Question
When do we use the term water pollution. Give examples.
Solution
The term water pollution is used when there is :
(i) Addition of undesirable substances to water bodies. For example, addition of industrial wastes containing poisonous salts like mercury salts, pesticides, insecticides, etc. Addition of disease causing organisms, like cholera causing bacteria through sewage.
(ii) The removal of desirable substances from water bodies. For example, depletion of dissolved oxygen and nutrients which adversely affects aquatic animals and plants.
(iii) A change in temperature of water in water bodies which adversely affects the organisms living in the water bodies.
