Indicators of total mineralization mg l. General water mineralization
Total mineralization refers to the sum of particles dissolved in water. Salts that, under the influence of water molecules, break down into ions (dissociate) have maximum solubility.
The indicator of total mineralization of water reflects the content of salts in it, among which the most represented are compounds of sodium, potassium, calcium, magnesium and residues of hydrochloric, carbonic, and sulfuric acids.
Where is it used?
The value of total mineralization is used constantly and everywhere to characterize the composition of water. Its taste and physiological properties depend on the total concentration of dissolved salts. This, in particular, is the basis for the effect of healing waters at balneological resorts. In everyday practice, the indicator reflects the characteristics of the water of each region, the degree of natural purity, and cleaning efficiency.
The total mineralization of wastewater is a value that informs about the efficiency of treatment facilities at enterprises.
For packaged water of the first category, the standard value is 1000 mg/l. In bottled water of the highest category, the value of the total concentration of dissolved salts should be lower: from 200 mg/l to 500 mg/l.
In SanPiN, as well as in some other sources, the terms “total mineralization” and “dry residue” are considered synonymous. Strictly speaking, this is not entirely legal. The method for determining the dry residue is based on evaporation of the solvent. When heated, bicarbonate is destroyed with the release of carbon dioxide and turns into carbonate anion. Consequently, there is always a slight difference between the total mineralization indicators and the amount of dry residue.
Total mineralization is calculated by adding up all ion concentrations obtained in standard analyzes according to GOST standards. The method for determining this indicator is arithmetic. The resulting value will differ from the dry residue value by a small amount equal to half the concentration of carbonate anions.
Sometimes they talk about the presence of a small amount of organic substances in the total ion concentration indicator. This is not true. The mineralization indicator includes compounds of mineral origin. Organic compounds are not one of these.
Impact on human health
Most consumers like the taste of water containing about 600 mg/l of salts. People's attachments and habits differ. In regions where water has always had increased or decreased mineralization, taste adaptation occurs. The population considers it quite normal, even tasty. However, WHO considers concentrations exceeding 1000 mg/l unacceptable. Indicators equal to 1200 mg/l cause the presence of bitterness. The majority of the population does not like this water.
When discussing the physiological importance of the salt composition of water, it should be noted that no more than 7% of the required minerals enter the human body from this source. This way of saturating the body with useful elements is important, but not decisive.
Sources of pollution
Mineral components enter water from the soil, the composition of which is specific to each area. Poorly treated wastewater from industrial enterprises can make a noticeable contribution to the increase in salt concentration. To fully meet a person’s daily need for water, it makes sense to purchase bottled products with good taste.
Protect yourself from all risks and use the Aqua Market service.
The most valuable information about the effects of low calcium concentrations in drinking water on an entire population of people came from studies conducted in the Soviet city of Shevchenko (now Aktau, Kazakhstan), where the city water supply used desalination plants (water source - the Caspian Sea). Decreased alkaline phosphatase activity, decreased plasma calcium and phosphorus concentrations, and increased bone decalcification were observed in the local population. These changes were most noticeable in women, especially pregnant women, and depended on the length of residence in Shevchenko. The need for calcium in drinking water is also confirmed in a one-year experiment on rats that were provided with a completely adequate diet in terms of nutrients and salts, but were fed distilled water to which 400 mg/l of calcium-free salts and one of these calcium concentrations were added: 5 mg/l, 25 mg/l or 50 mg/l. Rats fed water with 5 mg/l calcium showed a decrease in the functionality of thyroid hormones and other related functions compared to the rest of the animals participating in the experiment.
It is believed that a general change in the composition of drinking water affects human health after many years, and a decrease in the concentration of calcium and magnesium in drinking water affects well-being almost instantly. Thus, residents of the Czech Republic and Slovakia in 2000-2002 began to actively use reverse osmosis systems in their apartments for the purification of city water. Within a few weeks or months, local doctors were inundated with complaints indicating acute magnesium (and possibly calcium) deficiency: cardiovascular disorders, fatigue, weakness and muscle cramps.
3. The risk of a deficiency of vital substances and microelements when drinking low-mineralized water.
Although drinking water, with rare exceptions, is not the main source of vital elements for humans, it can make a significant contribution to their intake for several reasons. Firstly, the food of many modern people is a rather poor source of minerals and trace elements. In the case of a borderline deficiency of any element, even its relatively low content in consumed drinking water can play a corresponding protective role. This is due to the fact that the elements are usually present in water as free ions and are therefore more easily absorbed from water compared to food, where they are mainly found in complex molecules.
Animal studies also illustrate the importance of micro-sufficiency of certain elements present in water. Thus, according to V.A. Kondratyuk, a slight change in the concentration of microelements in drinking water dramatically affects their content in muscle tissue. These results were obtained in a 6-month experiment in which rats were randomized into 4 groups. The first group was given tap water, the second - low-mineralized water, the third - low-mineralized water with the addition of iodide, cobalt, copper, manganese, molybdenum, zinc and fluoride. The last group received low-mineralized water with the addition of the same elements, but ten times higher concentration. It was found that low-mineralized water affects the process of hematopoiesis. In animals that received demineralized water, the average hemoglobin content in erythrocytes was 19% lower compared to rats that were given tap water. The differences in hemoglobin content were even higher compared to animals receiving mineral water.
