Question

Match column I with column II and select the correct option.

Column I	Column II
A. Eutrophication	i. Amount of organic pollutants in water body
B. Sanitary landfill	ii. Deforestation
C. BOD	iii. Nutrient enrichment
D. Jhum cultivation	iv. Waste disposal

• A. A - iii, B - iv, C - i and D - ii
• B. A - i, B - iii, C - iv and D - ii
• C. A - ii, B - i, C - iii and D - iv
• D. A - i, B - ii, C - iv and D - iii

Answer 1

The correct option is A A - iii, B - iv, C - i and D - ii

Eutrophication is the excessive richness of nutrients in a lake or other body of water, frequently due to run-off from the land, which causes a dense growth of plant life. The excessive growth of algae and plankton in a water body called algal bloom is the indicator of it. It is a serious environmental concern and results in the deterioration of water quality and the depletion of dissolved oxygen.

Figure : Eutrophication

Sanitary landfill is a method where waste is allowed to decompose into biologically and chemically inert materials in a setting isolated from the environment. In this method the waste materials that cannot be reused or recycled is separated and spread as a thin layer in low-lying areas. A layer of soil after each layer of garbage has been added. Such areas are declared unfit for construction of buildings for the next 20 years. These areas can later be used as a playground or a park.

Figure : Sanitary landfill

The amount of oxygen needed by microorganisms or decomposers such as bacteria to breakdown organic matter present in one litre of water, by oxidation process is called the Biochemical Oxygen Demand (BOD). It measures the amount of oxygen utilized by microorganisms for the process of decomposition of the organic matter in the water bodies which symbolizes the amount of organic pollution present in an aquatic ecosystem or a water body.

Figure : Biochemical Oxygen Demand (BOD)

Jhum cultivation or Slash and burn agriculture is a process of cutting down the vegetation in a particular area, setting that remaining foliage on fire and using that area for cultivation for a limited period. Burning provides suitable conditions for upcoming crops because their main competitors like weeds, pests are destroyed and the ash provides nutrients (potash) to the soil. This can lead to deforestation.