12.1.1 Classification of Pollutants

In terms of eco-system, pollutants can be classified into two basic groups – Non- degradable and degradable. Based on the time taken to breakdown into their ingredients, degradable pollutants are classified as rapidly degradable (non-persistent) and slowly degradable (persistent). a) Rapidly degradable or non-persistent pollutants: These can be broken down by natural processes. Domestic sewage and vegetable waste are examples of such pollutants.

b) Slowly degradable or persistent pollutants: These are pollutants that remain in the environment for many years in an unchanged condition and take decades or longer to degrade, as in the case of DDT. c) Non-degradable pollutants : These cannot be degraded by natural processes. Once they are released into the environment, they are difficult Lightning Volcanoes Wildfires Fertilizer Industry, power plants, Sewage treatment Cities