Waste management (AQA GCSE Biology): Revision Notes
Waste management
What is pollution?
Pollution happens when harmful or poisonous substances get released into our environment. This damages animals and plants, which reduces biodiversity in our ecosystems.
Biodiversity refers to the variety of different species of plants and animals living in an ecosystem. When pollution increases, many species cannot survive, leading to reduced biodiversity.
When we don't manage waste properly, it creates pollution that affects the air, land and water around us.
Sources of pollution
Pollution affects three main areas of our environment, each with different types of harmful substances:
Air pollution
- Smoke and gases from factories and vehicles
- Sulphur dioxide which causes acid rain
- These substances make the air harmful to breathe
Land pollution
- Pesticides - chemicals used to kill pests on crops
- Herbicides - chemicals used to kill weeds on crops
- Toxic chemicals dumped in landfill sites
- These substances poison the soil and harm wildlife
Water pollution
- Sewage containing waste water and human waste
- Fertiliser washed off from farmland
- Toxic chemicals that flow into rivers and seas
- These substances kill fish and water plants
All three types of pollution are interconnected. For example, toxic chemicals from land pollution can eventually wash into water sources, while air pollution can fall as acid rain onto both land and water.
Why is pollution increasing?
The human population is growing rapidly around the world. This creates more pollution because:
- More people = more waste produced
- Higher living standards = people use more resources and create more waste
- More land needed for buildings, farming and waste disposal
- Less space left for wild animals and plants
If we don't handle waste properly, it causes even more pollution problems. This creates a dangerous cycle where increasing population leads to more waste, which leads to more pollution, which further damages our environment.
Real example: Sulphur dioxide pollution
Real World Case Study: Sulphur dioxide emissions from power stations
Coal and oil power stations release sulphur dioxide when they burn fuel. This toxic gas is a major cause of acid rain.
Timeline of changes:
- 2000: Electricity companies began switching from coal and oil to cleaner natural gas
- Result: This change helped reduce sulphur dioxide emissions significantly
- 2010-2012: More coal was used because it was cheaper than oil and gas
- Consequence: This caused total emissions to increase again during these years
This example shows how economic factors can sometimes work against environmental protection.
Key Points to Remember:
- Pollution occurs when harmful substances enter the environment
- Three main targets: air, land and water
- Growing population leads to more waste and pollution
- Proper waste management is essential to protect biodiversity
- Switching to cleaner energy can reduce harmful emissions