3. Cylinder with a capacity of 200 cm3. Glass rods. Flasks with a capacity of 250 cm3. Measuring pipettes with a capacity of 10 cm3. Burettes. Reagents Aluminum sulfate - 1% solution. Soda - 1% solution. Hydrochloric acid - 0.1 N. solution. Methyl orange - 0.1% solution. Determination of the optimal dose of the coagulant is carried out experimentally and is carried out in 3 stages: ...

Determination procedure Place 3 cylinders with a diameter of 20 - 25 mm made of colorless glass on a sheet of white paper. The wastewater to be tested is poured into the 1st cylinder (layer height 10 cm), into the 3rd cylinder the same amount of distilled water, into the 2nd cylinder the same amount of diluted wastewater, each time increasing the degree of dilution (1:1, 1: 2, 1:3, etc.),…

Removable water hardness is 5 mmol/dm3. This means that you need to pour 4 cm3 of 1% alumina solution into the 1st glass, 3 cm3 into the 2nd glass, and 2 cm3 into the 3rd glass. If the removable hardness of the water is less than 2 mmol/dm3 and coagulation proceeds sluggishly, with insignificant formation of small, slowly settling flakes, then the water should be alkalized by adding 1% to each glass...

Determination is carried out using a Gooch crucible. A filter is placed on the retina at the bottom of the Gooch crucible and dried in an oven at a temperature of 105 ° C until constant weight. Then the crucible is placed in a filter funnel and 100 to 500 cm3 of thoroughly shaken test water is passed through the filter, depending on the content of substances in it. After filtering the precipitate into...

Bleached lime should contain 25 - 30% active chlorine, but under the influence of increased temperature, humidity, light, carbon monoxide (IV) in the air, this value may decrease, therefore, before chlorinating water, bleach should be checked for active chlorine content. Principle of the method The determination is based on the fact that chlorine displaces an equivalent amount of iodine from potassium iodide. The released iodine is titrated in...

I. Introductory part

Importance of the Chemical Industry

The role of analytical control

Functions and tasks of the laboratory

II. Analytical part

Characteristics of the analyzed products

Requirements for natural water

Analysis methods

Device, universal ion meter EV-74

III. Occupational Safety and Health

TB with acids and alkalis

TB while working in a laboratory

Fire and electrical safety

IV. Environmental protection

Bibliography

І. Introductory part

. Importance of the Chemical Industry

The chemical industry is a complex industry that, along with mechanical engineering, determines the level of scientific and technological progress, providing all sectors of the national economy with chemical technologies and materials, including new, progressive ones, and producing consumer goods.

The chemical industry is one of the leading branches of heavy industry, is the scientific, technical and material basis for the chemicalization of the national economy and plays an extremely important role in the development of productive forces, strengthening the defense capability of the state and in ensuring the vital needs of society. It unites a whole complex of industries in which chemical methods of processing objects of embodied labor (raw materials, materials) predominate, allows solving technical, technological and economic problems, creating new materials with predetermined properties, replacing metal in construction, mechanical engineering, increasing productivity and saving costs of social labor. The chemical industry includes the production of several thousand different types of products, the number of which is second only to mechanical engineering.

The importance of the chemical industry is expressed in the progressive chemicalization of the entire national economic complex: the production of valuable industrial products is expanding; Expensive and scarce raw materials are replaced with cheaper and more abundant ones; complex use of raw materials is carried out; Many industrial wastes, including environmentally harmful ones, are captured and disposed of. Based on the integrated use of various raw materials and the recycling of industrial waste, the chemical industry forms a complex system of connections with many industries and is combined with the processing of oil, gas, coal, ferrous and non-ferrous metallurgy, and the forestry industry. Entire industrial complexes are formed from such combinations.

The production process in the chemical industry is most often based on the transformation of the molecular structure of a substance. The products of this sector of the national economy can be divided into items for industrial purposes and items for long-term or short-term personal use.

Consumers of chemical industry products are found in all spheres of the national economy. Mechanical engineering needs plastics, varnishes, paints; agriculture - in mineral fertilizers, preparations for controlling plant pests, in feed additives (livestock farming); transport - in motor fuel, lubricants, synthetic rubber. The chemical and petrochemical industries are becoming a source of raw materials for the production of consumer goods, especially chemical fibers and plastics.

2. The role of analytical control

Analytical chemistry is the science of methods and means for determining the chemical composition of substances and their mixtures. Objectives of analytical chemistry: detection, identification and determination of the constituent parts (atoms, ions, radicals, molecules, functional groups) of the analyzed object. The corresponding branch of analytical chemistry is qualitative analysis;

Determination of the connection sequence and relative position of the components in the analyzed object. The corresponding branch of analytical chemistry is structural analysis;

Determination of changes in the nature and concentration of the component parts of an object over time. This is important for establishing the nature, mechanism and rate of transformations, in particular, for monitoring technological processes in production.

Many methods of analytical chemistry use the latest achievements of natural and technical sciences. Therefore, it is quite natural to consider analytical chemistry as an interdisciplinary science.

