Knowlet

Unit 5: Environmental Pollution

Contents

1. Definition and Classification

Environmental Pollution is the unfavorable alteration of our surroundings, wholly or largely as a by-product of human actions. A Pollutant is any substance or energy (heat, noise) that, when introduced into the environment, has undesirable effects.

2. Air and Water Pollution

Air Pollution

Presence of contaminants in the atmosphere like CO, SO2, NOx, and Particulate Matter (PM).

  • Sources: Vehicle emissions, industrial smoke, and burning of fossil fuels.
  • Effects: Respiratory diseases, Acid rain, and Global Warming.

Water Pollution

Contamination of water bodies like lakes, rivers, and oceans.

  • Sources: Industrial effluents, domestic sewage, and agricultural runoff (fertilizers).
  • Effects: Water-borne diseases (Cholera, Typhoid), Bio-magnification, and Eutrophication.

3. Soil, Marine, and Noise Pollution

Type Major Causes Major Effects
Soil Pesticides, Plastics, Mining. Loss of fertility, food chain toxicity.
Marine Oil spills, Plastic dumping. Death of coral reefs and marine life.
Noise Traffic, Construction, Honking. Hearing loss, hypertension, stress.

4. Thermal Pollution and Nuclear Hazards

Thermal Pollution

Degradation of water quality by any process that changes ambient water temperature. Power plants use water for cooling and release warm water back, which lowers Dissolved Oxygen (DO) levels, killing fish.

Nuclear Hazards

Exposure to radioactive substances from nuclear power plants or medical waste.

  • Effects: Genetic mutations, cancer, and long-term environmental toxicity.

5. Solid Waste Management

Management of non-liquid waste from municipal, industrial, and agricultural sources.

  • Landfills: Disposing waste in large pits. Must be lined to prevent Leachate (toxic liquid) from entering groundwater.
  • Composting: Converting organic waste into manure.
  • Incineration: Burning waste at high temperatures.

6. Exam Focus Enhancements

Exam Tips
  • Bio-magnification: Explain how toxins (like Mercury or DDT) increase in concentration at each higher trophic level in a food chain.
  • BOD: Mention Biochemical Oxygen Demand. Higher BOD means more polluted water.
  • Acid Rain Formula: Mention SOx and NOx combining with water vapor to form H2SO4 and HNO3.
Common Mistakes
  • Global Warming vs Ozone Depletion: These are different! Global Warming is caused by CO2 and Methane; Ozone Depletion is caused by CFCs.
  • Pollutant vs Pollution: Don't use them interchangeably. The substance is the pollutant; the process is pollution.
  • Dissolved Oxygen: Forgetting that hot water holds less oxygen than cold water (Thermal Pollution).
Frequently Asked Questions

Q: What is the 3R principle?
A: Reduce, Reuse, and Recycle. It is the most effective way to manage solid waste.

Q: What is a Point Source?
A: A single, identifiable source of pollution, like a pipe from a factory. Non-point sources are scattered, like farm runoff.

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