Pollution is defined as the existence of impurities or pollutant substances in sufficient concentration levels, causing harmful effects on human beings, animals, plant life or material resources when exposed for a sufficient duration of time, thus reducing the quality of life in the environment.
From an ecological perspective, pollutants can be classified as degradable, slowly degradable and non-degradable. The Degradable or called as non-persistent pollutants can be rapidly broken down by natural process. For example domestic sewage, discarded vegetables, Slowly-degradable or persistent pollutants are pollutants that exist in the environment for many years in a stable condition and take decades or longer to degrade.
Pollutants: The substances which are present in harmful concentration and is the agent who causes pollution is termed as the pollutant.
Classification of Pollutants:
On the basis of existence in nature
a) Quantitative Pollutants- The substances which are already present in the environment, but are termed as pollutants when their concentration (quantity) increases in the environment. eg. CO2 is present in the environment in greater quantity than normal and is hence termed as a quantitative pollutant.
b) Qualitative Pollutant- The substances which are not normally present in the environment and are added by human beings and are pollutants by nature. Eg. insecticides, pesticides
On the basis of the form in which they persist
a) Primary Pollutants- The substances which are directly emitted from the source and remain in that form are termed as primary pollutants eg, smoke, fumes, ash, dust, nitric oxide and sulphur dioxide
b) Secondary pollutants- The substances which are formed by chemical reaction between the primary pollutants and constituents of the environment (i.e. those which are already present in the environment) .eg smog, ozone, sulphur trioxide, nitrogen dioxide.
On the Basis of Disposal
a) Bio-Degradable Pollutants- the pollutants which are decomposed by natural processes eg domestic (municipal) sewage.
b) Non Bio-degradable Pollutants- The pollutants which don’t decompose naturally or decompose slowly eg. DDT, Aluminium cans.
List of Industries causing different types of pollution:
|Type of Industries||Type of Pollution|
|Manufacture of chemicals, pesticides, medicines||Water pollution, air pollution|
|Manufacture of gases||Air pollution|
|Cement, steel and other mine based industries||Air pollution and solid wastes, noise pollution|
|Textile industries and their ancillaries||Water pollution, air pollution, noise pollution|
|Transport vehicle manufacturing||Solid wastes, noise pollution, air pollution|
|Petroleum based industries||Water pollution, air pollution|
|Forest dependent industries||Air pollution, solid wastes and sound pollution|
|Food industries||Water pollution, air pollution, food pollution|
|Paper industries||Water pollution, air pollution, solid wastes, sound pollution|
|Sugar industry||Water pollution, air pollution, solid wastes|
|Brick industry||Air pollution, water pollution|
|Aircraft industry||Solid wastes, water pollution, air pollution|
|Electrical appliances and electric goods industries||Solid wastes, air pollution|
|IT based industries||Air pollution|
|Telecom industries||Solid wastes and air pollution|
Most pesticides are non-selective; they kill or damage life forms other than those intended For example, pesticides used in an effort to control or destroy undesirable vegetation and insects often destroy birds and small animals. The biological effect of water pollution is its danger to our water supplies. Water pollutants are also dangerous to all forms of marine life.