Sampling of water for sanitary and chemical research. Water sampling. Sampling requirements

It has been established that drinking water of inadequate quality is important factor development intestinal infections, malignant neoplasms of the intestine. Excess of certain substances in water can lead to a variety of diseases.

People who are seriously interested in maintaining their health understand the importance of drinking water that is adequate state standards quality. At the same time, it’s no secret that not only tap water, but even bottled water is not always suitable for drinking.

In order to determine the quality of bottled, tap, or any other water that may be suitable for drinking, you can sample the water and send the sample to a laboratory. If you want to find out what kind of bottled water you can drink, or if you want to approach the choice of a water filter with a full understanding of the situation, analyzing the water for the content of chemicals and bacterial contamination is simply necessary. This will allow you to accurately determine which filter needs to be installed on your water tap to make the water drinkable.

If you decide to take a tap water sample, in order for the result to be reliable, you must take samples in compliance with all the rules established by GOST.

Procedure for sampling for chemical analysis

To collect the analysis, we will need a plastic water container with a volume of 1.5-2 liters. It is worth mentioning right away that even a bottle of other drinks (soda, juice, etc.) that has been washed most thoroughly may contain traces of dyes, substances dissolved in water, stabilizers and other components on its walls, which can distort the water analysis. For this reason, only water containers are used to collect water. An alternative to a plastic bottle can be a glass container with a silicone or plastic (polyethylene) lid that screws tightly or closes with pressure.

Water analysis should be performed using disposable rubber gloves, which can be easily purchased at a pharmacy.

Turn on the water at the tap. Let the water drain for 10-15 minutes. Rinse the container with the same running water, then carefully pour water into the container, running a stream along its wall so as to avoid bubbling. While sampling, be careful to ensure that the neck of the bottle does not come into contact with the faucet or sink.

Since oxygen is capable of participating in many chemical reactions, if taken incorrectly, the real picture may be distorted. Pour water to the top, then squeeze the sides of the container so that the water flows out of the bottle a little. In this state, tightly screw the lid on the bottle. This manipulation will prevent air from getting under the bottle cap.

Wipe the bottle.

Attach (or better yet, stick) a document containing the following information to the water sample:

• the exact date and time when the sample was taken;
• the exact location where the water was taken;
• where the water came from (for example, from a water tap);

Additional information:

• for example, how long the water was run before taking the sample;
• the reason why the sample is sent to the laboratory: for example, the taste of water has changed, bad smell And so on;
• how the water was collected.

It is better if the water sample for chemical analysis is delivered to the laboratory by specially trained personnel. The fact is that GOST gives precise recommendations regarding the transportation of water samples: containers must be packed in special containers that protect the container with water from mechanical shocks and environmental influences. If this is not possible, you can deliver a bottle of water to the laboratory yourself. In this case, until transportation, you must place the container in a cool, dark place (a regular refrigerator will do). Sample analysis must be carried out no later than 6 hours after picking her up.

In a similar way, water is taken for chemical analysis from a well or well, with the only difference being that water from the well or well must first be taken using a clean container (bucket or other) and only then poured into a bottle.

Before opening the bottle, rinse the outside of the bottle with well water, then unscrew the cap and fill the container to the brim. Squeeze the sides of the bottle so that the water completely fills the neck of the bottle to the brim, then screw the cap tightly. Complete the accompanying documents.

Procedure for sampling for bacteriological analysis

To collect samples for microbiological analysis, it is better to use special sterile bags. GOST for water sampling says that containers with water, as well as lids or plugs with which the container is closed, must withstand high temperatures. For this reason, water cannot be delivered in a regular plastic bottle.

If the package is not available, you can use a regular glass bottle or jar with a volume of more than 0.5 liters with a tightly screwed or pressure-closed lid made of polyethylene, silicone, or rubber. Metal lids should not be used, as it can have a toxic effect on microorganisms contained in the water, thereby distorting the sample. The glass container and lid must be thoroughly washed and sterilized by boiling or steam before taking a sample.

