UPSC Prelims 2017 · Question 89 of 99

UPSC Prelims 2017 question on Bioremediation Advantages

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:

  1. 1 only
  2. 2 and 3 only
  3. 1 and 3 only
  4. 1, 2 and 3
Show answer

Answer: C. 1 and 3 only

Verdict

The answer is 1 and 3 only. Bioremediation enhances natural biodegradation and can use genetically engineered organisms, but it cannot readily treat heavy metals.

Analysis

Statement 1 is CORRECT. Bioremediation uses naturally occurring organisms to break hazardous substances into less toxic or non toxic ones, with microorganisms degrading organic contaminants by using them as an energy source or cometabolising them. Statement 3 is CORRECT. Genetic engineering can produce microorganisms designed for particular contaminants. Statement 2 is INCORRECT. Heavy metals such as cadmium and lead are elements and cannot be degraded at all, so they can at best be immobilised or accumulated, never readily and completely treated.

Source

Environment reference material.

How to crack it

The chemistry settles statement 2 without any knowledge of bioremediation. Microbes break molecules apart, but an element cannot be broken into anything less toxic, so heavy metals are outside the reach of biodegradation by definition. Whenever a remediation claim covers heavy metals, check whether the mechanism proposed can act on an element. The words readily and completely compound the error and are the usual signature of a planted statement.

More questions on Pollution

All 40 questions on Pollution →

← Full 2017 question paper · All Environment and Ecology questions