The Human Causes of River Pollution

River pollution occurs when harmful substances enter a river as a result of human activities. Pollution reduces water quality, damages ecosystems, and poses risks to human health. Most river pollution is caused by activities that increase runoff or release waste directly into river systems.

Industrial Pollution

• Factories may discharge chemicals, heavy metals and toxic waste into rivers.
• Pollution can enter rivers directly through pipes or indirectly through surface runoff.
• In some countries, weak environmental regulations increase pollution levels.
• Industrial pollution can kill aquatic life and make water unsafe for human use.

Sewage and Wastewater

• Untreated or poorly treated sewage may be released into rivers.
• Sewage contains bacteria, nutrients and organic waste.
• This can cause disease and reduce oxygen levels in the water.
• During heavy rainfall, sewage systems may overflow, increasing pollution.

Agricultural Pollution

• Fertilisers used on farmland can be washed into rivers by rainfall.
• These fertilisers contain nitrates and phosphates.
• They can cause eutrophication, leading to excessive plant growth and reduced oxygen.
• Pesticides may also enter rivers, harming wildlife.

Urban Runoff

• Rainfall washes pollutants from roads and buildings into rivers.
• Pollutants include oil, fuel, litter and chemicals.
• Urban areas have impermeable surfaces, increasing runoff.
• This causes pollution to reach rivers quickly and in large quantities.

Litter and Solid Waste

• Plastic waste and rubbish may be dumped directly into rivers.
• Litter can block channels and damage habitats.
• Animals may ingest plastic or become trapped.
• Waste can travel long distances downstream, increasing pollution elsewhere.

Mining

• Mining releases toxic metals, including mercury and lead.
• Waste material may be washed into rivers.
• Acid mine drainage can make river water acidic.
• This severely damages aquatic ecosystems.

River Transport and Tourism

• Boats and ships may release oil, fuel or waste into rivers.
• Tourism increases litter and sewage pollution near rivers.
• Increased human activity places pressure on river environments.

Construction and Land Clearance

• Building work exposes soil.
• Rain washes loose sediment into rivers.
• This causes sedimentation, reducing water quality.
• Sediment can smother habitats and block sunlight.