Before taking a sample, it is necessary to burn the water tap using an alcohol torch and wipe it with 96% alcohol. After this, you need to run the water for 10-15 minutes, turning the valve completely out (opening the tap “at full power”). To prevent bacteria from the skin of your hands from getting into a sterile bag or other container, it is better to use sterile rubber gloves (available at any pharmacy). Pour water into a sterile container with a volume of at least 0.5 liters (or better - 1.5-2 liters), avoiding the neck of the bottle touching the tap or sink.

If you are using a special bag (it can be taken in advance from the laboratory in which the analysis will be carried out), tear off its upper part along the perforated line immediately before taking the sample, then open it by grasping the special plastic holders (“ears”) attached to the edges of the bag. ).

Open the container of water that will be tested, or pour tap water into the bag until the white line. After this, close the bag, squeezing the upper part not occupied by water between the index and thumbs and making movements with your hands in the direction from the center to the top edge of the bag: this way you will remove the air from the bag and close it. Wrap the water-free edge of the bag into a tube, then tie the ends together. Check for water leaks. In accordance with GOST, water for microbiological testing must be taken for analysis within 2 hours after its collection, at least within 6 hours. Until the container is transferred to the laboratory, store it in a dark place at a temperature of 2-8 0 C (for example, in a refrigerator). The sample must be transported in a special container in which the temperature can be maintained at +2+8 0 C throughout the trip. In addition, during transportation, containers with water should not be exposed to sunlight or mechanical stress. If the container has a lid or stopper, water should not be allowed to come into contact with them to prevent microbial contamination of the water.

The container must be provided with an accompanying document. It must indicate the following:

• the exact date;
• time;
• sample collection location;
• how the water was selected for analysis;
• for what purpose is the sample being examined?

If necessary, provide additional information.

If you meet all the requirements for collecting a water sample for research, you will receive reliable result within 1-3 days, if we are talking about chemical analysis of water, and within (maximum) 7-10 days - when conducting a test for microbiological contamination. As a rule, upon completion of the study, laboratories issue an analysis protocol with detailed calculations on the content of certain substances or microorganisms.

GOST 31862-2012

Group H08

INTERSTATE STANDARD

DRINKING WATER

Sample selection

Drinking water. Sampling

Text Comparison of GOST 31862-2012 with GOST R 51593-2000, see the link.
- Database manufacturer's note.
____________________________________________________________________

ISS 13.060.45
TN VED 220100000

Date of introduction 2014-01-01

Preface

The goals, basic principles and basic procedure for carrying out work on interstate standardization are established by GOST 1.0-92 "Interstate standardization system. Basic provisions" and GOST 1.2-2009 "Interstate standardization system. Interstate standards, rules and recommendations for interstate standardization. Rules for development, adoption, application, renewal and cancellation"

Standard information

1 PREPARED by Limited Liability Company "Protector"

2 INTRODUCED by the Federal Agency for Technical Regulation and Metrology

3 ADOPTED by the Interstate Council for Standardization, Metrology and Certification (protocol dated November 15, 2012 N 42)

The following voted for the adoption of the standard:

4 This standard conforms to the international standard ISO 5667-5:1991* Water quality - Sampling - Part 5: Guidance on sampling drinking water and water used for food and beverage processing and water used in food and beverage production technology).
________________
* Access to international and foreign documents mentioned in the text can be obtained by contacting Customer Support. - Database manufacturer's note.

The degree of compliance is nonequivalent (NEQ).

