Question

The most hazardous metal pollutant of automobile exhausts is
a. Mercury
b. Cadmium
c. Lead
d. Copper

Answer 1

Hint: A pollutant is a substance that has an undesired effect in the environment. These harms and pollute the usefulness of resources in the environment.

Complete answer:
Mercury, Cadmium, Lead and copper are hazardous metal pollutants out of which lead is the most hazardous immobile pollutant. “Lead” is a common pollutant from dry cell or battery manufacturing plants and automobile exhausts. Lead is released by combustion of petrol as tetraethyl lead is used as antiknock in petrol. This lead is very harmful and causes plumbism or lead poisoning, which disturbs the nervous system, liver, kidneys in adults and also causes brain damage in children. Because of its immobility, lead poisoning is localised.

Environmental pollution from hazardous metals and minerals can arise from natural as well as anthropogenic sources. Natural sources are: seepage from rocks into the water, volcanic activity, forest fires etc. Pollution also arises from partitioning of polluting elements (which are concentrated in clay minerals with high absorption capacities), between sedimentary rocks and their precursor sediments and water. With rapid industrialization and consumerist lifestyle, anthropogenic sources of environmental pollution have increased.

The pollution occurs both at the level of industrial production as well as end use of the products and run-off. These toxic elements enter the human body mostly through food and water and to a lesser extent through inhalation of polluted air, use of cosmetics, drugs, poor quality herbal formulations particularly Ayurvedic (herbo-mineral preparations) and `Unani’ formulations, and even items like toys which have paints containing lead.

Note: Heavy metal contamination in drinking water poses a threat to humans and is often the root cause of various severe health issues such as cancer and organ damage. The presence of heavy metals cannot be seen with naked eyes. The heavy metals are slow poison to your health as they don’t have any immediate effects in your body.