Biochemical Oxygen Demand , (BOD) is a measure of organic material present in water . bOD value less than 5 ppm indicates a water sample to be `……….`.

Options

A. rich in dissolved oxygen
B. poor in dissolved oxygen
C. highly polluted
D. not suitable for aquatic life

Explanation

To determine the quality of a water sample based on its Biochemical Oxygen Demand (BOD) value, we can follow these steps:

### Step-by-Step Solution:

1. **Understand BOD**: Biochemical Oxygen Demand (BOD) is a measure of the amount of organic material present in water. It indicates how much oxygen is required by microorganisms to decompose organic matter in the water.

2. **Identify the BOD Value**: The question states that the BOD value is less than 5 parts per million (ppm).

3. **Interpret BOD Values**:
- A BOD value of less than 5 ppm generally indicates that the water is clean and has a low level of organic pollution.
- If the BOD value is between 5 ppm and 12 ppm, the water may be moderately polluted.
- A BOD value greater than 12 ppm indicates that the water is polluted and has a high level of organic waste.

4. **Conclusion**: Since the BOD value is less than 5 ppm, we conclude that the water sample is rich in dissolved oxygen and is considered to be of good quality.

5. **Final Answer**: Therefore, a BOD value of less than 5 ppm indicates that the water sample is **rich in dissolved oxygen**.