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Water
Pollution
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Overview |
Water
pollution is contamination of water by foreign matter that
deteriorates the quality of the water. Water pollution covers
pollutions in liquid forms like ocean pollution and river pollution.
As the term applies, liquid pollution occurs in the oceans, lakes,
streams, rivers, underground water and bays, in short
liquid-containing areas. It involves the release of toxic
substances, pathogenic germs, substances that require much oxygen to
decompose, easy-soluble substances, radioactivity, etc. that become
deposited upon the bottom and their accumulations will interfere
with the condition of aquatic ecosystems. For example, the
eutrophication: lack of oxygen in a water body caused by excessive
algae growths because of enrichment of pollutants.
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Water Cycle and
Pollution
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Water cycle is,
simply saying, the circulation of water in
earth. In fact, the water in the earth's
biosphere is used and reused again and again.
This is called water cycle or continuous
movement of water between the earth and the
atmosphere. It involves the following
mechanisms:
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Evaporation:
changing of water from liquid to gas
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Transpiration:
Release of water vapor from plant leaves
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Condensation:
changing of vapor to liquid (cooled down)
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Precipitation:
Water that returns to the earth (water droplets
in clouds become large enough and there comes
the rain).
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What's the
relation of water cycle and
pollution?
According to the
water cycle, naturally, water around us will be
absorbed to the land (soil) and rivers will
stream from the upstream to the downstream and
released to the sea. In normal situation
organic pollutants are biodegraded by microbes
and converted to a form that brings benefits to
the aquatic life. And for the inorganic
pollutants, in the same situation, don't bring
to much hazards because they are widely
dispersed and have almost no effect to the
environment which they are released
to.
In a small
scale, both inorganic and organic pollutants
safely decompose throughout the stream, their
concentration decrease in the sea, and they
don't harm the sea ecosystem and its
distribution. But in an excessive scale,
communities in beach and estuary will be
affected by the pollutants, and can heavily harm
them.
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Sources and
Methods
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We
can classify major sources that lead to water pollution
to the following categories:
Source
: http://library.thinkquest.org
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Nov 21, 2024
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