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.
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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:
Short name of the country according to MK (ISO 3166) 004-97 | Abbreviated name of the national standardization body |
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Armenia | Ministry of Economy of the Republic of Armenia |
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Belarus | State Standard of the Republic of Belarus |
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Kazakhstan | Gosstandart of the Republic of Kazakhstan |
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Kyrgyzstan | Kyrgyzstandard |
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Russian Federation | Rosstandart |
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Uzbekistan | Uzstandard |
4 This standard is in accordance with 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).
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* 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 of the Russian Federation on 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 those 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 sampling water from underground water sources, surface reservoirs and watercourses, as well as springs.
Sampling requirements are included as 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, farthest 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 of infectious diseases, to identify the source of microbial contamination of water, sampling is carried out taking into account the contamination of the external surface of the tap, 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 distributed water;
- 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, the top layer of 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 determining (method of analysis) 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, the container is closed 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 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 carrying out concentration at the sampling site, used adsorbents or filters are placed in sterile plastic bags or Petri dishes and transported in refrigerator containers at a temperature of 4 ° C - 10 ° C in the shortest possible time, but not more than 24 hours. When concentrated samples arrive in The laboratory must immediately begin eluting the 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 subject to filtration immediately after its collection (to prevent any possible changes in the composition of the sample), filtration methods are used, which 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 prevent exposure of water samples to light and elevated temperatures. 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
The sampling report must contain the following information: |
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Purpose of sampling | ||||||||||||
Location and name of sampling site | ||||||||||||
Selection date | ||||||||||||
Time (start and end) of sampling | ||||||||||||
Environmental climatic conditions at the sampling site (if necessary): |
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air temperature | ||||||||||||
water temperature | ||||||||||||
Water treatment stage (if sampling is carried out to control water treatment stages): |
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disinfection | ||||||||||||
oxidation | ||||||||||||
softening | ||||||||||||
other types of processing | ||||||||||||
Determinations made at the sampling site: |
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Preservation method (if necessary) | ||||||||||||
Features of sample collection and storage | ||||||||||||
Equipment used for sampling | ||||||||||||
Sampling containers (material) | ||||||||||||
Position, surname, name, patronymic of the person who took the sample, and his signature. |
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Electronic document text
prepared by Kodeks JSC and verified against:
official publication
M.: Standartinform, 2013
Sampling of water should be considered as a stage that largely determines the correctness of subsequent analysis, and errors made during the sampling process cannot subsequently be corrected even by the most qualified analyst. The place and conditions for collecting a water sample in each case are determined by the specific objectives of the research, however, the basic rules for sampling are of a general nature: - the water sample taken for analysis must reflect the conditions and place of sampling; - sample collection, storage and transportation must exclude the possibility of changing its original composition (contents of determined components or properties of water); - the sample volume must be sufficient to carry out the analytical procedure in accordance with the methodology.
Water sampling
Water sampling can be one-time or serial. One-time sampling is usually used to obtain initial information about the quality of the analyzed water. Taking into account the composition of the analyzed waters, which varies in time and space, serial sampling, which is carried out either from different depths of the source or at different points in time, is more justified. With this selection, one can judge the change in water quality over time or depending on its consumption.
By their type, samples can be simple or mixed. A simple sample is provided by a single selection of the entire amount of water required for analysis, and the information obtained corresponds to the composition at a given point at a given time. A mixed sample is obtained by combining simple samples taken at different time intervals or at different points, thus characterizing the average composition of water. If a sample is taken from an open stream, it is necessary to observe the conditions under which it will be typical: the best places for sampling are turbulent areas where more complete mixing occurs. When collecting a wastewater sample, the following conditions must be observed:
- - sampling speed of at least 0.5 m/s;
- - the diameter of the sampler hole is at least 9 - 12 mm;
- - high turbulence (if absent, it is created artificially).
When taking a sample of drinking water, you must first drain the water for 15 minutes with the tap fully open. Before closing the vessel with a stopper, the top layer of water is drained so that a layer of air with a volume of 5 - 10 cm 3 remains under the stopper.
