Hint: Degradation :A deleterious change in the chemical structure, physical properties or appearance of a material from natural or artificial exposure is called degradation. On the basis of degradability substances are of two types: Biodegradable and non biodegradable. Examples of biodegradable substances are: paper, cow dung, wood crumbles, municipal sewage etc. Examples of non-biodegradable substances are: DDT, BHC, broken glass, polythene bags, soft drink cans etc.
Biodegradable substances: They undergo degradation through the agency of microorganisms. They are generally biological in origin.. There is no biomagnification. They can be used as a resource. They cannot be recycled.
Non-biodegradable substances: They are the substances which don't break down or get converted to harmless state by microorganisms or decomposers. They are non biological in origin.. Because non-biodegradable substances are either not degraded or are very slowly acted upon by decomposers, they are difficult to manage. Except for recycling of some, there is no treatment process for handling disposal of non-biodegradable substances. Rather the non-biodegradable substances enter the food chains and undergo biomagnification resulting in extreme havoc to animals operating at higher trophic levels.
Two ways in which biodegradable substances would affect the environment are:
They will serve as breeding ground for flies and mosquitoes which are carriers of diseases like cholera, malaria etc.
They produce foul smell, thus causing air pollution.
Biodegradable substances are also called non-conservative pollutants. Non-biodegradable substances are also called conservative or persistent pollutants. Biodegradable substances do not accumulate in the ecosystem. Non-biodegradable substances tend to accumulate in ecosystems.