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Explain the changes that can be observed...

Explain the changes that can be observed in the characteristics of river water when sewage is discharged into it and a few weeks after the discharge with respect to :
(i) level of dissolved oxygen (ii) population of fresh water organisms.

A

Peak A- Sharp increase in BOD, disappearance of clean water organisms
Peak B- Increase in dissolved oxygen, reappearance of clean water organisms

B

Peak A- Increase in dissolved oxygen, reappearance of cleanwater organisms
Peak B- Sharp increase in BOD, appearance of clean water organisms

C

Peak A- Sharp increase in BOD, appearance of clean water organisms
Peak B- Increased number in dissolved oxygen, disappearance of clean water organisms

D

Peak A- Increased number of anaerobic bacteria, disappearance of clean water organisms
Peak B- Sharp decline in dissolved `O_(2)`, reappearance of clean water organisms

Text Solution

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The correct Answer is:
A
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