Recent epidemiological studies in Russia, conducted among population groups living in areas with varying salinity water, indicate that low-mineralized drinking water can lead to hypertension and coronary heart disease, gastric and duodenal ulcers, chronic gastritis, goiter, and pregnancy complications and a range of complications in newborns and infants, including jaundice, anemia, fractures and growth disorders. However, the researchers note that it remains unclear to them whether it is drinking water that has such an effect on health, or whether it’s all about the general environmental situation in the country.
Answering this question, G.F. Lutai conducted a large cohort epidemiological study in the Ust-Ilimsk district of the Irkutsk region in Russia. The study focused on the morbidity and physical development of 7658 adults, 562 children and 1582 pregnant women and their newborns in two areas supplied with water differing in total salinity. The water in one of these areas had a total salt content of 134 mg/l, of which calcium 18.7 mg/l, magnesium 4.9 mg/l, bicarbonates 86.4 mg/l. In another area, the total mineralization of water was 385 mg/l, of which calcium 29.5 mg/l, magnesium 8.3 mg/l and bicarbonates 243.7 mg/l. The content of sulfates, chlorides, sodium, potassium, copper, zinc, manganese and molybdenum in water was also determined. The population of these two areas did not differ from each other in social and environmental conditions, time of residence in the respective areas, or food habits. Among the population of the area with less mineralized water, higher rates of goiter, hypertension, coronary heart disease, gastric and duodenal ulcers, chronic gastritis, cholecystitis and nephritis were found. Children living in this area showed slower physical development and exhibited growth abnormalities. Pregnant women were more likely to suffer from edema and anemia. Newborns in this area were more susceptible to disease. The lowest incidence was observed in areas with hydrocarbonate water, which has a total mineralization of about 400 mg/l and contains 30-90 mg/l calcium and 17-35 mg/l magnesium. The author came to the conclusion that such water can be considered physiologically optimal.
4. Leaching of nutrients from food prepared in low-mineralized water.
It was found that when softened water is used for cooking, there is a significant loss of micro- and macroelements from food products (meat, vegetables, cereals). Up to 60% of magnesium and calcium, 66% of copper, 70% of manganese, 86% of cobalt are washed out of products. On the other hand, when hard water is used for cooking, the loss of these elements is reduced.
Since most nutrients come from food, using low-mineralized water for cooking and food processing can lead to significant deficiencies in some important micro- and macronutrients. The current menu of most people usually does not contain all the necessary elements in sufficient quantities, and therefore any factor that leads to the loss of essential minerals and nutrients during the cooking process further aggravates the situation.
5. Possible increase in the intake of toxic substances into the body.
Low-mineralized, and especially demineralized water is extremely aggressive and can leach heavy metals and some organic substances from materials with which it comes into contact (pipes, fittings, storage containers). In addition, calcium and magnesium contained in water have to some extent an antitoxic effect. Their absence in drinking water, which also got into your tin mug through copper pipes, can easily lead to heavy metal poisoning.
Among the eight cases of drinking water intoxication reported in the United States in 1993–1994, there were three cases of lead poisoning in infants whose blood levels of lead were found to be 1.5, 3.7, and 4.2 times higher, respectively. In all three cases, lead leached from lead-soldered seams in storage tanks for reverse osmosis drinking water used for baby formula.
It is known that calcium and, to a lesser extent, magnesium have antitoxic activity. They prevent the absorption of heavy metal ions such as lead and cadmium into the blood from the intestine by competing for binding sites. Although this protective effect is limited, it cannot be dismissed. At the same time, other toxic substances can react chemically with calcium ions, forming insoluble compounds and thus losing their toxic effect. Populations in areas supplied with low-salinity water may be at increased risk of toxic poisoning compared to those in areas where regular hard water is used.
6. Possible bacterial contamination of low-mineralized water.
This point in the original article is a little far-fetched, but still. Any water is susceptible to bacterial contamination, which is why pipelines contain a minimum residual concentration of disinfectants - for example, chlorine. It is known that reverse osmosis membranes are capable of removing almost all known bacteria from water. However, reverse osmosis water also needs to be disinfected and a residual concentration of the disinfectant must be kept in it to avoid secondary contamination. A case in point is the outbreak of typhoid fever caused by reverse osmosis treated water in Saudi Arabia in 1992. They decided to abandon the chlorination of reverse osmosis water, because, in theory, it was obviously sterilized by reverse osmosis. The Czech National Institute of Public Health in Prague tested products intended to come into contact with drinking water and found, for example, that the pressure tanks of household reverse osmosis units were susceptible to bacterial growth.
1. According to the 1980 WHO report (Sidorenko, Rakhmanin).Drinking water with low mineralization leads to the leaching of salts from the body. Since side effects, such as disruption of water-salt metabolism, were observed not only in experiments with completely demineralized water, but also when using low-mineralized water with a total salt content in the range from 50 to 75 mg/l, the group of Yu. A. Rakhmanin in their report WHO recommended setting the lower limit for the total mineralization of drinking water at 100 mg/l. The optimal level of salt content of drinking water, according to these recommendations, should be about 200-400 mg/l for chloride-sulfate waters and 250-500 mg/l for hydrocarbonate waters. The recommendations were based on extensive experimental studies conducted on rats, dogs and human volunteers. Moscow tap water was used in the experiments; desalinated water containing approximately 10 mg/l of salts; laboratory prepared water containing 50, 100, 250, 300, 500, 750, 1000 and 1500 mg/l of dissolved salts with the following ionic composition:
- among all anions there are 40% chlorides, 32% bicarbonate anions, 28% sulfates;
- among all cations there is sodium 50%, calcium 38%, magnesium 12%.
