Q. Given below are two statements :
Statement I : In polluted water values of both dissolved oxygen and BOD are very low.
Statement II : Eutrophication results in decrease in the amount of dissolved oxygen. In the light of the above statements,
choose the most appropriate answer from the options given below :

 177  121 JEE MainJEE Main 2022Environmental Chemistry Report Error

Solution:

Since eutrophication is result of excessive growth of weed in water bodies, which consume dissolved oxygen of water bodies.
Eutrophication decreases amount of dissolved oxygen in water bodies.
Polluted water has low value of dissolved oxygen, but high valueof BOD (Biological oxygen demand), since chemical and organic matter requires dissolved oxygen to get decompose.