|Pollution usually refers to contamination of land, air or water. Pollution refers to any direct or indirect alteration of the environment, that creates a hazard or potential hazard to any living creature. A pollutant can be any gas, liquid, solid contaminating a liquid, solid or gas.
We tend to refer to pollutants as lead in water, pesticides in food, or chemicals in workplaces. Pollutants do not necessarily cause damage, but they have the potential to do so. eg DDT insecticide residues were found in birds of prey in the 1960s, where they caused "thin eggs" leading to dramatic decline in bird numbers. There is now a second generation rat poisons that are being found in birds of prey, but there is no evidence of them causing damage. But they have the potential to do so Quick quiz on rat poison pollution. .
Pollution usually implies contamination by a foreign substance. The increased concentration by carbon dioxide in the atmosphere is not usually considered pollution, as its presence is not foreign to the atmosphere. It is merely its build up that is damaging, as explained in Unit 8 Carbon
The main pollution of airs come from power stations in the form of sulphur dioxide and soot. This leads to acid rain formation, once a major concern in this country leading it to be called "the dirty man of Europe" because it made acid rain that landed on the rest of Europe. More
The main concerns of freshwater pollution are fertilsers causing eutrophication. More
Land can be contaminated with a wide range of prestistant chemicals More
Pollutants are categorised according to their persistance and damge potential. (EU classification). Probably the worst pollutant is asbestos, responsible for about 3000 deaths each year in UK - due mesothelioma cancer alone.
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