Demineralized water - what is it. Distilled water and distillers. Effects on the intestinal mucosa, mineral metabolism and homeostasis, and other bodily functions

WORLD HEALTH ORGANIZATION

Nutrients in drinking water

Water, sanitation, health and environment

Geneva

2005

Information from the site: http://waterts.blogspot.com/search/label/Nutrient%20in%20drinking%20water

FOREWORD

In November 2003, a group of experts in nutrition and medicine met in Rome (European Center for Environment and Health) to work on issues related to the composition of drinking water and its possible contribution to total nutrient intake. The original purpose of this meeting was to contribute to the development of the Guidelines for Healthy and Environmentally Sound Desalination, introduced by the WHO Eastern Mediterranean Regional Office, for the preparation of the 4th edition of the WHO Guidelines for Drinking Water Quality (GWQC). A total of 18 experts were invited from Canada, Chile, the Czech Republic, Germany, Ireland, Italy, Moldova, Singapore, Sweden, the United Kingdom and the USA. Additionally, reports were presented by experts who could not come in person. The purpose of the meeting was to evaluate the possible health consequences of long-term use of "conditioned" or "modified" products, i.e. treated water, with a modified mineral composition, artificially purified, or vice versa, enriched with minerals.

In particular, the question arose about the consequences of long-term use of water that has undergone demineralization: about sea water and brackish water subjected to desalination, about fresh water that has been treated in a membrane system, as well as about recreating their mineral composition.

The following main issues were discussed at the meeting:

What is the contribution of drinking water to the total intake of nutrients in the body?

What is the average daily human consumption of drinking water? How does it change depending on climate, lifestyle, age and other factors?

Which of the substances found in water can significantly affect the state of health and well-being?

Under what conditions can drinking water become a significant source of some important substances for humans?

What conclusions can be drawn about the relationship of calcium, magnesium and other elements in water with mortality from cardiovascular diseases?

For which substances in treated water can recommendations be developed for mineral enrichment in terms of utility?

What is the role of fluoride in improving dental health, as well as in the development of dental and bone fluorosis?

As a rule, drinking water undergoes one or more types of treatment before being supplied to the consumer in order to achieve appropriate safety and aesthetic properties. fresh water usually subjected to coagulation, sedimentation, filtration through granular materials, adsorption, ion exchange, membrane filtration, slow filtration through sand, disinfection, sometimes softening. Obtaining drinking water from highly saline waters such as sea and brackish waters through desalination is widely practiced in regions experiencing its acute shortage. Such technology in the conditions of constantly growing water consumption is becoming more and more attractive from an economic point of view. More than 6 billion gallons of demineralized water are produced daily in the world. Remineralization of such water is mandatory: it is aggressive towards distribution systems. If the remineralization of demineralized water is a must, a logical question arises: are there water treatment methods that can restore the content of some important minerals?

Natural waters differ significantly in their composition due to their geological and geographical origin, as well as the treatment they have undergone. For example, rainwater and surface water, which is replenished mainly by precipitation, have a very low salinity and mineralization, while groundwater is characterized by a very high and even excessive mineralization. If remineralization of treated water is needed for hygienic reasons, then another logical question arises: Are natural waters containing the “right” amounts of important minerals more beneficial to health?

During the meeting, the experts came to the following conclusion: only some mineral substances in natural water are in quantities sufficient to take into account their contribution to the total intake. Magnesium and, possibly, calcium are two elements that enter the human body from water in significant quantities (provided that hard water is consumed). This conclusion was made on the basis of 80 epidemiological studies on the relationship between hard water consumption and a decrease in the frequency of cardiovascular diseases in the population. The studies cover a 50-year period. Despite the fact that the studies were mainly of an ecological nature and were carried out on different levels, the experts acknowledged that the hypothesis about the relationship between hard water consumption and the frequency of cardiovascular diseases is correct, and magnesium should be considered the most important beneficial component. This conclusion has been confirmed by both control and clinical studies. There are other elements in the composition of water that have a positive effect on health, but the available data were not enough to discuss the issue.

The meeting also agreed that the WHO should provide a more detailed assessment of the biological plausibility of the hypothesis. Only after that the Guide will be finalized. A follow-up symposium and meeting to discuss this recommendation is planned for 2006.

With regard to fluorine, experts concluded that the optimal intake of fluoride from drinking water is important factor dental health. It has also been noted that more than optimal fluoride intake can lead to dental fluorosis, and even higher concentrations can lead to skeletal fluorosis. Fluorine dosages when enriching demineralized water with fluoride should be calculated based on the following factors: fluoride concentration in source water, volume of water consumption, risk factors for dental diseases, oral hygiene practices, the level of development of hygiene and sanitation in the community, as well as the availability of alternative oral hygiene products and availability of fluorine for the population.

“Water should be a source of macro-microelements necessary for the human body....”

N.K.Koltsov, an outstanding Russian chemist-biologist

N.Koltsov proposed to use the concept of physiological usefulness for drinking water back in 1912, combining this term with a set of anions and cations necessary for the human body and contained in natural water. More recent studies have confirmed the importance of the mineral composition of drinking water and are reflected in many scientific papers. In particular, the report by Frantisek Kozisek (National Institute of Public Health, Czech Republic) "Health consequences arising from the use of demineralized drinking water", presented at a meeting of WHO experts in 2003, states:

Artificially treated demineralized water, which was originally obtained by distillation and then by reverse osmosis, should be used for industrial, technical and laboratory purposes.

Epidemiological studies carried out in different countries over the past 50 years have shown that there is an association between an increased number of cardiovascular diseases with subsequent death and the consumption of soft water. When comparing soft water with hard and rich in magnesium, the pattern can be traced very clearly.

Recent studies have shown that drinking soft water, such as one that is poor in calcium, can lead to an increased risk of fractures in children (16), neurodegenerative changes (17), premature birth and reduced birth weight (18), and some types of cancer (19,20). ). In addition to an increased risk of sudden death (21–23), drinking magnesium-poor water has been associated with heart failure (24), late pregnancy toxemia (so-called preeclampsia) (25), and some types of cancer (26–29). ).

Even in developed countries, food products cannot compensate for the deficiency of calcium and, especially, magnesium, if drinking water is poor in these elements.

Modern food preparation technologies do not allow most people to get enough minerals and trace elements. In the event of an acute deficiency of any element, even a relatively small amount of it in water can play a significant protective role. Substances in water are dissolved and are in the form of ions, which makes it much easier for them to be adsorbed in the human body than from food, where they are bound into various compounds.

Drinking water obtained through demineralization is enriched with minerals, but this does not apply to home-treated water.

Perhaps none of the methods of artificial enrichment of water with minerals is optimal, since saturation with all important minerals does not occur.

GRATITUDE

WHO is grateful to:

Hussein Abusaid, WHO Eastern Mediterranean Regional Office Coordinator - for the idea and work on the development of the Demineralized Water Guidelines

Roger Aertgirts, European Regional Consultant for Water and Sanitation and Helena Shkarubo, WHO Rome Center - for processing meeting materials

Joseph Contruvo, USA and John Fawell, UK for hosting the meeting

To Professor Chun Nam Ong, Singapore - for moderating the meeting Gunter Crown, USA - for contributing to the publication of the papers and reviewing the comments

WHO expresses special thanks to the experts without whom this work would not have been possible: Rebecca Calderon, Gerald Coms, Jean Estrand, Floyd Frost, Ann Grandjian, Susanne Harris, František Kolizek, Michael Lennon, Silvano Monarca, Manuel Olivares, Dennis O" Mullan, Soule Semalulu, Ion Salaru and Erica Sievers.

WHO also represents the sponsors who made the meeting possible. Among them: the International Institute of Life Sciences, the Division of Science and Technology of the US Environmental Protection Agency (Washington), the Division of Research and Development (Research "Triangle" Park, North Carolina), the American Joint Research Working Foundation for Water, the Center for Human Nutrition in the University of Nebraska (Omaha); and the Canadian Bureau of Water Quality and Health (Ottawa, Ontario).

12. Health effects of drinking demineralized drinking water

Frantisek Koziszek

National Institute of Public Health

Chech republic

I Introduction

The mineral composition of the waters can vary widely depending on the geological conditions of the area. Neither underground nor surface water can be represented as a pure substance, the composition of which is expressed by the formula H2O. In addition, natural waters contain a small amount of dissolved gases, mineral and organic matter natural origin. The total concentrations of substances dissolved in high quality water can reach hundreds of mg/l. Thanks to the continuous development of microbiology and chemistry since the 19th century, many waterborne infectious agents can be identified. The knowledge that water may contain undesirable components is the starting point for the creation of guidelines and regulations for the quality of drinking water. International standards governing the maximum permissible concentrations of organic and inorganic substances, as well as microorganisms, exist in many countries of the world. These standards are a guarantee of the safety of drinking water. The consequences of drinking fully demineralized water are not considered, due to the fact that such water does not actually occur in nature, except perhaps rainwater and natural ice. However, rainwater and ice are not used in the water supply systems of developed countries, which have certain drinking water quality standards. As a rule, the use of such water is special case. Many natural waters are not rich in minerals, have low hardness (lack of divalent ions), and hard waters are often softened artificially.

Knowledge about the importance of minerals and other components in drinking water goes back thousands of years and is already mentioned in the ancient Indian Vedas. The properties of good drinking water are described in the Rig Veda book as follows: “Shiitam (cool), Sushihi (clean), Sivam (must be biologically valuable, contain minerals, as well as trace amounts of many elements), Eastham (transparent), Vimalam lahu Shadgunam (indicator The pH should be within normal limits)" (1).

Artificially treated demineralized water, which was originally obtained by distillation and then by reverse osmosis, should be used for industrial, technical and laboratory purposes. Water treatment technologies began to be widely used in the 60s of the last century in coastal and inland areas. This is due to the scarcity of natural water supplies and increasing water consumption due to demographic growth, higher quality of life standards, industrial development and mass tourism. Water demineralization is needed when the available water resources are highly mineralized brackish or sea water. The problem of drinking water on ocean liners and spaceships. The listed treatment methods were previously used to provide water exclusively to these facilities due to technical complexity and high cost.

In this chapter, demineralized water means water completely or almost completely freed from dissolved minerals by methods of distillation, deionization, membrane filtration (reverse osmosis or nanofiltration), electrodialysis, etc. The composition of dissolved substances in such water may vary, but their total content should not be more than 1 mg/l. Electrical conductivity - less than 2 mS / m3 * and even less (<0,1 мС/м3). Начало применения таких технологий – 1960-е годы, в то время деминерализация не была широко распространена. Тем не менее, уже в то время в некоторых странах изучались гигиенические аспекты использования такой воды. В основном это касается бывшего Советского Союза, где планировалась применять обессоливание для обеспечения питьевой водой городов Средней Азии. Изначально было понятно, что обработанная вода не годна для употребления без дополнительного обогащения минеральными веществами:

Demineralized water is very aggressive and must be neutralized; otherwise, its supply to the distribution system, passing through pipes and storage tanks is impossible. Aggressive water destroys pipes and leaches metals and other materials out of them;

Distilled water has "poor" taste characteristics;

It has been proven that some substances present in drinking water are important for the human body. For example, the experience of artificial enrichment of water with fluorine showed that the number of oral diseases decreased, and epidemiological studies conducted in the 1960s showed that residents of regions with hard drinking water suffer less from cardiovascular diseases.

As a result, the researchers focused on two questions: 1) what adverse effects on human health can occur when drinking demineralized water and 2) what should be the minimum as well as the optimal content of elements important for humans (for example, minerals) in drinking water in order to to ensure that the water quality meets both technological and sanitary standards. The traditionally accepted methodology for assessing water quality, based on the analysis of risks arising from high concentrations of toxic substances, has now been revised: the possible adverse consequences of a deficiency in water of certain components are also taken into account.

