Question

Which of the following are non-degradable pollutants?
A. Mercuric salts
B. Long-chain phenolics
C. DDT
D. All of the above

Answer 1

Non-degradable pollutants are those that remain in the soil for prolonged periods of time. They are usually toxic and accumulate in the higher trophic levels.

Complete answer: They are the pollutants that cannot be broken down into simpler, less toxic/ harmless substances in nature
DDT, plastics, polythene, bags, insecticides, pesticides, mercuric salts, lead, arsenic compounds, metal substances like aluminum cans, synthetic fibers, glass objects, iron products silver foils, etc. are some of the examples of non-biodegradable pollutants.

Therefore the correct answer is option D: All of the above

Additional Information:
Mercury is a heavy metal that exists as a liquid at room temperature. They occur in nature as salts such as mercuric chloride ($Hg{Cl_2}$) and mercurous chloride (${Hg_2}$ ${Cl_2}$), etc. The latter is also known as calomel. Mercuric salts are more soluble in water. Hence, mercuric salts are usually more acutely toxic than mercurous salts.
The long-chain alkylphenols/ long-chain phenolics are extensively used as precursors in the manufacture of detergents. They are also used as additives for fuels and lubricants, polymers, and as components in phenolic resins.
DDT (dichloro diphenyl trichloroethane) was developed initially as one of the first modern and synthetic insecticides in 1940. It was initially used as an efficient measure to combat malaria, typhus, and other insect-borne human diseases amongst both the military and the civilian populations.
DDT is a class 2 insecticide. Hence, it is moderately toxic. It has the ability to prevent itself from degradation. Hence, they accumulate over time and add up in the higher trophic levels of the food chain. They have several harmful effects in humans such as cancers. They are also teratogens; they interfere with the development of the embryo in the mother if the latter has ingested some.

Notes: Some non-biodegradable substances can be recycled and used several times before their final disposal.
Landfills, incineration, etc. are some of the ways to dispose of non-degradable waste products.