Analytical chemistry methods are widely implemented in a wide variety of industries. For example, in petrochemistry, metallurgy, in the production of acids, alkalis, soda, fertilizers, organic products and dyes, plastics, artificial and synthetic fibers, building materials, explosives, surfactants, medicines, perfumes.

In petrochemistry and metallurgy, analytical control of feedstock, intermediate and final products is required.

The production of highly pure substances, in particular semiconductor materials, is impossible without determining impurities at a level of up to 10 -9%.

Chemical analysis is necessary when searching for minerals. Many conclusions of geochemistry are based on the results of chemical analysis.

Chemical analysis is of great importance for the sciences of the biological cycle. For example, finding out the nature of a protein is essentially an analytical task, since it is necessary to find out which amino acids are part of the protein and in what sequence they are connected. In medicine, methods of analytical chemistry are widely used in conducting various biochemical analyses.

Even the humanities use methods of analytical chemistry. Archeology ranks first among them. The results of chemical analysis of ancient objects serve as a source of important information that allows us to draw conclusions about the origin of objects and their age. The development of forensic science is also unthinkable without modern methods of analytical chemistry. As in archaeology, methods that do not destroy the sample under study are extremely important: local analysis, identification of substances.

3. Functions and tasks of the laboratory

The main objectives of the laboratory are to carry out experimental research work that ensures the introduction and development of new equipment and technology using modern achievements aimed at intensifying existing workshops, improving their economic performance, improving the quality of products, and protecting the environment.

To fulfill these tasks, the laboratory carries out work on:

Carrying out, with the required accuracy and reliability, quantitative chemical and microbiological analyzes of samples of drinking water, wastewater and industrial wastewater in order to establish compliance of their quality with the requirements of regulatory documents;

Full implementation of the “Work program for production control of the quality of drinking water”, monitoring the effectiveness of drinking water purification, as well as the “Schedule for production control of the quality of wastewater and industrial effluents”.

Preparation of initial data for the development of regulatory and technical documentation for enterprises and making decisions on improving water quality in accordance with sanitary and epidemiological surveillance and discharges.

Selection, development and implementation of new techniques for analyzing the quality of drinking and waste water.

Improvement of technological processes and full development of production capacities.

Improving industrial waste disposal methods.

II. Analytical part

. Characteristics of the analyzed products

Water(H 2 O) - odorless, tasteless, colorless liquid; the most common natural compound.

In terms of its physicochemical properties, V. is distinguished by the anomalous nature of the constants that determine many physical and biological processes on Earth. The density of water increases in the range of 100-4°, with further cooling it decreases, and when it freezes it drops abruptly. Therefore, in rivers and lakes, ice, being lighter, is located on the surface, creating the necessary conditions for preserving life in aquatic ecological systems. Sea water turns into ice without reaching its highest density, so more intense vertical mixing of water occurs in the seas.

The first sanitary and hygienic characteristics of fresh water were organoleptic indicators, which were based on the intensity of perception by the senses of the physical properties of water. Currently, this group includes as normative characteristics:

· Smell at 20 o C and heated to 60 o C,

· score Color scale, degree

· Transparency on the scale,

· Turbidity on a standard scale, mg/dm 3

Coloring of the painted column (no aquatic organisms and film)

Artesian waters contain suspended solids. They consist of particles of clay, sand, silt, suspended organic and inorganic substances, plankton and various microorganisms. Suspended particles affect water clarity. The content of suspended impurities in water, measured in mg/l, gives an idea of the contamination of water with particles mainly with a nominal diameter of more than 1·10-4 mm . When the content of suspended substances in water is less than 2-3 mg/l or

greater than the specified values, but the nominal diameter of the particles is less than 1 × 10-4 mm, water pollution is determined indirectly by the turbidity of the water.

2. Requirements for natural water

The main requirements for drinking water are safety in terms of epidemics, harmlessness in terms of toxicological indicators, good organoleptic characteristics and suitability for household needs. The optimal water temperature for drinking purposes is in the range of 7-11 °C. The closest to these conditions are the waters of underground sources, which are characterized by a constant temperature. They are primarily recommended for use for domestic and drinking water supply.

Organoleptic indicators (turbidity, transparency, color, odors and tastes) of water consumed for household and drinking purposes are determined by substances found in natural waters, added during water treatment in the form of reagents and resulting from domestic, industrial and agricultural pollution of water sources. Chemical substances that affect the organoleptic characteristics of water, in addition to insoluble impurities and humic substances, include chlorides, sulfates, iron, manganese, copper, zinc, aluminum, hexameta- and tripolyphosphate, calcium salts found in natural waters or added to them during processing and magnesium.

The pH value of most natural waters is close to 7. The constancy of the pH of water is of great importance for the normal occurrence of biological and physicochemical processes in it, leading to self-purification. For domestic drinking water it should be in the range of 6.5-8.5.

The amount of dry residue characterizes the degree of mineralization of natural waters; it should not exceed 1000 mg/l and only in some cases 1500 mg/l is allowed.

The general norm of hardness is 7 mg * eq/l.

In groundwater that is not subject to iron removal, an iron content of 1 mg/l can be allowed.

