Hygienic evaluation of different water supply sources

As water sources can be used precipitation, surface waters and groundwater of different depth.
Precipitation composition close to that of distilled water. When passing in the atmosphere, especially over the settlements, they may be contaminated with dust, gases, various microorganisms. Because of its contamination, poor taste, lack of essential micronutrients atmospheric water unsuitable for drinking and is used for a short time in the absence of other sources of water supply.
In contact with soil meteoric water dissolve in organic and inorganic substances, enriched by microorganisms become cloudy. Part meteoric water is filtered through the soil pores, while it gradually released from suspended particles, bacteria, humic compounds, enriched with mineral salts (and therefore increases the rigidity), rare elements (elements); the amount of oxygen in it is reduced and the amount of carbon dioxide increases.
The movement of water in the soil depends on the structure of the rocks through which it flows. With respect to water breeds are divided into permeable sand, gravel, fractured limestone and waterproof clay, solid granite, limestone. These alternate layers in the earth's crust.
Underground water accumulating in filtering on the ground from the ground surface waterproof layer is called ground, or non-pressure.
The flow of ground waters is usually moves in the direction of the slope waterproof layer. The slope direction you need to know to determine where you are coming from pollution.
The result is a simple filtration through the soil cover structure of ground water reflects the composition of the soil, so the massive pollution of soil settlement and the closer to the surface are ground water, the more real the risk of pollution and contamination.
Water in the aquifer, lying between the two waterproof layers are called cross. When tilted cross horizons become the pressure and the water in the wells that uses this horizon, rises above the upper waterproof horizon. Such water is called artesian (Fig. 13).

the scheme of groundwater
Fig. 13. The scheme of groundwater;
K1 - the downward spring; K2 - upward spring; G - the well's on groundwater; - the well's on the "bleak"; And - flowing well on the cross water; M - nezavisiamaia well (well) to cross the water.

Artesian water are transparency, absence of suspended particles, low temperature. Their chemical composition depends on the rocks which they move. These waters are usually characterised by high rigidity, low bacterial colonization, an almost complete absence of oxygen. Physical-chemical composition of artesian water of particular aquifer very permanent, and changing it is a sign of health problems. Typically, this is pure water. In practice, however, one cannot completely exclude the risk of contamination of the deep aquifers. Pollution can occur through cracks in the earth's rocks, abandoned mines, etc. So when using such sources systematic obligatory laboratory control.
Part atmospheric water flows over the land surface to the water reservoirs (rivers, lakes, reservoirs, and so on).
The river water is a mixture of atmospheric and ground water. Its physical, chemical and bacteriological properties depend largely on the health of the river and situated on the banks of settlements and the industrial enterprises. The river, which is mainly soil nutrition, cleaner than the rivers that feed mainly due to surface runoff. In the latter case, the quality of river water will depend on the availability of human settlements and their improvement, the season of the year. So, in the winter under ice river lose surface power and water becomes somewhat clearer in bacterial respect, and in the spring and autumn period in the flow of atmospheric waters, sanitary condition of the rivers is deteriorating.
The peculiarities of changes in the composition of the rivers also depend on the nature channel, current velocity, an abundance of water. For example, the yellow color of the Dnieper, Kama suggests that these rivers start in the swamps and carry out humic substances. If the river-bed of clay, then washed out over the clay suspension makes the water cloudy (Syr-Darya river in flood contains up to 6500 mg/l suspended solids).
Thus, as a result of natural conditions, an external influence of physico-chemical composition and the presence of bacteria in river water vary widely. Polluted water is gradually cleared the result of self-purification, because of the dilution of effluent settling to the bottom of the river suspended particles, decomposition of organic matter under the influence of oxygen, water bacteria, antibacterial action of solar beams. However, it rarely reaches its initial purity.