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River Pollution

Exam code: 2217
Written by: Ashika|Reviewed by: Caroline Carroll|Updated 2 July 2026

Specification link

This page covers section 1.3.5, 1.3.6 and 1.3.7 of the CIE O Level Geography Specification.

  • 1.3.5 - The human causes of river pollution

  • 1.3.6 - The impacts of river pollution

  • 1.3.7 - An evaluation of the strategies and techniques used to manage river pollution; including sustainable.

Human causes of river pollution

Human causes of river pollution

  • Human activity is the main source of river pollution

  • River pollution occurs when harmful substances contaminate the water

Agriculture

  • Pollutants from agriculture enter the water in several ways:

    • Wastewater from silage and slurry

    • Fertilisers, herbicides and pesticides dissolve in rainwater

    • Soil erosion

    • Traces of medicine from those used to treat animals

Industry

  • Industry pollutes water in several ways, including:

    • Spillages of oil

    • When water is used as a coolant and returned to rivers at higher temperatures

    • Toxic substances from industrial processes being released into rivers

Domestic

  • Domestic premises also discharge polluted water into rivers through:

    • Untreated sewage

    • Water which has been used for washing clothes and bathing

    • Water which has been used for leisure may be treated with chlorine

    • Traces of medicines taken by humans

Impacts of river pollution

Impacts of river pollution

Agriculture

  • Pesticides, herbicides, and fertilisers entering the water lead to the following:

    • Death of fish and other river wildlife which introduces bacteria into the water

    • Eutrophication

    • Poisoning fish and other wildlife

    • More sediment entering the river which increases turbidity, leading to a decrease in oxygen levels

Industry

  • The impacts of industry on the water quality are that:

    • Oil stays on the surface of the water, wildlife and plants become coated in oil and cannot eat/move/fly 

    • Animals and plants within the water system cannot survive in higher temperatures

    • Toxins enter the food chain and are harmful to wildlife and humans

Domestic

  • Sewage and water used in cleaning or that has been treated with chlorine may:

    • Increase the levels of nitrogen in the water and introduce bacteria

    • Be harmful to wildlife

    • Causes chemical burns

  • Medicines are difficult to remove in water treatment so remain in the water

    • These may contain a range of ingredients which are harmful to humans or wildlife

Management of river pollution

Management of river pollution

  • There are three levels of pollution management:

    • Changing human activity

    • Regulating and reducing quantities of pollutants released at the point of emission

    • Cleaning up the pollutants and restoring the ecosystem after pollution has occurred

Reducing human activities that produce pollutants

  • Alternative practices and technologies:

    • Identifying and adopting alternatives to fertilisers and detergents that have less harmful environmental impacts

    • For example, promoting the use of organic fertilisers and eco-friendly detergents can reduce the release of pollutants into water bodies

  • Public awareness and education:

    • Educating the public about the environmental consequences of certain human activities and encouraging changes in behaviour

    • This includes promoting sustainable agricultural practices, responsible waste management, and water conservation

Reducing the release of pollution into the environment

  • Wastewater treatment:

    • Implementing effective wastewater treatment systems to remove pollutants, such as nitrates and phosphates, before the water is discharged back into the environment

    • This includes processes like biological treatment, chemical precipitation, and advanced filtration techniques

  • Industrial regulations:

    • Enforcing strict regulations and standards for industries to control and reduce the release of pollutants into water bodies

    • This can include effluent discharge limits, mandatory pollution control measures, and regular monitoring and reporting of pollution levels

Removing pollutants from the environment and restoring ecosystems

  • Remediation and restoration projects:

    • Introducing strategies to remove pollutants from contaminated sites and restore ecosystems

    • This can involve techniques including:

      • Dredging to remove accumulated sediment, using activated carbon or other absorbents to capture pollutants

      • Re-establishing native vegetation and aquatic species

  • Ecosystem management:

    • Adopting holistic approaches to manage ecosystems and their water quality

    • This includes implementing integrated watershed management plans (sometimes known as the Catchment Based Approach), promoting natural filtration systems (e.g. constructed wetlands), and restoring riparian buffers to minimise pollution runoff