Nitrogen-containing substances (ammonia, nitrites and nitrates) are formed in water as a result of chemical processes and decay of plant residues, as well as due to the decomposition of protein compounds, which almost always enter with domestic wastewater; the final product of the decomposition of protein substances is ammonia. The presence of ammonia of plant or mineral origin in water is not dangerous from a sanitary point of view. Waters in which the formation of ammonia is caused by the decomposition of protein substances are unsuitable for drinking. Water containing only traces of ammonia and nitrites is considered suitable for drinking purposes, and according to the standard, the content of no more than 10 mg/l of nitrates is allowed.

Hydrogen sulfide may be contained in natural waters in small quantities. It gives the water an unpleasant odor, causes the development of sulfur bacteria and intensifies the corrosion process of metals.

Toxic substances (beryllium, molybdenum, arsenic, selenium, strontium, etc.), as well as radioactive substances (uranium, radium and strontium-90) enter the water with industrial wastewater and as a result of prolonged contact of water with soil layers containing the corresponding mineral salts . If there are several toxic or radioactive substances in water, the sum of concentrations or radiation, expressed in fractions of concentrations permissible for each of them separately, should not exceed one.

3. Analysis methods

Methodology. Determination of overall hardness.

The method is based on the formation of a strong complex compound of Trilon B with calcium and magnesium ions.

The determination is carried out by titrating the sample with Trilon B at pH 10 in the presence of an indicator.

SAMPLING METHODS

2. The volume of the water sample to determine the total hardness must be at least 250 cm3.

3. If the determination of hardness cannot be carried out on the day of sampling, then the measured volume of water, diluted with distilled water 1:1, can be left for determination until the next day.

Water samples intended to determine total hardness are not preserved.

EQUIPMENT, MATERIALS AND REAGENTS.

Measuring laboratory glassware in accordance with GOST 1770 with a capacity of: pipettes 10, 25, 50 and 100 cm3 without divisions; burette 25 cm3.

Conical flasks according to GOST 25336 with a capacity of 250-300 cm3.

Dropper according to GOST 25336.

Trilon B (complexon III, disodium salt of ethylenediaminetetraacetic acid) according to GOST 10652.

Ammonium chloride according to GOST 3773.

Hydroxylamine hydrochloric acid according to GOST 5456.

Citric acid according to GOST 3118.

Sodium sulphide (sodium sulfide) according to GOST 2053.

Rectified ethyl alcohol according to GOST 5962.

Metal granulated zinc.

Magnesium sulfate - fixanal.

Chromogen black special ET-00 (indicator).

Chrome dark blue acidic (indicator).

All reagents used for analysis must be analytical grade (analytical grade)

PREPARATION FOR ANALYSIS.

1. Distilled water, distilled twice in a glass apparatus, is used to dilute water samples.

2. Preparation 0.05 n. Trilon B solution.

31 g of Trilon B are dissolved in distilled water and adjusted to 1 dm3. If the solution is cloudy, then it is filtered. The solution is stable for several months.

3. Preparation of a buffer solution.

g ammonium chloride (NH 4 Cl) is dissolved in distilled water, 50 cm 3 of a 25% ammonia solution is added and adjusted to 500 cm 3 with distilled water. To avoid loss of ammonia, the solution should be stored in a tightly closed bottle.

4. Preparation of indicators.

5 g of indicator is dissolved in 20 cm3 of buffer solution and adjusted to 100 cm3 with ethyl alcohol. The dark blue chromium indicator solution can be stored for a long time without changing. The black chromogen indicator solution is stable for 10 days. It is allowed to use a dry indicator. To do this, 0.25 g of the indicator is mixed with 50 g of dry sodium chloride, previously thoroughly ground in a mortar.

5. Preparation of sodium sulfide solution.

g sodium sulfide Na 2 S × 9H 2 O or 3.7 g Na 2 S × 5H 2 O is dissolved in 100 cm 3 of distilled water. The solution is stored in a bottle with a rubber stopper.

6. Preparation of a solution of hydroxylamine hydrochloride.

g hydroxylamine hydrochloride NH 2 OH × HCl is dissolved in distilled water and adjusted to 100 cm 3.

7. Preparation 0.1 N. zinc chloride solution.

An exact weighed portion of granulated zinc, 3.269 g, is dissolved in 30 cm 3 of hydrochloric acid, diluted 1:1. Then the volume in the volumetric flask is adjusted to 1 dm 3 with distilled water. Get exact 0.1 N. solution. By diluting this solution by half, 0.05 N is obtained. solution. If the sample is inaccurate (more or less than 3.269), then calculate the number of cubic centimeters of the original zinc solution to prepare an accurate 0.05 N. solution, which should contain 1.6345 g of zinc per 1 dm 3.

8. Preparation 0.05 n. magnesium sulfate solution.

The solution is prepared from the fixanal supplied with the set of reagents for determining water hardness and designed to prepare 1 dm3 of 0.01 N solution. To receive 0.05 n. solution, the contents of the ampoule are dissolved in distilled water and the volume of the solution in the volumetric flask is adjusted to 200 cm 3 .

