Water Pollution and Microbial Diseases for All India Sainik Schools Entrance Examination
1. What is water pollution?
Answer: Water pollution is the contamination of water bodies (such as rivers, lakes, and oceans) due to the discharge of harmful substances like chemicals, waste, and microorganisms, making it unsafe for human use and aquatic life.
2. What are the major sources of water pollution?
Answer: The major sources of water pollution include:
- Industrial Waste: Factories release chemicals and toxins into water bodies.
- Sewage and Wastewater: Untreated sewage water contains harmful bacteria and viruses.
- Agricultural Runoff: Excess fertilizers and pesticides mix with water sources.
- Oil Spills: Leakage from ships and industries pollutes water bodies.
- Plastic Waste: Non-biodegradable plastics choke marine life and contaminate water.
3. How does water pollution affect human health?
Answer: Water pollution can cause various health issues, such as:
- Diarrhea and dysentery
- Cholera
- Typhoid
- Hepatitis A
- Skin infections
- Heavy metal poisoning (lead, mercury)
4. What are microbial diseases? Give examples.
Answer: Microbial diseases are infections caused by microorganisms like bacteria, viruses, fungi, and protozoa. Examples include:
- Cholera (caused by Vibrio cholerae)
- Typhoid (caused by Salmonella typhi)
- Hepatitis A (caused by Hepatitis A virus)
- Dysentery (caused by Shigella bacteria or Entamoeba histolytica)
5. How can we prevent water pollution?
Answer: Water pollution can be prevented by:
- Treating industrial and sewage waste before discharge.
- Using organic fertilizers instead of chemical fertilizers.
- Avoiding plastic disposal in water bodies.
- Promoting rainwater harvesting and water conservation.
- Spreading awareness about the importance of clean water.
6. How can microbial diseases be controlled?
Answer: Microbial diseases can be controlled by:
- Drinking boiled or purified water.
- Practicing good hygiene and sanitation.
- Proper waste disposal.
- Vaccination against diseases like Hepatitis A and Typhoid.
- Using antibiotics and medicines as prescribed by doctors.
7. Do You Know?
💧 Over 80% of wastewater is discharged untreated into water bodies worldwide.
💧 A single liter of untreated sewage can contaminate thousands of liters of clean water.
💧 Cholera outbreaks are common in areas with poor sanitation and unsafe drinking water.
8. What are the effects of water pollution on the environment?
Answer: Water pollution negatively impacts the environment in several ways:
- Death of Aquatic Life: Pollutants reduce oxygen levels, harming fish and other aquatic organisms.
- Disruption of Ecosystem: Toxic substances can disrupt the food chain.
- Loss of Biodiversity: Contaminated water leads to the extinction of certain species.
- Eutrophication: Excess nutrients from fertilizers cause excessive algae growth, depleting oxygen levels.
- Groundwater Contamination: Pollutants seep into underground water sources, making them unsafe for drinking.
9. What are some common waterborne diseases, their causes, and symptoms?
| Disease | Caused by | Symptoms |
|---|---|---|
| Cholera | Vibrio cholerae | Severe diarrhea, dehydration |
| Typhoid | Salmonella typhi | High fever, weakness, stomach pain |
| Hepatitis A | Hepatitis A virus | Jaundice, fatigue, nausea |
| Dysentery | Shigella/Entamoeba | Bloody diarrhea, stomach cramps |
| Polio | Poliovirus | Muscle weakness, paralysis |
10. How does water get naturally purified?
Answer: Water undergoes natural purification through:
- Sedimentation: Heavy particles settle at the bottom.
- Filtration through soil: Soil acts as a natural filter, removing impurities.
- Evaporation and Condensation: The water cycle purifies water through evaporation and rainfall.
- Bacterial Action: Some bacteria decompose organic waste, helping to clean water.
11. What are some methods of water purification at home?
Answer:
- Boiling: Kills harmful microorganisms.
- Filtration: Removes physical impurities.
- Chlorination: Adding chlorine to kill bacteria.
- RO (Reverse Osmosis): Removes dissolved impurities.
- UV Purification: Destroys bacteria and viruses using ultraviolet light.
12. Conceptual Questions
✅ Why is boiling considered the safest way to purify drinking water?
✅ What are the long-term effects of consuming polluted water?
✅ How can communities work together to prevent water pollution?
✅ Why do slum areas suffer more from waterborne diseases?
13. Quick Revision Points
✔ Water pollution is caused by industrial waste, sewage, plastics, and chemicals.
✔ Microbial diseases like cholera and typhoid spread through contaminated water.
✔ Preventing water pollution helps in reducing waterborne diseases.
✔ Clean drinking water can be obtained through filtration, boiling, and purification.
✔ Waterborne diseases can be controlled by improving hygiene and sanitation.
14. Worksheet (Practice Questions)
📝 Fill in the blanks:
- The main cause of cholera is ________ water.
- ________ is a viral disease that affects the liver and is caused by contaminated water.
- The process of removing contaminants from water is called ________.
- Untreated sewage water contains harmful ________ and ________.
- The excessive growth of algae due to high nutrient levels in water is called ________.
📝 True or False:
- Boiling water does not kill bacteria. (False)
- Eutrophication increases oxygen levels in water. (False)
- Hepatitis A is caused by bacteria. (False)
- Industrial waste is a major cause of water pollution. (True)
- Using RO filters can help purify drinking water. (True)
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📖 Written by Neeraj Anand
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