Māris kļaviņŠ, azamat azizov, JĀnis zaļoksnis environment, pollution, development: the case of uzbekistan

India
USA
Lithuania
5%
92%
3%
Domestic
Agriculture
Industry
8%
27%
65%
3%
82%
15%
Although the Baltic States and Latvia in particular are among 
the best provided with underground water resources in the world, 
nevertheless, also in these countries the conservation and efficient 
use of the water resources is just as important as in the rest of the 
world. 
 8.2. 
 Natural water composition and conditions 
of formation 
The formation of the natural water sources is complex and it 
is influenced by a number of factors, among which the conditions 
of physical geography and geology are of particular importance 
(such as the relief, climate, rock formation and weathering, soil 
cover, vegetation). The composition of water also depends on the 
environ ment, in which it is located; it is different in seas and oceans, 
rain, underground and on the surface. It should be noted that the 
water composition and properties vary depending on the external 
conditions and that the natural variability of the water content is 
due to the ability of the substances forming the litho sphere and 
atmo sphere to dissolve in water. Today the composition of water can 
be very significantly influenced by the human economic activities.
Figure 8.4. 
The use 
of water resources 
depending on the 
national economy – 
the U.S.A, India and 
Lithuania

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166 
ENVIRONMENT, POLLUTION, DEVELOPMENT:  THE CASE OF UZBEKISTAN
Site-specific relief indirectly affects the water composition. The 
relief  primarily  affects  water  change  regime  –  surface  and  under-
ground runoff, distribution of precipitation. The relief of the place 
also affects the migration of salts in the soils, their bogging trends, 
which in turn affect the water content. The climate influences the 
water composition by weather conditions, and the main factors here 
are the amount of precipitation, temperature and water evaporation 
regime. Since the mineralization of atmo spheric precipitation is 
lower than the surface water mineralization, great amounts of pre-
ci pi tation may decrease it. On the other hand, as a result of the 
cross-border transfer of air masses, particularly in modern times, the 
substances in air masses can affect the composition of precipitation. 
The development of ‘acid rain’ takes place in this manner, and 
this type of process is largely responsible for the environ mental 
contamination with persistent pollutants – mercury, organo-chlorine 
substances.
Another  set  of  factors  affecting  the  chemical  composition  of 
water is related to the solubility changes of various salts due to 
tem perature changes and other processes which determine the 
amount and form of dissolved substances. The regional climate 
significantly influences such a factor of water composition formation 
as evaporation. Rock weathering also has an important role in the 
formation process of water content.
Minerals and rocks are formed and disintegrated (weathered) 
as a result of exposure to physical (mechanical), chemical and bio-
logical factors. The rock weathering is determined by the fact that 
the minerals formed in high-temperature and pressure conditions, 
can be unstable in contact with water, especially if it is saturated 
with carbon dioxide and oxygen. Chemical weathering of rocks is 
caused by the impact of natural waters and carbon dioxide gas, 
salts and organic substances dissolved therein. This reaction is 
based on the oxidation or reduction, which occurs with mineral-
bound substances, their hydrolysis, dissolution, ion hydration 
and transformation in such particles, which are found in natural 
waters. Chemical weathering predominantly takes place with active