At one of the working meetings on the preparation of guidelines for the quality of drinking water, the World Health Organization (WHO) considered the question of what should be the optimal mineral composition of demineralized drinking water. Experts focused on the possible adverse effects of drinking water that has been stripped of some of the substances that are always present in natural drinking water (2). In the late 1970s, WHO became a sponsor of studies that could provide background information for the production of guidelines on the quality of demineralized water. This study was conducted by a group of scientists from the Institute of Public Health named after A.N. Sysin and the Academy of Medical Sciences of the USSR under the guidance of prof. Sidorenko and Dr. med. Sciences Rakhmanin. In 1980 the final report was published as an internal working paper (3). It contained the following conclusion: "Demineralized (distilled) water not only has unsatisfactory organoleptic characteristics, but also has an adverse effect on the human and animal body." After assessing the hygienic, organoleptic properties and other information, the scientists made recommendations on the composition of demineralized water:

1 min. mineralization 100 mg/l; the content of bicarbonate ions 30 mg/l; calcium 30 mg/l; 2) optimal dry residue (250-500 mg/l for chloride-sulphate waters and 250-500 ml for hydrocarbonate waters); 3) the maximum level of alkalinity (6.5 meq/l), sodium (200 mg/l), boron (0.5 mg/l) and bromide ion (0.01 mg/l). Some of the recommended values ​​are discussed in more detail in this chapter.

* - mS / m3 - millisiemens per cubic meter, unit of electrical conductivity

Over the past three decades, demineralization has become widespread as a method of providing drinking water. There are over 11 thousand enterprises producing demineralized water in the world; total output of finished products - 6 billion gallons of demineralized water per day (Kontruvo). In some regions, such as Central East and West Asia, more than half of all drinking water is produced in this way. As a rule, demineralized water undergoes further processing: various salts are added to it, for example, calcium carbonate or limestone; mixed with small volumes of highly mineralized water to improve taste characteristics and reduce aggressiveness towards distribution networks and sanitary equipment. However, demineralized waters can vary greatly in their composition, such as the minimum content of mineral salts.

Many explored water resources do not correspond in composition to the unified drinking water quality guidelines.

The potential for adverse health effects of demineralized water has interested not only those countries where there is a shortage of drinking water, but also those where home water treatment systems are popular and bottled water is also consumed. Some natural drinking waters, in particular glacial ones, are not rich in minerals (less than 50 mg/l), and in a number of countries distilled drinking water is used for drinking purposes. Some brands of bottled drinking water are demineralized water, subsequently fortified with minerals to give it a favorable taste. People who drink such water may not receive the minerals that are present in more highly mineralized water. Therefore, when calculating the level of consumption of minerals and risks, it is necessary to analyze the situation not only at the level of society, but also at the level of the family, each person individually.

II. Health risks from drinking demineralized or low-mineralized water

Information about the impact of demineralized water on the state of the body is based on experimental data and observations. Experiments were carried out on laboratory animals and human volunteers, observations - on large groups of people consuming demineralized water, as well as individuals ordering water treated by reverse osmosis and children for whom baby food was prepared with distilled water. Since the information available over the period of these studies is limited, we must also take into account the results of epidemiological studies comparing the health effects of low-mineralized (softer) and highly mineralized water. Demineralized water that has not been subsequently enriched with minerals is an extreme case. It contains solutes such as calcium and magnesium, which are the major contributors to hardness, in very small amounts.

The possible consequences of drinking mineral-poor water fall into the following categories:

Direct effects on the intestinal mucosa, mineral metabolism and homeostasis, and other bodily functions;

Low intake / lack of intake of calcium and magnesium;

Small intake of other macro- and microelements;

Loss of calcium, magnesium and other macronutrients during cooking;

Possible increase in the intake of toxic metals into the body.

1. Direct effects on the intestinal mucosa, mineral metabolism and homeostasis, and other bodily functions

Distilled and low-mineralized water (total mineralization< 50 мг/л) может быть неприятной на вкус, однако с течением времени потребитель к этому привыкает. Такая вода плохо утоляет жажду (3). Конечно, эти факты еще не говорят о каком-либо влиянии на здоровье, однако их нужно учитывать, принимая решение о пригодности использования слабоминерализованной воды для нужд питьевого водоснабжения. Низкая способность утолять жажду и неприятный вкус могут повлиять на объемы употребления воды или заставить людей искать новые источники воды, зачастую не лучшего качества.

Williams (4) showed in his report that distilled water can cause pathological changes in epithelial cells in the intestines of rats, possibly due to osmotic shock. However, Schumann (5), who later conducted a 14-day experiment with rats, did not get such results. Histological studies did not reveal any signs of erosion, ulceration, or inflammation of the esophagus, stomach, and small intestine. There were changes in the secretory function of animals (increased secretion and acidity of gastric juice) and changes in the muscle tone of the stomach; these data are given in the WHO report (3), but the available data do not allow unequivocally to prove the direct negative effect of water with low salinity on the mucosa of the gastrointestinal tract.

To date, it has been proven that the consumption of water, poor in minerals, has a negative impact on the mechanisms of homeostasis, the metabolism of minerals and water in the body: increased fluid excretion (diuresis). This is due to the washing out of intra- and extracellular ions from biological fluids, their negative balance. In addition, the total water content in the body and the functional activity of some hormones that are closely related to the regulation of water metabolism change. Experiments on animals (mainly rats) lasting about a year helped to establish that the use of distilled water, or water with a total mineralization of up to 75 mg / l, leads to:

1) an increase in water consumption, diuresis, extracellular fluid volume, sodium and chloride ion concentrations in serum and their increased excretion from the body; resulting in an overall negative balance, 2) a decrease in the number of red blood cells, hematocrit index; 3) a group of scientists led by Rakhmanin, studying the possible mutagenic and gonadotoxic effects of distilled water, found that distilled water does not have such an effect.

However, there was a decrease in the synthesis of the hormones triiodothyranine and aldosterone, increased secretion of cortisol, morphological changes in the kidneys, including severe atrophy of the glomeruli and swelling of the layer of cells lining the vessels from the inside, preventing blood flow. Insufficient ossification of the skeleton was found in the embryos of rats whose parents consumed distilled water (1-year experiment). Obviously, the lack of mineral substances was not replenished in the body of rats even at the expense of nutrition, when the animals received their standard diet with the necessary energy value, nutrients and salt composition.

The results of an experiment conducted by WHO scientists on human volunteers showed a similar picture (3), which made it possible to outline the main mechanism of the effect of water with a mineralization of up to 100 mg/l on the exchange of water and minerals:

1) increased diuresis (by 20% compared with the norm), the level of fluid in the body, the concentration of sodium in the serum; 2) reduced serum potassium concentration; 3) increased excretion of sodium, potassium, chloride, calcium and magnesium ions from the body.

Presumably, water with low salinity affects the osmotic receptors of the gastrointestinal tract, causing an increased release of sodium ions into the intestine and a slight decrease in osmotic pressure in the portal venous system, followed by an active release of sodium ions into the blood as a response. Such osmotic changes in the blood plasma lead to a redistribution of fluid in the body. The total volume of extracellular fluid increases, water moves from erythrocytes and tissue fluid into the plasma, as well as its distribution between intracellular and tissue fluids. Due to changes in the volume of plasma in the bloodstream, receptors that are sensitive to volume and pressure are activated. They prevent the release of aldosterone and, as a result, the release of sodium increases. The reaction of volume receptors in the vessels can lead to a decrease in the release of antidiuretic hormone and increased diuresis. The German Nutrition Society came to similar conclusions and recommended against drinking distilled water (7). The message was published in a response to the German publication The Shocking Truth About Water (8), whose authors recommended drinking distilled water instead of ordinary drinking water. The Society in its report (7) explains that the fluids of the human body always contain electrolytes (potassium and sodium), the concentration of which is under the control of the body itself. The absorption of water by the intestinal epithelium occurs with the participation of sodium ions. If a person drinks distilled water, the intestines are forced to "add" sodium ions to this water, removing them from the body. The liquid is never excreted from the body in the form of pure water, in parallel, a person also loses electrolytes, which is why it is necessary to replenish their supply from food and water.

Improper distribution of fluid in the body can even affect the functions of vital organs. The first signals are fatigue, weakness and headache; more serious - muscle cramps and heart rhythm disturbances.

Additional information was collected during experiments with animals, clinical observations in some countries. Animals fed water enriched with zinc and magnesium had a much higher concentration of these elements in the blood serum than those fed enriched feed and drinking low-mineralized water. An interesting fact is that during enrichment, significantly more zinc and magnesium were added to the feed than to the water. Based on experimental results and clinical observations of mineral-deficient patients receiving intravenous distilled water nutrition, Robbins and Sly (9) hypothesized that the consumption of low-mineralized water was the cause of increased mineral excretion from the body.

The constant use of low-mineralized water can cause the changes described above, however, symptoms may not appear, or they may appear many years later. However, serious damage, for example, the so-called. water intoxication, or delirium, may result from strenuous physical work and drinking some distilled water (10). The so-called water intoxication (hyponatremic shock) can occur not only as a result of the consumption of distilled water, but also drinking water in general. The risk of such "intoxication" increases with a decrease in water salinity. Serious health problems arose among climbers who ate food cooked on melted ice. Such water does not contain anions and cations necessary for a person. Diseases such as cerebral edema, convulsions, and acidosis have occurred in children who consumed drinks prepared with distilled or low-mineralized water (11).

2. Low intake / no intake of calcium and magnesium

Calcium and magnesium are very important for humans. Calcium is an important component of bones and teeth. It is a regulator of neuromuscular excitability, participates in the work of the conduction system of the heart, contraction of the heart and muscles, transmission of information within the cell. Calcium is an element responsible for blood clotting. Magnesium is a cofactor and activator of over 300 enzymatic reactions, including glycolysis, ATP synthesis, transport of minerals such as sodium, potassium and calcium across membranes, protein and nucleic acid synthesis, neuromuscular excitability, and muscle contractions.

If we evaluate the percentage contribution of drinking water to the total intake of calcium and magnesium, it becomes clear that water is not their main source. However, the importance of this source of minerals cannot be overestimated. Even in developed countries, food products cannot compensate for the deficiency of calcium and, especially, magnesium, if drinking water is poor in these elements.

Epidemiological studies carried out in different countries over the past 50 years have shown that there is an association between an increased number of cardiovascular diseases with subsequent death and the consumption of soft water. When comparing soft water with hard and rich in magnesium, the pattern can be traced very clearly. The review of research is accompanied by recently published articles (12-15), the results are summed up in other chapters of this monograph (Calderón and Crown, Monarca). Recent studies have shown that drinking soft water, such as one that is poor in calcium, can lead to an increased risk of fractures in children (16), neurodegenerative changes (17), premature birth and reduced birth weight (18), and some types of cancer (19,20). ). In addition to an increased risk of sudden death (21-23), drinking magnesium-poor water has been associated with heart failure (24), late pregnancy toxemia (so-called preeclampsia) (25), and some types of cancer (26-29 ).

Specific information about changes in calcium metabolism in people forced to drink demineralized water (for example, distilled, filtered through limestone) with a low calcium content and mineralization was obtained in a Soviet city

Shevchenko (3, 30, 31). In the local population, decreased activity of alkaline phosphatase and concentrations of calcium and phosphorus in plasma and pronounced decalcification of bone tissue were observed. Changes were most pronounced in women (especially pregnant women) and depended on the length of stay in the city of Shevchenko. The importance of sufficient calcium content in the water was established in the above experiment with rats fed a complete diet rich in nutrients and salts and demineralized water artificially enriched with minerals (400 mg/l) and calcium (5 mg/l, 25 mg/l, 50 mg/l) (3, 32). In animals that drank water containing 5 mg/l of calcium, a decrease in thyroid function and a number of other body functions was noted compared to animals in which the dose of calcium was doubled.

Sometimes the consequences of insufficient intake of certain substances in the body are visible only after many years, but the cardiovascular system, which lacks calcium and magnesium, reacts much faster. A few months of drinking water deficient in calcium and/or magnesium is sufficient (33). An illustrative example is the population of the Czech Republic and Slovakia in 2000-2002, when the reverse osmosis method was used in the centralized water supply system.

Over the course of weeks or months, there have been many complaints related to severe magnesium (and possibly calcium) deficiency (34).

The complaints of the population related to cardiovascular disease, fatigue, weakness, muscle cramps and actually coincided with the symptoms listed in the report of the German Nutrition Society (7).