In addition to the level of total mineralization, this report justifies the minimum calcium content in drinking water - not lower than 30 mg/l. This requirement was introduced after studying the critical effects resulting from hormonal changes in calcium and phosphorus metabolism and decreased bone mineralization when drinking calcium-depleted water. The report also recommends maintaining bicarbonate anion content at 30 mg/L to maintain acceptable sensory characteristics, reduce corrosivity, and establish an equilibrium concentration for the recommended minimum calcium concentration.
Later research led to the emergence of refined requirements. Thus, one of them studied the effect of drinking water containing different concentrations of hardness salts on the health of women aged 20 to 49 years in four cities of Southern Siberia. Water in city A had the lowest content of these elements (3.0 mg/l calcium and 2.4 mg/l magnesium). The water in city B was harder (18.0 mg/l calcium and 5.0 mg/l magnesium). The highest hardness 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). Women living in cities A and B were more likely to have cardiovascular disease (ECG data), higher blood pressure, somatoform autonomic dysfunction, headache, dizziness and osteoporosis (X-ray absorptiometry) compared with those in cities C and D. These results indicate that the minimum magnesium content in drinking water should be 10 mg/l, and the minimum calcium content can be reduced to 20 mg/l (compared to the 1980 WHO recommendations).
Based on currently available data, various researchers have ultimately come to the following recommendations regarding the optimal hardness of drinking water:
A. magnesium - at least 10 mg/l, optimally about 20-30 mg/l;
b. calcium - at least 20 mg/l, optimally 40-80 mg/l;
V. their sum (total hardness) is 4-8 mEq/l.
At the same time, magnesium is limited from below in its effect on the cardiovascular system, and calcium is limited as a component of bones and teeth. The upper limit of the optimal hardness range was set based on concerns about the possible influence of hard water on the occurrence of urolithiasis.
The effect of hard water on the formation of kidney stones
Under certain conditions, the dissolved substances contained in the urine can crystallize and be deposited on the walls of the renal cups and pelvis, in the bladder, as well as other organs of the urinary system.Based on their chemical composition, there are several types of urinary stones, however, due to the hardness of the water, they are mainly of interest to phosphates and oxalates. If phosphorus-calcium metabolism is impaired or in the case of vitamin D hypervitaminosis, phosphate stones can form. An increased content of oxalic acid salts - oxalates - in food can lead to the appearance of oxalate stones. Both calcium oxalate and calcium phosphate are insoluble in water. By the way, there are a lot of oxalates not only in sorrel, but also in chicory, parsley, and beets. Oxalates are also synthesized by the body.
The effect of water hardness on the formation of urinary stones is difficult to determine. Most studies assessing the effect of water hardness on the occurrence and development of urolithiasis use data from hospital hospitals. In this sense, the study conducted by Schwartz et al. , differs significantly in that all data were collected in an outpatient setting, with patients remaining in their natural environment and going about their normal activities. This work presents the largest cohort of patients to date, allowing us to evaluate the effect of water hardness on various components of urine.
Scientists have processed extensive material. The US Environmental Protection Agency (EPA) has provided geo-referenced information on the chemical composition of drinking water in the United States. This information was combined with a national database of outpatients with urolithiasis (this contains the patient's postcode, so geo-referencing was possible). In this way, 3270 outpatients with calcium stones were identified.
In the minds of most people, increased water hardness is synonymous with an increased risk of developing urolithiasis (kidney stones are a special case of urolithiasis). The content of minerals, and especially calcium, in drinking water appears to be perceived by many people as a health threat.
Despite these common concerns about water hardness, no research supports the idea that drinking hard water increases the risk of developing urinary stones.
Sierakowski et al. studied 2,302 medical records from inpatient hospitals throughout the United States and found that patients who lived in areas with hard water had a lower risk of developing urolithiasis. Similarly, in the cited work it was found that the hardness of drinking water is inversely proportional to the incidence of urolithiasis.
In this study, the incidence of urolithiasis was slightly higher in patients living in areas with softer water, which is consistent with data from other authors, but contrary to public perception. It is known that in some cases, such as those suffering from hypercalciuria, increased oral calcium intake may aggravate the formation of urinary stones. In patients with hyperoxaluric calcium nephrolithiasis, in contrast, increased oral calcium supplementation can successfully inhibit stone formation by binding oxalic acid salts to calcium in the intestine and thus limiting the entry of oxalates into the urinary system. Calcium intake from drinking water may potentially have an inhibitory effect on calcium urinary stone formation in some patients and promote stone formation in others. This theory was tested in a study by Curhan et al., which assessed the effect of calcium intake in 505 patients with recurrent stone formation. After 4 years of observation, the group of patients taking calcium had the least number of episodes of urinary stones. The researchers concluded that high dietary calcium intake reduces the risk of symptomatic urolithiasis.