The standard was prepared based on the application of GOST R 51593-2000

5 By Order of the Federal Agency for Technical Regulation and Metrology dated November 29, 2012 N 1514-st, the interstate standard was put into effect as a national standard Russian Federation from January 1, 2014

6 INTRODUCED FOR THE FIRST TIME


Information about changes to this standard is published in the annual information index "National Standards", and the text of changes and amendments is published in the monthly information index "National Standards". In case of revision (replacement) or cancellation of this standard, the corresponding notice will be published in the monthly information index "National Standards". Relevant information, notifications and texts are also posted in the public information system - on the official website of the Federal Agency for Technical Regulation and Metrology on the Internet

1 area of ​​use

1 area of ​​use

This standard establishes requirements for sampling drinking water produced and supplied by centralized drinking water supply systems and intended for consumption for drinking and domestic purposes, including used for the production of food and beverages (hereinafter referred to as water), which should guide the development of programs and sampling methods, sample preparation for determination of composition and properties, their transportation and storage.

This standard is used when assessing the stability of water treatment technological processes, monitoring individual operations of water treatment technological processes, assessing the quality of water before entering the distribution network, in the distribution network, including internal water supply networks of houses, and searching for causes of network contamination.

The requirements of this standard can be used to control water contamination by corrosion products; assessing the impact of materials in contact with water on its quality; water quality control carried out at various stages of technological processes in the production of food and beverages.

This standard does not apply to the collection of water samples from underground water sources, surface reservoirs and watercourses, as well as springs.

Sampling requirements are included as an integral part of operational programs for industrial water quality control.

2 Normative references

This standard uses normative references to the following interstate standards:

GOST 2874-82* Drinking water. Hygienic requirements and quality control
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GOST R 51232-98 SanPiN 2.1.4.1074-01


GOST 18300-87 * Rectified technical ethyl alcohol. Specifications
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* In the Russian Federation, ethyl alcohol is also used in accordance with GOST R 51652-2000 "Rectified ethyl alcohol from food raw materials. Technical conditions."


GOST 23268.0-91 Mineral drinking waters for medicinal, medicinal table and natural table waters. Acceptance rules and sampling methods

GOST 31861-2012 Water. General sampling requirements

GOST 31942-2012 (ISO 19458:2006) Water. Sampling for microbiological analysis

Note - When using this standard, it is advisable to check the validity of the reference standards in the public information system - on the official website of the Federal Agency for Technical Regulation and Metrology on the Internet or using the annual information reference index "National Standards", which was published as of January 1 of the current year , and on issues of the monthly information index "National Standards" for the current year. If the reference standard is replaced (changed), then when using this standard you should be guided by the replacing (changed) standard. If the reference standard is canceled without replacement, then the provision in which a reference is made to it is applied in the part that does not affect this reference.

3 Requirements for sampling equipment

General requirements for sampling equipment and materials used for the construction of equipment components in contact with a water sample must comply with GOST 31861, GOST 31942.

General requirements for the preparation of containers (devices) for sampling must comply with GOST 31861, GOST 31942.

4 Sampling requirements

4.1 General requirements

The location and time of sampling are determined depending on the purpose of the analysis at the most characteristic points of the water supply system: before the water enters the distribution network, those furthest from the pumping station, at elevated and dead-end sections of the network, as well as at points where the quality of the water is in doubt.

Water samples from the distribution network are taken during periods of highest water flow.

Requirements for choosing a sampling location and ensuring the representativeness of sampling must comply with GOST 2874*.
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* In the Russian Federation, GOST R 51232-98 “Drinking water. General requirements for organization and control methods” is in force.


Before sampling, in accordance with the sampling program, a nomenclature of indicators (characteristics) of the composition and properties of water is determined, which are subject to analysis immediately after sampling at the sampling site. Indicators (characteristics) to be analyzed at the sampling site must be specified in the regulatory documents (ND) for the method of determining the indicator.

Methods of selection, preparation for determining the composition and properties, transportation and storage of water samples must ensure that the composition of the samples remains unchanged in the time interval between sampling and their analysis.

When sampling at the same point for different purposes, samples are taken first for bacteriological analysis.

4.1.1 Tank sampling

Water samples are taken from the reservoir before entering the distribution network through special samplers from taps on the water pipelines through which water is supplied from the reservoir.

