Question

High value of biochemical oxygen demand (BOD) indicates that

• A. Water is less polluted
• B. Water is highly polluted
• C. Water is pure
• D. Consumption of organic matter in water is higher by the microbes

Answer 1

The correct option is B

Water is highly polluted

The correct option is B.

Explanation for correct option:

1. Biochemical oxygen demand (B.O.D.) is a measurement of the quantity of dissolved oxygen that is used by aerobic microorganisms while organic matter decomposition.
2. It occurs due to pollution of water due to the presence of microorganisms or high content of organic material.

Explanation for incorrect options:

Option A:

1. Less polluted water will not show high B.O.D.

Option C:

1. A water supply with a BOD level of 3-5 ppm is considered moderately clean.

Option D:

1. Consumption of organic matter by microorganisms will lead to low B.O.D.

Final answer: High biochemical oxygen demand indicates that water is highly polluted.