The blue baby syndrome results from

Options

A. Excess of dissolved oxygen
B. Excess of TDS (total dissolved solids)
C. Excess of chloride
D. Methaemoglobinaemia

Answer

**Step-by-Step Solution:**

1. **Understanding Blue Baby Syndrome**: Blue baby syndrome is a condition that affects infants, leading to a bluish discoloration of the skin due to a lack of oxygen in the blood.

2. **Identifying the Cause**: The primary cause of blue baby syndrome is the presence of nitrates in drinking water. Nitrates can convert hemoglobin (the protein in red blood cells that carries oxygen) into methemoglobin, which is unable to effectively carry oxygen.

3. **Mechanism of Methemoglobinemia**: When nitrates are ingested, they are converted into nitrites in the body. These nitrites then react with hemoglobin to form methemoglobin. This process reduces the blood's ability to transport oxygen, leading to symptoms associated with blue baby syndrome.

4. **Symptoms**: Common symptoms of blue baby syndrome include difficulty in breathing, cyanosis (bluish skin), and in severe cases, loss of consciousness. This condition can be life-threatening, especially in infants.

5. **Eliminating Incorrect Options**:
- **Excess of dissolved oxygen**: This is incorrect because blue baby syndrome is related to a deficiency of oxygen in the blood.
- **Excess of total dissolved solids (TDS)**: This is also incorrect as TDS does not directly cause methemoglobinemia.
- **Excess of chloride**: This is incorrect as well; the primary concern is the excess of nitrates, not chlorides.

6. **Conclusion**: The correct answer to the question is that blue baby syndrome results from methemoglobinemia, which is caused by the presence of nitrates in contaminated drinking water.

---