The amount of sample that needs to be taken for analysis depends on the number of components being determined. For an incomplete analysis, in which only a few components are determined (or individual indicators: compliance with hygienic standards, some control determinations, etc.), it is enough to take 1 liter of water. For a more detailed analysis, you should take 2 liters; for a complete analysis or to determine components that are very small in water, an even larger sample volume is required (up to 10 l).
Glass, porcelain and plastic vessels (bottles of various shapes) with ground-in or screw-on stoppers (hermetic closure) that are chemically resistant to the water being tested are used as sampling vessels. The choice of vessel material depends on the nature of the impurities being determined. For example, drinking water can be collected in both glass and polyethylene vessels, if they are approved for contact with water; samples intended for analysis for the content of organic substances are taken only in glass vessels with ground-in stoppers. The capacity of the vessels must ensure that all planned components are identified.
The basic rule when taking water samples is the cleanliness of the vessel and stopper. Glassware is washed and degreased with a chrome mixture, thoroughly washed from acid and steamed with water steam. Polyethylene dishes are rinsed with acetone, hydrochloric acid (1:1), several times with tap water, and then with distilled water. The washed dishes are dried and, before taking a sample, rinsed several times with the water to be sampled. Corks, depending on the nature of the material, are cleaned in various ways: cork corks are boiled in distilled water, rubber corks are boiled in a 5% solution of hydrochloric acid (20-30 minutes), and then in a 20% solution of caustic soda, after which they are thoroughly washed with distilled water and stored in glass jars with lids.
The containers into which samples are taken must be numbered in a way that eliminates the possibility of labeling being violated. An accompanying document is drawn up for each sample, which must indicate: a) the number of the bottle (container); b) name of the type of water; c) sampling location; d) date and time of sampling; e) method of sampling (type of sampler, device); f) type of sample (simple, mixed); g) frequency of sampling; h) information about preserving the sample and ensuring its safety; i) position, surname and signature of the responsible person and specially authorized representative of the water user involved in sampling and their preparation.
To deliver samples to the laboratory, sample vessels are packaged in containers that ensure safety and protect against sudden temperature changes.
Water must be analyzed on the day of collection. In principle, any storage of water samples should be avoided. Since most types of water are characterized by variable composition, the substances being determined may change to varying degrees in the period of time between sample collection and analysis. Water temperature and pH change very quickly. Gases contained in water, such as oxygen, carbon dioxide, hydrogen sulfide or chlorine, may escape from the sample (or appear in it: O 2, CO 2). These and similar substances must be determined at the sampling site. Changes in pH, carbonate content, free CO 2, etc. can cause changes in the properties of other components contained in the sample. Some of them may precipitate or, conversely, go from an insoluble form into a solution. This especially applies to salts of iron, manganese, and calcium.
Various biochemical processes caused by the activity of microorganisms or plankton can occur in the sample. These processes occur in the selected sample differently than in the original environment, and lead to the oxidation or reduction of some components of the sample: nitrates are reduced to nitrites or, conversely, oxidation of sulfides, sulfites, iron (II), cyanides, etc. occurs. Organoleptic properties change properties of water (smell, taste, color, turbidity). Some dissolved metals (Fe, Cu, Cd, Al, Mn, Cr, Zn), phosphates, a number of organic compounds and other components can be adsorbed on the walls of the bottle or leached from the glass or plastic bottle (B, Si, Na, K, various ions , adsorbed by polyethylene during previous use of the bottle).
Polymerized substances can depolymerize and, conversely, simple compounds can polymerize. The duration of the processes considered depends on the chemical and biological nature of the sample, temperature, time the sample is exposed to light, the material of the glassware, the time interval between sampling and analysis, transportation conditions and leads to a discrepancy between the analysis results and the actual concentrations of components in a freshly collected sample. Therefore, every effort should be made to reduce the time between sample collection and analysis.
The latter must be carried out no later than 12 hours after sampling. If for some reason this is impossible to do, then to extend the shelf life of the water in the state in which it was at the time the sample was taken, the sample is preserved. Sample preservation involves adding preservatives to the selected sample.