Despite public concern about the potential lithogenesis of hard tap water, existing scientific evidence suggests that there is no relationship between water hardness and the prevalence of urinary stones. There appears to be a correlation between water hardness and urinary calcium, citrate and magnesium levels, but the significance of this is unknown.
By the way, the author makes an interesting comparison: consuming one glass of milk can be equivalent to two liters of tap water in terms of calcium content. Thus, according to the US Department of Agriculture (USDA), 100 g of milk contains 125 mg of calcium. The same amount of city water contains only about 4-10 mg of calcium.
Conclusion
Drinking water should contain minimum concentrations of certain essential minerals. Unfortunately, too little attention has always been paid to the beneficial properties of drinking water. The main emphasis was on the toxicity of untreated water. The results of recent research aimed at establishing the optimal mineral composition of drinking water should be heard not only by public and private structures responsible for the water supply of entire cities, but also by ordinary people who abuse water treatment systems at home.Drinking water produced by industrial desalination plants is usually remineralized, but reverse osmosis water is usually not mineralized at home. However, even with the mineralization of desalinated waters, their chemical composition may remain unsatisfactory from the point of view of the body's needs. Yes, calcium salts can be added to the water, but it will not contain other essential microelements - fluorine, potassium, iodine. In addition, desalinated water is mineralized more for technical reasons - to reduce its corrosiveness, and the importance of substances dissolved in water for human health is usually not thought about. None of the methods used for remineralizing desalinated water can be considered optimal, since only a very narrow set of salts is added to the water.
The effect of hard water on the formation of kidney stones has not been scientifically proven. There are concerns that increased consumption of oxalic acid salts or phosphates together with calcium may lead to crystallization of insoluble calcium salts of phosphoric or oxalic acids in the organs of the urinary system, but the body of a healthy person, according to existing scientific data, is not subject to such a risk. Persons suffering from kidney disease, hypervitaminosis of vitamin D, disorders of phosphorus-calcium, oxalate, citrate metabolism or consuming significant amounts of oxalic acid salts may be at risk. It has been established, for example, that a healthy body can process up to 50 mg of oxalates per 100 g of food without any consequences, but spinach alone contains 750 mg of oxalates/100 g, so vegetarians may be at risk.
In general, demineralized water is no less harmful than waste water, and in the 21st century it is high time to move away from rationing water quality indicators only from above. Now it is also necessary to establish lower limits for the content of minerals in drinking water. Physiologically, only a narrow corridor of concentrations and composition of drinking water is optimal. The currently available information on this issue can be presented in the form of a table.
Table 1. Optimal mineralization of drinking water
| Element | Units | Minimum content | Optimal level | Maximum level, SanPiN 2.1.4.1074-01 or *WHO recommendation |
|---|---|---|---|---|
| General mineralization | mg/l | 100 | 250-500 for hydrocarbonate waters 200-400 for chloride-sulfate waters |
1000 |
| Calcium | mg/l | 20 | 40-80 | - |
| Magnesium | mg/l | 10 | 20-30 | - Add tags |
The most important parameters of drinking water for health
Mineralization of drinking water
According to the requirements of SanPiN 2.1.4.1074-01, the maximum permissible level of mineralization (dry residue) in drinking water from centralized drinking water supply systems is 1 gram/liter or 1000 parts per million (ppm) to the total amount of solid particles dissolved in water. When the mineralization level exceeds 1000 mg/liter, such water is considered unsuitable for human consumption. A high level of mineralization is an indicator of potential danger and also confirms the need for laboratory testing. In most cases, high levels of mineralization are caused by potassium, hydrochloric acid and sodium salts, the ions of which have little or short-term effect. However, in addition, water may contain toxic heavy metal ions that pose a danger to living organisms.
It is also now known that there is a deficiency of the main ions of potassium, magnesium, sodium, iodine, etc. in water. leads to a number of diseases: hypertension, coronary heart disease, osteochondrosis (even in children 1.5 years of age), osteoporosis (fragile bones), poor posture, decreased intelligence and memory, increased stone formation in the biliary tract and urinary system, destruction tooth enamel, hair loss. Calcium and magnesium ions are essential for the normal development and functioning of the human body. Children, pregnant and lactating women, and the elderly are especially in need of them.
Normal water mineralization is 100-200 mg/liter.
Organic impurities in drinking water
The most dangerous for humans are large organic compounds, which are 90% carcinogens (carcinogens are substances that cause cancer) or mutagens (mutagens are any agents or factors that cause mutation - a persistent hereditary change). Particularly dangerous are organochlorine compounds formed when boiling chlorinated water, because they are strong carcinogens, mutagens and toxins (toxins are substances of bacterial, plant or animal origin that can inhibit physiological functions, leading to disease or death in animals and humans). The remaining 10% of large organic matter is at best neutral in relation to the body. There are only 2-3 large organic compounds dissolved in water that are useful for humans. These are enzymes (enzymes, also known as enzymes, are specific protein catalysts present in all living cells. Enzymes direct and regulate metabolism) required in very small doses.
The water that people use raw and for preparing various dishes must be of high quality and safe for their health. An important place in this is occupied by the mineralization of water - the concentration of mineral substances dissolved in it in the form of ions and colloids.
