Hygiene of water, maintaining its quality at the proper level, is one of the most important tasks facing humanity. The life and health of the inhabitants of the Earth directly depend on how we deal with it.
Water is the most common natural compound on our planet. Its heat capacity varies nonlinearly: it reaches its lowest values at a temperature of 37 ° C. Water conducts electric current poorly. In the presence of dissolved salts in it, its electrical conductivity increases.
Chemical Features
The molecules of the H 2 O compound are sufficiently stable, which, in combination with special electrical characteristics, turns it into a universal solvent. That is why there are always many chemical compounds in water. The main part of the elements presented in the table of D. I. Mendeleev is present in natural water. The increasingly active industrial activity of mankind leads to the emergence of a number of inorganic and organic compounds in it, because of which it is necessary to constantly monitor their quantity. As a result, water hygiene becomes especially relevant. The molecular structure (of the triatomic molecule, it is the smallest) explains many features of such an important compound as H 2 O.
The amount of water in organisms
In the body of an adult, the volume of water is approximately 65-70% of its total mass. Its content is very high in food. In fish, for example, it reaches 85%, in meat - 79%, in fruits and vegetable oils reaches 78-97%. Speaking about the total amount of water in organisms, it should be noted that they account for only half its volume compared to that which contains all the rivers of the Earth. A person is able to live without food for 65-70 days, but without water he can last only a few days. If its loss occurs, equal to 6-8% of the total body weight, severe dehydration of the body begins. If its loss is 10-20% of the total body weight, there is a threat to life.
Water Quality Assessment Indicators
Water hygiene is evaluated according to certain indicators. According to accepted standards, it must be harmless in its chemical composition and in the epidemic respect. Water hygiene is assessed by the following indicators: the presence of pathogens of parasitic diseases and pathogenic microorganisms in it; concentration in water of chemicals, including radioactive; a change in properties called organoleptic (the presence of color, taste, smell, the appearance of turbidity, film or foam).
Water quality and incidence
If the quality of drinking water is unsatisfactory, the health status of those who use it is significantly worsened. According to WHO, annually in developing countries, several hundred thousand people die as a result of its unacceptable properties. The spread of intestinal infections (500 million cases a year is recorded, of which about 80% of diseases account for developing countries) are attributed either to the low quality of drinking water or to its shortage.
It should be noted that not only when ingesting substandard water can cause various diseases, but also when eating unwashed vegetables that were grown in fields subjected to irrigation. Scientists have found that the number of people not provided with benign water is 1100 million. It is no accident that WHO put forward a 10-year program aimed at improving water supply as a global social and medical task for all states.
Water sources
It is very important that in the sources used for water supply, for medicinal purposes, for recreation and sports, for swimming, as well as in reservoirs located within settlements, the water quality should comply with sanitary standards. If the natural composition of the water is unsatisfactory or if the source is characterized by significant anthropogenic pollution, even the most advanced treatment methods cannot guarantee satisfactory quality.
Water sources are evaluated according to various hygienic characteristics, the most important of which are the following: water quality, its exposure to technogenic (social) and natural factors, as well as the sanitary reliability of the source, that is, its resistance to anthropogenic and natural factors. If we talk about centralized drinking water supply, the sanitary reliability of its source is determined by its ability to maintain water quality at a high level, as well as the sufficiency of the flow rate necessary to ensure an operated and designed water supply system.
Sources of water are both groundwater and atmospheric water, as well as open water bodies. If there is a choice, preference is usually given to underground, it is best to use deep-lying. Waterproof soil layers reliably protect them from surface contamination. If it is impossible to use these waters or in their absence, the water supply is based on other sources. In this case, the priority is as follows (from lower to higher):
- atmospheric waters;
- rivers with dams (with regulated flow);
- lakes;
- rivers without dams (with unregulated runoff);
- groundwater of aquifers;
- springs and keys (the best option).
Assessment of the quality of drinking water
Among the main documents on the basis of which water analysis is carried out, the following should be noted:
- GOST 2761-84.
- SanPiN 2.1.4.1074-01.