3. Small intake of other macro- and microelements

Despite the fact that drinking water, with rare exceptions, is not a significant source of important elements, its contribution is for some reason very important. Modern food preparation technologies do not allow most people to get enough minerals and trace elements. In the event of an acute deficiency of any element, even a relatively small amount of it in water can play a significant protective role. Substances in water are dissolved and are in the form of ions, which makes it much easier for them to be adsorbed in the human body than from food, where they are bound into various compounds.

Animal experiments have also shown the importance of the presence of trace amounts of certain substances in water. For example, Kondratyuk (35) showed in a report that the difference in the intake of trace elements led to a sixfold difference in their concentrations in the muscle tissue of animals. The experiment was carried out for 6 months; rats were divided into 4 groups and used different water: a) tap water; b) slightly mineralized; c) slightly mineralized, enriched with iodine, cobalt, copper, manganese, molybdenum, zinc and fluorine in normal concentrations; d) slightly mineralized, enriched with the same elements, but in 10-fold greater quantities. In addition, unenriched demineralized water has been found to have a negative effect on hematopoietic processes. In animals that received water that was not enriched with trace elements with low mineralization, the number of red blood cells was 19% lower than in individuals that received ordinary tap water. The difference in hemoglobin content was even greater when compared to animals fed enriched water.

Recent studies of the environmental situation in Russia have shown that the population that consumes water with a low content of minerals is at risk of many diseases. These are hypertension (high blood pressure) and changes in the coronary vessels, gastric and duodenal ulcers, chronic gastritis, goiter, complications in pregnant women, newborns and infants such as jaundice, anemia, fractures and growth problems (36). However, it is not entirely clear whether all these diseases are associated with a lack of calcium, magnesium and other important elements, or with other factors.

Lutai (37) has carried out numerous studies in the Ust-Ilim region of Russia.

The object of research were 7658 adults, 562 children and 1582 pregnant women and their newborns; morbidity and physical development were studied. All these people are divided into 2 groups: they live in 2 areas where the water has different mineralization. In the first of the selected areas, water is characterized by a lower mineralization of 134 mg/l, calcium and magnesium content - 18.7 and 4.9, respectively, bicarbonate ion - 86.4 mg/l. In the second region - more highly mineralized water 385 mg/l, calcium and magnesium content - 29.5 and 8.3, respectively, bicarbonate ion - 243.7 mg/l. The content of sulfates, chlorides, sodium, potassium, copper, zinc, manganese and molybdenum was also determined in water samples from two regions. The food culture, air quality, social conditions and time of residence in the region were the same for the residents of the two districts. Residents of an area with lower water salinity were more likely to suffer from goiter, hypertension, coronary heart disease, stomach and duodenal ulcers, chronic gastritis, cholecystitis, and nephritis. Children developed more slowly and suffered from some growth abnormalities, pregnant women suffered from edema and anemia, and newborns were more often ill.

A lower incidence rate was noted where the calcium content in the water was 30-90 mg/l, magnesium - 17-35 mg/l, and the total mineralization - about 400 mg/l (for water containing bicarbonates). The author came to the conclusion that such water is close to the physiological norm for humans.

4. Losses of calcium, magnesium and other macronutrients during cooking

It became known that in the process of cooking on soft water, important elements are lost from products (vegetables, meat, cereals). Losses of calcium and magnesium can reach 60%, other trace elements - even more (copper-66%, manganese-70%, cobalt-86%). In contrast, during hard water cooking, mineral loss is markedly lower, and the calcium content of the finished meal may even increase (38-41).

Although most nutrients come from food, cooking with brackish water can significantly reduce the overall intake of some elements. Moreover, this shortage is much more serious than when using such water only for drinking purposes. The modern diet of most people is not able to meet the body's needs for all the necessary substances and, therefore, any factor that contributes to the loss of minerals during cooking can play a negative role.

5. Possible increase in the intake of toxic metals into the body

The increased risk of toxic metal intake may be due to two reasons: 1) more intensive release of metals from materials in contact with water, leading to an increased concentration of metals in drinking water; 2) low protective (antitoxic) properties of water, poor in calcium and magnesium.

Water with low salinity is unstable and, as a result, exhibits high aggressiveness towards the materials with which it comes into contact. This water more easily dissolves metals and some organic components of pipes, storage tanks and containers, hoses and fittings, while not being able to form complex compounds with toxic metals, thereby reducing their negative impact.

In 1993-1994 in the United States, 8 outbreaks of chemical poisoning of drinking water were registered, among them - 3 cases of lead poisoning of infants. The blood test of these children showed

lead levels of 15 µg/100 ml, 37 µg/100 ml and 42 µg/100 ml, while 10 µg/100 ml is no longer safe. In all three cases, lead got into the water from copper pipes and lead-soldered seams of storage tanks. All three water supplies used water with low salinity, resulting in increased release of toxic materials (42). The first water samples obtained from taps showed a lead content of 495 and 1050 µg/l of lead; accordingly, children who drank this water had the highest lead content in their blood. In the family of the child who received the lower dose, the concentration of lead in tap water was 66 µg/L (43).

Calcium and, to a lesser extent, magnesium in water and food are protective factors that neutralize exposure to toxic elements. They can prevent the absorption of some toxic elements (lead, cadmium) from the intestines into the bloodstream, both through a direct reaction of the binding of toxins into insoluble complexes, and through competition for absorption (44-50). Although this effect is limited, it must always be taken into account. The population that consumes mineral-poor water is always more at risk of exposure to toxic substances than those that drink water of medium hardness and salinity.

6. Possible bacterial contamination of water with low salinity

In general, water is prone to bacterial contamination in the absence of trace amounts of disinfectant either at the source itself or due to microbial re-growth in the distribution system after treatment. Re-growth can also start in demineralized water.

Bacterial growth in the distribution system may be favored by initially high water temperatures, rising temperatures due to hot climates, lack of disinfectant, and possibly greater availability of some nutrients (inherently corrosive water easily corrodes pipe materials).

While an intact water purification membrane should ideally remove all bacteria, it may not be completely effective (due to leaks). The evidence is an outbreak of typhoid fever in Saudi Arabia in 1992 caused by reverse osmosis treated water (51). Nowadays, virtually all water is disinfected before reaching the consumer. Re-growth of non-pathogenic microorganisms in water treated with various home purification systems has been described by the groups of Geldreich (52), Payment (53, 54) and many others. Czech National Institute Public Health in Prague (34) tested a number of products intended for contact with drinking water and found that reverse osmosis pressurized tanks are prone to bacterial re-growth: inside the tank there is a rubber bulb, which is a favorable environment for bacteria.

III. Optimal mineral composition of demineralized drinking water

The corrosive properties and potential health hazards of demineralized water, the distribution and consumption of water with low salinity has led to the creation of recommendations on the minimum and optimal concentrations of minerals in drinking water. Additionally, in some countries, mandatory standards have been developed that are included in the relevant legislative or technical documentation on the quality of drinking water. The organoleptic properties and ability of water to quench thirst were also taken into account in the recommendations. For example, studies in which volunteers took part have shown that the optimal water temperature can be considered from 15 to 35 ° C. Water with a temperature below 15 °C or above 35 °C was consumed by the subjects in smaller volumes. Water with a dissolved salt content of 25-50 mg/l was found to be tasteless (3).

1. WHO report 1980

The use of drinking water with low mineralization contributes to the leaching of salts from the body. Changes in the water-salt balance in the body were noted not only with the use of demineralized water, but also with water with a mineralization of 50 to 75 mg/l. Therefore, the WHO research team that prepared the 1980 report (3) recommends drinking water with a mineral content of at least 100 mg/l. The scientists also concluded that the optimal mineralization is 200-400 mg/l for chloride-sulfate waters and 250-500 mg/l for hydrocarbonate waters (1980, WHO). The recommendations are based on experimental data in rats, dogs and human volunteers. Samples were taken: from the Moscow water supply network, demineralized water with a mineralization of about 10 mg/l and samples prepared in the laboratory (mineralization 50, 100, 250, 300, 500, 750, 1000 and 1500 mg/l) using the following ions: Cl- (40%), HCO3 - (32%), SO4 2- (28%), Na+ (50%), Ca2+ (38%), Mg2+ (12%).

Many indicators were studied: body weight dynamics, basal metabolism and nitrogen metabolism, enzyme activity, water-salt metabolism and its regulatory function, the content of minerals in tissues and body fluids, hematocrit and antidiuretic hormone activity. With the optimal content of mineral salts, negative changes were not noted either in rats, or in dogs, or in humans, such water has high organoleptic characteristics, removes thirst well, and its corrosive activity is low.

In addition to the conclusions about the optimal mineralization of water, the report (3) is supplemented with recommendations for the calcium content (not less than 30 mg/l). There is an explanation for this: at lower concentrations of calcium, the exchange of calcium and phosphorus in the body changes and a reduced content of minerals in bone tissue is observed. Also, when the concentration of calcium in water reaches 30 mg/l, its corrosivity decreases and the water becomes more stable (3). The report (3) also gives instructions for a concentration of 30 mg/l of bicarbonate ion to achieve acceptable organoleptic characteristics, reduce corrosiveness and achieve equilibrium with calcium ion.

Modern research has provided additional information on the minimum and optimum levels of minerals that must be present in demineralized water. For example, the effect of water with different hardness on the health status of women aged 20 to 49 years was the subject of 2 series of epidemiological studies (460 and 511 women) in 4 cities of Southern Siberia (55,56). The water in city A contains the least amount of calcium and magnesium (3.0 mg/l calcium and 2.4 mg/l magnesium). The water in city B is slightly more saturated with salts (18.0 mg/l calcium and 5.0 mg/l magnesium). The highest saturation of water with salts was observed in cities C (22.0 mg/l calcium and 11.3 mg/l magnesium) and D (45.0 mg/l calcium and 26.2 mg/l magnesium). Residents of cities A and B, compared with women from C and D, were more likely to experience changes in the cardiovascular system (according to ECG results), high blood pressure, somatic dysfunctions, headache and dizziness, osteoporosis (X-ray absorptiometry).

These results support the assumption that magnesium in drinking water should be at least 10 mg/l, calcium 20 mg/l, and not 30 mg/l, as indicated in a 1980 WHO report.

Based on available data, the researchers recommended the following concentrations of calcium, magnesium, and drinking water hardness:

For magnesium: minimum 10 mg/L (33.56), optimal 20–30 mg/L (49, 57);

For calcium: minimum 20 mg/l (56), optimal around 50 (40-80) mg/l (57, 58);

General water hardness, total content of calcium and magnesium salts 2-4 mmol/l (37, 50, 59, 60).

When the composition of drinking water complied with these recommendations, there were no or almost no negative changes in the state of health. The maximum protective effect or positive effect was observed in drinking water with supposedly optimal concentrations of mineral substances. Observations of the state of the cardiovascular system made it possible to determine the optimal levels of magnesium in drinking water, changes in calcium metabolism and ossification processes became the basis for calcium recommendations.

The upper limit of the optimal hardness interval was determined based on the fact that when drinking water with a hardness of more than 5 mmol / l, there is a risk of formation of stones in the gallbladder, kidneys, bladder, as well as arthrosis and arthropathy in the population.

In the work on determining the optimal concentrations, forecasts were based on long-term water consumption. For short-term water use, higher concentrations should be considered to develop therapeutic recommendations.

IV. Guidelines and directives for calcium, magnesium and drinking water hardness

In the second edition of the Guidelines for the Quality of Drinking Water (61), WHO rates calcium and magnesium in terms of water hardness, but does not specifically recommend minimum or maximum calcium, magnesium, or hardness values. The first European Directive (62) established minimum hardness requirements for softened and demineralized water (not less than 60 mg/l calcium or equivalent cation). This requirement became mandatory under the national legislation of all EU member states, but in December 2003 this directive expired and was replaced by a new one (63). The new Directive does not include requirements for calcium, magnesium and hardness values.

On the other hand, nothing prevents the introduction of such requirements into the national legislation of the Member States. Only a few countries that have joined the EU (for example, the Netherlands) have set the requirements for the content of calcium, magnesium and water hardness at the level of mandatory national standards.

