When huge amount of sewage is dumped into a river, its BOD will
A. increase
B. decrease
C. sharply decrease
D. remain unchanged

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1 Answers

Correct Answer - A
Degree of impurity of water due to organic matter is measured in terms of BOD (`O_(2)` in milligram required for five days in one litre of `H_(2)O` at `20^(@)C` for micro-organisms to metabolise organic wastes).
In polluted water reoxygenation decreases than deoxygenation. So, in this water BOD (Biological Oxygen Demand) increases.

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