- SanPiN 2.1.4.1175-02.
- SanPiN 2.1.4.1110-02.
Briefly tell about each of them.
GOST 2761-84
The first document from our list, GOST 2761-84, sets out the principles that must be followed when choosing water sources (surface or underground) for centralized water supply. Also in this document the principles of normalizing bacteriological, chemical, organoleptic and physical indicators of water are indicated. In addition, it presents methods for processing it, depending on the quality of a particular source. The analysis of water should show the absence of such properties and composition that cannot be reduced by existing processing methods to acceptable ones.
The chemicals contained in the water should not give it a foreign taste and smell, cause the presence of foam, change the color of the water. In other words, they should not impair its consumer qualities and organoleptic properties. It is the task of quality control pursues this GOST. Sampling of water should be carried out carefully so as to prevent distortion of indicators. In accordance with GOST, water should not adversely affect the sanitary regime (self-cleaning processes) of water bodies and the human body.
The standardization of the content of radioactive and chemical substances in the environment, including water, is based on the principle of threshold. This means that, within the limits of permissible concentrations (doses), the presence of certain substances is harmless (safe) for the body. Be sure to take into account the possible long-term consequences.
SanPiN 2.1.4.1074-01
Today, the main, fundamental among the regulatory acts that establish water hygiene rules in our country is the second of the above documents, SanPiN 2.1.4.1074-01. The standards for the composition of drinking water indicated in it, it should be noted, take into account substances whose content in it is undesirable and can be allowed only within certain limits. The ingredients that must be present in water are not considered in this document. It must be said that the hygienic standards contained in it, in their totality, do not represent a standard for the quality of water used for drinking, but a federal database. They turn to him when it becomes necessary to create a water quality control program for a specific (specific) water supply. In this case, the principle of a regional approach is applied to the regulation of composition.
SanPiN 2.1.4.1175-02
Another important document in accordance with which the hygiene of water and water supply is assessed is SanPiN 2.1.4.1175-02. According to him, according to its properties and composition, it must comply with certain standards, which are given in the table of this document. Much attention in SanPiN is paid to those properties of water that are organoleptic. The following chemical indicators are highlighted in the document: dry residue, hydrogen indicator, permanganate oxidizability, nitrate, chloride and sulfate content. In addition, there is an indication of the permissible content of certain chemicals at a certain level, not exceeding the maximum permissible concentration (maximum permissible concentration according to hygienic standards). In accordance with these indicators, water samples are estimated. For each source, the list of substances to be controlled should be established separately. In this case, one should proceed from local conditions, as well as from the results obtained during the sanitary examination.
SanPiN 2.1.4.1116-02
SanPiN 2.1.4.1116-02 was created to regulate the quality of drinking water packaged in containers. The sanitary norms and rules presented in it do not apply to canteens, medicinal-table and medicinal mineral waters. The main objective of these standards is to provide residents of the country with high-quality packaged water, the content of nutrients in which is optimal. It is important to note that in its production the use of chlorine preparations is unacceptable. Ozonation, as well as various physical processing methods (for example, UV treatment) are the most acceptable disinfection methods. The study of water intended for sale must be carried out by each producer.
Will there be enough water for humanity
The norms for water used for drinking are constantly being reviewed due to environmental degradation observed as a result of human activity, as well as in connection with the growth of scientific knowledge. To meet these changes, the equipment and technologies used for water purification are being improved. The task of man, of each of us, is to use it for our own benefit, while not destroying the aquatic ecosystem.
It must be remembered that the combination with the H2O formula is one of the main wealth on our planet. It is hard to imagine what would have happened to her if fresh water had disappeared or her hygiene had not been carried out. Drinking water is vital for a person. It should be drunk per day in an amount of approximately 1.7 liters. For cooking, washing and other needs, each of us needs an additional 20 times its quantity every day. The threat of extinction of the vitally important drinking water we are currently facing. All living things suffer from water pollution. It becomes harmful to the health of organisms. It is necessary to prevent catastrophic pollution of natural water, reducing its volume on our planet.