Question

a) What are the effects of ozone depletion?
b) BOD is an index of water pollution. Comment.

Answer 1

a) When the layer of ozone in the stratosphere gets depleted, the harmful UV radiations can enter into the Earth's atmosphere and cause adverse effects. These radiations can cause mutations in the genetic material of the living organisms. These radiations acts on the harmful gases and release radicals which can cause bleaching of the plants and animal tissues. These radiations can also cause skin cancer.

b) BOD is abbreviated form of Biological Oxygen Demand. It is the amount of oxygen required by microbes to break down the organic matter present in a certain volume of a sample of water. The amount of BOD in the water is a measure of the amount of organic material in the water. In polluted water, BOD is high as it contains large amount of organisms. High BOD values in the water of a river means that the water is highly polluted.