River Pollution (Cambridge International IGCSE Geography)

Specification checklist

This content page covers the following section of the 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

Spec point — The 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 are 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

Spec point — The impacts of river pollution

Agriculture

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

  • The death of fish and other river wildlife, which introduces bacteria into the water
  • Eutrophication
  • Poisoning fish and other wildlife
  • More sediment is entering the river, which increases turbidity, leading to a decrease in oxygen levels

Industry

• The impacts of industry on the water quality are:

  • Oil stays on the surface of the water, and 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 they remain in the water

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

Management of river pollution

Spec point — An evaluation of the strategies and techniques used to manage river pollution; including sustainable

• 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

Exam Hint In the exam you may be asked to "evaluate" the effectiveness of pollution reduction.

Make sure that you are confident in saying how effective a strategy is. Some examples of evaluation include:

• New laws are effective only if there is monitoring and enforcement, which can be lacking, particularly in LICs
• Treatment plants are effective but they are expensive to build and maintain
• Ecosystem management is sustainable but long-term and needs to be alongside education for farmers