Water Pollution Quiz for Grade 8 Science with Answer Key

📚 Quick Study Guide

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• What is Water Pollution? Contamination of water bodies (e.g., lakes, rivers, oceans, groundwater) usually caused by human activities.
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• Point Sources: Pollution originating from a single, identifiable source (e.g., factory discharge pipe).
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• Non-Point Sources: Pollution originating from diffuse sources (e.g., agricultural runoff, urban stormwater).
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• Types of Pollutants: Include pathogens (bacteria, viruses), nutrients (nitrogen, phosphorus), toxic chemicals (pesticides, heavy metals), and physical pollutants (sediment, heat).
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• Eutrophication: Excessive richness of nutrients in a lake or other body of water, frequently due to runoff from the land, which causes a dense growth of plant life and death of animal life from lack of oxygen.
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• Thermal Pollution: The degradation of water quality by any process that changes ambient water temperature. Common cause is the use of water as a coolant by power plants and industrial manufacturers.
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• Prevention: Reducing fertilizer use, proper disposal of waste, implementing erosion control, and improving wastewater treatment.

🧪 Practice Quiz

1. Which of the following is an example of a point source of water pollution?
   1. Agricultural runoff
   2. A factory discharging waste into a river
   3. Stormwater runoff from city streets
   4. Sediment from construction sites
2. What is eutrophication mainly caused by?
   1. Excessive heat in the water
   2. High levels of oxygen
   3. Excessive nutrients like nitrogen and phosphorus
   4. Increased water clarity
3. Which type of pollutant includes bacteria and viruses?
   1. Toxic chemicals
   2. Nutrients
   3. Pathogens
   4. Sediment
4. What is thermal pollution?
   1. Contamination by toxic chemicals
   2. Increase in water temperature that harms aquatic life
   3. Excessive nutrients in the water
   4. Physical debris in the water
5. Which of the following is a way to prevent water pollution?
   1. Increasing fertilizer use
   2. Improper waste disposal
   3. Implementing erosion control
   4. Ignoring wastewater treatment
6. What are common nutrients that cause eutrophication?
   1. Sodium and chloride
   2. Nitrogen and phosphorus
   3. Calcium and magnesium
   4. Potassium and iron
7. What is the most common cause of thermal pollution?
   1. Acid rain
   2. Use of water as a coolant by power plants
   3. Agricultural runoff
   4. Vehicle emissions