Ecological threats

Pollution is the introduction of contaminants into an environment. Pollution can take the form of chemical substances, or energy, such as noise, heat, or light energy.
The major forms of pollution are:
1) Air pollution
Worldwide air pollution is responsible for large numbers of deaths and cases of respiratory diseases such as diseases of the lungs, bronchial tubes, trachea, upper respiratory tract and of the nerves and muscles of breathing. Gases such as carbon dioxide and methane contribute to global warming, sulphur contributes to acid rain and some gases to stratospheric ozone depletion whose has long been recognized as a threat to human health and to the earth's ecosystems. It causes skin and brain cancer, meningitis and sunburn.
2) Water pollution is the contamination of water bodies such as lakes, rivers, oceans, and groundwater, which can be harmful to organisms and plants which live in these water bodies. They are grouped into two categories:
a) Point-source pollution refers to contaminants that enter a waterway through a discrete "point source", like savage from a factories and leaking underground tanks.
b) Non-point source pollution is often a cumulative effect of small amounts of contaminants gathered from a large area - vehicular traffic and fields.
Water pollution is a major problem in the global context. It is the leading worldwide cause of deaths and diseases and it causes more than 14,000 people daily.
3) Soil contamination is caused by the presence of man-made chemicals in the natural soil environment. This type of contamination typically arises from application of pesticides and oil dumping. The major concern is that there are many sensitive land uses where people are in direct contact with soils such as parks, schools and playgrounds. Other contact mechanisms include contamination of drinking water or eating vegetables and fruits growing on contaminated soil. Lead causes developmental damage to the brain and kidney damage.
4) Radioactive contamination, resulting from 20th century activities in atomic physics, such as nuclear power generation and nuclear weapons research, manufacture and deployment.
5) Global warming impacts on aquatic organisms - decreases oxygen supply, kills fish juveniles and affects ecosystem composition. Global warming causes floods, extends the zones for vectors conveying infectious disease such as malaria and Arctic shrinkage. Scientists say the melt of the most of Earth's 160,000 glaciers has accelerated dramatically since the 1995, which was the hottest decade in a thousand years. The World Health Organization estimates 150,000 deaths annually "as a result of climate change. As a result of increased temperatures, malaria is appearing in the highland areas of Papua New Guinea, where it has always been too cold for disease-spreading mosquitoes. The world's worst polluted countries are Azerbaijan, China, India, Peru, Russia, Ukraine and Zambia.
8) Acid rain is rain that is unusually acidic. It has harmful effects on the environment. Acid rain is mostly caused by emissions of sulfur and nitrogen which react in the atmosphere to produce acids. Acid rain was first found in Manchester. Sulfur dioxide comes from electricity generation, factories and motor vehicles. Some scientists have suggested direct links to cause illness and premature deaths such as cancer and other deadly diseases. To prevent us from acid rains factories should use desulfurisators.