Some EU members (Austria, Germany) have included these indicators in the technical documentation as optional standards (methods for reducing the corrosivity of water). All four European countries that joined the EU in May 2004 included these requirements in their respective regulatory documents, however, these requirements are different:

Czech Republic (2004): for softened water: not less than 30 mg/l calcium and not less than 1 mg/l magnesium; Guideline requirements: 40-80 mg/l calcium and 20-30 mg/l magnesium (hardness as

Σ Ca + Mg = 2.0-3.5 mmol/l);

Hungary (2001): hardness 50-350 mg/l (CaO); minimum required concentration for bottled water, new water sources, softened and demineralized water 50 mg/l;

Poland (2000): hardness 60-500 (CaCO3);

Slovakia (2002): Calcium requirements are the same as those in the Guidelines

> 30 mg/l, magnesium 10-30 mg/l.

The Russian Standard for Habitat in Manned Spacecraft - General Medical and Technical Requirements (64) - defines the requirements for the ratio of minerals in reprocessed drinking water. Among other requirements, mineralization is indicated in the range from 100 to 1000 mg / l; the minimum levels of fluorine, calcium and magnesium are set by a special commission of each space fleet separately. Emphasis is placed on the problem of enriching reused water with a mineral concentrate to give it a physiological value (65).

V.Conclusions

Drinking water should contain at least minimal amounts of essential minerals (and some other constituents such as carbonates). Unfortunately, in the past two decades, researchers have paid little attention to the beneficial effects of water and its protective properties, as they were absorbed in the problem of toxic pollutants. However, attempts have been made to define minimum levels of essential minerals or salinity in drinking water, and some countries have incorporated the requirements of the Guidelines for individual components into their legislation.

This issue is relevant not only for demineralized drinking water that has not been enriched with a complex of minerals, but also for water in which the mineral content is reduced due to home or centralized treatment, as well as for low-mineralized bottled water.

Drinking water obtained through demineralization is enriched with minerals, but this does not apply to home-treated water. Even after stabilization of the mineral composition, water may not have a beneficial effect on health. Usually, water is enriched with minerals by passing through limestone or other carbonate-containing minerals. At the same time, the water is saturated mainly with calcium, and the deficiency of magnesium and other trace elements, for example, fluorine and potassium, is not replenished by anything. In addition, the amount of calcium introduced is regulated more by technical (reduction of water aggressiveness) than by hygienic considerations. Perhaps none of the methods of artificial enrichment of water with minerals is optimal, since saturation with all important minerals does not occur. As a rule, methods for stabilizing the mineral composition of water are developed in order to reduce the corrosivity of demineralized water.

Unenriched demineralized water or water with a low mineral content - in light of its lack or lack of important minerals - is far from being an ideal product, therefore, its regular consumption does not adequately contribute to the overall intake of some important nutrients. This chapter substantiates this assertion. Confirmation of experimental data and discoveries obtained on human volunteers in the study of highly demineralized water can be found in earlier documents that do not always meet modern methodological requirements. However, the data of these studies should not be neglected: some of them are unique. Early studies, both animal studies and clinical observations of the health effects of demineralized water, have shown comparable results. This is confirmed by modern research.

Enough data has been collected to confirm that calcium and magnesium deficiency in water does not go away without consequences. There is evidence that higher magnesium content in water leads to a lower risk of cardiovascular disease and sudden death. This connection has been described in many papers independently of each other. At the same time, the studies were constructed in different ways and concerned different regions, populations and time periods. Consistent results have been obtained from autopsy, clinical observations, and animal experiments.

The biological plausibility of a protective effect of magnesium is not in doubt, but the specificity is less clear due to the diverse etiologies of cardiovascular disease. In addition to an increased risk of death from cardiovascular disease, low magnesium levels in water are associated with possible diseases motor nerves, complications of pregnancy (called pre-eclampsia), sudden death of young children, and certain types of cancer. Modern researchers suggest that drinking soft water with a low calcium content can lead to fractures in children, neurodegenerative changes, premature birth, low birth weight and some types of cancer. The role of aqueous calcium in the development of cardiovascular diseases cannot be ruled out.

International and national organizations responsible for the quality of drinking water should review the guidelines for the treatment of demineralized water, making sure to define minimum values ​​for important indicators, including calcium, magnesium and mineralization. Where necessary, competent organizations are required to support and promote targeted research in this area to improve the health status of the population. Where a quality manual is being developed for specific substances required in demineralised water, the competent authority must ensure that the document is applicable to consumers of home water treatment systems and bottled water.

14. Fluorine

Michael A. Lennon

School of Clinical Dentistry

University of Sheffield, United Kingdom

Helen Welton

Dennis O'Mullan

Oral Research Center

University College, Cork, Republic of Ireland

Jean Extrand

Karolinska Institute

Stockholm, Sweden

I Introduction

Fluoride has both positive and negative effects on human health. In terms of oral health, the incidence of dental disease is inversely related to the concentration of fluoride in drinking water; there is also a relationship between the concentration of fluoride in water and fluorosis (1). From a health standpoint in general, in regions where fluoride concentrations are high in both water and food, cases of skeletal fluorosis and bone fractures are common. However, there are other sources of fluoride. Demineralization and water treatment using membranes and anion exchange resins remove almost all fluorine from water. The use of such water for drinking purposes, the significance for the health of society is highly dependent on the specific circumstances. The main objective is to enhance the positive effect of the presence of fluoride in drinking water (protection against caries), while minimizing undesirable problems of the oral cavity and health in general.

The etiology of oral disease involves the interaction of bacteria and simple sugars (eg sucrose) on the tooth surface. In the absence of such sugars in food and drink, caries will no longer be a significant problem. However, the problem will persist with high sugar intake until the right move is made to address it. Removing fluoride from drinking water has the potential to exacerbate an existing or emerging problem of oral disease.

II. The intake of fluoride in the human body

Fluorine is fairly widespread in the lithosphere; often occurs in the form of fluorspar, fluorapatite and cryolite and is the 13th most abundant on the globe. Fluorine is present in seawater at a concentration of 1.2-1.4 mg/l, in groundwater up to 67 mg/l and in surface waters 0.1 mg/l (2). Fluoride has also been found in foods, particularly fish and tea (3).

While most foods contain trace amounts of fluoride, water and non-dairy beverages are the main sources of absorbed fluoride, accounting for 66 to 80% of intakes in US adults, depending on the fluoride content of drinking water.

Additional sources of fluoride are toothpaste (especially for young children who swallow most of the toothpaste), tea in regions where tea drinking is a well-established tradition, coal (by inhalation) in some regions of China where charcoal with a very high content is heated at home. fluorine. Absorption of ingested fluoride occurs in the stomach and small intestine (3).

For the most part, fluorine, whether originally present in water or added, is found there as the free fluoride ion (3). Water hardness of 0-500 mg/l (in terms of CaCO3) affects ionic dissociation, which in turn slightly changes the bioavailability of fluorine (4). Absorption of a normal dose of fluoride varies from 100% (on an empty stomach) to 60% (calcium-rich breakfast).

III. The effect of fluoride from food and drink on the state of the oral cavity

The effect of fluoride, naturally present in drinking water, on oral health was considered in the 1930s and 1940s by Trendley Dean and colleagues at the US Public Health Service. A number of studies have been conducted throughout the US; studies have shown that with an increase in the content of natural fluoride in water, the likelihood of fluorosis increased and decreased - caries (5). In addition, based on Dean's results, it could be assumed that at a concentration of 1 mg/l, the frequency, severity and cosmetic effect of fluorosis are not a socially significant problem, and caries resistance increases significantly.

When analyzing these facts, a natural question arises: will artificial fluoridation of drinking water allow the effect to be repeated? The first study on this topic was carried out in Grand Rapids under the direction of the USPHS in 1945. The results obtained over 6 years of water fluoridation were published in 1953. Additional studies were carried out in 1945-46. in Illinois (USA) and Ontario (Canada).

Also, scientists in the Netherlands (1953), New Zealand (1954), the United Kingdom (1955-1956) and East Germany(1959). The results were similar: there was a decrease in the incidence of caries (5). After the publication of the results, water fluoridation has become a common health promotion measure at the community level. Information about some countries involved in the project and the size of their population using artificially enriched water with fluorine is given in Table 1. The optimal concentration of fluorine, depending on climatic conditions, is 0.5-1.0 mg/l. Approximately 355 million people around the world drink artificially fluoridated water. In addition, about 50 million people use water containing natural fluorine at a concentration of about

1 mg/l. Table 2 lists countries where a population of 1 million people or more uses water rich in natural fluorine (content 1 mg/l). In some countries, in particular in certain areas of India, Africa and China, water may contain natural fluorine in rather high concentrations, above 1.5 mg / l, the norm established by the WHO Guidelines for the Quality of Drinking Water.

Many countries that have introduced artificial enrichment of water with fluoride continue to monitor the incidence of caries and fluorosis using a cross-sectional random sample of children aged 5 to 15 years. An excellent example of monitoring is the recently published report on children's oral health in Ireland (mostly fluoridated water) and the north of Ireland (non-fluoridated) (7). (see table 3).

IV. Fluoride intake and health

The effect of ingested fluoride on health was considered by Moulton in 1942, which preceded the study by Grand Rapids; since then, a number of organizations and individual scientists have been continuously involved in the problem. More recently, IPCS (3) has conducted a detailed review of fluoride and its effects on health. Studies and reviews have focused on bone fractures, skeletal fluorosis, cancer, and abnormalities in the newborn, but have included other abnormalities that may be caused or exacerbated by fluoridation (1, 9, 10, 11, 12, 13, 14). No evidence or adverse effects from drinking water containing natural or added fluoride in concentrations

0.5 - 1 mg/l was not detected, except for the cases of oral fluorosis described above. In addition, studies in areas of the United States where natural fluoride content reaches 8 mg/l have not shown any adverse effects of drinking such water. At the same time, there is evidence from India and China, where an increased risk of bone fractures is the result of long-term use a large number fluoride (total intake 14 mg/day) and the assumption that the risk of fractures already occurs at intakes above 6 mg/day (3).

The Institute of Medicine of the US National Academy of Sciences (15) gives a recommended total dose of fluoride intake (from all sources) of 0.05 mg/kg of human body weight, arguing that the intake of this amount of fluoride minimizes the risk of caries in the population, while not causing negative side effects (for example, fluorosis). The US Environmental Protection Agency (EPA) considers the maximum allowable concentration (not causing skeletal fluorosis) to be 4 mg/l, and the value of 2 mg/l is not to cause oral fluorosis. The WHO Guidelines for Drinking Water Quality recommend 1.5 mg/L (16). WHO emphasizes that when developing national standards, it is necessary to take into account climatic conditions, the volume of consumption, the intake of fluorine from other sources (water, air). WHO (16) notes that in regions with naturally high levels of fluoride, it is difficult to meet the recommended amount for the population to consume.

Fluorine is not an element bound in bone tissues irreversibly. During the period of skeletal growth, a relatively large part of the fluorine entering the body accumulates in the bone tissue. "Balance" of fluorine in the body, i.e. the difference between the incoming and outgoing amount can be positive or negative. With the intake of fluorine from mother's and cow's milk, its content in biological fluids is very low (0.005 mg / l), and excretion with urine exceeds intake into the body, while a negative balance is observed. Fluorine enters the body of infants in very small quantities, so it is excreted from bone tissue into extracellular fluids and leaves the body with urine, which leads to a negative balance. The situation with the adult population is opposite - about 50% of the fluorine entering the body is deposited in the bone tissue, the remaining amount leaves the body through the excretion system. Thus, fluorine can be released from bone tissue slowly, but over a long period. This ratio is possible due to the fact that the bone is not a frozen structure, but is constantly formed from the nutrients that enter the body (17,18).

V. Importance of desalination

Demineralization removes virtually all of the fluorine from seawater, so if the water is not remineralized, it will be deficient in fluorine and other minerals. Many natural drinking waters are initially poor in minerals, including fluorine. The significance of this fact for the health of society is determined by the balance of benefit and risk.

When comparing residents of different continents and within the continent, a significant difference in incidence is visible. WHO recommended the introduction of the DMFT index, which is determined in children of 12 years of age (this includes the number of affected, missing and healed teeth) as the most appropriate indicator; more information is available in the WHO oral health database (19). The etiology of caries involves the interaction of bacteria and simple sugars (eg, sucrose) from food. In the absence of sugar in drinks and foods, this problem would be negligible. Under these circumstances, the goal of public health is to prevent the harmful effects of excessive concentrations of fluoride in water.

