Page 3 - 2. Lesson notes- Water; water pollution
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does the count of decomposers. They use up a lot of oxygen which results in the depletion of
oxygen content in water. This adversely affects aquatic life.
3.Chemical Pollutants
Chemical pollutants include heavy metals such as mercury, lead, cadmium, etc., solvents from
industries, pesticide run-offs, oil spills through ships, etc. They are poisonous to aquatic life
forms and cause their infertility and death.
The metal wastes are dangerous to humans as well when they get absorbed in our body. They
can damage the nervous system, kidney, cause skin allergies, etc.
EFFECTS OF WATER POLLUTION:
1.The addition of undesirable substances into water bodies. ex- pesticides, fertilizers pathogens
make the water poisonous.
2.Removal of desirable substances from water: Nutrients and oxygen once depleted harm
aquatic life as they are dependent on nutrients dissolved in water.
3.A drastic change in temperature: (thermal pollution)- A common cause of thermal pollution is
the use of water as a coolant by power plants and industrial manufacturers. Thermal pollution
damages water ecosystems and reduces aquatic animal populations. It affects their breeding,
egg and larvae.
4. Eutrophication:
when a body of water becomes overly enriched with minerals and nutrients which induce
excessive growth of algae. This process may result in oxygen depletion of the water body.
