Question

Which of the following is a biodegradable pollutant?
A: Plastic
B: Sewage
C: Asbestos
D: Mercury

Answer 1

Hint: We already know the term “Biodegradable” means capability of the matter to get disintegrated through the action of micro-organisms like bacteria or fungi (with or without oxygen). So the term ‘Biodegradable pollutant’ refers to those pollutants that can be decomposed or broken down into simpler or harmless substances in due course of time through the action of micro-organisms like bacteria or fungi.

Complete step by step answer:
It is clear that biodegradable pollutants can be broken down into simpler substances through the action of micro-organisms like bacteria or fungi. Few examples of these biodegradable pollutants include urine, faecal matter, domestic waste, sewage, agriculture residues, wood, paper, cloth, cattle dung, plants, vegetable stuff, animal bones, leather, wool, etc. On the other hand, non-biodegradable pollutants refer to the pollutants which cannot be decomposed into simpler substances. Few examples of these non-biodegradable pollutants include plastics, DDT, polythene, bags, mercury, arsenic, lead, insecticides, pesticides, synthetic fibres, iron products, etc. Now, let us look at each of the given options one by one:
A: Plastic: Plastic waste include Polyethylene Terephthalate (PETE or PET), Polystyrene (PS), High Density Polyethylene (HDPE), Polypropylene (PP), Polyvinyl Chloride (P or PVC), etc. which cannot be broken down into simpler substances. Thus plastic is a non-biodegradable pollutant.
B: Sewage: Sewage is mainly composed of the organic waste generated by various organisms and sewage is commonly utilised as a fertilizer. Sewage can be decomposed into simpler substances by the action of microorganisms that are naturally biodegradable in nature. Thus, sewage is a biodegradable pollutant.
C: Asbestos: Asbestos is considered to be a good water resistant material and is most commonly used in roofing as well as in the siding of factories, buildings and farms. Thus asbestos is a non-biodegradable pollutant.
D: Mercury: Mercury is actually a liquid metal and is utilized in the manufacturing of various equipment. Mercury is a non-biodegradable pollutant.

Hence, Option B is correct.

Note: Bioplastics prove to be an eco-friendly alternative to the petro-chemical plastics owing to their production from the renewable resources and they are also biodegradable. Examples of such plastics include Starch-based blends, cellulose based plastics, Polylactic acid-based blends (PLA blends), etc.