The task of sample preservation and storage is very difficult. Not all components of water can be preserved: residual ozone and chlorine, pH, taste, smell, color, turbidity, total hardness, dry residue, fluorine, chlorides, sulfates, borates, nitrates, fluorides, xanthates, suspended substances, coarse impurities cannot be preserved , fatty acids, sugars, etc. Since there is no universal preservative substance, the substances determined in the sample cannot be preserved in the same way: in this case, samples are taken into separate bottles and preservation is carried out appropriate for each of the determinations.
For example, to determine sulfides, sulfites, and carbon dioxide, samples are taken in separate bottles for each of these determinations. A preservative may have an interfering effect, especially if the sample contains insoluble substances, which is especially true for wastewater.
A wide range of different substances are used as preservatives, the choice of which is determined by the nature of the components being determined. For example, Al, As, Cu and Sb are preserved by adding concentrated hydrochloric acid; Fe (total content), Be, Mo, Se, U, Cd, Co, Sr, Mn, Ni, Hg, Pb, Ag, Cr (total) - by adding concentrated nitric acid; ammonia and ammonium ions - by adding sulfuric acid; cyanides and phenols - by adding NaOH or KOH; sulfates - by adding NaOH and glycerin; petroleum products, nitrites, phosphates - by adding chloroform. The amount of preservative is 3 ml/l of sample.
It is best to store samples in vessels made of borosilicate glass, high-density polyethylene or polypropylene at pH = 2. Under these conditions, chemisorption of trace metal ions on surfaces is reduced, hydrolysis and precipitation of cations is prevented.
However, the use of preservatives does not completely protect the analyte from changes. The purpose of preservation is only to preserve the relevant component unchanged for the period between sampling and analysis. Therefore, canned samples should be analyzed the next day, but no later than 3 days from the moment of collection. Storing samples for a long time is only possible to determine a limited number of parameters. The duration of water storage is noted in the analysis protocol.
In general, it is impossible to establish uniform requirements for sample storage. Storage periods, vessel material and other conditions depend not only on the components being determined, but also on the nature of the sample and the analytical methods that will be used. Generally, surface and groundwater samples are more stable during storage than wastewater.
Deep cooling or freezing for an indefinite period is widely used as a method of preserving water. This method is especially effective if applied immediately after sampling. But refrigerated samples cannot be stored for a long time. Samples in glass containers are not frozen.
Selection rules
in accordance with the requirements of GOST R 51592-2000 "Water. General requirements for sampling", GOST R 53415-2009 (ISO 19458:2006) "Water. Sampling for microbiological analysis", MP 0100/13609-07-34 "Sampling and preparation of water samples to determine radiological indicators of drinking water."
1. General requirements for sampling
When collecting water samples at the same point for different purposes, samples are taken first for microbiological analysis.
When sampling from a tap (well), the time to drain the water before sampling depends on the purpose of sampling. If the purpose of sampling is to assess the quality of consumed water, then samples should be taken without first draining the water. To assess the quality of water in a water point (well, well) to establish equilibrium conditions before sampling, 5 minutes of draining the water is sufficient.
The water supply system from wells and wells in which the pump is permanently installed must have a metal tap or outlet. An open container for sampling is placed under a tap in a stream of water and filled (in a thin stream along the wall of the container). While filling the container, it is not allowed to change the water pressure (by closing or opening the tap).
Sampling from wells and wells at the point of consumption that do not have a permanently installed pump is carried out using a bucket, can or ladle, etc., which are filled with water, after which the water is poured into sampling containers.
Water sampling from springs is carried out at the outlet of the capture structure or, if there is none, at the point where the head of the spring (“griffin”) exits the surface of the earth.
For transportation, it is preferable to cool the samples to a temperature of 2-5 °C (for example, using cold accumulators). During transportation, containers must be protected from contamination, damage and spontaneous opening of caps.