The composition of water contains a certain amount of various solids, among which there is a small amount of organic salts and a much larger amount of inorganic ones. The latter include salts of chlorides, bicarbonates, sulfates of calcium, sodium, magnesium, potassium and others. Total mineralization of water is the total indicator of all dissolved substances.
Many people believe that salt content and dry residue are identical indicators. However, there is a difference between them. When establishing the dry residue, volatile organic substances are not taken into account. Therefore, the indicators of total mineralization and dry residue differ within 8-12%.
Water classification
The main indicators that are taken into account when classifying mineral waters include, in addition to mineralization, gas and ionic compositions, acidity, temperature and radioactivity.
Mineralization levels
Depending on the level of mineralization, there are the following types of water:
- drinking fresh (less than 1 g/l);
- low-mineralized (1-2 g/l);
- low-mineralized (2-6 g/l);
- medium mineralized (6-16 g/l);
- highly mineralized (16-35 g/l);
- mineral brine (35-155 g/l);
- strong brine (above 155 g/l).
Streams emerging from melting glaciers and river streams forming in equatorial rain forests are characterized by ultra-fresh water.
Hygienic standards
The vast majority of lakes and rivers on planet Earth are freshwater. But surface water bodies in arid and desert regions, as a rule, are characterized by a mineralization of more than 1 ppm (1 ppm equals 0.1%). The seas are characterized by high salinity, and the oceans contain approximately 37% of various salts, a significant part of which is sodium chloride (NaCl).
Thanks to desalination by river water, inland seas are characterized by less salinity. Brine waters are located mainly in the depths of the earth. However, there are salt lakes on the earth's surface, such as the Dead Sea.
In accordance with hygienic standards, water with mineralization up to 1000 mg/l is considered suitable for drinking; in some cases this figure can reach 1400-1550 mg/l. The normal level of mineralization of tap water is up to 1000 mg/l of salts, although most often this figure is in the range of 350-650 mg/l.
Artificial mineralization
Simulated mineralization is carried out to give drinking water a familiar taste. In addition, using this process, the liquid can be artificially saturated with minerals beneficial to the human body. Even if their content is minimal, such water will be much healthier.
Total mineralization is a total quantitative indicator of the content of substances dissolved in water. This parameter is also called the content of soluble solids or total salt content, since the substances dissolved in water are in the form of salts. The most common are inorganic salts (mainly bicarbonates, chlorides and sulfates of calcium, magnesium, potassium and sodium) and small amounts of organic substances soluble in water.
Very often the total mineralization of water is confused with dry residue. The solids are determined by evaporating a liter of water and weighing what is left. As a result, more volatile organic compounds dissolved in water are not taken into account. This leads to the fact that the total mineralization and dry residue may differ by a small amount - as a rule, no more than 10%.
Depending on the mineralization, natural waters can be divided into the following categories:
|
Mineralization g/dm 3 |
|
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Ultra-fresh |
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Waters with relatively high mineralization |
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Salty |
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High salinity waters |
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The level of acceptability of total salinity in water varies greatly depending on local conditions and established habits. Typically, the taste of water is considered good if the total salt content is up to 600 mg/l. At values greater than 1000-1200 mg/l, water may cause complaints from consumers. Therefore, according to organoleptic indications, the WHO recommends an upper limit of water mineralization of 1000 mg/l.
The question of water with low salinity content is also open. It is believed that such water is too fresh and tasteless, although many thousands of people who drink reverse osmosis water, which has a very low salt content, on the contrary, find it more acceptable.
“Water” topics are increasingly heard in the press, and discussions are often made about the advantages or disadvantages of water from the point of view of supplying the body with minerals. Some materials published in reputable publications state quite categorically: “As you know, with water we receive up to 25% of the daily requirement of chemicals.” However, it is not possible to get to the original sources. Let's try to find an answer to the question: “How much minerals can an average person get from drinking water that meets sanitary standards?” In our reasoning we will be guided by simple everyday common sense and high school knowledge. Let's summarize the results in a table. Let us explain the contents of its columns, and at the same time the course of reasoning.
First you need to decide on several starting positions:
1. What minerals and in what quantities does a person need?
The question of the “mineral composition” of a person and, accordingly, the needs of his body is very complex. At the everyday level, we very easily juggle (unfortunately, in the mass press too) with the terms “useful” elements, “harmful” or “toxic” elements, etc. Let's start with the fact that the very formulation of the question of the harmfulness and usefulness of chemical elements is relative. Even in ancient times it was known that it’s all about concentration. What is useful in minimal quantities can be a powerful poison in large quantities. A list of basic (vital) macroelements and several microelements from the Popular Medical Encyclopedia is given in the 1st column.
Data from the Popular Medical Encyclopedia were also used as the daily requirement norms (2nd column). Moreover, the minimum value for an adult man is taken as the base value (for teenagers and women, especially nursing mothers, these norms are often higher).
2. What is the mineral composition of “average” water?
It is clear that there is no “average” water and cannot be. As such, it is proposed to use hypothetical water, that is, “certain” water is accepted as consumed, in which the content of basic macro- and microelements is equal to the maximum permissible from the point of view of health safety - 3rd column of the table.