9. Setting a correction factor for the normality of the Trilon B solution.

Add 10 cm 3 0.05 N to a conical flask. zinc chloride solution or 10 cm3 0.05 N. solution of magnesium sulfate and diluted with distilled water to 100 cm 3. Add 5 cm 3 of buffer solution, 5-7 drops of indicator and titrate with strong shaking with Trilon B solution until the color changes at the equivalent point. The color should be blue with a violet tint when adding a dark blue chromium indicator and blue with a greenish tint when adding a black chromogen indicator.

Titration should be carried out against the background of a control sample, which can be a slightly overtitrated sample.

The correction factor (K) to the normality of the Trilon B solution is calculated using the formula:

where v is the amount of Trilon B solution consumed for titration, cm 3.

CONDUCTING THE ANALYSIS

1. Determination of the total hardness of water is hindered by: copper, zinc, manganese and a high content of carbon dioxide and bicarbonate salts. The influence of interfering substances is eliminated during the analysis.

The error when titrating 100 cm3 of sample is 0.05 mol/m3.

Add 100 cm3 of filtered test water or a smaller volume diluted to 100 cm3 with distilled water into a conical flask. In this case, the total amount of substance equivalent to calcium and magnesium ions in the taken volume should not exceed 0.5 mol. Then add 5 cm3 of buffer solution, 5-7 drops of indicator or approximately 0.1 g of a dry mixture of black chromogen indicator with dry sodium and immediately titrate with strong shaking with 0.05 N. Trilon B solution until the color changes at the equivalent point (the color should be blue with a greenish tint).

If more than 10 cm3 of 0.05 N was spent on titration. solution of Trilon B, this indicates that in the measured volume of water the total amount of substance equivalent to calcium and magnesium ions is more than 0.5 mol. In such cases, the determination should be repeated, taking a smaller volume of water and diluting it to 100 cm3 with distilled water.

A vague color change at the equivalent point indicates the presence of copper and zinc. To eliminate the influence of interfering substances, 1-2 cm3 of sodium sulfide solution is added to the water sample measured for titration, after which the test is carried out as indicated above.

If, after adding a buffer solution and an indicator to a measured volume of water, the titrated solution gradually becomes discolored, acquiring a gray color, indicating the presence of manganese, then in this case, five drops of a 1% solution should be added to the water sample taken for titration before adding the reagents hydroxylamine hydrochloride and then determine the hardness as indicated above.

If the titration becomes extremely protracted with an unstable and unclear color at the equivalent point, which is observed with high alkalinity of water, its influence is eliminated by adding 0.1 N to the water sample taken for titration before adding the reagents. hydrochloric acid solution in the amount necessary to neutralize the alkalinity of the water, followed by boiling or blowing the solution with air for 5 minutes. After this, a buffer solution and an indicator are added and then the hardness is determined as indicated above.

PROCESSING RESULTS

1. The total hardness of water (X), mol/m3, is calculated using the formula:

where v is the amount of Trilon B solution consumed for titration, cm 3;

K - correction factor to the normality of the Trilon B solution; - volume of water taken for determination, cm 3.

The discrepancy between repeated determinations should not exceed 2 rel. %.

Methodology. Determination of dry residue content.

The amount of dry residue characterizes the total content of non-volatile mineral and partially organic compounds dissolved in water.

SAMPLING METHODS.

1. Samples are taken according to GOST 2874 and GOST 4979.

2. The volume of the water sample to determine the dry residue must be at least 300 cm3.

EQUIPMENT, REAGENTS AND SOLUTIONS.

Drying cabinet with thermostat.

Water bath.

Laboratory glassware according to GOST 1770, capacity: volumetric flasks 250 and 500 cm2; pipettes without division 25 cm3, porcelain evaporating cup 500-100 cm3.

Desiccators according to GOST 25336.

Anhydrous sodium carbonate according to GOST 83.

Sodium carbonate Na 2 CO 3, chemically pure, precise solution, is prepared as follows: 10 g of anhydrous soda (dried at 200 ° C and weighed on an analytical balance) is dissolved in distilled water and the volume of the solution is adjusted to 1 dm3 with distilled water. 1 cm3 of solution contains 10 mg of soda.

CONDUCTING THE ANALYSIS.

500 cm3 of filtered water is evaporated in a porcelain cup previously dried to a constant weight. Evaporation is carried out in a water bath with distilled water. Then the cup with the dry residue is placed in a thermostat at 110 ° C and dried to constant weight.

1.1. Processing the results.

where m is the mass of the cup with dry residue, mg; 1 is the mass of the empty cup, mg; is the volume of water taken for determination, cm3.

This method for determining the dry residue gives slightly overestimated results due to the hydrolysis and hygroscopicity of magnesium and calcium chlorides and the difficult release of crystallization water by calcium and magnesium sulfates. These disadvantages are eliminated by adding chemically pure sodium carbonate to the evaporated water. In this case, chlorides, sulfates of calcium and magnesium turn into anhydrous carbonates, and of the sodium salts, only sodium sulfate has water of crystallization, but it is completely removed by drying the dry residue at 150-180 ° C.

