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Pollution - Coggle Diagram
Pollution
NUCLEAR FALL-OUT
This can be the result of a leak from a nuclear power station, or from a nuclear explosion.
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If the radiation has a long half-life, it remains in the environment and is absorbed by living organisms.
The radioactive material bioaccumulates in food chains and can cause radiation diseases like cancer in carnivores.
Probably the worst nuclear fall-out accident in history was Chernobyl in April 1986 Russia. One of the reactor vessels exploded and the resulting fire produced a cloud or radioactive gas, which was carried by the winds over other parts of the Soviet Union and Europe.
The fallout of Chernobyl included more than 4000 deaths(people). Many suffered from birth defects and cancers associated with exposure to radiation.
The fall-out contaminated the soil it fell on and was absorbed by plants, which were grazed on by animals.
Nuclear effects usually tend to last years, and even generations. After Chernobyl, the farmers in Lake District, England were forbidden to sell sheep for meat until June 2012, 26 years after the incident that contaminated the land.
DISCARDED RUBBISH
The development of towns and cities, and the growing population leads to problems of waste disposal.
If not disposed properly, the collective waste of a town (several thousand people), can cause diseases and pollution.
Most of the waste ends up on landfill sites, polluting the air and ground. Th decay from food waste and the overall unhygienic environment attracts insects and vermin. which can spread disease.
Most food products come in packaging which either ends up in a landfill site- poisoning the area, or in the ocean, killing fish and other marine life.
Sometimes, plastic is burned releasing green house gases in the air.
Oil pollution: The oil is lighter than water and thus floats on top, forming an impenetrable layer between the air and water. This kills many aquatic life forms as the oxygen is unable to enter the water.
Birds like ducks, that swim on the water often get covered in oils, and the get poisoned when they try to clean it away.
INSECTICIDES
DDT: was used to control the spread of malaria by killing mosquitos which are the carriers of the disease. Unfortunately, DDT remains in the environment after it was been sprayed and can be absorbed by microscopic organisms and thus, enter food chains.
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example: The insecticide made only a weak solution of 0.015 parts per million (ppm) in the lake water. ----> The microscopic plants and animals that fed in the lake water built up a concentration of 5ppm in their bodies. ----> The small fish that fed on the microscopic plants and animals had a concentration of 10ppm.
Insecticides like DDT are called persistent because they last a long time without breaking down. This makes them good pesticides, but it also means that it stays in the bodies of organisms longer, including humans.
Example 2: In the 1950's in USA, DDT was sprayed on to elm trees to try and control the beetle that spread Dutch elm disease. The fallen, still contaminated, leaves were eaten by earthworms, and then they were eaten by birds. The concentration increased by ten times in each organism, leaving the birds with a mortality rate of about 30-90%.
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SEWAGE
Diseases like typhoid and cholera are caused when certain bacteria find their way into the human intestine.
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If the bacteria gets into the drinking water they may spread to hundreds of other people. This is why, among other reasons, untreated sewage must not be emptied into rivers.
It is treated at the sewage works so that all the solids are removed. The human waste is broken down and made harmless (free from harmful bacteria and poisonous chemicals).
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When the treated water is discharged into water bodies, the phosphates and nitrates allow the microscopic plant life to grow very rapidly.
EUTROPHICATION
1) Nitrates or phosphates from raw sewage, fertilisers, or other sources enter a water system.
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3) algae form a blanket on the surface of the water, blocking the light from reaching the age below.
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5) bacteria decompose the dead algae, using up the oxygen in the water for respiration.
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CHEMICAL WASTE
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Example: Electroplating produces waste containing copper and cyanide. If these chemicals are released into the rivers they poison the plants and animals and could poison humans who might drink the water.
Sewage treatment or any other kind of purification process would cost the factory time and money. To avoid this, they simply dump their waste into rivers/water.
River Trent receives 850 tonnes of Zinc, 4000 tonnes of Nickel and 300 tonnes of copper each year from industrial processes
In 1971, 45 people in Minamata Bay in Japan died and 120 people were seriously ill as a result of mercury poisoning. It was found that a factory had been discharging a compound of mercury into the bay as part of its waste. Even though the discharged amount was small, it increased in amount as it went further down the food chain, poisoning the fish along the way. The poisoning in the fish was concentrated enough to cause brain damage, deformity and death.
HERBICIDES
These chemicals are used by farmers to control the growth of weeds (harmful plants that leech on resources like the sun and nutrients from the soil. They can be harmful to the crop if not removed.
However, if the herbicides aren't used and broken down straight away they can slip into other ecosystems. They can leach from farmlands into water bodies like rivers and lakes, killing the aquatic plants. This harms various aquatic food chains as the main producer has been removed.
Herbivores lose their food source and die, or migrate. Carnivorous animals are also affected.
Herbicides are non-specific chemicals. They kill any broadleaved plant they come in contact with or are absorbed by.
If herbicides are sprayed in a random manner then there is a risk of them blowing onto surroundings plants and animals, causing them to kill plants beside the one they were supposed to. This can put a lot of ecosystems and food chains at risk.
FERTILISERS
When nitrates and phosphates from farmlands and sewage escape into water they cause excessive growth of microscopic green plants.
Too much growth requires a lot of oxygen too. Thus, this rapid growth may cause a shortage of oxygen in the water, resulting in the death of aquatic animals.