In the 4th column of the table, it is calculated how much water needs to be consumed in order to reach the daily requirement for each element. The huge assumption here is that in calculations the digestibility of minerals from water is taken as 100%, which is far from true.
3. What is the daily water consumption of the average person?
A person consumes an average of 1.2 liters of water per day directly in the form of liquid (drink and liquid food). By dividing this figure by the corresponding one from the 4th column, the percentage of intake of each element with water is calculated, which theoretically (taking into account all the above assumptions) can be received per day by the average person (5th column).
For comparison, the 6th column provides a mini-list of food sources of the same elements entering the body. A list of several products is used to illustrate the fact that the body receives one or another macro- or microelement not from one product, but, as a rule, a little from different ones.
The 7th column shows the amount of a particular product in grams, the consumption of which will give the body per day (with the same assumption of 100% digestibility as for water) the same amount of the corresponding macro- or microelement as hypothetical drinking water.
|
Element |
Daily requirement |
MPC in water |
Required amount of water to obtain 100% of the norm |
Theoretically possible % of min. Substances from water |
Alternative |
Quantity of product that provides macro- and microelements equal to that supplied with water |
|
Hard cheese |
12 g |
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|
Phosphorus (phosphates) |
Mushrooms (dried) |
24 g |
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|
Watermelon |
27 g |
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|
Dried apricots |
0.86 g |
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|
Table salt |
0.6 g |
|||||
|
Chlorine (chlorides) |
Table salt |
0.5 g |
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|
Beef liver |
42 g |
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|
White mushroom sushi. |
1.1 g |
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|
Mackerel |
129 g |
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|
Beef liver |
32 g |
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|
Sea kale |
9 g |
From the data obtained it is clearly seen that we can theoretically obtain only 2 microelements - fluorine and iodine - from drinking water in sufficient quantities.
Of course, the data provided can in no way serve as nutritional recommendations. The whole science of dietetics deals with this. This table is intended only to illustrate the fact that it is much easier and, most importantly, more realistic to obtain all the macro- and microelements necessary for the body from food than from water.
Removing mineral salts from water
The process used to remove all minerals from water is called demineralization.
Demineralization carried out using ion exchange is called deionization. During this process, water is treated in two layers of ion exchange material to more effectively remove all dissolved salts. A cation exchange resin “charged” with hydrogen ions H + and an anion exchange resin “charged” with hydroxyl ions OH - are used simultaneously or sequentially. Since all salts soluble in water consist of cations and anions, a mixture of cation-exchange and anion-exchange resins completely replaces them in the purified water with hydrogen ions H + and hydroxyl OH -. Then, through a chemical reaction, these ions (positive and negative) combine to create water molecules. In fact, complete desalination of water occurs.
Deionized water has a wide range of industrial uses. It is used in the chemical and pharmaceutical industries, in the production of television cathode ray tubes, in industrial leather processing and in many other cases.
Distillation is based on the evaporation of the water being treated, followed by the concentration of steam. The technology is very energy-intensive; in addition, during the operation of the distiller, scale forms on the walls of the evaporator.
Electrodialysis is based on the ability of ions to move in a volume of water under the influence of an electric field. Ion-selective membranes allow either cations or anions to pass through. In the volume limited by ion-exchange membranes, the salt concentration decreases.
Reverse osmosis is a very important process that is part of highly professional water purification. Reverse osmosis was originally proposed for desalination of seawater. Together with filtration and ion exchange, reverse osmosis significantly expands the possibilities of water purification.
Its principle is extremely simple - water is forced through a semi-permeable thin-film membrane. Through the smallest pores, which have dimensions comparable to the size of a water molecule, only water molecules and low-molecular gases - oxygen, carbon dioxide - are able to leak under pressure, and all impurities remaining on the other side of the membrane are drained.
In terms of cleaning efficiency, membrane systems have no equal: it reaches almost 97-99.9% for any type of contaminant. The result is water that, in all its characteristics, resembles distilled or highly demineralized water.
Deep cleaning of the membrane can only be done with water that has undergone preliminary comprehensive cleaning. Removal of sand, rust and other insoluble suspended matter is carried out by a mechanical cartridge with cells up to 5 microns. A cartridge based on high-quality granulated coconut carbon absorbs compounds of iron, aluminum, heavy and radioactive metals, free chlorine and microorganisms dissolved in water. The last stage of the preliminary stage is very important, where the final purification from the smallest doses of chlorine and organochlorine compounds, which have a destructive effect on the membrane material, occurs. It is produced in a cartridge from pressed coconut charcoal.
After comprehensive pre-treatment, the water is supplied to a membrane, after which drinking water of the highest purity class is obtained. And in order to remove dissolved gases from it, which give an unpleasant odor and taste, the water at the final stage is passed through high-quality pressed activated carbon with the addition of silver. The fact that the water after purification in the membrane system is almost completely free of mineral salts has been causing lively discussions for many years. Although it is much more efficient to obtain the amount of macro- and microelements necessary for the body through food (see above), many are so accustomed to the taste that mineral salts give water that in their absence the water seems tasteless and “lifeless.” However, it turns out to be so difficult and expensive to completely remove harmful impurities while maintaining minerals in useful concentrations that usually the water is first purified as much as possible, and then additives are added if necessary.
