Study the picture given below (industrial effluent and oil being discharged into a water body, with dead fish visible) and answer the following questions: Study the picture given below (industrial effluent and oil being discharged into a water body, with dead fish visible) and answer the following questions:
What is a ‘Pollutant’? Explain the term.
Topic: Pollutant
Answer
A POLLUTANT is any substance — solid, liquid or gaseous — released into the environment in such quantity that it alters the natural quality of the air, water or land, and causes harm to living organisms.
Two elements make the definition: it ALTERS the natural quality of the environment, and it causes HARM.
THE POINT WORTH ADDING: many pollutants are harmless or even necessary in small amounts. Carbon dioxide is essential to photosynthesis; it becomes a pollutant only in excess. So it is the QUANTITY and the PLACE that make a substance a pollutant, not the substance itself.
Pollutants divide into BIODEGRADABLE (sewage, paper — broken down by decomposers) and NON-BIODEGRADABLE (plastics, heavy metals, DDT — which persist and accumulate in food chains). The second kind is the more dangerous for exactly that reason.