UPSC Prelims 2017 · GS Paper I
Question 14: Environment and Ecology
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 :
AnswerUPSC’s answer is (c).
Bioremediation uses living organisms, mostly microbes, to break down pollutants, and it works by enhancing the biodegradation that already occurs in nature, so Statement 1 is right. Genetically engineered microbes designed for a particular pollutant are possible, so Statement 3 is right. Statement 2 is wrong: heavy metals such as cadmium and lead cannot be destroyed by microbes; at best they are immobilised or transformed, so such contamination is not readily and completely treated. Remember: bioremediation is slow and works best on organic pollutants, not metals.
- 1. It speeds up natural biodegradation to clean up pollution.
- 2. Heavy metals cannot be degraded; microbes cannot readily and completely remove them.
- 3. Microbes can be genetically engineered for particular pollutants.
How you could have got this
- If you were sure statement 2 is not correct, (b) and (d) go: each of them includes 2.
What you needed to know: Heavy metals cannot be degraded; microbes cannot readily and completely remove them.
- Then, if you were sure statement 3 is correct, (a) goes: it leaves 3 out.
What you needed to know: Microbes can be genetically engineered for particular pollutants.
Only (c) is left. You didn’t need statement 1.
Which options go is worked out from UPSC’s key and the options, not by a model.
Why each option is right or wrong
- (a) Incomplete: genetic engineering of microbes (3) is also an advantage.
- (b) Wrong: statement 2 is false, since heavy metals are not readily and completely cleared by microbes.
- (c) Right: statements 1 and 3 are correct; statement 2 is false.
- (d) Wrong: statement 2 overstates what microbes can do with heavy metals.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2017, General Studies Paper I, Series A. The paper on upsc.gov.in.