Question

Drawback of DDT as pesticide is
A. It becomes ineffective after sometime
B. It is less effective than others
C. It is not easily/rapidly degraded in nature
D. Its high cost

Answer 1

Hint: DDT Dichlorodiphenyltrichloroethane is a non biodegradable pesticide which is used to kill the pests. It is toxic to humans and animals as it enters the food chain and passes from one trophic level to another causing health hazards. It is very toxic for aquatic and marine animals as well.

Complete Answer:
- Dichlorodiphenyltrichloroethane (DDT) is an organochlorine compound which is used as an insecticide in agricultural fields. DDT is highly efficient against the pests but due to its environmental hazards it is not used any more.(Option A incorrect)
- DDt is the least expensive insecticide which is highly effective and can be easily available.(Option D, B are incorrect)
- DDT shows bioaccumulation or not easily degraded by nature. (Option C correct)
- Due to its fat solubility it is accumulated in living tissues, this is its major disadvantage. The human body even is not able to break it which causes its build up in the food chain.
It also causes poisoning in the animals. Its effects can be seen in birds as the production of thin eggshells is vulnerable to damage.
- In fish the chemical accumulates, when birds feed on them, the chemical accumulates in their fat tissue, resulting in weaker eggs. Enzyme carbonic anhydrase is responsible for the thinning of eggshells and breakage of eggs is attributed to the effects of DDT.
- Once DDT enters the environment, it can remain there for several years which happens while using it during agriculture or vector control.

Hence the correct answer is C.

Note: It attaches to sediment particles or is broken down by microorganisms into DDE. It does not easily dissolve in water. In soil, DDT lasts for a very long time because it binds strongly to soil particles. DDT and its byproducts can stay in the environment for as long as 15 years.