Question

The water quality of a pond was analysed and its BOD was found to be 4. The pond has

• A. Water has high amount of fluoride compounds
• B. Highly polluted water
• C. Very clean water
• D. Slightly polluted water

Answer 1

The Correct Option is C

The question pertains to the Biochemical Oxygen Demand (BOD) of water in a pond, measured at a value of 4. Biochemical Oxygen Demand is the amount of dissolved oxygen needed by aerobic biological organisms to break down organic material in a given water sample. BOD is an important parameter for assessing water quality.

Let's analyze the given options:

1. Water has high amount of fluoride compounds: Fluoride concentration in water is unrelated to BOD. Thus, this option is irrelevant in the context of measuring BOD.
2. Highly polluted water: Typically, a BOD value greater than 6-8 indicates polluted water. Since the BOD here is only 4, this option does not apply.
3. Very clean water: A BOD value of 1-4 is generally considered indicative of very clean water. A value of 4 suggests that the water is clean, but not at the highest quality. Thus, this option is plausible.
4. Slightly polluted water: While a BOD of 4 suggests there is some organic matter in the water, it does not qualify as pollution. A BOD value in this range is typical of natural, uncontaminated water.

The correct choice, therefore, is Very clean water, since a BOD of 4 is on the lower end of the pollution scale.