However, when the risk of caries is high, the effect of removing fluoride from the centralized drinking water supply will be complex. In the Scandinavian countries, where oral hygiene is at high level and alternative sources of fluoride are widely used (e.g. toothpaste), the practice of permanently removing fluoride from drinking water may have little impact. On the other hand, in some developing countries, where oral hygiene is at a rather low level, water fluoridation in the amount of 0.5-1 mg/l remains an important public concern. There are also countries where there is a mixed situation. In particular, in the south of England, the incidence is under control and without artificial fluoridation of water; elsewhere, in the North West of England, the incidence is higher and water fluoridation is an important measure.

VI. conclusions

The value of using demineralized water, not subsequently enriched with fluoride, depends on:

Concentrations of fluoride in drinking water of a particular source;

Climatic conditions and the volume of water consumed;

The risk of caries (for example, sugar consumption);

The level of knowledge about oral problems in society and the availability of alternative sources of fluoride for the population of a particular region.

However, it is necessary to address the issue of total intake from other sources and establish a reasonable lower limit of fluoride intake to prevent its loss from bone tissue.

1M . McDonagh, P. Whiting, M. Bradley, A. Sutton, I. Chestnut, C. Misso, P. Wilson, E. Trager, J. Kleinen. Systematic review of water fluoridation in centralized systems water supply. York: University of York, Center for Information Review and Dissemination, 2000.

2. F.A. Smith, J. Ekstrand. Origin and chemistry of fluorine. Published in: O. Fairskov, J. Ekstrand, B.A. Burt et al. Fluoride in dentistry, 2nd edition. Copenhagen: Munksgaard, 1996: 20-21.

3. IPCS. Ecological health criteria: fluoride. Geneva: WHO, 2002.

4. P. Jackson, P. Harvey, W. Young. Chemistry and bioavailability of fluorine in drinking water. Marlow, Buckinghamshire: WRc-NSF, 2002.

5. J.J. Murray, A.J. Rugg-Gun, J.N. Jenkins. Fluoride in caries prevention. 3rd edition, Oxford: Wright, 1991: 7-37.

6. WHO Expert Committee on Health and Fluorine Use. Fluoride and oral health. WHO Technical Report Series No. 846. Geneva: WHO, 1994.

7. H. Welton, E. Crowley, D. O'Mullan, M. Cronin, W. Kelleher. Oral health in children in Ireland: preliminary results. Dublin: Irish State Department of Children's Health, 2003.

8. F. Moulton. Fluoride and oral health. Washington DC: American Association scientific achievements, 1942.

9. L . Demos, H Kazda, F. Ciccutini, M. Sinclair, S. Fairily. Water fluoridation, osteoporosis, fractures are the latest discoveries. Austrian Dental Journal 2001; 46:80-87.

10. ed. F. Fottrell. Irish Fluoridation Forum. Dublin, 2002.

11. E.G. Knox. Water fluoridation and cancer: a review of epidemiological evidence. London: HMSO, 1985.

12. Medical Research Council. Working Group Report: Water Fluoridation and Health. London, MRC, 2002.

13. Toxicology Committee of the National Research Council of the National Academy of Sciences. Washington DC: National Academic Press, 1993.

14. Royal Medical College. Fluoride and dental health. London: Pitman Medical, 1976.

15. Institute of Medicine. Reference data on the intake of calcium, phosphorus, magnesium, vitamin D and fluorine in the body. Washington DC: National Academic Press, 1997.

16. WHO, Guidelines for drinking water quality. Volume 1, Recommendations. 2nd edition. Geneva: WHO, 1993.

17. J. Ekstrand. fluorine metabolism. Published in: O. Fairskov, J. Ekstrand, B.A. Burt et al. Fluoride in dentistry, 2nd edition. Copenhagen, Munksgaard, 1996: 55-68.

18. J. Ekstrand, E.E. Ziegler, S.E. Nelson, S.J. Fomon. Absorption and accumulation of fluoride from nutrition and complementary foods by the body of an infant. Advances in Dental Research 1994; 8:175-180.

19. WHO Oral Health Database. Online: http://www.whocollab.od.mah.se/countriesalphab.html

Table 1. Countries using water fluoridation with a population of 1 million or more

Links

1. P. Sadgir, A. Vamanrao. Water in Vedic Literature. Protocols 3rd international conference Water Historical Association (http:/www.iwha.net/a_abstract.htm), Alexandria, 2003

2. Report of the working group (Brussels, March 20-23, 1978). Influence of water purification from substances present in natural water, features of demineralized and desalinated water. Euro Reports and Research 16. Copenhagen, WHO, 1979.

3. Guidance on hygienic aspects of water desalination. ETS/80.4. Geneva, WHO, 1980.

4. A.U. Williams. Studies using an electron microscope of water adsorption in the small intestine. Gut 1964; 4:1-7.

5. K. Schumann, B. Elsenhans, F. Reichl, et al. Does drinking highly purified water cause GI damage in rats? Vet Hum Toxicol 1993; 35:28-31.

6. Yu.A. Rakhmanin, R.I. Mikhailova, A.V. Fillipova and others. Some aspects biological influence distilled water (in Russian). Hygiene and sanitation 1989; 3:92-93.

7. German Nutrition Society. Should you drink distilled water? (German). Medical pharmacology, 1993; 16:146.

8. P.S. Bragg. R. Bragg. The shocking truth about water. 27th edition, Santa Barbara, CA, Health Science, 1993.

9. D.J. Robbins, M.R. Sly. Zinc in blood serum and demineralized water. American Journal of Clinical Nutrition 1981; 34:962-963.

10. B. Basnayat, J. Slaggs, M. Suthers Springer: consequences of excessive water consumption. Wilderness Ecological Medicine 2000; 11:69-70.

11. Attacks of hyponatremia in children using bottled drinking water

12. M .-P. Savant, D. Pepin. Drinking water and cardiovascular disease. Food and Chemical Toxicology 2002; 40:1311-1325.

13. F. Donato, S. Monarca, S. Premi, U. Gelatti. Drinking water hardness and chronic degenerative changes. Part III. Tumors, urolithiasis, fetal malformations, memory impairment in the elderly and atonic eczema (in Italian). Annual Hygiene Journal - Preventive Medicine in Society 2003; 15:57-70.

14. S. Monarca, I. Dzerbini, C. Simonatti, U. Gelatti. Drinking water hardness and chronic degenerative changes. Part II. Cardiovascular diseases (in Italian). Annual Hygiene Journal - Preventive Medicine in Society 2003; 15:41-56.

15. G. Nardi, F. Donato, S. Monarca, U. Gelatti. Drinking water hardness and chronic degenerative changes. Part I. Analysis of epidemiological studies (in Italian).

Annual Hygiene Journal - Preventive Medicine in Society 2003; 15:35-40.

16. S. Werd Vallespir, J. Sanchez Domingos, M. Quintal Gonzalez et al. Association between calcium content in drinking water and fractures in children (in Spanish). Pediatrics in Spain 1992; 37:461-465.

17. Jaskmine H, Commenges D, Letennevre L, et al. Drinking water components and memory impairment in the elderly. American Journal of Epidemiology 1994; 139:48-57.

18. Sea Wye. Young, H.F. Chiu, C. Chang et al. Association between very low birth weight infants and calcium in drinking water. Environmental Studies 2002; Section A, 89:189-194.

19. Si. Wye. Young, H.F. Chiu, J.F. Chiu et al. Calcium and magnesium in drinking water and the risk of mortality from colorectal cancer. Japanese Journal of Cancer Research 1997; 88:928-933.

20. Sea Wye. Young, M.F. Cheng, S.S. Cai et al. Calcium, magnesium, and nitrates in drinking water and mortality from gastric cancer. Japanese Journal of Cancer Research 1998; 89:124-130.

21. M .J. Eisenberg. Magnesium deficiency and sudden death. American Journal of Cardiology 1992; 124:544-549.

22. D. Bernardi, F.L. Dini, A. Azzarelli et al. Sudden death rate due to heart disease in regions with frequent coronary vascular disease and low drinking water hardness. Angiology 1995; 46:145-149.

23. P. Garzon, M.J. Eisenberg. The difference in the mineral composition of bottled drinking water industrial production: step towards health or disease. American Medical Journal 1998; 105:125-130.

24. O. Iwami, T. Watanabe, Ts.S. Moon et al. Neuromotor diseases in the Kii Peninsula in Japan: excessive manganese intake combined with magnesium deficiency in drinking water as a risk factor. General Science Magazine on the environment 1994; 149:121-135.

25. Z. Melles, S.A. Kiss. Influence of magnesium content in drinking water and magnesium therapy in case of demineralized water. Magnes Res 1992; 5:277-279.

26. Sea Wye. Young, H.F. Chiu, M.F. Cheng et al. Gastric cancer mortality and drinking water hardness levels in Taiwan. Environmental Study 1999; 81:302-308.

27. Sea Wye. Young, H.F. Chiu, M.F. Cheng et al. Pancreatic cancer mortality and drinking water hardness levels in Taiwan. Journal of toxicology, health, environment 1999; 56:361-369.

28. Sea Wye. Young, S.S. Tsai, T.S. Lai et al. Colon cancer mortality and drinking water hardness levels in Taiwan. Environmental Study 1999; 80:311-316.

29. Sea Wye. Young, H.F. Chiu, M.F. Cheng et al. Calcium and magnesium in drinking water and the risk of mortality from breast cancer. Journal of Toxicology, Health, Environment 2000; 60:231-241.

30. Yu.N. Profits. The status of phosphorus-calcium metabolism (turnover) among residents of the city of Shevchenko using demineralized drinking water (in Russian). Hygiene and sanitation 1972; 1:103-105.

31. Yu.A. Rakhmanin, T.D. Lichnikova, R.I. Mikhailov. Water hygiene and public protection water resources(in Russian). Moscow: Academy medical sciences, USSR, 1973: 44-51.

32. Yu.A. Rakhmanin, T.I. Bonashevskaya, A.P. Lestrovoy. Hygienic aspects of environmental protection (in Russian). Moscow: Academy of Medical Sciences, USSR, 1976 (fasc 3), 68-71.

33. E. Rubenovich, I. Molin, J. Axelsson, R. Rylander. Magnesium in drinking water: association with myocardial infarction, morbidity and mortality. Epidemiology 2000; 11:416-421.

34. National Institute of Public Health. Internal data. Prague: 2003.

35. V.A. Kondratyuk. Trace elements: health significance in low-mineralized drinking water. Hygiene and sanitation 1989; 2:81-82.

36. I.V. Wise. The influence of the mineral composition of drinking water on the health of the population (review). (In Russian). Hygiene and sanitation 1999; 1:15-18.

37. G .F. Lutai. Influence of the mineral composition of drinking water on the health of the population. (In Russian). Hygiene and sanitation 1992; 1:13-15.

38. Ultramicroelements in water: contribution to health. WHO Chronicle 1978;32: 382-385.

39. B.S.A. Hairin, W. Van Delft. Changes in the mineral composition of food as a result of cooking with hard and soft water. Arch Environmental Health 1981; 36:33-35.

40. C.K. Oh, P.V. Luker, N. Wetselsberger et al. Determination of magnesium, calcium, sodium and potassium in various foods with analysis of electrolyte loss after different types culinary processing. Mag Bull 1986; 8:297-302.

41. J. Durlach (1988) Importance of magnesium in water. Magnesium in clinical practice, J. Durlach. London: ed. John Libby and Company, 1988: 221-222.

42. M .X. Kramer, B.L. Nerwaldt, J.F. Crown et al. Surveillance for outbreaks of waterborne infectious diseases. USA, 1993-1994. MMWR 1996; 45 (No. SS-1): 1-33.

43. Epidemiological notes and reports on lead contamination of drinking water stored in storage tanks. Arizona, California, 1993. MMWR 1994; 43 (41): 751; 757-758.

44.D. J. Thompson. Ultramicroelements in animal nutrition. 3rd edition, Illinois: International Society for Mineral and Chemical Substances, 1970.

45. O.A. Levander. Nutritional factors in relation to toxic pollutants - heavy metals. Fed Proc 1977; 36: 1783-1687.

46. ​​F.V. Ohm, ed. Toxicity of heavy metals in the environment. Part 1. New York: M. Dekker, 1979.

