Consider the following statements regarding mercury pollution: How many of the above statements are correct?

Answer: (c) All three

Gold mining and coal plants release mercury, and no exposure level is known to be safe.

Statement by statement

1. ✓ CORRECT Small-scale gold mining uses mercury to extract gold — the largest human source of mercury emissions.

2. ✓ CORRECT Coal contains traces of mercury, released when it is burnt in power plants.

3. ✓ CORRECT WHO says there is no known safe level of exposure to mercury.

The idea

Mercury is dangerous because of what happens after it is released. In water, bacteria change it into methylmercury, which living things absorb easily and get rid of slowly. It builds up at each step of the food chain, and the people who eat the fish get the largest dose.

Mercury released to air or water → Settles in lakes and seas → Bacteria convert it to methylmercury → Plankton → small fish → big fish: the amount rises at each step → People eat the fish → Damage to the brain and nerves

Why the others are wrong

(b) Doubts one of three well-documented facts.

The trap

“No known safe level” sounds like an absolute trap. WHO says exactly that.

Also know

In small-scale gold mining, mercury is mixed with crushed ore to catch the gold and is then boiled off. Minamata disease is named after the Japanese bay where a factory’s mercury waste poisoned fish-eating families in the 1950s. The Minamata Convention (2013) controls mercury; India ratified it in 2018.