The quality of life depends on the quality of water, because a person himself is two-thirds water. In various tissues of the human body, it contains from 22% to 99%. What is hard water, and what problem can it pose to humans?
Water hardness is determined by the content of calcium and magnesium salts in it. These substances, in turn, are found in calcareous rocks. Accordingly, in those areas where limestone, calcareous rocks and soils are abundant, water is of increased hardness. Therefore, in the regions of the Volga region, the North Caucasus, the water of increased hardness, in the Leningrad region, where the soils do not contain limestone, is soft. Passing through the soil, water washes away calcium and magnesium salts, and in this form enters the water supply system. When the content of hardness salts (calcium and magnesium) is less than 2 milligrams per liter, the water is considered soft, from 2 to 4 milligrams per liter - normal hardness and suitable for cooking and drinking, from 4 to 6 milligrams - hard, and above that - very hard … Distinctive properties of such water: it is salty and pleasant to the taste, detergents dissolve poorly in it, but the most unpleasant thing is that it contributes to the formation of stones in the kidneys and pancreas. Since detergents contain alkali, when they interact with hard water salts during washing, a precipitate is formed that covers the surface of plumbing fixtures and dishes with a film. The film does not wash off the surface of the skin during washing, clogs its pores and causes irritation and itching. When heated in hard water, crystals of hardness salts are formed, which are deposited on the walls of the kettle, on the surface of the heating element of the washing machine. In regions where the water is of increased hardness, there is a high percentage of urolithiasis and the formation of stones in the pancreas. Household water softening methods are boiling (for food water) and adding soda ash (for washing). When boiled, calcium bicarbonate decomposes into carbon dioxide and calcium carbonate, which precipitates. After boiling, the water is defended and filtered. To soften the wash water, add two teaspoons of baking soda to a bucket of water, stir, wait for the sediment to settle and drain, leaving sediment at the bottom. Industrial methods of water softening are: reagent (similar to household, reduced to the addition of alkalis), ion-exchange (using resins, the ions of which are replaced by ions of water hardness).