Samples are taken in places located as close as possible to the tank. Before sampling, stagnant water should be drained for at least 10 minutes. In technically justifiable cases, the volume of water that needs to be drained before sampling should be determined by determining (approximately) the time required for the volume of water to flow at the existing flow rate and then setting a time equal to five times the time of flow of this volume.

4.1.2 Sampling when monitoring the stability of water treatment processes

To monitor the various stages of water treatment, sampling should be carried out before and after the relevant stage (for example, coagulation, filtration). Sampling to control water quality at various stages of water treatment (including at the inlet and outlet of water treatment devices) is carried out in accordance with the technological regulations for the water treatment process.

4.1.3 Sampling during disinfection control

Samples of water supplied for disinfection should be taken from a tap on the water supply line located at the entrance to the disinfection installation. Samples of water leaving the disinfection installation are taken at the outlet of the installation after the duration of contact between the water and the disinfectant established in the RD. It is allowed (in technically justified cases) to assess the stability of the water disinfection process, to take samples of treated water from the distribution network or directly from the disinfection installation. In this case, the sampling method should exclude the possibility of introducing polluting components into the water; the equipment used must be sterilized before sampling.

4.1.4 Sampling from the main distribution network

Sampling from the main distribution network is carried out at the outlet of water treatment facilities, from street water distribution facilities, at the most elevated and dead-end areas, after storage tanks, at the entrances before water flows to the consumer.

When taking samples from hydrants, the surfaces of the hydrant that come into contact with water should be cleaned, disinfected, and rinsed repeatedly with the test water to exclude the presence of a disinfectant in the sample.

The sampling point and its location are determined depending on the purpose specified in the program.

If the purpose of sampling is to assess the impact of materials in contact with water on water quality, to assess the fouling of materials by microorganisms, or to assess the quality of stagnant water in dead-end sections of the network, then samples should be taken from the first portion of water drainage, and the drainage time should be minimal ( approximately 5-10 s).

If it is necessary to take samples from dead-end sections of the pipeline, the time for draining stagnant water can reach 30 minutes.

The length of the conduit supplying water to the sampling tap should be as short as possible.

4.1.5 Taking water samples from the indoor distribution network

Water sampling is carried out at the outlet of the taps of the internal water supply networks of houses.

When sampling from a tap, the time to drain the water before sampling depends on the purpose of sampling. If the purpose of sampling is to assess the effect of materials in contact with water on water quality, then samples should be collected without first draining the water. For other purposes, 2-3 minutes of draining the water is sufficient to establish equilibrium conditions before sampling. When taking samples to determine microbiological parameters, metal taps should be pre-sterilized by burning with a burning swab moistened with a 96% solution of ethyl alcohol, and plastic taps should be disinfected by treating with a 70% solution of ethyl alcohol, and drain the water for at least 10 minutes. with the tap fully open.

4.1.6 Taking water samples from the consumer’s tap

Water sampling from the consumer's tap is carried out, if necessary, in accordance with the requirements of 4.1.5.

When determining the quality of water from a consumer's tap during outbreaks infectious diseases To identify the source of microbial contamination of water, sampling is carried out taking into account contamination of the external surface of the faucet, as well as all fixtures and devices used by the consumer. All fixtures and fittings should be left in place.

In this case it is not allowed:

- disinfect the tap, as well as fixtures and devices before sampling;

- carry out preliminary drainage of water from the tap before sampling.

4.1.7 Sampling of water packaged in containers, as well as poured into large containers intended for storage on trains, planes, ships

Sampling of water packaged in containers is carried out in accordance with GOST 23268.0.

Water sampling from containers is carried out in accordance with the requirements of 4.1.1. Sampling from the container is carried out from a tap intended for sampling drinking water, after its preliminary disinfection, as specified in 4.1.5.

4.1.8 Sampling of water used for food and beverage preparation

Food and beverage manufacturing processes that include one or more water treatment units that provide a number of special water requirements (for example, softening) must be capable of collecting water samples before and after each water treatment step.

Sampling is carried out in accordance with the requirements of 4.1.2.

