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Occupational exposure limits are the maximum allowable concentrations of hazardous elements in the air. They are defined by scientific laboratories in order to control the level of pollution in different areas. Among the main atmosphere pollutants are large-scale industry, domestic boilers and transport. The portion of each of these pollutants is different from place to place, but industrial companies are considered to be the worst pollutants. The major sources of artificial aerosol pollution of the atmosphere are thermal power plants that burn a large amount of coal with high ash content, concentrating mills, metallurgical, cement, magnesite and soot plants. |
Sewage water
Industrial sewage water is among the major sources of pollution by its scale and the harm it does to the nature, that's why the problem of its drainage into water reservoirs must be solved as soon as possible. Pollution caused by sewage waters causes various biogenetic mutations. Hundreds of invaluable species of fish are disappearing in rivers and lakes, and the ones that remain are not eatable any more. The flora and fauna of water reservoirs grows scanty. Due to industrial wastewater drainage the water has excess oxygen, that's why we can often see such a phenomenon as the green scum. Many of us have probably seen the oil film on the surface of water with different colors playing in the sun. But in reality this film prevents light from penetrating into the water. The chemical composition of the water changes, the content of nitrogen, phosphor and chloride-bearing wastes increases.
The pollution of water with agricultural wastes is also a serious problem. Sometimes the water we drink can have a strange smell in the spring. This smell is caused by the fact that rapid water flows in this time of year wash down the fecal masses lying on the fields. Then these masses get into rivers and lakes and after that due to insufficient filtering can retain the unpleasant smell.
The third serious problem, especially in developing countries, is the amount of domestic and industrial waste getting into water bodies.