47. H.S. Hopps, J.L. Feder. The chemical properties of water that have a beneficial effect on health. General Scientific Journal of the Environment 1986; 54:207-216.

48. V.G. Nadeenko, V.G. Lenchenko, G.N. Krasovsky. The effect of the combined effect of metals when they enter the body with drinking water (in Russian). Hygiene and sanitation 1987; 12:9-12.

49. J. Durlach, M. Bara, A. Guet-Bara. Magnesium concentration in drinking water and its importance in assessing the risk of cardiovascular diseases. W. Itokawa, J. Durlach. Disease and health: the role of magnesium. London: J. Libby and Company, 1989: 173-182.

50. S.I. Plitman, Yu.V. Novikov. N.V. Tulakina et al. On the issue of correcting standards for demineralized water, taking into account the hardness of drinking water (in Russian). Hygiene and sanitation 1989; 7:7-10.

51. S.N. Al-Kwarawi, H.E. El Bushra, R.E. Fontaine. Transmission of the causative agent of typhoid fever through a reverse osmosis water system. Epidemiology 1995; 114:41-50.

52. E.E. Geldreich, R.Kh. Taylor, J.S. Blannon et al. Growth of bacteria in water treatment devices intended for use at the point of connection. Working Journal of the Water Association of America 1985; 77:72-80.

53. P. Payment. Growth of bacteria in reverse osmosis water filtration devices.

54. Payment P, Franco E, Richardson L, et al. Relationship between gastrointestinal health and consumption of potable water treated with home reverse osmosis systems operating at the point of connection. Applied Environmental Microbiology 1991; 57:945-948.

55. A.I. Levin, Zh.V. Novikov, S.I. Plitman et al. Effects of water with varying degrees of hardness on the cardiovascular system (in Russian). Hygiene and sanitation 1981; 10:16-19.

56. J.V. Novikov, S.I. Plitman, A.I. Levin et al. Hygienic standards for the minimum content of magnesium in drinking water (in Russian). Hygiene and sanitation 1983; 9:7-11.

57. F. Kozichek. Nutrient value of drinking water (in Czech). Dissertation abstracts for the degree of candidate of sciences. Prague: National Institute of Public Health, 1992.

58. Yu.A. Rakhmanin, A.V. Fillipova, R.I. Mikhailov. Hygienic assessment of limestone materials used to correct the mineral composition of water with low salinity (in Russian). Hygiene and sanitation 1990; 8:4-8.

59. L .WITH. Muzalevskaya, A.G. Lobkovsky, N.I. Kukarina. Connection ... and urolithiasis, osteoarthritis and saline arthropathy with the hardness of drinking water. (in Russian). Hygiene and sanitation 1993; 12:17-20.

60. I.M. Golubev, V.P. Zimin. According to the standard for total hardness in drinking water (in Russian). Hygiene and sanitation 1994; 3:22-23.

61. Guidelines for the quality of drinking water. 2nd edition, 2nd volume, Health Safety Criteria and other related information. Geneva: WHO, 1996: 237-240.

62. European Directive 80/778/EEC of 15 July 1980 on the quality of drinking water intended for human consumption. From the Journal of the European Community 1980; L229: 11-29.

63. European Directive 98/83/EC of 3 November 1998 on the quality of drinking water intended for human consumption. From the Journal of the European Community 1998; L330; 32-54.

64. GOST R 50804-95. Habitat in manned spacecraft - general medical and technical requirements (in Russian). Moscow: Gosstandart of Russia, 1995.

65. E.F. Sklyar, M.S. Amigarov, S.V. Berezkin, M.G. Kurochkin,

V.M. Skuratov. Recycled water mineralization technology. Aerospace Ecology and Medicine 2001; 35(5):55-59.

Designed primarily for the normal and economical operation of systems and installations using extra pure water. Demineralized water is water from which almost all salts have been removed. Demineralized water is widely used in industry, medicine, in the operation of various instruments, devices and equipment, for household needs and other purposes.

Prices for water are given taking into account the cost of its delivery in Yekaterinburg.
At the first order of water, reusable containers are additionally redeemed.

In some cases, salts present in water, even in small quantities, can create certain problems when using water in production or everyday life. The purpose of obtaining demineralized, ie desalinated water is the maximum possible extraction of mineral substances contained in it from the source water at a reasonable cost.

Methods for reducing the content of hardness salts in water using ion-exchange plants and reducing the total salt content by distillation have become widespread. Softened water in the first case and distilled water in the second are widely used, in particular, in thermal power engineering and medicine. The first method is relatively cheap and productive, but by removing calcium and magnesium salts, it leaves the rest and even increases their concentration. Distilled water is very pure, almost demineralized, but expensive. High labor intensity and cost limit its widespread use.

Demineralized water can also be obtained by multi-stage deep purification. This is achieved by using the most efficient reverse osmosis membrane plants at its final stages. The total content of mineral substances in this case decreases hundreds of times compared with the initial one. In this regard, water purification by reverse osmosis can be the most cost-effective way of its demineralization, devoid of the disadvantages of both ion-exchange and distillation technologies.

Demineralized by means of reverse osmosis (reverse osmosis) water "Crystal-demineralized" is produced by LLC "Drinking Water" in accordance with the approved technical specifications (TU 0132-003-44640835-10) by deep post-treatment at industrial reverse osmosis membrane plants of pretreated water from an underground source (well 1p of the Institute of Geophysics, Ural Branch of the Russian Academy of Sciences). Water preparation includes its preliminary mechanical cleaning (filtration) and ultraviolet bactericidal treatment (disinfection).

Water "Crystal-demineralized" in terms of physical and chemical parameters must comply with the requirements given in the table, established by TU 0132-003-44640835-10

Name of indicator	Acceptable level value	RD for research methods
1. Mass concentration of the residue after evaporation, mg/dm3, no more		GOST 6709-72
2. Mass concentration of nitrates (NO3), mg/dm3, no more		GOST 6709-72
3. Mass concentration of sulfates (SO4), mg/dm3, not more than		GOST 6709-72
4. Mass concentration of chlorides (Сl), mg/dm3, no more		GOST 6709-72
5. Mass concentration of aluminum (Al), mg/dm3, no more		GOST 6709-72
6. Mass concentration of iron (Fe), mg/dm3, no more		GOST 6709-72
7. Mass concentration of calcium (Сa), mg/dm3, no more		GOST 6709-72<
8. Mass concentration of copper (Сu), mg/dm3, no more		GOST 6709-72
9. Mass concentration of lead (Рb), mg/dm3, not more than		GOST 6709-72
10. Mass concentration of zinc (Zn), mg/dm3, no more		GOST 6709-72
11. Mass concentration of substances that reduce KMnO4, mg/dm3, not more than		GOST 6709-72
12. Water pH		GOST 6709-72
13. Electrical conductivity at 20 °C, Sm/m, not more than		GOST 6709-72
14. Bicarbonates, mg/dm3, no more		RD 52.24.493-2006
15. Alkalinity, mg-eq/dm3		RD 52.24.493-2006
16. Rigidity general, hail. Zh, no more		GOST R 52407-2005
17. Sodium, mg/dm3, no more		GOST R 51309-99
18. Magnesium, mg/dm3, no more		GOST R 51309-99

Due to the extremely low salinity, Crystalline-demineralized water is not suitable for drinking purposes. It is intended primarily for the normal and economical operation of systems and installations associated with heating and evaporation of water and using extra pure water.

Demineralized water finds the greatest application in various technical, medical and other installations, as well as for household purposes. Demineralized (desalinated) water is recommended for office and home air humidifiers, steam generators and irons, steam convectors, steamers, coffee machines and other installations and devices. It is used to dilute coolants in heating systems, in the preparation of antifreeze, cooling and other liquids, for filling into batteries, etc.

Due to its high dissolving power, this water is used in the final washing of glass and double-glazed windows, mirrors, jewelry and other products, preparation of metal and other surfaces for powder coating. Demineralized water is used in perfumery and medicine in the preparation of various gels and solutions, in many installations for lubricating and cooling friction parts and parts (in particular, dental ones), in steam sterilization of instruments in autoclaves, in ultrasonic therapy devices (for example, inhalers.

In a number of industries, demineralized water is used for cooling and washing products (manufacturing of molded products - shots, galvanic production, coating shops), for filling cooling and washing circuits with demineralized water and maintaining the desired quality of circulating water using make-up (i.e. addition) new portions of demineralized water.

Demineralized water is used in the restoration of inkjet cartridges, when there are unpleasant cases of burning of the contact groups and the printing element. One of the main reasons for this is the use of tap water or insufficiently purified water to flush the inside of the inkjet cartridge and print head.

Water with salts is a good conductor, which is not very good for the contact groups of the inkjet cartridge. On the other hand, as experts note, metal impurities contained in ordinary water react with the tantalum spirals of the print head, thereby increasing the likelihood of failure of the printing element itself as a whole. In the manufacture of double-glazed windows, if the glasses are washed with plain water before packaging, salt stains remain on the glass after the water dries, which cannot be removed after packaging in a bag. It is therefore necessary to wash the glass with hot demineralized water. Demineralized water leaves no salt after drying on glass. Accordingly, as a result, the double-glazed window in the package will be transparent and without salt drips.

The specific mineral-salt composition of any water (natural, including artesian and spring, purified, tap water, conditioned with various artificial additives, for example, iodine and fluorine, etc.) to a certain extent determines the taste and aftertaste of those prepared on these types water food and drink. At the same time, the content of salts and other impurities that determine the taste and other consumer properties of natural and tap water is constantly changing in space and time. This circumstance complicates quality management and comparative evaluation of food and drinks produced from this water. The need to maintain a stable composition and taste of many drinks (and not only expensive alcohol or cheap beer!) Forces their manufacturers to minimize the mineralization of the original drinking water.

That is why desalinated demineralized water, which also has a high extractive ability, can be used in cooking when preparing high-quality and dietary dishes, for brewing elite varieties of tea and coffee, preparing infusions and decoctions of medicinal herbs in order to emphasize and preserve their individual natural aroma and beneficial properties. properties.

When hard water is boiled, a film forms on its surface, and the water itself acquires a characteristic taste. When brewing tea or coffee in such water, a brown precipitate may form. In addition, nutritionists have found that meat is less boiled in hard water. This is due to the fact that hardness salts react with animal proteins, forming insoluble compounds. This leads to a decrease in the digestibility of proteins. It has been noticed that food cooked with demineralized water looks more appetizing, does not lose its attractive shape, and has a richer and richer taste. When preparing drinks and dishes from concentrates, a smaller (up to 20%) amount of dry concentrate is required to obtain the finished product.

Demineralized water, having increased permeability, perfectly removes dirt, grease stains on fabrics, dishes, bathtubs, sinks, saves a significant amount of detergents and cleaners (up to 90%), washing and cleaning the apartment is reduced (up to 15%), life expectancy linen increases (by 15%).

Scale deposits are responsible for up to 90% of water heater failures. Scale deposited on the walls of water heating devices (boilers, columns, etc.), as well as on the walls of pipes of the hot water supply line, disrupts the heat exchange process. Accordingly, the heating elements overheat, there is an excessive consumption of electricity and gas. Studies have shown that when using demineralized water, savings on electric water heaters or gas equipment is 25-29%.

Water containing iron, upon short contact with oxygen, acquires a yellowish-brown color, and when the iron content is above 0.3 mg / l, it causes rusty streaks on plumbing and stains on linen during washing. When using demineralized water, plumbing remains clean. Demineralized water does not pollute plumbing communications, resists corrosion and, by dissolving salt deposits, washes it out, extending the life of plumbing by almost half.

Storage conditions:

Store in a dark place at a temperature of +5 o C to +20 o C and relative air humidity not more than 75%.

Best before date: 18 months from date of bottling.

Manufacturer: Drinking Water LLC, Yekaterinburg.

Natural water always contains various impurities, the nature and concentration of which determines its suitability for certain purposes.

Drinking water supplied by centralized drinking water supply systems and water pipelines, according to GOST 2874-73, can have a total hardness of up to 10.0 meq/l, and a dry residue of up to 1500 mg/l.