4.2 Frequency and frequency of sampling

The frequency and frequency of water sampling are established in accordance with the requirements of GOST 2874*, depending on the purpose of sampling and the following factors:
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* In the Russian Federation, GOST R 51232-98 “Drinking water. General requirements for organization and methods of control” and Sanitary and epidemiological rules and norms SanPiN 2.1.4.1074-01 “Drinking water. Hygienic requirements for water quality of centralized drinking water supply systems. Control” are in force. quality. Hygienic requirements for ensuring the safety of hot water supply systems."


- number of consumers served;

- volume of water distributed;

- quality of raw water;

- identified deviations from the quality of raw water;

- presence of identified content of polluting components hazardous to health;

- method of water purification;

- complexity and specific features of the distribution system;

- features of the determined indicators.

4.3 Statistical processing of sampling data is carried out in accordance with the requirements of GOST 2874*.
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* In the Russian Federation, GOST R 51232-98 “Drinking water. General requirements for organization and methods of control” and Sanitary and epidemiological rules and norms SanPiN 2.1.4.1074-01 “Drinking water. Hygienic requirements for water quality of centralized drinking water supply systems. Control” are in force. quality. Hygienic requirements for ensuring the safety of hot water supply systems."

5 Sampling depending on the type of analysis performed

5.1 Sampling for chemical-analytical and radiological monitoring of water quality

Samples are taken in containers made of chemically resistant glass with ground-in stoppers or polymer materials approved for contact with water. Cork or polyethylene plugs may be used.

Samples intended to determine the content of organic substances in water are taken only in glass containers.

Requirements for the preparation of containers for sampling and (or) storage of samples must comply with the requirements of GOST 31861 and standards for the method of determining the indicator.

Before taking a sample, sampling containers, if they do not contain preservatives or are not disposable, are rinsed at least twice with the water to be analyzed and the container is filled to the top with it. When taking samples to be stored, before closing the container with a stopper upper layer The water is drained so that a layer of air remains under the stopper and the stopper is not wetted during transportation, unless otherwise provided by the applicable standard for the method of determination (method of analysis) of the composition and properties of water samples.

To determine oxygen or other dissolved gases in a sample during sampling, it is necessary to use a hose attached to a tap or pump outlet and reaching the bottom of the sample container to avoid contact of the water sample with atmospheric air. Water should flow slowly into the container through the hose.

Water must be analyzed on the day of sampling. If this is not possible, the collected sample is cooled and (or) preserved.

Requirements for preservation and storage of samples must comply with those established in GOST 31861 and (or) the applicable standard for the method for determining the composition and properties of water samples.

5.3 Sampling for microbiological control of water quality

The sample is taken directly from the sampling tap. Hoses, water distribution nets, nozzles, etc. are not allowed.

When sampling, water should flow freely from the sampling valve and fill the sampling container in a stream.

To prevent secondary contamination of the water sample, the sampling tap is pre-cleaned and disinfected by firing, as specified in GOST 31942. Before sampling, water is drained from a sterilized tap for at least 10 minutes with the tap fully open. When taking a sample, the water pressure may be reduced.

For sampling, use glass containers with a capacity of at least 500 cm3 with tightly closing stoppers on the ground or with screw caps (glass, silicone or other materials that do not affect the life of microorganisms) and can withstand sterilization. The neck of the container must be protected with a protective cap made of aluminum foil or thick paper. Sterilization of containers is carried out in accordance with the requirements of GOST 31942. The shelf life of sterile containers is no more than 10 days.

It is allowed to use disposable sterile containers.

The sample is collected in sterile containers. The container is opened immediately before sampling, removing the stopper along with the sterile cap. During sampling, avoid contamination of the container neck and cap. Containers should not be rinsed.

If there is a constant flow of water through the sampling tap, sampling is carried out without preliminary sterilization of the tap, without changing the water pressure and the existing design of the tap.

