River pollution Cambridge IGCSE Geography revision
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In plain words
A river carries away whatever is put into it, which makes it a tempting place to dump waste. But the people and wildlife downstream then have to live with it.
6 things to know
- Human causes of river pollution: untreated sewage from towns; waste and hot water from factories; fertilisers and pesticides washed off farmland; oil and litter, including plastic; and waste from mining.
- Fertilisers and sewage add nutrients to the water. Algae grow quickly and block the light. When they die, bacteria that decompose them use up the oxygen, and fish die. This is eutrophication.
- Impacts on people: diseases such as cholera and typhoid from dirty drinking water, loss of fishing, and higher costs of treating water.
- Impacts on the environment: fish and other wildlife are killed, food chains are damaged, and the river becomes unpleasant to see and smell.
- Management: treating sewage before it is released; laws limiting what factories can discharge, with fines; buffer strips of vegetation between fields and rivers; and less use of fertiliser.
- Other measures: education and clean-up campaigns, and monitoring water quality. These need money and enforcement, which is harder in low-income countries.
Worked example
Explain how fertiliser from a farm can kill fish in a nearby river.
- Rain washes fertiliser from the fields into the river, adding nutrients to the water.
- The nutrients make algae grow rapidly, covering the surface and blocking sunlight.
- Plants below die. Bacteria decompose them and the dead algae, using up the oxygen dissolved in the water.
- Fish die from lack of oxygen.
Tips and tricks
- Follow the chain all the way to the oxygen. "Fertiliser poisons the fish" is wrong: they suffocate.
- Give causes from three different places: farms, factories and homes. It shows the range of your knowledge.
It lands in your notebook with its questions as flashcards.
River pollution: 5 questions and answers
These are the quiz’s questions. Do the quiz first, then come back here for the ones that got you.
Which is a cause of river pollution from farming?
Rain carries it into the river.
What is eutrophication?
Fish die when the oxygen is used up.
Which disease is spread by polluted drinking water?
It is caused by bacteria in water contaminated by sewage.
Which is a way of reducing pollution from sewage?
Treatment works remove harmful material.
Why is managing river pollution harder in low-income countries?
Clean water needs investment.
Quiz
5 questions
Tap an answer and you’ll see straight away whether it’s right, and why.
Worksheet
3 questions, 9 marks. Write your answers on paper, then check them.
River pollution
Cambridge IGCSE Geography 0460 · 9 marks · papermunch.org
Name ______________________________ Date ______________
State three human causes of river pollution.[3]
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Untreated sewage. Fertilisers and pesticides washed from farmland. Waste discharged by factories. (Also: plastic litter, mining waste.)
Describe two strategies used to manage river pollution.[4]
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Sewage treatment works clean waste water before it reaches the river. Laws limit what factories may discharge, with fines for breaking them. (Also: buffer strips beside fields.)
Give two impacts of river pollution on people.[2]
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Diseases such as cholera, from drinking polluted water. Loss of income from fishing.
Answers: River pollution
- 1. Untreated sewage. Fertilisers and pesticides washed from farmland. Waste discharged by factories. (Also: plastic litter, mining waste.)
- 2. Sewage treatment works clean waste water before it reaches the river. Laws limit what factories may discharge, with fines for breaking them. (Also: buffer strips beside fields.)
- 3. Diseases such as cholera, from drinking polluted water. Loss of income from fishing.