Which of the following in drinking water causes blue baby syndrome ?

Options

A. `NO_3^(-)` ions
B. `SO_4^(2-)` ions
C. `F^(-)` ions
D. Lead

Answer

**Step-by-Step Solution:**

1. **Understanding Blue Baby Syndrome**: Blue Baby Syndrome refers to a condition where a baby's skin appears blue due to a lack of oxygen in the blood. This condition is particularly concerning in infants.

2. **Identifying the Cause**: The primary cause of Blue Baby Syndrome is nitrate poisoning. Nitrates can interfere with the ability of blood to carry oxygen, leading to the characteristic blue discoloration.

3. **Source of Nitrates**: Nitrates often enter drinking water supplies from agricultural runoff, fertilizers, and sewage. High levels of nitrates in drinking water can be harmful, especially to infants.

4. **Safe Limit of Nitrates**: The safe limit for nitrate ions (NO3-) in drinking water is established at 50 parts per million (ppm). If the concentration exceeds this limit, it poses a risk of nitrate poisoning and subsequently Blue Baby Syndrome.

5. **Conclusion**: Therefore, the presence of high levels of nitrates in drinking water is responsible for causing Blue Baby Syndrome.

**Final Answer**: Nitrate ions (NO3-) in drinking water cause Blue Baby Syndrome.

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