If water is taken after disinfection with chemicals, then to neutralize the residual amount of disinfectant, sodium thiosulfate in the form of crystals is added to the container intended for sampling before sterilization at the rate of 10 mg per 500 cm3 of water or a solution with a mass concentration of 18 mg/dm.

After filling, close the container with a sterile stopper and cap.

When filling containers, there must be space between the stopper and the surface of the water so that the stopper does not become wet during transportation.

Sample analysis in the laboratory must be carried out as quickly as possible from the moment of collection.

Transport samples in refrigerated containers at a temperature of 4 °C - 10 °C. During the cold season, containers must be equipped with thermal insulating linings to protect samples from freezing. If the specified conditions are met, the duration from the moment of sampling to the start of testing should not exceed 6 hours.

If samples cannot be refrigerated, they should be analyzed within 2 hours after collection.

5.4 Sampling for sanitary-virological testing of water

To take water samples, use sterile disposable containers or reusable containers specially designed for sanitary and virological research, made of materials that do not have an inactivating effect on viruses, with a capacity of 5,000 to 10,000 cm3. Containers must be equipped with tightly closing stoppers.

Sampling from the tap is carried out in accordance with the requirements of 5.3.

Transportation of samples - no more than 6 hours.

Concentration of viruses from water samples is carried out immediately after the samples are received by the laboratory according to the ND for the method approved for use.

When performing concentration at the sampling site, used adsorbents or filters are placed in sterile plastic bags or Petri dishes and transported in refrigerated containers at a temperature of 4 ° C - 10 ° C at minimum possible deadline, but not more than 24 hours. When concentrated samples arrive in the laboratory, it is necessary to immediately begin elution of viruses. The resulting sterile sample eluates are subjected to virological testing within one day.

At a temperature of minus (20±2) °C, eluates can be stored for no more than one year.

5.5 Features of the sampling procedure according to 5.1-5.4 are established in the RD for the method for determining the indicator; all deviations from the procedure must be indicated in the sampling report.

6 Requirements for the volume of samples, their preparation for transportation and storage

6.1 Sample volume

The sample volume is determined depending on the number of indicators being determined and the type of analysis in accordance with the ND for the method of determining the indicator.

6.2 Preparation of samples for transportation and storage

To minimize changes in the composition of water samples during the time required to collect, prepare, package, transport and store samples, these procedures should be performed as quickly as possible.

If contact of the sample with air is to be avoided, the container must be filled completely with water and then immediately sealed.

If the sample needs to be vigorously mixed before taking a portion for analysis, the container should not be filled completely.

If the sample is to be filtered immediately after collection (to prevent any possible changes as part of the sample) use filtration methods that must comply with the ND on the method for determining the indicator. In this case, avoid contamination of the container neck and cap.

In case of preservation of water samples, a note about the method of preservation is made in the test report.

For delivery to the laboratory, sample containers are packaged in clean containers to ensure their safety and protect them from sudden temperature changes.

The packaging of the collected samples must comply with the transportation conditions.

Requirements for water sample packaging must comply with GOST 31861

Storage conditions should exclude exposure to light and elevated temperatures for water samples. Joint storage of water samples and chemical substances is not allowed.

The conditions and periods of storage of samples must comply with GOST 31861 and ND on the method for determining the composition and properties of a water sample.

7 Requirements for recording sampling results

7.1 Requirements for recording sampling results must comply with GOST 31861.

7.2 Information that must be indicated in the sampling report is given in Appendix A.

Appendix A (recommended). Information that must be indicated in the sampling report

Electronic document text
prepared by Kodeks JSC and verified against:
official publication
M.: Standartinform, 2013

