In this lesson, students will
The term ‘pollution’ refers to any substance that negatively impacts the environment or organisms that live within the affected environment. There are different types of pollution, which are either caused by natural events like forest fires or by man-made activities like cars, factories, nuclear wastes, etc. Some forms of pollution can be seen, some are invisible.
There are following five major types of pollution:
1. Air pollution
2. Water pollution
3. Soil pollution
4. Noise pollution
5. Radioactive pollution
When unwanted chemicals, gases, and particles enter the air and the atmosphere causing harm to animals and damaging the natural cycles of the Earth.
Natural sources of air pollution are volcanic eruptions, dust storms and forest fires.
Common manmade sources of air pollution are factories, power plants, cars, airplanes, chemicals, fumes from spray cans, and methane gas from landfills.
Burning of fossil fuels leads to the formation of smog, a dense layer of particulate matter that hangs like a cloud over many cities and industrial zones.
Air pollution contributes to respiratory problems such as asthma, lung cancer, chronic bronchitis, and other lung ailments. Nitrogen and sulfur oxides in the air contribute to acid rain, which is a form of precipitation with a lower (more acidic) pH than normal. Acid rain harms forests, species that live in water bodies, and degrades outdoor statues, monuments, and buildings.
It is the pollution of bodies of water, such as lakes, rivers, the oceans, as well as groundwater. It occurs when pollutants reach these bodies of water, without treatment.
Runoff from agricultural fields, industrial sites, or urban areas is a major source of water pollution. Runoff disrupts the water body’s natural balance. For example, agricultural runoff typically includes fertilizer or toxic chemicals. Fertilizer can cause algal blooms (an explosive growth of algae) choking out other plants and decreasing the amount of available oxygen necessary for the survival of other species.
Another type of water pollutant is raw sewage. When sewage gets into the drinking water supply, serious stomach and digestive issues may result, including the spread of diseases such as thyroid or dysentery. Bacteria in the water will use oxygen to break down the sewage. If there is too much sewage, the bacteria could use up so much oxygen that there won’t be enough left for the fish.
Trash is another source of water pollution. Improperly disposed items such as plastic bags, fishing line, and other materials may accumulate in the water and lead to the premature death of animals that get tangled within the garbage.
Oceans are polluted by oil on a daily basis from oil spills. An oil spill from a tanker is a severe problem as there is a huge quantity of oil spill into one place. Oils cannot dissolve in water and form a thick sludge in the water. This suffocates fish, gets caught in the feathers of marine birds stopping them from flying and blocks light from photosynthetic aquatic plants.
Land pollution is damage or contamination of the soil. It is also known as soil pollution. You have seen garbage on the streets that are not cleaned – this is a form of land pollution.
It is caused by many chemical substances which come from different sources like
The evaporation of irrigation water leaves salt in soil producing salinization – a type of soil pollution.
Land pollution damages our environment which is very harmful to all living things. Increase land pollution can cause many diseases including cancer and skin infections. Pollutants often get absorbed in the land and mix with the groundwater below the surface which further pollutes the land.
Landfills are used to dispose of the waste products by burying them into the land. As a result, the surrounding land is damaged. Moreover, landfills also release methane gas which increases the effect of global warming.
It is also known as sound pollution. It is generally defined as regular exposure to elevated and disruptive sound levels that may lead to adverse effects in humans or other living organisms.
According to the WHO, sound levels less than 70dB are not damaging to living organisms, regardless of how long or consistent the exposure is. Exposure for more than 8 hours to constant noise beyond 85dB may be hazardous.
Sound from the wind, rain, storms, trees, birds, and animals are natural noises.
Sounds from vehicles, loudspeakers, construction machines, and airplane engines are all man-made noises.
This type of pollution impacts the movement of sea mammals, such as dolphins and whales, and also impacts the nesting success of birds.
It is rare but extremely detrimental, and even deadly when it occurs. It is the contamination of the environment with radioactive materials, where these materials are not present. Many radioactive substances have very long half-lives; this means that if they are present in the environment, they can be very dangerous for a very long time. Many nuclear power plants produce such substances; usually, they are processed to radioactive waste.
Sources of radioactive contamination include:
Radioactive pollution can cause genetic mutations. It damages DNA strands and causes a genetic break up in the course of time. Infertility, birth defects and impairment are reported due to genetic mutations. The resulting mutation makes one highly susceptible to cancer. For example, radiation in the bone marrow causes leukemia.
Exposure of radiation to the atmosphere also causes radiation to enter the soils. Radioactive substances react with the nutrients in the soil and destroy them, thus rendering the soil infertile and highly toxic. The crops grown on such soils are also toxic for human and animal consumption.
