Poluarea Apei

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Profesor indrumator / Prezentat Profesorului: Ion Dichiseanu

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Domenii: Geografie, Engleza

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Water Pollution, contamination of streams, lakes, underground water, bays, or oceans by substances harmful to living things. Water is necessary to life on earth. All organisms contain it; some live in it; some drink it. Plants and animals require water that is moderately pure, and they cannot survive if their water is loaded with toxic chemicals or harmful microorganisms. If severe, water pollution can kill large numbers of fish, birds, and other animals, in some cases killing all members of a species in an affected area. Pollution makes streams, lakes, and coastal waters unpleasant to look at, to smell, and to swim in. Fish and shellfish harvested from polluted waters may be unsafe to eat. People who ingest polluted water can become ill, and, with prolonged exposure, may develop cancers or bear children with birth defects.

Polluted River

The pollution of rivers and streams with chemical contaminants has become one of the most critical environmental problems of the century. Chemical pollution entering rivers and streams can be classified according to the nature of its sources: point pollution and nonpoint pollution. Point pollution involves pollution from a single concentrated source that can be identified, such as an outfall pipe from a factory or refinery. Nonpoint pollution involves pollution from dispersed sources that cannot be precisely identified, such as runoff from agricultural or mining operations or seepage from septic tanks or sewage drain fields.

The major water pollutants are chemical, biological, or physical materials that degrade water quality. Pollutants can be classed into eight categories, each of which presents its own set of hazards.

Industrial Water Pollution

Industrial pollutants that run into streams, rivers, or lakes can have serious effects on wildlife, plants, and humans. In the United States there are strict rules for the amount and composition of substances that factories can release into bodies of water. These rules are not always enforced, and much industrial water pollution comes from accidental chemical or oil spills.

Polluted River

The pollution of rivers and streams with chemical contaminants has become one of the most critical environmental problems of the century. Chemical pollution entering rivers and streams can be classified according to the nature of its sources: point pollution and nonpoint pollution. Point pollution involves pollution from a single concentrated source that can be identified, such as an outfall pipe from a factory or refinery. Nonpoint pollution involves pollution from dispersed sources that cannot be precisely identified, such as runoff from agricultural or mining operations or seepage from septic tanks or sewage drain fields.

The major water pollutants are chemical, biological, or physical materials that degrade water quality. Pollutants can be classed into eight categories, each of which presents its own set of hazards.

Oil and chemicals derived from oil are used for fuel, lubrication, plastics manufacturing, and many other purposes. These petroleum products get into water mainly by means of accidental spills from ships, tanker trucks, pipelines, and leaky underground storage tanks. Many petroleum products are poisonous if ingested by animals, and spilled oil damages the feathers of birds or the fur of animals, often causing death. In addition, spilled oil may be contaminated with other harmful substances, such as polychlorinated biphenyls (PCBs).

Chemicals used to kill unwanted animals and plants, for instance on farms or in suburban yards, may be collected by rainwater runoff and carried into streams, especially if these substances are applied too lavishly. Some of these chemicals are biodegradable and quickly decay into harmless or less harmful forms, while others are nonbiodegradable and remain dangerous for a long time.

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