1. To take samples, prepare a clean plastic drinking water bottle: 1.5 - 2 liters in volume. You cannot use bottles of beer, Pepsi-Cola, kvass and other sweet drinks.
2. A sample from the well should be taken after the water has been drained for a long time. On average, you will need to drain 3 liters of water for every 10 meters of well depth.
3. Before collecting water, it is necessary to thoroughly rinse the bottle several times with the analyzed water.
4. The bottle is filled to the neck. It is very important that the water does not become agitated and does not come into contact with atmospheric air. For this purpose, one end of the siphon hose is lowered to the sampling point, and the other to the bottom of the bottle. While filling the container, it is not allowed to change the water pressure (by closing or opening the tap). The bottle is filled to the top and then the water being analyzed is continued to pass through it until the water in the bottle is changed several times. Then immediately close the bottle with a stopper, squeezing out the remaining air bubble. This method of collecting a sample allows you to reduce the saturation of water with atmospheric oxygen and, as a result, prevents chemical reactions from occurring!
5. The sample taken is ready for chemical analysis of the water, but remember: the faster the sample gets to the laboratory, the more accurate the result will be.

This image shows how the organoleptic characteristics of a water sample from a well change over a short period of time. After just over four hours, analyzing the water of this sample becomes meaningless.

A person drinks at least 1.5 liters of water per day. Health depends on its purity, general health and even life expectancy. According to WHO, diseases associated with the use of poor-quality water annually claim the lives of 5 million people on the planet. Therefore, the issue of water treatment, without exaggeration, can be considered a matter of life and death. Water from hydraulic structures and centralized water supply systems requires additional purification. To know which filters should be installed, it is necessary to obtain the results of chemical and microbiological studies. How to properly collect water samples for analysis?

What criteria are used to determine water quality?

Water quality requirements are determined by regulatory documents:

• legislation on sanitary and epidemiological welfare;
• SanPiN 4630-88;
• GOST 2874-82.

To find out the composition of the water, a sample is taken for analysis and sent to the nearest laboratory. This could be a local sanitary and epidemiological station or a private laboratory. Experts determine which elements are present in the water, in what quantities and to what extent their concentration complies with the standards.

When submitting a sample for analysis, you should always remember that water quality criteria in the post-Soviet countries are too low. It is advisable to familiarize yourself with the relevant standards of European countries where water quality is more strictly controlled, and focus on these standards.

A full analysis is carried out according to the following criteria:

• physical properties;
• chemical composition;
• contamination with bacteria.

Chemical analysis of water in the laboratory

Physical Requirements

Color, degree of transparency, temperature, smell, taste are controlled. Normally, the water temperature in a hydraulic structure should be within 7-12 degrees. More low temperature promotes development colds, and a higher one leads to the loss of water’s refreshing properties. The turbidity of water depends on the amount of suspended particles. The deeper the source, the clearer the water. Foreign odors and color may indicate the presence of dissolved chemical elements and a large number of bacteria. Even minor changes in physical indicators can affect the functioning of the human body.

Turbidity and color are important indicators of water quality

Research of chemical properties

Check the degree of hardness, salt concentration, active reaction. Water hardness affects not only human health. Such water is unsuitable not only for drinking, but also for domestic needs, because... affects the operation of plumbing fixtures, washing machines. Hardness depends on the concentration of calcium and magnesium salts. Deeper springs tend to have harder water. The permissible standard of hardness is 10 mEq/l. The active reaction is determined by the number of hydrogen ions. The pH norm is 7. High oxidation indicates contamination of the well with wastewater.

Household appliances quickly fail if exposed to hard water

What is bacteriological contamination

Typically, the problem of bacteriological contamination is relevant for shallow hydraulic structures. Bacteria enter them with wastewater, animals, and worms. Laboratory analysis necessarily includes testing for the presence of E. coli, pathogenic bacteria, pathogens various diseases. This analysis must be carried out after the construction of a well or borehole and repeated regularly, at least once a year. If the water is heavily contaminated, it should not be consumed until disinfection filters are installed.

Contaminated water should not be drunk. It's dangerous to your health

How to properly take a water sample for analysis

To take a water analysis, you should prepare the dishes. Will do glass jar or plastic bottle from under mineral water for 1.5-2 l. Flavored drink bottles should not be used. Even well washed, they retain traces of “chemistry” on the walls. You should only collect water while wearing medical gloves.

