Pollution

Pollution is when various contaminants are introduced into a natural environment that causes instability, disorder, harm or discomfort to an ecosystem.

Pollution can take a number of forms including:

• Air pollution - comes from both natural and man-made sources. Motor vehicle emissions are one of the leading causes, but other principal pollution sources include chemical plants, coal-fired power plants, oil refineries, petrochemical plants, nuclear waste disposal activity, incinerators, large livestock farms, PVC factories, metal production factories, plastic factories and other heavy industry.

• Odour pollution - related to air pollution and although not necessarily harmful, is environmentally most unpleasant. Sources can include industrial processes and landfill sites.

• Soil pollution - when chemicals or other substances are released into the ground deliberately, accidentally or by underground leakage. These can include hydrocarbons, herbicides, pesticides, chlorinated hydrocarbons and heavy metals such as chromium and cadmium from batteries.

• Thermal pollution - temperature change to natural water by, for instance, the addition of water used in the cooling of power plants.

• Noise pollution - chiefly associated with transport and heavy industry. This will include roadway noise, aircraft noise, industrial noise and can also include high intensity sonar.

• Visual pollution - can include a proliferation of overhead power lines, advertising signboards alongside major roads, scarred landscapes following opencast mining and open storage of scrap metal and waste. There is also a strong body of opinion that considers wind farms to be a form of visual pollution.

• Water pollution - the discharge of wastewater, intentionally or otherwise, from commercial, industrial premises or industrial processes into surface water. Water pollution can include untreated sewage plus the chemical contaminants used to treat sewage such as chlorine; runoff from surface...