Lesson 2: Contaminants in the environment

In this lesson, we explore the sources and types of contaminants that impact the environment.

Typical Sources of Pollution

  • Industrial Processes: Manufacturing, mining, and energy production can release chemicals and contaminants into the environment.
  • Agricultural Techniques: The use of pesticides and fertilizers in agriculture has the potential to contaminate water and soil.
  • Transportation: Pollutants like carbon monoxide, nitrogen oxides, and particulate matter are emitted into the atmosphere during transportation.
  • Waste Disposal Facilities: Malfunctions in waste disposal facilities, such as landfills and sewage treatment plants, can lead to contaminant release.
  • Household Activities: Even everyday activities, such as the use of pesticides, cleaning products, and personal care items, can contribute to environmental pollution.
  • Climate Change: Increasing the frequency and severity of natural disasters like floods and wildfires can spread pollutants and waste into the environment, contributing to pollution.

Global Impact of Pollution

  • It’s essential to understand that pollution affects ecosystems and populations worldwide, and it can spread over great distances through wind and water currents.

Chemical Decomposition

  • Chemical decomposition is the process by which a chemical substance is broken down into simpler compounds or components through chemical reactions.
  • This can occur due to human activities like industrial processes and waste disposal, or it can happen naturally due to environmental factors such as sunlight, heat, or other variables.

Mechanisms of Chemical Decomposition

  • Various mechanisms facilitate chemical decomposition, including biological degradation, oxidation, hydrolysis, and photolysis.
  • Some reactions can be catalyzed in the presence of specific chemicals, enzymes, or microorganisms.
  • Factors such as the chemical composition of the compound, the presence of additional chemicals, temperature, and environmental pH can all influence the speed at which chemical decomposition occurs.


  • Pollution sources are diverse, including industrial processes, agriculture, transportation, and household activities.
  • Pollution has a global impact, affecting ecosystems and populations around the world.
  • Chemical decomposition is a key process in understanding how contaminants break down in the environment.
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