2. Determination of dry residue with the addition of soda.

500 cm3 of filtered water is evaporated in a porcelain cup, dried to a constant weight at 150 ° C. After the last portion of water has been poured into the cup, 25 cm3 of an exact 1% solution of sodium carbonate is pipetted so that the mass of the added soda is approximately twice the mass of the expected dry residue. For ordinary fresh water, it is enough to add 250 mg of anhydrous salt (25 cm3 of 1% Na 2 CO 3 solution). The solution is mixed well with a glass rod. The stick is washed with distilled water, collecting the water in a cup with sediment. The dry residue evaporated with soda is dried to a constant weight at 150 ° C. The cup with the dry residue is placed in a cold thermostat and then the temperature is raised to 150 ° C. The difference in mass between the cup with the dry residue and the initial mass of the cup and soda (1 cm3 of soda solution contains 10 mg Na 2 CO 3) gives the value of the dry residue in the taken volume of water.

2.1. Processing the results.

Dry residue (X), mg/dm3, is calculated using the formula:

where m is the mass of the cup with the dry residue, mg; 1 is the mass of the empty cup, mg; 2 is the mass of added soda, mg; is the volume of water taken for determination, cm3.

The discrepancies between the results of repeated determinations should not exceed 10 mg/dm3, if the dry residue does not exceed 500 mg/dm3; at higher concentrations, the discrepancy should not exceed 2 rel. ooo.

Methodology. Determination of chloride content.

1. SAMPLING METHODS.

1. Sampling is carried out in accordance with GOST 2874 and GOST 4979.

2. The volume of the water sample to determine the chloride content must be at least 250 cm3.

3. Water samples intended for determination of chlorides are not preserved.

2. DETERMINATION OF CHLORINE ION CONTENT BY TITRATION WITH SILVER NITRIC

2.1. Essence of the method

The method is based on the precipitation of chlorine ion in a neutral or slightly alkaline medium with silver nitrate in the presence of potassium chromate as an indicator. After the precipitation of silver chloride at the equivalence point, silver chromate is formed, and the yellow color of the solution turns into orange-yellow. The accuracy of the method is 1-3 mg/dm3.

2 Equipment, materials and reagents

Laboratory glassware according to GOST 1770, GOST 29227, GOST 29251, capacity: pipettes 100, 50 and 10 cm3 without divisions; pipette 1 cm3 with divisions every 0.01 cm3; graduated cylinder 100 cm3; burette 25 cm3 with glass stopcock.

Conical flasks according to GOST 25336, capacity 250 cm3.

Dropper according to GOST 25336.

Colorimetric tubes with a 5 cm3 mark.

Glass funnels according to GOST 25336.

Filters without ash “white tape”.

Silver nitrate according to GOST 1277.

Sodium chloride according to GOST 4233.

Potassium alum (aluminum-potassium sulfate) according to GOST 4329.

Potassium chromate according to GOST 4459.

Aqueous ammonia according to GOST 3760, 25% solution.

Distilled water according to GOST 6709.

All reagents used for analysis must be analytical grade (analytical grade).

3. Preparation for analysis

3.1. Preparation of a titrated solution of silver nitrate.

40 g of chemically pure AgNO3 are dissolved in distilled water and the volume of the solution is adjusted with distilled water to 1 dm3.

cm3 of solution is equivalent to 0.5 mg Cl-.

The solution is stored in a dark glass bottle.

3.2. Preparation of a 10% solution (acidified with nitric acid) of silver nitrate

g AgNO3 is dissolved in 90 cm3 of distilled water and 1-2 drops of HNO3 are added.

3.3. Preparation of titrated sodium chloride solution

8245 g of chemically pure NaCl, dried at 105 °C, are dissolved in distilled water and the volume of the solution is adjusted to 1 dm3 with distilled water.

cm3 of solution contains 0.5 mg Cl-.

3.4. Preparation of aluminum hydroxide

g of potassium alum is dissolved in 1 dm3 of distilled water, heated to 60 °C and 55 cm3 of concentrated ammonia solution is gradually added with constant stirring. After settling for 1 hour, the precipitate is transferred to a large glass and washed by decantation with distilled water until the reaction to chlorides disappears.

3.5. Preparation of a 5% solution of potassium chromate

g K2CrO4 is dissolved in a small volume of distilled water and the volume of the solution is adjusted with distilled water to 1 dm3.

3.6. Setting a correction factor for a silver nitrate solution.

Pipette 10 cm3 of sodium chloride solution and 90 cm3 of distilled water into a conical flask, add 1 cm3 of potassium chromate solution and titrate with a solution of silver nitrate until the lemon-yellow color of the cloudy solution changes to orange-yellow, which does not disappear within 15-20 s. The result obtained is considered indicative. Add 1-2 drops of sodium chloride solution to the titrated sample until a yellow color is obtained. This sample serves as a control sample for repeated, more accurate determination. To do this, take a new portion of the sodium chloride solution and titrate it with silver nitrate until a slight difference in the shades of faint orange in the titrated solution and yellow in the control sample is obtained. The correction factor (K) is calculated using the formula

where v is the amount of silver nitrate spent on titration, cm 3.

