Waste and pollution
Definition
Pollution
The release of harmful substances into the air, water or land.
- A growing human population and a rising standard of living mean more resources are used and more waste is produced.
- Unless this waste and the chemicals in it are handled properly, they cause pollution.
- Pollution kills plants and animals, which reduces biodiversity.
Key Idea
More people living at a higher standard of living produce more waste, and poorly handled waste becomes pollution that lowers biodiversity.
The three kinds of pollution
- Water is polluted by sewage, fertilisers and toxic chemicals that drain into rivers, lakes and seas.
- Air is polluted by smoke and by acidic gases such as sulfur dioxide, which cause acid rain.
- Land is polluted by landfill waste and by toxic chemicals such as pesticides and industrial waste.
Common Mistake
- Do not just write that pollution is bad.
- Say where it happens (water, air or land) and what causes it, such as sewage or acidic gases.
How pollution reduces biodiversity
Definition
Biodiversity
The variety of all the different species of organisms in an ecosystem or on Earth.
- Pollutants can kill organisms directly or make a habitat unsuitable for them.
- When sensitive species die out, the variety of species in the habitat falls, so biodiversity is reduced.
- Fertilisers washed into water cause extra harm by removing the oxygen that aquatic animals need.
Self review
- Why does a growing population produce more waste and pollution?
- Give one cause of water pollution, one of air pollution and one of land pollution.
- How does pollution reduce biodiversity?
- Which acidic gas causes acid rain?