Home reverse osmosis installations are usually equipped with storage tanks for purified water, since the rate of water filtration through the membrane is low. The storage tank, usually with a total capacity of 12 liters, is a hydraulic accumulator divided inside by an elastic silicone partition. On one side, the partition is in contact with purified water, and on the other, air is pumped under a pressure of 0.5 atm. Such a tank is capable of storing no more than 6-8 liters of purified water. This usually takes from 2 to 6 hours. To ensure the operability of the system when the pressure in the line is insufficient (less than 2.5 - 2.8 atm), a booster pump is installed.
It should be noted that if the source water is very hard and contains an excessive amount of mechanical or dissolved impurities, then before the reverse osmosis system it is recommended to install additional water treatment systems (iron remover, softener, disinfection systems, mechanical cleaning, etc.).
Theoretically, membranes remove almost all microorganisms known to us, including viruses, however, when used in domestic drinking water systems, membranes cannot provide complete protection against microorganisms. Potential gasket leaks and manufacturing defects may allow some microorganisms to enter the treated water. This is why small home reverse osmosis systems should not be used as the primary means of eliminating biological contamination.
It is very important to understand that the reverse osmosis process occurs only when the water pressure in the system is at least 2.5-2.8 atm. The fact is that on the semi-permeable membrane on the side of purified (desalted) water there is always excess osmotic pressure, which interferes with the filtration process. It is this pressure that must be overcome.
IRON (Fe)
Typically, iron is present in natural waters in various forms:
1. divalent iron ions, soluble in water (Fe 2+);
2. trivalent iron ions, soluble only in very acidic water (Fe 3+);
3. insoluble ferric hydroxide;
4. ferric oxide (Fe 2 O 3), present in the form of rust particles from pipes;
5. in combination with organic compounds or iron bacteria. Iron bacteria often live in water containing iron. As these bacteria multiply, they can form red-brown growths that can clog pipes and reduce water pressure. The decaying mass of these iron bacteria can cause water to smell, taste, and stain.
Iron is rarely found in terrestrial bodies of water. When it reaches the surface, water containing dissolved iron is usually clear and colorless, with a strong iron taste. Under the influence of air, the water acquires a kind of milky haze, which soon turns red (a precipitate of iron hydroxide appears). This water leaves marks on almost everything. Even with an iron content of 0.3 mg/l in water, it leaves rusty stains on any surface.
The presence of iron in water is extremely undesirable. Excess iron accumulates in the human body and destroys the liver, immune system, and increases the risk of heart attack.
A satisfactory method of removing small amounts of dissolved iron from water is the use of ion exchange softeners. It is impossible to immediately say how much iron can be removed. The answer to this question in each individual case depends on the design of the device, as well as on other specific conditions. Iron, present in water in undissolved form, is not removed by softeners; moreover, it spoils them. Therefore, in the case of using softeners to remove dissolved iron, for example, from a well, in no case should the well water be allowed to come into contact with air.
The most effective way to remove moderate concentrations of iron may be to use oxidizing filters. Such a filter should be installed on the water pipe in front of the water softener. Oxidizing filters typically contain a filter media coated with manganese dioxide (MnO2). This may be manganese-treated glauconitic sand, synthetic manganese material, natural manganese ore and other similar materials. Manganese oxide converts soluble ferrous ions found in water into ferric iron. In addition, manganese compounds are a powerful catalyst for the oxidation of ferrous iron with oxygen dissolved in water. Since there is very little oxygen in underground water, for a more efficient oxidation process, the water in front of the deferrization filter is saturated with oxygen (air). As insoluble ferric hydroxide forms, it is filtered out of the water by the granular material contained in the filter.
In the case of high iron concentrations, small pumps, ejectors and other devices can be used to add chemical oxidizers, such as sodium hypochlorite (household bleach "Belizna") or potassium permanganate solution, to the water. Just like manganese dioxide in iron filters, these chemical oxidizers convert dissolved ferrous iron into insoluble ferric iron.
MANGANESE (Mn)
Manganese is usually found in iron-containing water. Chemically, it can be considered related to iron, because. it is found in the same compounds. Manganese is most often present in water in the form of bicarbonate or hydroxide, much less often it is found in the form of manganese sulfate. When manganese comes into contact with anything, it leaves dark brown or black marks, even at minimal concentrations in water. Manganese sediment appears during plumbing and plumbing work, as a result of which the water often leaves a black sediment and becomes cloudy. Excess manganese is dangerous: its accumulation in the body can lead to a serious disease - Parkinson's disease.
To solve the problem of manganese removal, the same methods are suitable as for iron.
Reverse osmosis is a method that can be used to reduce the concentration of fluoride in water at home.
SODIUM (Na)
Sodium salts are present in all natural water. They do not form scale when boiled, nor a cheesy sediment when mixed with soap. Their high concentrations increase the corrosive effect of water and can give it an unpleasant taste. Large amounts of sodium ions interfere with the operation of ion exchange water softeners. Where the water is very hard and contains a lot of sodium, softened water can retain many ions that cause hardness.
An effective method for removing sodium from water at home is reverse osmosis.