4. Conducting analysis

4.1. Qualitative definition

5 cm 3 of water is poured into a colorimetric test tube and three drops of a 10% silver nitrate solution are added. The approximate content of chlorine ion is determined by sediment or turbidity in accordance with the requirements of the table.

4.2. quantitation

Depending on the results of the qualitative determination, 100 cm 3 of the test water or a smaller volume (10-50 cm 3) is selected and adjusted to 100 cm 3 with distilled water. Chlorides are determined at concentrations up to 100 mg/dm 3 without dilution. The pH of the titrated sample should be in the range of 6-10. If the water is cloudy, it is filtered through an ash-free filter washed with hot water. If the water has a color value above 30°, the sample is decolorized by adding aluminum hydroxide. To do this, add 6 cm3 of aluminum hydroxide suspension to 200 cm 3 of sample, and the mixture is shaken until the liquid becomes discolored. The sample is then filtered through an ash-free filter. The first portions of the filtrate are discarded. A measured volume of water is added to two conical flasks and 1 cm 3 of potassium chromate solution is added. One sample is titrated with a solution of silver nitrate until a faint orange tint appears, the second sample is used as a control sample. If the chloride content is significant, an AgCl precipitate is formed, which interferes with the determination. In this case, add 2-3 drops of titrated NaCl solution to the titrated first sample until the orange tint disappears, then titrate the second sample, using the first as a control sample.

The following interfere with the determination: orthophosphates in concentrations exceeding 25 mg/dm 3 ; iron in a concentration of more than 10 mg/dm3. Bromides and iodides are determined in concentrations equivalent to Cl - . When normally present in tap water, they do not interfere with determination.

5. Processing of results.

where v is the amount of silver nitrate spent on titration, cm 3;

K is the correction factor to the titer of the silver nitrate solution;

g - the amount of chlorine ion corresponding to 1 cm 3 of silver nitrate solution, mg; - the volume of the sample taken for determination, cm 3.

The discrepancies between the results of repeated determinations when the Cl content is from 20 to 200 mg/dm 3 - 2 mg/dm 3; at a higher content - 2 rel. %.

4. Design of the analyzed device. Universal ion meter EV-74

. Purpose.

The EV-74 universal ion meter is intended for determining, in combination with ion-selective electrodes, the activity of mono- and divalent anions and cations (pX values) in aqueous solutions, as well as for measuring redox potentials (Eh values) in the same solutions.

The ion meter can also be used as a high-resistance millivoltmeter.

When working with an automatic titration unit, the device can be used for mass titration of the same type.

The EV-74 ion meter can make measurements both by sampling and directly in laboratory installations.

The ion meter is intended for use in laboratories of research institutions and industrial enterprises.

2. Design and principle of operation.

2.1. General information

To measure the activity of mono- and divalent ions in solutions, an electrode system with ion-selective measuring electrodes and a transducer is used. The electromotive force of the electrode system depends on the activity of the corresponding ions in the solution and is determined by equations (1) or (2).

The рХ value of the controlled solution is determined by measuring the emf. electrode system using a transducer, the scale of which is calibrated in pX units. The emf calibration values can be calculated using equations (1) and (2).

2. Operating principle and circuit diagram of the ionomer converter

The operation of the ion meter is based on the conversion of emf. electrode system into a direct current proportional to the measured value. Conversion of e.m.f. electrode system into direct current is carried out by a high-resistance auto-compensation type converter.

The electromotive force Ex of the electrode system (Fig. 1) is compared with the voltage drop across the resistance R through which the current Iout flows. amplifier Voltage drop Uout. at resistance R, the opposite sign of the electromotive force Ex is applied to the input of the amplifier:

input =Ex-Uout. =Ex-Iout.×R (4)

With a sufficiently large gain, the voltage Uout. differs little from e.m.f. electrode system Sx due to this, the current flowing through the electrodes during the measurement process is very small, and the current Iout. flowing through resistance R is proportional to the emf. electrode system, i.e. pH of the controlled solution.

3. Design of the EV-74 ion meter

The ion meter consists of a transducer and a stand designed for attaching electrodes and installing vessels with a controlled solution.

Converter.

The general view of the converter and its design elements are shown in Fig. 5.

For ease of installation and maintenance during repairs, the inclined front panel 9 (Fig. 5) is strengthened in such a way that when removing the back wall and the bottom bar, it can be folded forward after unscrewing 2 screws.

On the front panel there are operational controls and indicating device 1. Factory setting and adjustment controls 7 are located under the front panel.

The scale of the indicating device has the following numbers: “-1-19” for measurements on a wide range and “0-5” for measurements on narrow ranges (the readings of the device are summed up with the value corresponding to the beginning of the range). For convenience, the range “-1-4” has additional digitization.

To set the temperature of the measured solution there is a digitization “0-100”.

