Question

Most hazardous metal pollutant of automobile exhaust is:
A. Mercury
B. Tin
C. Cadmium
D. Lead

Answer 1

Hint: In this question from the name itself we can say that the poison caused due to the metals. Automobile industry is related to the motor vehicles etc. We can identify the metal pollutant related to the automobile; and look for the localised pollutant in the given options.

Complete answer:
- Now, first we will define the hazardous metal pollutant, or we can say heavy metal pollutants.
- As mentioned, the metals that cause the pollution. Mainly this type of pollution is caused in the freshwater, due to the volcanic eruptions, or the weathering of rocks.
- We can say that the pollutants are differentiated on the basis of localised, and non-localised.
- If we define the localised, it means pollution caused by a source that can be identified; whereas non-localised means pollution caused by the source that cannot be identified easily.
- If we talk about the given options, then the mercury, cadmium, and lead belong to the category of main examples in case of heavy metal pollutants.
- We know that metals cannot be degraded, or that are non-biodegradable.
So, we can say that when the industrial waste is released in water; it will be consumed by living beings, and mainly aquatic life.
- Among the given options, lead is the heaviest pollutant, as it belongs to the category of localised pollutants.
- We know that the lead is used in the batteries, cells, and automobile industry.
- Thus, we can say that lead is being considered to be persistent in the atmosphere/environment and can get added to the soil and further, it could be consumed by human beings too.
- If we discuss the pollutants released in the automobile industry, then it includes greenhouse gases, sulphur dioxide, and nitrogen oxides too.
- In the last, we can conclude that the most hazardous metal pollutant of automobile exhausts is lead.
Hence, the correct option is (D).

So, the correct answer is “Option D”.

Note:
1- Although Lead is considered the most polluting of the given heavy metal elements. It is often confused for having no important uses at all.
2- One would be surprised to know that Lead is a corrosion resistant metal; hence it is used to store corrosive liquids. We can hence see the application of lead in dry batteries.