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 ✓ UPSC's answer
- (d) 1, 2 and 3
Why the answer is (c)
• Bioremediation uses microbes, fungi or plants to break down pollutants; it works by stimulating the natural biodegradation processes already present in the environment (statement 1).
• Genetically engineered microbes — such as the oil-eating 'superbug' patented by Ananda Chakrabarty — can be designed for specific pollutants (statement 3).
• Statement 2 is wrong: heavy metals like cadmium and lead cannot be biodegraded; microbes can at best immobilise or accumulate them, and treatment is neither ready nor complete.
• Hence 1 and 3 only, option (c).
Why the other options are wrong
- (a) 1 only
- Statement 3 on engineered microbes is also correct.
- (b) 2 and 3 only
- Statement 2 is wrong: heavy metals cannot be biodegraded.
- (d) 1, 2 and 3
- Statement 2 is wrong.
Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2017, held on 18 June 2017. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.