The operational controls include: the “NETWORK” toggle switch, the knobs of the variable resistors “CALIBRATION”, “STEENness”, “pHi” and “SOLUTION TEMPERATURE”; 5 buttons for selecting the type of work: “ANIONS/CATIONS (+/-)”, “Х”/Х”, “mV”, “рХ” and “t°”; 5 measurement range selection buttons: “-1-19”, “-1-4”, “4-9”, “9-14”, “14-19”; indicating device corrector. The “ANIONS/CATIONS (+/-)” button allows you to measure the activity of anions or positive potentials in the pressed position, or negative potentials in the pressed position, the “X" X" button allows you to measure the activity of monovalent or divalent ions, respectively, in the depressed or pressed position ; Buttons with dependent fixation “mV”, “рХ” and “t°” allow you to turn the device into the mode of a millivoltmeter (“mV”), ion meter (“pX”) or setting the solution temperature with manual temperature compensation (“t°”).

When adjusting with knobs located on the front panel, it should be taken into account that the device uses high-resolution potentiometers, which have zones of smooth and coarse adjustment.

The “CALIBRATION”, “STEENness” and “pH” resistors are used to quickly configure the device for a given electrode system.

Factory setting controls are closed with a sealed bar and are designed: R52 - for additional adjustment of the beginning of the scales when measuring cations; R54 - the same when measuring anions; R37 - for balancing the temperature bridge; R11 - for the basic setting of the beginning of the scales when measuring pX; R40 - for calibrating a manual temperature compensator when measuring divalent ions; R21 - for setting the beginning of the scales when measuring emf. (mV); R23 -- to adjust the span (slope) when measuring emf. (mV); R1 - to set the current in the рХи control circuit.

The axes of these potentiometers are fixed with collet clamps.

The factory settings also include resistors located on the board of the measuring unit: R48 - for adjusting the indicating device in the range “-1-19”; R35 - for calibrating a manual temperature compensator when measuring monovalent ions.

Elements of external connections are located on the rear plate.

The jumper that shorts the terminals of the indicating device in working condition must be removed.

ІІІ. Occupational Safety and Health

drinking water chloride hardness

1. Safety precautions when working with acids and alkalis

Concentrated acids cause dehydration of the skin and other tissues.

According to the speed of action and the rate of destruction of body tissue, acids are arranged in the following order, starting with the most powerful: aqua regia (a mixture of nitric and hydrochloric acids). Nitric acid, acetic acid (90 - 100%), lactic acid, oxalic acid, etc. Burns from the lame mixture are very dangerous. Fuming acids (concentrated hydrochloric and nitric acids) have a strong irritant effect on the mucous membranes of the respiratory tract and eyes.

Concentrated acids are stored under draft. They are also poured under draft, using personal protective equipment (goggles or protective mask, rubber gloves, gown, rubber apron).

When using a bottle of acid, you must ensure that each bottle has a clear name for the acid. The acid must be poured so that when the bottle is tilted, the label is at the top to avoid damage.

When diluting or strengthening acid solutions, pour in an acid of higher concentration; When making a mixture of acids, it is necessary to pour a liquid of higher density into a liquid of lower density.

When diluting acids, you need to remember the rule: the acid should be poured in a thin stream while stirring into cold water, and not vice versa, and only in heat-resistant and porcelain glasses, since this generates significant heat.

You can pour strong HNO3, H2SO4 and HCl only when the draft in the fume hood is on. Cabinet doors should be closed if possible.

When pouring the solution, you should remove the last drop of the reagent from the bottle with a test tube to avoid the liquid getting on your robe (clothing) or shoes.

When working with strong acids, it is necessary to wear safety glasses, and when working with fuming sulfuric and hydrochloric acid, in addition to glasses, wear a long rubber apron and a gas mask (or at least a gauze bandage, respirator).

When preparing alkali solutions, take solids from containers containing them only with a special spoon and never pour them in, because dust can get into your eyes and skin. After use, wash the spoon thoroughly, as the alkali firmly adheres to many surfaces.

When taking a sample, thin-walled porcelain cups are used. You cannot use paper, especially filter paper, because alkali corrodes it.

Solutions are prepared in thick-walled porcelain vessels in two stages. First, make a concentrated solution, cool it to room temperature, and then dilute it to the desired concentration. This sequence is caused by a significant exothermic effect of dissolution.

2. General safety requirements for working in the laboratory

When performing chemical analytical studies, it is necessary to comply with safety requirements when working with hazardous substances in accordance with GOST 12.1.007.

To avoid possible negative effects on the human body, reagents used in preserving water samples, preparing and conducting analyzes must be stored in the minimum required quantity.

The room in which chemical analytical studies are carried out must be equipped with general supply and exhaust ventilation that complies with building codes and rules for heating, ventilation and air conditioning in accordance with GOST 12.4.021.

It is necessary to organize orderly storage of spent reagents and their appropriate disposal. Laboratory waste determined in the established manner should be sent to specialized waste processing organizations in accordance with legal requirements.

The devices are installed in a dry room, free from dust, acid and alkali vapors. Electric heating devices, as well as sources of electromagnetic vibrations and radio interference, should not be located near the devices.