NITRATES (NO 3 -)
Typically, the soil contains small amounts of natural nitrates. The presence of nitrates in water indicates that it is contaminated with organic substances. Basically, water contaminated with nitrates is found in shallow wells and wells, but sometimes such water occurs in deep wells. Even such a low concentration of nitrates, such as 10-20 mg/l, can cause serious illness in children, and cases of death are known.
Nitrates can be removed from water using reverse osmosis.
CHLORIDES AND SULPHATES (Cl - , SO4 2-)
Almost all natural water contains chloride and sulfate ions. Low to moderate concentrations of these ions give water a pleasant taste and their presence is desirable. Excessive concentrations can make the water unpleasant to drink. Both chlorides and sulfates contribute to the total mineral content of water. The total concentration of these substances can have a variety of effects - from giving water increased hardness to electrochemical corrosion. Water containing more than 250 mg/l of sulfates acquires a pronounced “medicinal taste”. In excess concentrations, sulfates can also act as a laxative.
Water can be purified from chlorides and sulfates using reverse osmosis.
HYDROGEN Sulfide (H 2 S)
Hydrogen sulfide is a gas that is sometimes found in water. The presence of this gas can be easily determined by the disgusting smell of “rotten eggs”, which appears even at low concentrations (0.5 mg/l).
There are several ways to remove hydrogen sulfide from water. Most of them come down to oxidation and conversion of gas into pure sulfur. Then, this insoluble yellow powder is removed by filtration. An activated carbon filter is sufficient to remove very low concentrations of hydrogen sulfide. In this case, the coal simply adsorbs gas onto its surface.
PHENOL (C 6 H 5 OH)
One of the most dangerous types of industrial waste is phenol. In chlorinated water, phenol enters into chemical reactions with chlorine and creates chlorophenol compounds that have an unpleasant “medicinal” taste and odor. In this case, an unpleasant odor appears at phenol concentrations equal to one part per billion. Phenol and chlorophenolic compounds are removed by passing water through activated carbon.
It has been established that the main radiation background on our planet (at least for now) is created by natural sources of radiation. According to scientists, the share of natural sources of radiation in the total dose accumulated by the average person throughout his life is 87%. The remaining 13% comes from human-made sources. Of these, 11.5% (or almost 88.5% of the “artificial” component of the radiation dose) is formed through the use of radioisotopes in medical practice. And only the remaining 1.5% are the result of the consequences of nuclear explosions, emissions from nuclear power plants, leaks from nuclear waste storage facilities, etc.
Among natural sources of radiation, radon confidently holds the palm, causing up to 32% of the total radiation dose.
Radon is a radioactive natural gas, absolutely transparent, tasteless, odorless, and much heavier than air. It is formed in the bowels of the Earth as a result of the decay of uranium, which, although in small quantities, is part of almost all types of soils and rocks. The uranium content is especially high (up to 2 mg/l) in granite rocks.
Accordingly, in areas where granite is the predominant rock-forming element, one can expect increased radon content. It is not detected by standard methods. If there is a reasonable suspicion of the presence of radon, it is necessary to use special equipment for measurements. Radon gradually seeps from the depths to the surface, where it immediately dissipates in the air, as a result of which its concentration remains negligible and does not pose a danger. Problems arise when there is not enough air exchange, for example in houses and other premises. In this case, the radon content in a closed room can reach dangerous concentrations. Radon enters the human body through breathing and can cause harmful health effects. According to the US Public Health Service, radon is the second leading cause of lung cancer in people after smoking.
Radon dissolves very well in water, and when groundwater comes into contact with radon, it becomes saturated with it very quickly. When wells are used to supply a house with water, radon enters the house with water. Radon dissolved in water acts in two ways. On the one hand, it enters the digestive system along with water. On the other hand, when water flows from a faucet, radon is released and can accumulate in significant quantities in kitchens and bathrooms. The concentration of radon in a kitchen or bathroom can be 30-40 times higher than in other rooms, such as living rooms. Inhalation exposure to radon is considered more dangerous to health.
A measure of radioactivity is the activity of the radionuclide in the source. Activity is equal to the ratio of the number of spontaneous nuclear transformations in this source over a short time interval to the value of this interval. In the SI system it is measured in Becquerels (Bq, Bq), which corresponds to 1 decay per second. The activity content of a substance is often assessed per unit weight of the substance (Bq/kg) or its volume (Bq/l, Bq/cubic m).
In Novosibirsk, the level of radon in well water ranges from 10 to 100 Bq/l, in some areas (Nizhnyaya Eltsovka, Akademgorodok, etc.) reaching several hundred Bq/l. In the Russian Radiation Safety Standards (NRB-99), the maximum level of radon content in water at which intervention is required is set at 60 Bq/l (American standards are much stricter - 11 Bq/l).
One of the most effective methods of combating radon is water aeration (the “bubbling” of water with air bubbles, in which almost all the radon literally “flies to the wind”). Therefore, those who use municipal water have practically nothing to worry about, since aeration is part of the standard water treatment procedure at city water treatment plants. As for individual users of well water, studies conducted in the USA have shown the fairly high efficiency of activated carbon. A filter based on high-quality activated carbon is capable of removing up to 99.7% of radon. However, over time this figure drops to 79%. Using a softener in front of the carbon filter allows you to increase the latter figure to 85%.
information taken from the site http://aquafreshsystems.ru/index.htm
