Pollution - Environmental Pollution
Pollution refers to any undesirable change in the physical, chemical or biological characteristics of our environment, i.e. air, water and oil that may or will adversely affect humans or other species and life support systems of our biosphere directly or indirectly. A substance whose introduction into a resource damages the latter's usefulness is called a pollutant. Pollutants are grouped into two broad categories:
The non-biodegradable pollutants such as heavy metals, pesticides, move through the food chain and may get magnified to dangerous levels in higher trophic level organisms. Some of these combine with other compounds and produce toxic substances. However, biodegradable materials such as human and animal wastes, agro-based residues and fertilisers can also pose a threat if their quantities or inputs exceed the Assimilative capacity of the environment.