Water pollutants affect human beings by causing different kinds of diseases or through contaminated crops, vegetables or flesh of animals.
Some of the effects are mentioned below:
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The industrial effluents:
Contain heavy metals like Cu, Zn, Pb, Hg etc. are toxic to animals and human beings.
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Transmission of diseases through polluted water:
The polluted water is the main source of many infectious diseases. Many viral diseases like infective hepatitis, bacterial diseases like cholera, Typhoid, Dysentery, Gastroenteritis, etc. are water borne.
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Fluoride:
Containing minerals results in dental Fluorosis and skeletal Fluorosis (knock knee syndrome).
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Cadmium:
Causes growth retardation, damage to kidney, liver and cardiovascular disorder (Itai-Itai disease in Japan)
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Mercury:
It produces Minamata disease [numbness, visual disturbances dysphasia (inability to speak), ataxia (inability to walk properly), mental retardation and convulsions (fits)]. It is a slow poison which enters the body through food change.
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Eggs and embryos of certain parasitic worms enter into human system through polluted water.
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Drinking water becomes unpleasant due to the smell of various organic chemicals and micro-organisms.
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Sewage causes depletion of oxygen affecting aquatic life.
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Thermal pollution affects fish population by disturbing reproduction.