8.7 - Human Impact on the Environment

Pollution of air, water and land

• Humans release waste and harmful substances into the environment.
• This pollution can occur in three places: water, air, and land.
• Whatever its form, pollution harms or kills plants and animals - either directly, or by damaging the conditions they depend on.
• As organisms die, ecosystems change and biodiversity falls.

Pollution in water

• Sewage from homes, fertiliser washed off farmland, and toxic chemicals from industry can all enter lakes, rivers, and oceans.
• These harm the plants and animals that live there.
• A common named example: untreated sewage.

Pollution in air

• Many industrial processes and the burning of fuels release smoke and acidic gases, such as sulfur dioxide, into the atmosphere.
• Carbon monoxide is another harmful gas released when fuels burn - it binds to haemoglobin in red blood cells, reducing the amount of oxygen the blood can carry.
• These gases can harm organisms directly, or sulfur dioxide can fall as acid rain that damages ecosystems.

Pollution on land

• Household and industrial waste is buried in landfill.
• Toxic chemicals can seep from it into the surrounding soil and water, harming the organisms there.