Analysis of water samples must begin on the same working day on which the samples were taken. The storage time of water samples from collection to the beginning of their analysis includes the duration of transportation, registration and preparation of samples for analysis. The maximum storage period for samples is 6 hours. Increasing this period may reduce the reliability of the results. By agreement with the Customer, it is possible to increase the maximum storage period of samples to 8 hours.
2. Sampling water intended for microbiological analysis, carried out with disinfected [for example, treatment with ethyl alcohol 70% or disinfectant wipes for personal use] immediately before sampling with hands or with sterile gloves in a sterile container (volume 0.5 l, which must be obtained in advance from the laboratory).
Immediately before sampling, the tap is sterilized, preferably by flambéing (treating the tap with a burning swab moistened with 96% ethyl alcohol). The quality of flambéing is determined by the appearance of a hissing sound upon contact with water after opening the tap. (Superficially burning the faucet with a lighter is not enough to disinfect it). Only if flame sterilization is not possible, the neck of the tap is disinfected by immersion for 2-3 minutes in a glass with 70% ethyl alcohol. After sterilization, the tap is opened to provide the minimum flow of water necessary to flush away the disinfectant that was used on the tap, after which water samples are taken.
When sampling, aseptic conditions must be ensured and samples must be protected from dust and splashes.
The sterile sampling container is opened immediately before sampling, removing the stopper along with the sterile cap. The stopper and edges of the container should not touch foreign surfaces. Not allowed Rinse sterile sampling containers!
After filling, the container is immediately closed with a sterile stopper, which ensures a tight seal and does not get wet during transportation, and a sterile cap. When filling the container, there should be space between the stopper and the surface of the poured water so that the stopper does not become wet during transportation and to ensure mixing of the sample before analysis.
3. When sampling water intended for chemical analysis, 2 containers with a volume of 1.5 liters (or 1 container with a volume of 5 liters) made of polymer material intended for contact with food products are rinsed at least three times with the water to be analyzed and the containers are filled to the top with it.
4. When sampling water intended for determining radiological indicators, incl. specific activity of radon ( 222 Rn), a 1.5 liter container made of polymer material intended for contact with food products is pre-rinsed at least three times with water to be analyzed. After filling the container with water to the top, you need to squeeze it so that the water is at the very edge of the neck, and then screw on the lid. The sample is transported with the lid turned down. The maximum sample storage period is no more than 48 hours.
Modern water sources and underground lakes are polluted due to mass industrial production and soil contamination. Due to the fact that large amounts of toxic and hazardous substances to human health are constantly released into the soil and air, even the most environmentally friendly and green areas may contain water sources with high concentrations of harmful impurities and metals. In order to protect people from poisoning and other problems that develop due to the use of poor-quality water, any new development or purchase of a new home should be accompanied by specialized water sampling for thorough study in a specialized laboratory.
It is worth saying that it is necessary to carry out two main ones. According to the rules for collecting water samples for analysis, one check should be carried out before purchasing filtering units and treatment facilities. The second stage of the examination should be carried out after purchasing the filter. Such comprehensive analytics will help to find out how effective the filter element is, whether the water is purified in accordance with all regulated standards and whether it is safe for widespread domestic and industrial use.
It is important to note that modern filters and water purifiers do not have a universal testing function. Each of these structures is made with a built-in purification function for strictly defined groups of substances. The method of water sampling showed that some filters are effective when they filter out excess metal impurities from water, others when their work is aimed at bactericidal purification of water, etc. It is impossible to buy a filter to remove all pathogenic impurities. For this reason, it is very important to follow the instructions for sampling water, conduct analytics and test water quality before purchasing a purifier, in order to know exactly what type of pathogenic substances need to be filtered.
Taking water samples for analysis requires compliance with a number of rules when collecting liquid into containers. It is important to remember that simply drawing water from a tap or well will be a rash act, which will most likely negatively affect the results of the research and will not allow obtaining reliable data. Given the nature of the test, sampling of drinking water is carried out according to a number of basic regulated rules. The rules for water sampling are drawn up and certified by state standards under the identifiers R 51592-2000 and R 53415-2009.