Naturally, such water is unsuitable for preparing titrated solutions, for performing various studies in the aquatic environment, for many preparative works associated with the use of aqueous solutions, for rinsing laboratory glassware after washing, etc.

Distilled water

The method of water demineralization by distillation (distillation) is based on the difference in pressure of water vapor and salts dissolved in it. At not very high temperatures, it can be assumed that salts are practically non-volatile and demineralized water can be obtained by evaporating water and then condensing its vapors. This condensate is called distilled water.

Water purified by distillation in distillation apparatuses is used in chemical laboratories in quantities greater than other substances.

According to GOST 6709-72, distilled water is a transparent, colorless liquid, odorless, with pH = 5.44-6.6 and a dry residue content of not more than 5 mg / l.

According to the State Pharmacopoeia, the dry residue in distilled water should not exceed 1.0 mg / l, and pH = 5.0 4-6.8. In general, the requirements for the purity of distilled water according to the State Pharmacopoeia are higher than according to GOST 6709-72. So, the pharmacopoeia allows the content of dissolved ammonia not more than 0.00002%, GOST not more than 0.00005%.

Distilled water should not contain reducing substances (organic substances and reducing agents of inorganic nature).

The clearest indicator of water purity is its electrical conductivity. According to literature data, the electrical conductivity of ideally pure water at 18°C ​​is 4.4*10 V minus 10 Sm*m-1,

With a small need for distilled water, the distillation of water can be carried out at atmospheric pressure in conventional glass installations.

Once distilled water is usually contaminated with CO2, NH3 and organic matter. If very low conductivity water is required, the CO2 must be completely removed. To do this, a strong jet of air purified from CO2 is passed through water at 80-90 ° C for 20-30 hours and then the water is distilled at a very slow air flow.

For this purpose, it is recommended to use compressed air from a cylinder or to suck it in from the outside, since it is very contaminated in a chemical laboratory. Air is first passed through a wash bottle with conc. H2SO4, then through two wash bottles with conc. KOH and finally through a bottle of distilled water. In this case, the use of long rubber tubes should be avoided.

Most of the CO2 and organic matter can be removed if about 3 g of NaOH and 0.5 g of KMnO4 are added to 1 liter of distilled water and some of the condensate is discarded at the beginning of the distillation. VAT residue should be at least 10-15% of the load. If the condensate is re-distilled with 3 g KHSO4, 5 ml 20% H3PO4 and 0.1-0.2 g KMnO4 per liter, this ensures complete removal of NH3 and organic impurities.

Prolonged storage of distilled water in glassware always results in contamination with glass leaching products. Therefore, distilled water cannot be stored for a long time.

Metal distillers

Distillers with electric heating. On fig. 59 shows the D-4 distiller (model 737). Productivity 4 ±0.3 l/h, power consumption 3.6 kW, cooling water consumption up to 160 l/h. The mass of the apparatus without water is 13.5 kg.

In the evaporation chamber 1, the water is heated by electric heaters 3 to a boil. The resulting steam through the pipe 5 enters the condensation chamber 7, built into the chamber 6, through which tap water continuously flows. From the condenser 8, the distillate flows out through the nipple 13.

At the beginning of operation, tap water, continuously flowing through the nipple 12, fills the water chamber 6 and through the drain tube 9 through the equalizer 11 fills the evaporation chamber to the set level.

In the future, as it boils away, water will only partially enter the evaporation chamber; the main part, passing through the condenser, more precisely through its water chamber 6, will merge through the drain pipe into the equalizer and then through the nipple 10 into the sewer. The escaping hot water can be used for household needs.

The device is equipped with a level sensor 4, which protects the electric heaters from burnout in case the water level drops below the permissible level.

Excess steam from the evaporation chamber exits through a tube built into the condenser wall.

The device is installed on a flat horizontal surface and, by means of a ground bolt 14, is connected to a common ground loop, to which an electrical panel is also connected.

During the initial start-up of the apparatus, it is possible to use distilled water for its intended purpose only after 48 hours of operation of the apparatus.

Periodically, it is necessary to mechanically descale the electric heaters and the float of the level sensor.

The distiller D-25 (model 784) is similarly arranged, the productivity of which is 25 ± 1.5 l / h, the power consumption is 18 kW.

This apparatus has nine electric heaters - three groups of three heaters. For normal and long-term operation of the device, it is enough that six heaters are turned on simultaneously. But this requires periodically, depending on the hardness of the supply water, to mechanically descale the tube through which water enters the evaporation chamber.

At the initial start-up of the D-25 distiller, it is recommended to use distilled water for its intended purpose after 8-10 hours of operation of the apparatus.

Of considerable interest is the apparatus for obtaining pyrogen-free water for injection A-10 (Fig. 60). Productivity 10 ±0.5 l/h, power consumption 7.8 kW, cooling water consumption 100-180 l/h.

In this apparatus, reagents for its softening (potassium alum Al2(SO4)3-K2SO4-24H2O) and for the removal of NH3 and organic contaminants (KMnO4 and Na2HPO4) enter the evaporation chamber along with distilled water.

The solution of alum is poured into one glass vessel of the dosing device, and the solutions of KMnO4 and Na2HPO4 - into the other - based on 1 liter of pyrogen-free water alum 0.228 g, KMnO4 0.152 g, Na2HPO4 0.228 g.

At the initial start-up or at the start-up of the device after a long-term conservation, it is possible to use the obtained pyrogen-free water for laboratory needs only after 48 hours of operation of the device.

Before using electrically heated metal distillers, check that all wires are connected correctly and that there is a ground connection. It is strictly forbidden to connect these devices to the mains without grounding. In case of any malfunction, the distillers must be disconnected from the mains.

The quality of distilled water to a certain extent depends on the duration of the apparatus. So, when using old distillers, the water may contain chloride ions.

The receivers must be made of neutral glass and, in order to avoid the ingress of CO2, connected to the atmosphere through calcium chloride tubes filled with soda lime granules (a mixture of NaOH and Ca(OH)2).

fire distiller. Distiller DT-10 with a built-in firebox is designed for operation in the absence of water supply and electricity and allows you to get up to 10 liters of distilled water in 1 hour. It is a cylindrical structure made of stainless steel with a height of about 1200 mm, mounted on a base 670 mm long and 540 mm wide.

The distiller consists of a built-in firebox with furnace fittings, an evaporation chamber for 7.5 liters, a cooling chamber for 50 liters and a collection of distilled water for 40 liters.

Water is poured into the evaporation and cooling chambers manually. As water is used up in the evaporation chamber, it is automatically replenished from the cooling chamber.

Obtaining bidistillate

Once distilled water in metal stills always contains small amounts of foreign matter. For particularly precise work, they use re-distilled water - bidistillate. The industry commercially produces devices for bidistillation of water BD-2 and BD-4 with a capacity of 1.5-2.0 and 4-5 l/h, respectively.

Primary distillation takes place in the first section of the apparatus (Fig. 61). KMnO4 is added to the resulting distillate to destroy organic impurities and transferred to the second flask, where secondary distillation takes place, and the bidistillate is collected in a receiving flask. Heating is carried out using electric heaters; glass water refrigerators are cooled by tap water. All glass parts are made from Pyrex glass.

Determination of quality indicators of distilled water

pH determination. This test is carried out by the glass electrode potentiometric method or, in the absence of a pH meter, by the colorimetric method.

Using a stand for colorimetry (a stand for test tubes equipped with a screen), four numbered identical test tubes with a diameter of about 20 mm and a capacity of 25-30 ml, clean, dry, made of colorless glass are placed: in test tubes No. 1 and 2 - 10 ml of the water to be tested , in test tube No. 3 - 10 ml of a buffer mixture corresponding to pH = 5.4, and in No. 4 - 10 ml of a buffer mixture corresponding to pH = 6.6. Then, 0.1 ml of 0.04% water-alcohol solution of methyl red is added to test tubes No. 1 and 3 and mixed. Add 0.1 ml of a 0.04% aqueous solution of bromthymol blue to test tubes No. 2 and 4 and mix. Water is considered to comply with the standard if the contents of tube No. 1 are not redder than the contents of tube No. 3 (pH = 5.4), and the contents of test tube No. 2 are not bluer than the contents of test tube No. 4 (pH = 6.6).

Determination of dry residue. In a pre-calcined and weighed platinum dish, evaporate to dryness 500 ml of the water to be tested on a water bath. Water is added to the cup in portions as it evaporates, and the cup is protected from contamination by a protective cap. Then the cup with the dry residue is kept for 1 hour in an oven at 105–110°C, cooled in a desiccator, and weighed on an analytical balance.

Water is considered to comply with GOST 6709-72 if the mass of dry residue is not more than 2.5 mg.

Determination of the content of ammonia and ammonium salts. 10 ml of the test water is poured into one test tube with a ground glass stopper with a capacity of about 25 ml, and 10 ml of the reference solution prepared as follows: 200 ml of distilled water are placed in a 250-300 ml conical flask, 3 ml of a 10% solution are added NaOH and boil for 30 min, after which the solution is cooled. Add 0.5 ml of a solution containing 0.0005 mg of NH4+ to the test tube with the reference solution. Then, 1 ml of reagent for ammonia (see Appendix 2) is simultaneously added to both test tubes and mixed. Water is considered to be in accordance with the standard if the color of the contents of the tube observed after 10 minutes is not more intense than the color of the reference solution. Color comparison is made along the axis of the test tubes on a white background.

Test for reducing agents. 100 ml of the test water is brought to a boil, 1 ml of 0.01 N sodium hydroxide is added. KMnO4 solution and 2 ml of dilute (1:5) H2SO4 and boil for 10 minutes. The pink color of the test water should be maintained.

Demineralization of fresh water by ion exchange method

When water is deionized, the processes of H+ cationization and OH- anionization are successively carried out, i.e., the replacement of cations contained in water with H+ ions and anions with OH- ions. Interacting with each other, H+ and OH- ions form the H2O molecule.

The deionization method makes it possible to obtain water with a lower salt content than conventional distillation, but non-electrolytes (organic impurities) are not removed.

The choice between distillation and deionization depends on the hardness of the source water and the costs associated with its purification. Unlike water distillation, deionization consumes energy in proportion to the salt content of the water being treated. Therefore, at a high concentration of salts in the source water, it is advisable to first apply the distillation method, and then carry out post-purification by deionization.

Ion exchangers are solid substances of mineral or organic origin, practically insoluble in water and organic solvents, natural and synthetic. For the purposes of water demineralization, synthetic polymeric ion exchangers are of practical importance - ion-exchange resins, which are distinguished by high absorption capacity, mechanical strength and chemical resistance.

Demineralization of water can be carried out by sequentially passing tap water through a column of cation exchanger in H + form, then through a column of anion exchanger in OH - form. The filtrate from the cation exchanger contains acids corresponding to the salts in the source water. The completeness of removal of these acids by anion exchangers depends on their basicity. Strongly basic anion exchangers remove all acids almost completely, weakly basic ones do not remove such weak acids as carbonic, silicic and boric.

If these acidic groups are acceptable in demineralized water or their salts are absent in the source water, then it is better to use weakly basic anion exchangers, since their subsequent regeneration is easier and cheaper than the regeneration of strongly basic anion exchangers.

For water demineralization in laboratory conditions, cation exchangers of grades KU-1, KU-2, KU-2-8chS and anion exchangers of grades EDE-10P, AN-1, etc. are often used. 2-0.4 mm using a set of sieves. They are then washed with distilled water by decantation until the washings are completely clear. After that, the ion exchangers are transferred into glass columns of various designs.

On fig. 62 shows a small-sized water demineralization column. Glass beads are placed at the bottom of the column and glass wool is placed on top of them. To prevent air bubbles from getting between the grains of the ion exchangers, the column is filled with a mixture of the ion exchanger with water. Water is drained as it accumulates, but not below the level of the ion exchanger. From above, the ion exchangers are covered with a layer of glass wool and beads and left under a layer of water for 12-24 hours. After draining the water from the cation exchanger, the column is filled with 2 N. HCl solution, left for 12-24 h, HCl is drained and the cation exchanger is washed with distilled water until neutral with methyl orange. The cation exchanger, converted to the H + form, is kept under a layer of water. Similarly, the anion exchanger is transferred to the OH form, keeping it in the column after swelling in 1 N. NaOH solution. Washing of the anion exchanger with distilled water is carried out until the reaction is neutral with respect to phenolphthalein.

