Earth has different types of surroundings. This surrounding is called Environment. The physical environment on earth provides favourable condition for the existence, and growth of different life forms.

These living being constituted the biological environment. Both physical and biological environment are in a close interaction with each other, and forms a stable self perpetuating system. The diagrammatic presentation of different chemical regions.

The environment is constantly changing and this affects life on earth. Some of these effects can be lasting and irreversible. Each living organism has specific surroundings or medium with which it interacts continuously. This surrounding is the natural environment. Natural environment includes broad aspects of landscape such as soil, water, desert or mountain which can be described in terms of physical influences such as differences in moisture, temperature, soil and biological influences.

The environment is the sum total of living and non-living components including the influences and events surrounding organisms. Living components are called biotic components while non-living is called abiotic components.


The development of activities by man has created adverse effects on all living organism in the biosphere. As a result of rapid industrialisation, the environment has been contaminated undesirable and harmful for the health of living organisms including man. This has led to pollution of the environment. Thus, pollution is defined as “The addition of the constitutents to water, air or land which adversely affect the natural quality of the environment.