Basic requirements for the procedure for collecting water for examination
First of all, it is worth remembering that there are two methods for collecting water samples:- Microbiological, which allows you to determine the content of foreign microorganisms in water;
- Chemical, which allows you to determine the amount of foreign impurities and elements contained in the liquid.
- If water samples are taken from the same source, biological material is first collected for microbiological testing. The water that will be tested for its chemical composition is collected last.
- Depending on the depth of the water sampling site and the purpose of the test, water from any source should be collected without prior ebb of stagnant water or with a low tide of 5 minutes. It is worth noting that most modern examinations require first draining water from a tap or well before taking samples of natural waters, since stagnant water in pipes can have many impurities and metal particles that affect the final test results.
- When taking water samples for analysis from a tap, you need to remember that the liquid should flow in a thin stream along the walls of the collection container. This method will prevent large amounts of air from entering the vessel and causing pathogenic chemical reactions. It is worth remembering that any water pumping installation must be equipped with a high-quality metal tap from which water is delivered.
- If the sampling points do not have a tap and a special water supply connection, water samples for laboratory research are taken by using clean improvised materials such as buckets, cans or bottles. However, in the process of draining water into containers, it is important to remember to minimize the ingress of air and the accumulation of excess impurities and bacteria.
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The liquid, which is intended for delivery to the laboratory for examination, must be pre-cooled to 3-5 degrees Celsius. You can cool the container by keeping it in a refrigerator or using special cooling units. The method of collecting water samples for chemical analysis determines that during the transportation of samples for examination, a lot of air, by-products, impurities and sun should not enter the liquid, since chemical reactions carried out in the collected liquid during transportation can affect the final results of the examination - distort data.
The maximum permissible storage period for a water sample, after which the liquid becomes unsuitable for testing, is 48 hours. The frequency of sampling drinking water is twice or thrice a year, taking into account the type of analysis. The ideal option would be to transport the liquid to the laboratory on the day of sample collection. After water samples have been taken, the liquid can be stored in the laboratory for 6-8 hours, after which the biological material is considered unsuitable for testing and requires re-sampling.
Water for microbiological studies
Depending on the specific testing purposes, principles and methods of water sampling, containers and liquid for collection must comply with some basic regulated standards: - Microbiological analysis of water is carried out using equipment for sampling water under conditions close to sterile, in order to avoid side impurities of bacteria and microorganisms from the outside, the presence of which may affect the quality of the test. Liquid intake should be carried out after pre-treatment of the tap with a bactericidal agent, alcohol or fire.
- Taking water samples should be carried out in containers washed under running water, wearing sterile medical gloves, avoiding touching the neck of the bottle.
- Water collected for microbiological laboratory testing must be protected from dust and impurities.
- The lid of the container must be sterile and prevent air from entering the sample taken for examination.
Taking water samples for chemical testing
Chemical analysis has several distinctive features that affect the rules for collecting water and transporting biological material for examination. - Devices for sampling water and containers where water is collected for chemicals. research must be as pure as possible and intended for food use. The container must be filled to the very top, avoiding getting a large amount of air into the sample liquid.
- After collecting the liquid, you need to squeeze the bottle slightly in order to eliminate the last remaining air and then tightly close the lid. Considering the specifics of the test and the importance of correctly determining the composition of the water, the container for collection should be washed several times immediately before collecting liquid and should not contain any impurities or microelements on its walls.
- It is worth storing the liquid for chemical testing for no more than 48 hours. If it is not possible to transport the water on the same day when the collection was made, the container can be stored in a dark, cold place, having first eliminated the presence of side factors that may affect the composition or quality of the liquid during its storage.
EcoTestExpress laboratory offers modern services for conducting examination of the chemical and microbiological type of water. Regardless of the customer’s requirements and the specifics of the test, we guarantee a minimum amount of errors in measurements and high-quality advice upon completion of the work. Many years of experience give us the opportunity to keep up with the times and be the best in the field of microbiological testing and examination of water of any type and nature.
