A person was using water supplied by Municipality. Due to shortage of water he started underground water. He felt laxative effect. What could be the cause?

Explanation

### Step-by-Step Solution:

1. **Understanding the Situation**: The person initially used municipal water but switched to underground water due to a shortage. After using the underground water, he experienced a laxative effect.

2. **Identifying the Laxative Effect**: The laxative effect is often associated with high concentrations of certain substances in water, particularly sulfates.

3. **Analyzing Sulfate Presence**: Sulfates can cause a laxative effect when present in high concentrations in drinking water. This effect is not typically observed with moderate levels of sulfates.

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