Pollution: Physical, Chemical & Biological
- 0:05 Pollution
- 1:32 Physical Pollution
- 3:00 Chemical Pollution
- 5:00 Biological Pollution
- 6:19 Lesson Summary
Pollution is the presence of unwanted substances in an environment. It is often the result of human interference. Learn about physical, chemical and biological pollutants and see examples of each.
Ask someone to describe pollution, and you will get a variety of answers. For some, their mind turns to factories that spew out black smoke into the atmosphere. Others might think about pollution in rivers and streams that is not easily seen but leads to the loss of fish and other aquatic life. Still others will look at the side of the road and notice litter that was carelessly thrown out. Each of these individuals is correct in their description of pollution, and we see that pollution takes many forms. In this lesson, we will learn about different types of pollution and how they impact the environment.
A pollutant is a substance that pollutes the air, water or land. This term is used to describe things in the environment that do not belong. In a broader sense, the term 'pollutant' has even been used to describe undesirable levels of sound or light. For example, the lights and never-ending traffic noise on the Las Vegas Strip are examples of light and noise pollutants.
Pollution is the presence of a pollutant in the environment and is often the result of human actions. Pollution has a detrimental effect on the environment. Animals, fish and other aquatic life, plants and humans all suffer when pollution is not controlled.
Of the different types of pollution, physical pollution may be the most recognizable. Simply stated, physical pollution is the introduction of discarded materials into the environment. Physical pollution is what you might refer to as trash and is the direct result of human actions. In other words, nature does not produce physical pollution because in natural systems, all byproducts or wastes are eventually recycled back into the environment. For example, in nature, a fallen tree will degrade and eventually return nutrients to the soil.
However, physical pollutants, such as discarded water bottles and plastic bags along with waste materials from industrial or manufacturing processes, do not naturally degrade and can accumulate or leach chemicals into the ground or water supplies as they breakdown. Physical pollutants are often sent to landfills, which are designated areas for trash disposal in which the waste is dumped and then covered by soil.
Landfills keep physical pollutants confined to one area, and many modern landfills are lined with layers of clay or plastic to prevent leakage. However, as buried waste products and organic matter decompose, they can release methane gas, carbon dioxide and other gases that are harmful to the environment.
Chemical pollution is another type of pollution. It is defined as the introduction of chemicals into the environment. Chemicals may not be seen by the naked eye, but they can cause problems in all areas of the environment, from the air we breathe to the freshwater we drink to the soil we use for growing crops.
Agricultural practices are one example of a chemical pollution source. Pesticides used to control insects and fertilizers used to make soil more fertile contain nitrogen, phosphorus and other chemicals. These chemicals can run off of a farmer's field and enter waterways. Nitrogen and phosphorus fertilize tiny plant life in the body of water, causing rapid growth and eventually depleting oxygen levels in the water to the point where fish and other species of life cannot survive. Chemical pollution from pesticides and fertilizers can also contaminate soil if used in excess. Other sources of soil contamination include the leaking of chemicals from mines and landfills.
Chemical pollution is also seen in the air. The burning of fossil fuels, such as coal, oil and natural gas, release chemical pollutants into the atmosphere. These fossil fuels may be used in our vehicles or by utilities or industries. These chemical pollutants are referred to as greenhouse gases, which are gases in the atmosphere that absorb infrared radiation and trap heat.
For example, the car you drive to work most likely runs on fossil fuels. As this fuel is burned, the greenhouse gas carbon dioxide is released into the atmosphere. Another example is the release of sulfur dioxide into the atmosphere when coal is burned. Sulfur dioxide contributes to acid rain, which is the phenomenon by which impurities combine with water vapor and fall to the earth.
Up to this point, we have looked at pollution caused by non-living materials or chemicals. However, biological pollution is the introduction of living organisms, which grow and become invasive, into the environment. Like physical and chemical pollution, biological pollution is mainly due to human interference. Not all foreign organisms will thrive in a new environment; however, biological pollutants not only thrive but they adapt to their new surroundings, multiply and spread at a rapid rate.
This can choke-out native species. For this reason, biological pollutants are sometimes referred to as invasive alien species or invasive exotic pests. Some microorganisms, such as bacteria, viruses or fungi that contaminate water or lead to human disease, are examples of biological pollution.
Other examples include invasive weed species that grow in unwanted areas or pests that cause destruction in natural environments, such as the gypsy moth, which is an invasive forest pest that made its way from Europe to the United States where it causes widespread defoliation of trees.
Let's review. A pollutant is a substance that pollutes the air, water or land and pollution is the presence of a pollutant in the environment. Pollution is often the result of human actions and has a detrimental effect on the environment.
Physical pollution is the introduction of discarded materials into the environment, what you might refer to as trash. Physical pollutants are often sent to landfills, which are designated areas for trash disposal in which the waste is dumped and then covered by soil.
Chemical pollution is another type of pollution. It is defined as the introduction of chemicals into the environment. Agricultural practices are one example of a chemical pollution source. Pesticides used to control insects and fertilizers used to make soil more fertile contain nitrogen, phosphorus and other chemicals. These chemicals can contaminate soil or run off into bodies of water where they can deplete oxygen levels. The burning of fossil fuels release chemical pollutants into the air called greenhouse gases and can also lead to acid rain.
Biological pollution is the introduction of living organisms, which grow and become invasive, into the environment. This can choke-out native species. Examples include some microorganisms, invasive weed species and the gypsy moth, which is an invasive forest pest.
Chapters in Environmental Science 101: Environment and Humanity
- 1. Introduction to Environmental Science (5 lessons)
- 2. Ecosystems (10 lessons)
- 3. Interaction Among Organisms in the Ecosystem (8 lessons)
- 4. Evolving Ecosystems (8 lessons)
- 5. Atmospheric Science and the Environment (11 lessons)
- 6. Geological Science (15 lessons)
- 7. Biological Science (12 lessons)
- 8. Pollution of Freshwater Resources (10 lessons)
- 9. Land Resources (8 lessons)
- 10. Population and the Environment (12 lessons)
- 11. Food and Agricultural Resources (12 lessons)
- 12. Solid and Hazardous Waste (9 lessons)
- 13. Human Impact on the Environment (8 lessons)
- 14. Renewable Resources (10 lessons)
- 15. Nonrenewable Resources (7 lessons)
- 16. Environmental Sustainability (5 lessons)
- 17. Environmental Risk Analysis (13 lessons)
- 18. Ethical and Political Processes of the Environment (13 lessons)
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