The 'blue baby' syndrome results from

Options

A. excess of TDS (total dissolved solids)
B. excess of chloride
C. methaemoglobin
D. excess of dissolved oxygen

Answer

### Step-by-Step Solution:

1. **Understanding Blue Baby Syndrome**: Blue baby syndrome refers to a condition where infants exhibit a bluish tint to their skin, particularly around the lips and fingertips. This is primarily due to a lack of oxygen in the blood.

2. **Identifying the Cause**: The syndrome is often linked to environmental factors, particularly the consumption of contaminated water. The main culprit is the presence of nitrates in drinking water.

3. **Mechanism of Action**: When infants consume water that is high in nitrates, their bodies convert these nitrates into nitrites.

4. **Impact on Hemoglobin**: The nitrites produced from nitrates bind to hemoglobin in the blood. Hemoglobin is responsible for carrying oxygen throughout the body.

5. **Formation of Methemoglobin**: When nitrites bind to hemoglobin, they convert it into methemoglobin. Unlike regular hemoglobin, methemoglobin cannot effectively bind to oxygen.

6. **Consequences**: The formation of methemoglobin leads to reduced oxygen transport in the blood, resulting in hypoxia (lack of oxygen) and causing the characteristic blue discoloration of the skin.

7. **Conclusion**: Therefore, the correct answer to the question regarding the cause of blue baby syndrome is option C: Methamoglobin.