UPSC Prelims 2017 Q14: Indian Polity – Political Theory & Concepts
In the context of solving pollution problems, what is/are the advantage/advantages of
bioremediation technique?
1. It is a technique for cleaning up pollution by enhancing the same biodegradation process that
occurs in nature.
2. Any contaminant with heavy metals such as cadmium and lead can be readily and completely
treated by bioremediation using microorganisms.
3. Genetic engineering can be used to create microorganisms specifically designed for
bioremediation.
Select the correct answer using the code given below:
- (a) 1 only
- (b) 2 and 3 only
- (c) 1 and 3 only
- (d) 1, 2 and 3
Answer: (c) 1 and 3 only
Explanation
Bioremediation
Bioremediation uses microbes or plants to break down or remove pollutants.
| Statement | Verdict | Why |
|---|---|---|
| 1. It speeds up the natural biodegradation process | Correct | It enhances what microbes already do in nature |
| 2. Any heavy-metal contaminant can be readily and completely treated | Incorrect | Metals like cadmium and lead cannot be broken down; microbes can only change or immobilise them, often slowly and partly |
| 3. Genetic engineering can create microbes for it | Correct | Engineered strains, such as oil-eating bacteria, are designed for cleanup |
Types:
| Type | Example |
|---|---|
| In situ | Treating soil or water on site |
| Ex situ | Removing soil to treat it elsewhere |
| Phytoremediation | Plants absorb pollutants |
India's TERI developed Oilzapper, a microbial mix to clean oil spills.
Answer: (c) 1 and 3 only.
Why each option is right or wrong
- (a) Incorrect. Statement 3 is also true; genetically engineered microbes are used.
- (b) Incorrect. Statement 2 is false: heavy metals cannot be completely degraded by microbes.
- (c) CORRECT. Bioremediation enhances natural biodegradation and can use engineered microbes.
- (d) Incorrect. The words 'any', 'readily' and 'completely' make statement 2 false.
Key point
Bioremediation enhances natural biodegradation and can use engineered microbes; heavy metals cannot be fully degraded. Example: TERI's Oilzapper.
Remember
Bioremediation: natural process boosted; not a cure-all for metals.
Common mistakes
- Accepting statement 2 despite the extreme words 'any', 'readily', 'completely'.
- Thinking microbes can destroy metals; they can only transform or bind them.
- Not knowing Oilzapper as an Indian bioremediation example.
Exam tip
Elements cannot be destroyed, only moved or changed. Any claim of complete heavy-metal removal is suspect.
Sources
- NCERT Class XII — Biology, Ch 10 (Microbes in Human Welfare)
- TERI — Oilzapper bioremediation technology