Demineralization of relatively large volumes of water with the separate use of ion exchangers can be carried out in a larger plant. The material for two columns with a height of 700 and a diameter of 50 mm can be glass, quartz, transparent plastic. 550 g of the prepared ion exchanger are placed into the columns: in one - the cation exchanger in the H+ form, in the other the anion exchanger - in the OH - form. Tap water at a rate of 400-450 ml/min enters the cation exchanger column and then passes through the anion exchanger column.

Since the ion exchangers are gradually saturated, it is necessary to control the operation of the installation. In the first portions of the filtrate passed through the cation exchanger, the acidity is determined by titration with alkali over phenolphthalein. After about 100 liters of water have been passed through the installation, or it has been operating continuously for 3.5 hours, a water sample should be taken again from the cation exchanger and the acidity of the filtrate determined. If a sharp decrease in acidity is observed, the passage of water should be stopped and the ion exchangers should be regenerated.

The cation exchanger is poured from the column into a large jar with 5% HCl solution and left overnight. Then the acid is drained, the cation exchanger is transferred to a Buchner funnel and washed with distilled water until a negative reaction to the Cl- ion with AgNO3. The washed cation exchange resin is reintroduced into the column.

The anion exchange resin is regenerated with a 5% NaOH solution, washed with water until a negative reaction for phenolphthalein, and then the column is refilled with it.

At present, the demineralization of water is mostly carried out by the mixed layer method. The source water is passed through a mixture of a cation exchanger in the H+ form and a strong or weakly basic anion exchanger in the OH form. This method provides high purity water, but the subsequent regeneration of ion exchangers requires a lot of labor.

For water deionization using mixed ion-exchange filters, a mixture of KU-2-8chS cation exchange resin and EDE-10P anion exchange resin in a volume ratio of 1.25: 1 is loaded into a column with a diameter of 50 mm and a height of 600-700 mm. Plexiglas is preferred as the material for the column, and polyethylene is preferred for the inlet and outlet pipes.

One kilogram of an ionite mixture can purify up to 1000 liters of once distilled water.

Regeneration of used mixed ion exchangers is carried out separately. The mixture of ion exchangers from the column is transferred to a Buchner funnel and sucked off until an air-dry mass is obtained. Then the ion exchangers are placed in a separating funnel of such capacity that the mixture of ion exchangers occupies 1/4 of its volume. After that, a 30% NaOH solution is added to the funnel up to 3/4 volume and vigorously mixed. In this case, the mixture of ion exchangers due to their different density (cation exchanger 1.1, anion exchanger 1.4) is divided into layers. After that, the cation exchanger and anion exchanger are washed with water and regenerated as described above.

In laboratories where the need for deeply desalinated water exceeds 500-600 l/day, a commercially available apparatus Ts 1913 can be used. Estimated productivity is 200 l/h. The capacity of the deionizer for the inter-regeneration period is 4000 liters. The weight of the set is 275 kg.

The demineralizer is equipped with a system for automatically shutting off the supply of tap water when its electrical resistance drops below the permissible value and float valves that allow automatic removal of air from the columns. Regeneration of ion-exchange resins is carried out by treating them directly in columns with NaOH or HCl solution.

Water is life. We all know from childhood that our body consists almost entirely of water. We drink plenty of water to be healthy, and we always try to drink only clean, safe water. But why then the water of deep purification harmful to the body? What is demineralized water and why is it needed?

Deep cleaning water

Demineralized or deionized water is deeply purified water, in which the salt content is reduced. It differs from distilled water by the fact that non-electrolytes are present in it.

Today, there are many ways to obtain deionized water. Water of more or less deep purification is needed for different needs, so different methods are used for different purposes.

Evaporation

The essence of the method is that polluted water is evaporated. Wherein impurities remain and pure water condenses. This method is very energetically expensive, but it also allows removing non-electrolytic impurities.

Electrolysis

A method of cleaning water under the action of an electric field. The field acts on free ions dissolved in water and attracts them, and the water becomes cleaner.

Reverse osmosis

The principle of cleaning is that water under high pressure is passed through semipermeable membrane, the smallest pores of which allow water molecules to pass through, but retain impurities. This method, in combination with the rest, allows you to get bidistilled water, which is considered the purest to date.

Areas of use

Any water contains mineral salts, we even often buy special mineral water with a high content of certain salts.

But we also know that hard water, or water with a high content of potassium and calcium salts, is of little use for household needs. When washing, it forms a precipitate that disables washing machines, and appears in the form of scale on the kettle.

But if for everyday life we ​​only need to slightly reduce the salt content, then for the pharmacological and food industries. Such water is needed in petrochemical plants and industries involved in metal processing.

Another group using demineralized water is motorists. They add deep cleaning water to the antifreeze. The coolant contains water, but when the weather changes, it can evaporate. Also, such water is necessary for the operation of the glass washer.

Only demineralized water can be a dielectric, since salt ions in solution are capable of conducting electricity. This opens up another field of use: for research purposes. Demineralized water has found its application in the field energy.

Recently, deionized water is more popular than distilled water. Distillation devices wear out faster due to the presence of salts in the liquid, while demineralization is less expensive.

Harm from drinking demineralized water

If demineralized water is useful for appliances and machines, then the effect on humans is not so clear. Deep cleaning water is able to flush out salts from the body, sometimes it is necessary. For example, it has been proven positive influence moderate consumption of demineralized water with:

• detection of deposits in the liver;
• violation of the kidneys;
• diabetes
• allergies;
• intoxication and poisoning.

In addition to harmful impurities, useful ones are also present in the water, but deeply purified water is devoid of any impurities, as doctors often say: it "dead" water.

Some impurities are necessary for the normal functioning of the body, but deionized water does not contain these impurities and does not support reactions. In addition, such water is tasteless, it is absolutely fresh and does not eliminate the feeling of thirst.

Regular consumption of deep-cleansed water in food can lead to the destruction of the mucous membrane of the gastrointestinal tract. This is shown by experiments on rats.

The detrimental effect on the process of mineral metabolism when drinking demineralized water has been unambiguously proven. This water washes out minerals from biological fluids. What affects the hormonal background and the production of red blood cells. At the same time, the excretion of water from the body increases.

With frequent use of weakly mineral water, the concentration of calcium and magnesium in the body decreases. Calcium is the building block of many bones and tissues of the body, and magnesium is essential for more than 300 biological processes.

It has also been proven that with regular consumption of demineralized water, the intake of toxic metals. "Dead" water has weak protective properties.

In the last decade, the technology of water demineralization with the help of ion exchange resins (ion exchangers) has developed significantly. Ion-exchange resins are divided into two groups: 1) cation exchangers, which are resins with an acidic, carboxyl or sulfonic group, which have the ability to exchange hydrogen ions for alkali and alkaline earth metal ions; 2) anion exchangers - most often polymerization products of amines with formaldehyde, exchanging their hydroxyl groups for anions.

Demineralization of water is carried out in special apparatus-columns, and in principle it is possible either to pass water first through a column with a cation exchanger, and then with an anion exchanger or in the reverse order (the so-called conventional system), or to pass water through one column containing both a cation exchanger and anion exchanger (mixed column).

We give a description of one of the domestic industrial desalination plants with a capacity of 10 t/h, operating according to the scheme: mechanical filters - H-cationization - decarbonization - OH-anionation (Fig. 79).

Water from the city water supply system with the help of pumps / enters a mechanical unit consisting of two filters loaded with sulfonated coal. Water passes through the filter from top to bottom and enters H-cationization 2. The operation of the mechanical filter provides for loosening (once every 3 days), which is necessary to prevent caking of the sulfo coal and washing away the dirt formed due to the abrasion of the sulfo coal. Loosening is carried out by a stream of water from below. The scheme also provides for the supply of tap water for cationization, bypassing mechanical filters. H-cation block consists of three filters and a calciner 3, installed after them. Cationite filters are loaded with KU-1 resin, obtained by the condensation of phenol sulfonic acid and formaldehyde, which, under certain conditions, is capable of absorbing various cations from aqueous solutions. Cation exchanger KU-1, like other cation exchangers, is characterized by unequal ability to absorb various cations.

For most cation exchangers, the distribution of absorption activity of various cations and their corresponding absorption capacity can be represented by the following series:

The cation exchange process proceeds according to the scheme:

where K is the organic anion of the cation exchanger.

In the future, due to the different ability to exchange individual cations, the sodium ion, which has the lowest mobility, will be the first to be displaced into the filtrate by more mobile calcium and magnesium cations. A decrease in the amount of hydrogen ions capable of exchange in the cation exchanger will entail a decrease in acidity by an equivalent value and an increase in sodium ions in the filtrate.

The H-cationite filter is a cylindrical apparatus equipped with upper and lower bottoms attached to the body with bolts. The surface of the filters is gummed. Quartz sand with a layer height of 300 mm is loaded onto the bottom of the filter, then cation exchanger with a layer height of 3 m. Along with quartz sand, the filter is provided with upper and lower drainage devices that prevent the removal of cation exchange resin during filter operation.

Drainage devices consist of rubberized discs, in which slotted caps are fixed on the thread. In addition to the above, drainage devices are designed for uniform distribution over the entire cross-sectional area of ​​the filter of water passing through it, both during cationization and during loosening and washing. The operation of the filter consists in the periodic implementation of four operations: 1) H-cationization; 2) loosening; 3) regeneration; 4) washes. The loosening of the cation exchanger is carried out to eliminate compaction, remove dirt caused by water and acid solution, and fines formed due to abrasion of the cation exchanger. Loosening is done with source water.

Regeneration of H-cation exchange filters is carried out with a 5% solution of hydrochloric acid, prepared in a special container -

reactor 10 with stirrer 12. Initial water is used to prepare the solution; concentrated hydrochloric acid is supplied from a hopper 9, where with the help of compressed air it enters from the storage tank 8. The acid solution prepared for regeneration is stored in the collection 11. Acid after regeneration is discharged through a layer of marble chips into the sewer.

After passing the required amount of acid through the filter, the filter is immediately washed with source water. H-cationized water after the decomposition of carbonate hardness contains a large amount of free carbon dioxide, which is removed in the calciner 3 due to desorption, due to the creation above the water surface with a fan 4 low partial pressure CO 2 . Desorption increases with an increase in the temperature of the medium, since the solubility of the gas in water decreases. The decarbonized water is collected in tank 5, from where it is pumped 6 fed into the anion block

Anion filters are loaded with EDE-10p resin obtained by condensation of polyethylene polyamides and epichlorohydrin, which is capable of absorbing various anions from aqueous solutions under certain conditions. EDE-10p, like other anion exchangers, is characterized by unequal ability to absorb various anions. Anion exchangers are divided into two groups: weakly basic and strongly basic. Weakly basic anion exchangers are able to absorb anions of strong acids (SO 4 -2 CI - , NO 3 -), and anions of weak acids (HCO 3 - , HSiO 3 - others) do not retain them. Strong base anion exchangers extract anions of both strong and weak acids from aqueous solutions. The anion exchange process proceeds according to the scheme:

where A is the organic cation of the anion exchanger.

The anionite block consists of three filters with a diameter of 800 mm and a height of 3.5 m. Anionite filters are arranged similarly to cationite ones. The operation of an anion-exchange filter consists in the periodic implementation of the same four operations: 1) anionization; 2) loosening; 3) regeneration; 4) washes.

Loosening of anion-exchange filters is carried out with decarbonized water 5. Regeneration of OH-anion-exchange filters is carried out with a 3-4% alkali solution. To prepare a regenerating alkali solution, the required amount of a concentrated solution obtained from solid NaOH on demineralized water in a reactor with a stirrer 13, served through a meter 14 in tanks 15, where demineralized water is supplied for dilution. Regeneration solution from tanks 15 is then supplied with compressed air to the filter 16 and then to the OH-anion filter. Washing is designed to remove excess regeneration solution and regeneration products from the filter and is carried out with decarbonized water. Wash water is discarded. With the help of ion exchangers, it is possible to obtain demineralized water, which in its qualities corresponds to pharmacopoeial standards. In some cases it is useful to combine water demineralization with its distillation (for injection solutions).