With reference to perfluoroalkyl and polyfluoroalkyl substances (PFAS) that are used in making many consumer products, consider the following statements: Which of the statements given above are correct?

Answer: (d) 1, 2 and 3

All three are true.

Statement by statement

1. ✓ CORRECT PFAS are found widely in drinking water, food and packaging.

2. ✓ CORRECT The carbon–fluorine bond is very strong, so they barely break down.

3. ✓ CORRECT They build up in the bodies of animals and people.

The idea

PFAS are a family of man-made chemicals built on the carbon–fluorine bond, one of the strongest in chemistry. That makes them repel both water and oil, which is useful. It also means almost nothing in nature can break them down. All three statements follow from that one fact.

Very strong carbon–fluorine bond → Does not break down → “forever chemicals” → Spreads into water and soil → Enters food and drinking water → Builds up in the body over years

Elimination technique

All three statements are plain descriptions with no absolute word. Plain statements of this kind are usually true in Environment PYQs, which points to all three.

Also know

Uses: non-stick cookware, waterproof clothing, food wrappers, fire-fighting foam. Linked health risks include some cancers, thyroid problems and weaker immunity. Three of them (PFOS, PFOA and PFHxS) are listed under the Stockholm Convention on persistent organic pollutants.