Sequence of water sampling for analysis:

• Treat the tap with open fire.

• Open the tap for 10-15 minutes. Let the water drain.

• Rinse the bottle under the tap.

• Pour a full bottle of water. Squeeze it until a little comes out and screw the lid on.

• Wipe the bottle, stick a piece of paper on it with exact information about the date, time, place of collection, and the reason for sending the sample for analysis. It is advisable to provide additional information about how the sample was taken.

• Deliver the bottle to the SES within 6 hours.

• Water from a hydraulic structure that is not connected to an autonomous water supply is collected in almost the same way, but first it is collected into another container, from which it is poured into a jar or bottle.

• For bacteriological analysis, it is better to take a sterile bag from the sanitary and epidemiological station. If this is not possible, then a half-liter jar with a tight non-metallic lid will do. It is advisable to submit the sample for analysis within 2 hours, 6 is the deadline.

Pour water into a sterile bag to the level marked with a white stripe

Some laboratories provide on-site water sampling services. This will cost slightly more than doing the procedure yourself. But the sample will be taken correctly and sent to the laboratory in a special container. If you have the opportunity to call laboratory staff to the site, do not miss it. Your health is worth paying a little extra for the quality of sampling.

When taking water samples from a surface reservoir or a mine well, its temperature is measured using a special thermometer (Fig. 16.1.) or a conventional chemical thermometer, the reservoir of which is wrapped in several layers of gauze bandage. The temperature is determined directly at the water source. The thermometer is lowered into the water for 5-8 minutes, then quickly pulled out and the water temperature is taken.

Rice. 16.1. Thermometer for measuring water temperature in reservoirs, wells (a), bathometers for taking water samples for analysis (b).

Water sampling from surface reservoirs and wells is carried out using bottles of various designs, which are provided with double twine: for lowering the device to a given depth and for opening the vessel plug at this depth (Fig. 16.1-b).

To take water samples from flowing reservoirs (rivers, streams), a bottlemeter with a stabilizer is designed, which directs the neck of the vessel against the flow.

A water sample from a water tap or equipped drainage system is taken:

for bacteriological analysis, after preliminary burning the outlet of the tap or captage with an alcohol torch, draining water from the tap for at least 10 minutes, into a sterile bottle with a capacity of 0.5 liters, with a cotton-gauze stopper, wrapped on top with a paper cap. In order not to soak the cotton-gauze stopper, fill the bottle about three-quarters full so that 5-6 cm of air space remains under the stopper.

Dishes with a cotton-gauze stopper are sterilized in advance in an oven at 160 0 C for an hour;

for a short sanitary-chemical analysis (organoleptic indicators, basic indicators of chemical composition and indicators of water pollution), up to one liter is taken into a chemically clean container, after rinsing it with the sampled water (for a complete sanitary-chemical analysis, 3-5 liters of water are taken). During sampling, a covering letter is drawn up, in which they note: the type, name, location, address of the water source (surface reservoir, artesian borehole, mine well, captage, water tap, standpipe); its brief description; weather conditions at the time of sampling and during the previous 10 days; reason and purpose of sampling ( routine examination

Samples are delivered to the laboratory as quickly as possible. Bacteriological studies should begin within 2 hours after sampling or, if stored in a refrigerator at a temperature of 1-8°C, no later than 6 hours. Physico-chemical analysis is carried out within 4 hours after taking the sample or, if stored in a refrigerator at 1-8°C, no later than 48 hours. If it is impossible to conduct research within the specified time frame, the samples must be preserved (except for samples for physical, organoleptic and bacteriological studies, as well as BOD determination, which must be carried out within the above time frame). Preserve samples with a 25% solution of H 2 SO 4 at the rate of 2 ml per 1 liter of water or in another way, depending on the indicators that will be determined.

An accompanying form is attached to the selected sample, which indicates the address, type of water source where the sample is sent, the purpose of the analysis, the date and time of sampling, and the signature of the official who took the sample.