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Definition: pollution from The Penguin Dictionary of Science

Any deleterious effect on the natural environment caused by the release of any substance. Water can be polluted by untreated sewage or overuse of fertilizers (➤eutrophic). Air pollution is commonly caused by oxides of nitrogen (collectively known as ➤NOx), sulfur dioxide, soot and other particulate matter. ➤Ozone is another cause of pollution at ground level, although its presence in the stratosphere is beneficial (➤ozone layer; ➤➤ozone hole).


Summary Article: Pollution
from Encyclopedia of Global Health

The concept of pollution consists of the inappropriate or undesirable mixing of items or elements that may in themselves be quite appropriate or desirable. An item of food on a plate is an item that is desirable, clean, and in its right place; if the food item falls off the plate onto the floor, then it suddenly becomes dirty and undesirable—it has been polluted by contact with the floor. In traditional Indian society, people are divided into castes and a person from the highest, Brahmin caste, will fear pollution from proximity to a person from the lowest Untouchable (Dalit) caste or something touched or manufactured by such a person. Although the two people in themselves may be quite virtuous and valuable in their own right, their coming together results in contamination or pollution.

In the early part of 2007, a boat carrying cargo of many tonnes of sugar capsized in the Chao Phraya River, north of Bangkok. The sugar entered the water, lowered the level of oxygen in the water, and led to the deaths of many thousands of fish being raised by people along the length of the affected water. Characteristically, then, the act of pollution is caused by a pollutant which is generally a very desirable and valuable item. Nevertheless, the interaction that it has had with the surrounding environment has led to disastrous results.

The processes of industrialization have greatly increased the production of new types of pollution and the intensification of existing forms.

Environmental pollution involves the addition of a new substance into the environment and this has a negative impact on some or all of the living creatures in that part of the environment. The substance may be tangible or intangible in nature: carbon particles in the air can lead to respiratory diseases, but noise can also provoke sleeplessness, stress, and cardiovascular problems. Although pollution is thought of as being produced exclusively by human activities, there are also forms of naturally occurring pollution (i.e., without human involvement) when, for example, rotting vegetation reduces water quality in a river or well. Even so, the processes of industrialization have greatly increased the production of new types of pollution and the intensification of the severity of existing forms. People living in urbanized areas tend to suffer disproportionately from the impact of pollution; as the numbers of people living in cities continues to increase, especially in the developing world, the impact of pollution on humanity will also increase and the need for more efficiency in production and supervision to prevent breaches of legislation on pollution will be magnified.

The principal forms of pollution include air pollution, water pollution, and land pollution. Air pollution includes the release of a wide range of particles and gases into the atmosphere. Much air pollution arises from the burning of hydrocarbon fuels, either as part of power plant operation or through operating personal automobiles. Because air moves, the impact of pollution may be felt quite a long way away from the place where it was caused. Acid rain, for example, created by industrial activity in Britain fell on the forests of Scandinavia, while the intense industrialization of China has given rise to air pollution which has begun to cause disease in the United States as well as closer to home.

Despite the impact of human involvement in air pollution, this can be dwarfed by the effect of volcanic explosions which can release millions of tonnes of pulverized rock and dust into the atmosphere. The effect of the explosion of Tambora in Indonesia in 1815 killed perhaps 10,000 people outright from the blast and the tsunami waves and the resulting air pollution led to deposit of ash and waste on agricultural land subsequently caused famines killing about 80,000 people.

Water pollution involves the release of any type of material into waterways and subsequent impacts on people and other living creatures which draw upon the resources of that waterway. In some cases, the pollution can have some apparent beneficial effects: for example, power plants or other industrial facilities release thermal energy into the water and this can lead to a blooming of life-forms in the vicinity. However, most types of water pollution are much less positive and involve the killing of maritime creatures or of plants living in or next to the water. In some cases, water pollution leads to a chain of events that can lead to concentrated effects after some years.

Mercury released into the sea can reside inside fish and build in its actual level until, when the fish is caught and processed for human food, it then represents a serious threat to health.

Many millions of people rely on rivers and the resources they provide. Some 50 million people rely upon the Mekong River, for example, and the livelihoods of many of these people will be threatened if cargo boats now carrying oil to southern China run aground or lose their cargo.

Land pollution involves the introduction of non-biodegradable waste matter into the land, either in designated waste storage facilities or, perhaps illegally, in nondesignated areas. Biodegradable items can still cause problems if they are present in nonmanageable concentrations. Nonbiodegradable items are more problematic: there are now significant problems with the amount of waste materials being gathered in urban areas, including for example disposable diapers, mobile telephone batteries, personal computer equipment, and automobile tires. Large dumps of these products are difficult to dispose of effectively—the most likely option is to burn them, but this leads to air pollution and may not be possible in any case. An international trade is being created in the export of this waste, generally moving it from developed countries to developing countries, which have fewer resources for effectively dealing with it. Dumps close to large, developing country cities can act as a magnet for poor people as a place for scavenging for salable items or even as a home. Clearly, many health issues derive from such a situation.

In recent years, citizens and governments have started to realize the importance of pollution as a contributor to global warming and because of the health issues resulting from it. Of course, some people have been drawing attention to the impact of pollution for centuries and attempting to bring about societal and legal change to end it. However, the modern world has produced hugely more human-created pollution that ever before and awareness of what is happening around the world is so much more accessible than before that people are much more attuned to the issues. Consequently, there is a great deal of political will (although not always able to constitute an effective majority in a democratic country) for pollution guidelines which are properly enforced and with sanctions which have a genuinely deterrent effect. A general realization is also occurring that this may be better managed through international consensus rather than on the level of individual states.

    SEE ALSO:
  • Environmental Health; Environmental Protection Agency (EPA).

BIBLIOGRAPHY
  • C. David Cooper; F. C. Alley, Air Pollution Control (Waveland Press, 2002).
  • Marquita K. Hill, Understanding Environmental Pollution: A Primer (Cambridge University Press, 2004).
  • Ian L. Pepper, Environmental and Pollution Science (Academic Press, 2006).
  • John Walsh
    Shinawatra University
    Copyright © 2008 by SAGE Publications, Inc.

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