PROBLEM OF SOIL POLLUTION AND DEGRADATION 
M. R. Spanova, G. A. Tussupbekova,
al-Farabi Kazakh National University, 
Almaty, Republic of Kazakhstan

The soil cover is a native habitat of people and forms a basis for creation of recreational zones. The cover allows to create an optimum ecological situation for life, work and rest of people. Purity and structure of the atmosphere, land and underground waters depend on character of a soil cover, the properties of the soil proceeding in soils of chemical and biochemical processes. Soil cover is one of the most powerful regulators of a chemical composition of the atmosphere and hydrosphere. The soil was and remains the main condition of life support of the nations and mankind in general [1].

A certain part of soils around the world go out of the agricultural circulation due to various reasons every year. Thousand and more than hectares of the earth suffer from a deflation, water erosion, acid rains, the wrong processing and toxic waste. The soil cover is the major natural formation. Its value for life of society is defined by that the soil is the main source of the food providing 97-98% of food resources of the population of the planet. At the same time, the soil cover is a place of activity of the person on which industrial and agricultural production is placed.
The most important property of a soil cover its fertility which is understood as set of the properties of the soil providing production of crops. Natural fertility of the soil is regulated by a reserve of nutrients in the soil and its water, air and thermal modes. The role of a soil cover in efficiency of land ecological systems is great as the soil feeds overland plants with water and many compositions and is the most important component of photosynthetic activity of plants. Fertility of the soil also depends on the size of solar energy accumulated in it. The live organisms, plants and animals occupying Earth fix solar energy in the form of phyto - or zoomasses. Efficiency of land ecological systems depends on thermal and water balance of a terrestrial surface by which the variety of forms of an exchange of a material and substance within a geographical envelope of the planet is defined.
The wide use of lands which especially increased during a scientific and technological revolution era led to increase in spread of water and wind erosion (deflation). Under their influence there is a carrying out (water or a wind) of soil units from the top, most valuable layer of earth which leads to decrease in its fertility. Water and wind erosion, causing exhaustion of soil resources, are a dangerous ecological factor. The total area of the lands subject to a water and wind erosion is measured by many millions of hectares.
Industrial pollution of the soil. The term "acid rains" calls all types of meteorological rainfall - a rain, snow, a hail, fog, sleet, - рН of which is less, than average рН value of rain water (average рН for rain water equals 5,6). The dioxide of sulfur and oxides of nitrogen which are emitted in the course of human activity are transformed in the atmosphere of the earth to acid-forming particles. These particles react with atmosphere water, turning it into solutions of acids which lower рН of rain water.
The term “heavy metals” characterizing wide group of the polluting substances gained considerable distribution recently. As criteria of belonging numerous characteristics are used: the atomic mass, density, toxicity, prevalence in environment, degree of an involvement into natural and technogenic cycles. In the works devoted to problems of pollution of surrounding environment and environmental monitoring today more than 40 metals of periodic system of D. I. Mendeleyev with atomic mass over 50 nuclear units are referred to heavy metals: V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Cd, Sn, Hg, Pb, Bi, etc. Thus the important role in categorization of heavy metals is played by the following conditions: their high toxicity for live organisms in compareable low concentration, and also ability to bio-accumulation and a biomagnification. On N. Reymers's classification, it is necessary to consider as heavy metals with a density more than 8 g/cm3.
Many metals form quite strong complexes with organic chemistry; these complexes are one of the most important forms of migration of elements in soils and natural waters. The majority of organic complexes are formed on chelate cycle and are steady. The complexes formed by soil acids with salts of iron, aluminum, the titan, uranium, vanadium, copper, molybdenum and other heavy metals, rather well soluble in the conditions of neutral, subacidic and alkalescent environments. Therefore metal-organic complexes are capable to migrate in natural waters on very considerable distances.
The biological interrelation between the soil and the person is carried out mainly by a metabolism. The soil is as the supplier of the mineral substances necessary for a metabolism cycle, for growth of the plants consumed by the person and herbivores eaten in turn by the person and carnivores. Thus, the soil provides with food many representatives of a plant and animal world. Therefore, deterioration of the soil, decrease of its biological value, ability to self-cleaning causes biological chain reaction which in case of long harmful effects can lead to the most various frustration of health at the population. Moreover, in case of delay of processes of a mineralization the nitrates which are formed at disintegration of substances, nitrogen, phosphorus, potassium etc. can get to the underground waters used for drinking needs and be the reason of serious diseases.
Now researchers are directed on identification of the factors providing biological balance of the natural soil and also on clarification of a question, what amount of solid waste (and what their structure) can lead to violation of biological balance of the soil. It should be noted that the hygienic condition of the soil in the cities as a result of its overload quickly worsens though ability of the soil to self-cleaning is the main hygienic requirement for preservation of biological balance. The soil in the cities isn't able to cope without the aid of the person with the task any more. The only way out of the created situation - full neutralization and destruction of waste according to hygienic requirements. Therefore activities for construction of municipal buildings have to be directed on preservation of natural ability of the soil to self-cleaning and if this its ability became already unsatisfactory, it is necessary to restore it in the artificial way. The most adverse is toxic action of industrial wastes - both liquid, and firm. An increasing number of such waste with which it isn't able to cope gets to the soil. So, for example, pollution of the soil by arsenic in vicinities of plants on production of superphosphates is established (in a radius 3km). It is known that some pesticides, such as the chlor-organic compounds which got to the soil it is long aren't exposed to disintegration [2]. Some synthetic packing materials (polyvinylchloride, polyethylene etc.) acts in a similar way. Some toxic compounds sooner or later get to underground waters, as a result not only biological balance of the soil is broken, but also quality of underground waters worsens to such an extent that they can't already be used as the drinking.
Literature
1. Dobrovolsky  G. V. "Soil. City. Ecology", Moscow, 1997.
2. Butovsky R.O. Degradation of the soil: current state of a problem. - es .scribd.com]