Devices that are designed to work with flammable gas must be installed on tables under exhaust devices that ensure the removal of combustion products.

Safety regulations for handling and working with gas cylinders must be observed, if applicable. Gas cylinders must be kept away from the appliance and heating radiators, and also protected from direct exposure to sunlight. When working with gas under pressure, you must comply with the “Rules for the design and safety of operation of pressure vessels” established for this work. When supplying gas, you need to ensure that all systems of underwater and outlet pipes of the system are completely sealed.

3. Fire and electrical safety

De-energize the room, turn off electric heating devices and traction.

Immediately report the fire to the fire department by phone at 20-01 (give the location of the fire and your name).

Report to the head of the bureau, the head of the laboratory, the head of the workshop.

Take measures to limit the spread of fire and extinguish the fire using all primary fire extinguishing means under the guidance of your immediate supervisor; burning organochlorine products listed in these instructions can be extinguished by any means.

Organize a fire department meeting.

If you are exposed to gas, wear a gas mask.

To activate the OU-2 fire extinguisher, you need to remove it from the socket, turn the socket towards the source of fire, grab the handle with your left hand, break the seal with your right hand, and turn the valve handwheel all the way. Direct the jet towards the source of fire. The fire should be extinguished from the periphery, trying to cover the burning surface with a gas stream. Do not direct the gas stream at the surface of the burning liquid to avoid its splashing, which can lead to an increase in the combustion area. After eliminating the source of fire, turn the valve to close the shut-off head valve.

When extinguishing with asbestos cloth, it is necessary to cover the source of fire with it and stop the access of air to the combustion products.

If, when using the fire extinguishing agents indicated above, the fire could not be extinguished, use the fire hydrant located in the corridor.

Work in the laboratory must be carried out in the presence of working electrical equipment. If defects are detected in the insulation of wires, malfunctions of switch starters, plugs, sockets, plugs and other fittings, as well as grounding and fences, you should immediately report this to your immediate supervisors. All detected faults must be repaired only by an electrician.

When working with live electrical equipment, it is necessary to use faulty personal protective equipment, dielectric gloves, and mats.

Do not carry electric heating devices that are turned on.

In the event of a power outage, all electrical heating devices and electrical equipment must be turned off immediately.

If electrical wires and electrical installations catch fire, you must immediately turn off the power and begin to extinguish the fire with a carbon dioxide or powder fire extinguisher, as well as felt or sand.

IV. Environmental protection

Environmental protection is any activity aimed at maintaining the quality of the environment at a level that ensures the sustainability of the biosphere. This includes both large-scale activities carried out at the national level to preserve reference samples of untouched nature and preserve the diversity of species on Earth, organize scientific research, train environmental specialists and educate the population, as well as the activities of individual enterprises for the purification of wastewater and waste from harmful substances. gases, reducing standards for the use of natural resources, etc. Such activities are carried out mainly by engineering methods.

There are two main directions of environmental protection activities of enterprises. The first is the purification of harmful emissions. This method “in its pure form” is ineffective, since with its help it is not always possible to completely stop the flow of harmful substances into the biosphere. In addition, a reduction in the level of pollution of one component of the environment leads to increased pollution of another.

And for example, installing wet filters during gas purification reduces air pollution, but leads to even greater water pollution. Substances captured from waste gases and waste waters often poison large areas of land.

The use of treatment facilities, even the most efficient ones, sharply reduces the level of environmental pollution, but does not completely solve this problem, since during the operation of these plants, waste is also generated, although in a smaller volume, but, as a rule, with an increased concentration of harmful substances. Finally, the operation of most treatment facilities requires significant energy costs, which, in turn, is also unsafe for the environment.

In addition, the pollutants that huge amounts of money are spent on neutralizing are substances that have already been worked on and that, with rare exceptions, could be used in the national economy.

To achieve high environmental and economic results, it is necessary to combine the process of cleaning harmful emissions with the process of recycling captured substances, which will make it possible to combine the first direction with the second.

The second direction is the elimination of the very causes of pollution, which requires the development of low-waste, and in the future, waste-free production technologies that would allow for the comprehensive use of raw materials and the disposal of a maximum of substances harmful to the biosphere.

However, not all industries have found acceptable technical and economic solutions to sharply reduce the amount of waste generated and their disposal, so at present it is necessary to work in both of these areas.

When caring about improving the engineering protection of the natural environment, we must remember that no treatment facilities or waste-free technologies will be able to restore the stability of the biosphere if the permissible (threshold) values for the reduction of natural systems not transformed by man are exceeded, which is where the law of the irreplaceability of the biosphere manifests itself.

Such a threshold may be the use of more than 1% of the energy of the biosphere and the deep transformation of more than 10% of natural territories (the rules of one and ten percent). Therefore, technical advances do not eliminate the need to solve the problems of changing the priorities of social development, stabilizing the population, creating a sufficient number of protected areas and others discussed earlier.

Bibliography

Analytical chemistry. Vasiliev V.P. Year of publication: 1989

Gerasimov I.P. Environmental problems in the past, present and future geography of the world. M.: Nauka, 1985.

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