Prelims 991

Which one of the following is the best description of the term ‘bioremediation’?
It is the enrichment of the nutrient quality of the soil using biological agents.
It is the increase of organo-metallic compounds in the organism through energy flow in an ecosystem.
It is the use of microorganisms to degrade the environmental contaminants into less toxic form.
It is the adoption of genetic variable plants for breeding of high yielding varieties
Explanation :
Bioremediation is the use of living organisms primarily microorganisms to degrade the environmental contaminants or pollutants into less toxic forms. It uses naturally occurring bacteria and fungi or plants to degrade or detoxify substances hazardous to human health and the environment. The microorganisms may be indigenous to a contaminated area or they may be isolated from elsewhere and brought to the contaminated site. Contaminant compounds are transformed by living organisms through reactions that take place as a part of their metabolic processes. For bioremediation to be effective microorganisms must enzymatically attack the pollutants and convert them to harmless products.