The values of dissolved oxygen (DO) content in heavily polluted water is less than

Options

A. `6.0 mg L^(-1)`
B. `9.0 mg L^(-1)`
C. `4.0 mg L^(-1)`
D. `8.0 mg L^(-1)`

Answer

To solve the question regarding the values of dissolved oxygen (DO) content in heavily polluted water, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Dissolved Oxygen (DO):**
- Dissolved oxygen refers to the amount of gaseous oxygen that is dissolved in water. It is crucial for the survival of aquatic life.

2. **Identify Factors Affecting DO Levels:**
- The levels of dissolved oxygen can be influenced by various factors, including temperature, water movement, and the presence of pollutants.

3. **Consider the Impact of Pollution:**
- In heavily polluted water, there is an increase in the number of microorganisms that decompose organic matter. This process consumes oxygen, leading to a decrease in the levels of dissolved oxygen.

4. **Analyze the Given Options:**
- The options provided are:
- A) 6.0 mg/L
- B) 9.0 mg/L
- C) 4.0 mg/L
- D) 8.0 mg/L

5. **Determine the Correct Answer:**
- Since heavily polluted water has a significantly reduced level of dissolved oxygen due to the high activity of decomposing microorganisms, the value of DO in such water is typically less than 4.0 mg/L. Therefore, the correct answer is:
- **C) 4.0 mg/L**

### Final Answer:
The values of dissolved oxygen (DO) content in heavily polluted water is less than **4.0 mg/L**.

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