Human activities play a major role in water pollution.
Which of the following human activities does not cause water pollution?

Options

A. Discharge of human waste into water
B. Leaching of pesticides into water
C. Exhaust from automobiles
D. Mining of heavy metals

Answer

To determine which human activity does not cause water pollution, let's analyze each option provided in the question:

1. **Discharge of human waste into rivers**: This activity contributes significantly to water pollution. Human waste contains pathogens and organic matter that can degrade water quality, leading to health hazards.

2. **Leaching of pesticides into rivers**: Pesticides are chemicals used in agriculture that can wash into water bodies during rain or irrigation. This leaching introduces toxic substances into the water, causing pollution.

3. **Exhaust from automobiles**: This primarily contributes to air pollution rather than water pollution. The exhaust gases released from vehicles contain harmful substances that affect air quality but do not directly pollute water bodies.

4. **Mining of heavy metals**: Mining activities often lead to the contamination of nearby water sources with heavy metals and other pollutants, which can degrade water quality.

Based on this analysis, the activity that does not cause water pollution is:

**Answer: Exhaust from automobiles.**

### Step-by-Step Solution:
1. **Identify the activities listed**: Look at the four options provided.
2. **Analyze each activity**: Determine whether each activity contributes to water pollution or not.
3. **Evaluate the impact**: Consider the effects of each activity on water quality.
4. **Select the correct answer**: Choose the option that does not contribute to water pollution.