Question

how is polluted water harmfull to us? name some water borne diseases.

Answer 1

When chemicals (excess of fertilisers and pesticides) enter water bodies, they cause an increase in the growth of algae (this process is called eutrophication). This excess growth covers the surface of water and reduces the amount of oxygen available to the aquatic organisms.When we consume such fishes then we are also affected by many communicable diseases.

Sewage water may contain harmful bacteria which cause diseases such as cholera, dysentery, typhoid etc.

A change in the water temperature not only affects aquatic organisms but also their eggs and larvae, which are sensitive to temperature changes.