Question

B.O.D values of four samples of water A, B C and D are given below
A. 160 ppm
B. 35 ppm
C. 180 ppm
D. 25 ppm
The decreasing order of extent of pollution in water is ?

• A. C > A > D > B
• B. D > B > A > C
• C. C > A > B > D
• D. D > A > B > C

Answer 1

Answer: (C)

C > A > B > D

BOD is the amount of oxygen dissolved in water, which is required by the micro organisms to oxidize inorganic and organic compounds. More amount of BOD means more polluted water. If the BOD is more than 17 ppm it is said to polluted. So, the decreasing order of content of polluted water is C>A>B>D.