UPSC Prelims 2024 Q17: Environment & Ecology – Pollution & Waste Management
With reference to perfluoroalkyl and polyfluoroalkyl substances (PFAS) that are used in
making many consumer products, consider the following statements:
1. PFAS are found to be widespread in drinking water, food and food packaging materials.
2. PFAS are not easily degraded in the environment.
3. Persistent exposure to PFAS can lead to bioaccumulation in animal bodies.
Which of the statements given above are correct?
- (a) 1 and 2 only
- (b) 2 and 3 only
- (c) 1 and 3 only
- (d) 1, 2 and 3
Answer: (d) 1, 2 and 3
Explanation
PFAS — 'Forever Chemicals'
| Statement | Claim | Verdict | Why |
|---|---|---|---|
| 1 | PFAS found in drinking water, food, packaging | TRUE | PFAS leach from non-stick cookware, food packaging, waterproof clothing, firefighting foam (AFFF) into water supplies and food. Detected in drinking water supplies worldwide. |
| 2 | Not easily degraded in environment | TRUE | The C-F (carbon-fluorine) bond is among the strongest bonds in organic chemistry. PFAS resist degradation by heat, water, microbes, and most chemicals - hence 'forever chemicals' that persist for centuries. |
| 3 | Persistent exposure leads to bioaccumulation | TRUE | PFAS accumulate in fatty tissues (bioaccumulation) and up the food chain (biomagnification). Long-term exposure linked to thyroid disorders, cancer, immune dysfunction, reproductive harm. |
PFAS Quick Reference:
| Full name | Per- and Polyfluoroalkyl Substances |
|---|---|
| Number of compounds | > 12,000 types |
| Key examples | PFOA, PFOS, GenX |
| Why 'forever' | C-F bond = strongest organic bond, biologically inert |
| Sources | Non-stick pans (Teflon), waterproof gear, food packaging, AFFF |
| Health effects | Cancer, thyroid issues, immune suppression, birth defects |
| Regulatory focus | US EPA set first enforceable limits for PFAS in 2024 |
All three statements are correct → Answer: 1, 2 and 3
Answer: (d) 1, 2 and 3.
Why each option is right or wrong
- (a) Incorrect. '1 and 2 only' would mean PFAS do NOT bioaccumulate — but PFAS are well-documented bioaccumulators, found at high concentrations in polar bears, dolphins, and human blood.
- (b) Incorrect. '2 and 3 only' would exclude statement 1 — but PFAS contamination of drinking water and food is one of the most extensively documented environmental health crises globally.
- (c) Incorrect. '1 and 3 only' would mean PFAS DO degrade — they do not. The C–F bond's extreme strength is precisely why they are called 'forever chemicals.'
- (d) CORRECT. All three are accurate: PFAS contaminate water/food/packaging (1), resist environmental degradation (2), and bioaccumulate with persistent exposure (3).
Key point
PFAS = 'forever chemicals' (C–F bond = strongest organic bond). Found in water, food, packaging. Do NOT degrade. Bioaccumulate in body. > 12,000 types including PFOA, PFOS. Linked to cancer, thyroid issues.
Remember
PFAS (forever chemicals) are found in water, food, and packaging; resist degradation due to strong C–F bonds; and bioaccumulate in human tissues. All three statements about PFAS are correct.
Common mistakes
- Thinking PFAS eventually break down — the C–F bond is so stable that PFAS persist in the environment for centuries without degradation; this is their defining characteristic.
- Underestimating PFAS sources — they are in non-stick cookware, food packaging, waterproof clothing, carpets, firefighting foam, and even some cosmetics.
- Not knowing PFAS bioaccumulate — they concentrate in human blood and fatty tissues, and biomagnify up the food chain; found in blood of Arctic wildlife far from any industrial source.
Exam tip
PFAS = Per- and PolyFluoroAlkyl Substances. 'Forever chemicals' because C–F bond is unbreakable. Sources: PFAS, PFOA, PFOS, Teflon, AFFF (firefighting foam). Effects: cancer, thyroid, immune system. EPA set limits in 2024.
Sources
- US EPA — PFAS Explained
- UNEP — Global Assessment of PFAS Contamination
- WHO — Per- and Polyfluoroalkyl Substances (PFAS) and Health