Detailed Specific Example: Nairobi River

Causes of pollution in the Nairobi River

Causes of pollution in the Nairobi River

Background

• The Nairobi River is 390 km long

• Its source is in the Ondiri swamp to the west of Nairobi

• Flowing through Nairobi, the capital city of Kenya

• Over 50% of the state's population lives on the banks of the river

• Much of the pollution in the river comes from the informal settlements such as Kibera and Mathare which do not have sewage or sanitation systems

  • This introduces pathogens into the water

• The city does not have an effective waste management system

• The river contains various types of pollutants as well as sewage, including:

  • plastics

  • petrochemicals

  • heavy metals

  • disinfectants

  • detergents

Solid waste

• It is estimated that 2475 tonnes of waste is produced in the city every day

  • Much of this is disposed of in the river

khyk54, CC BY 2.0, via Wikimedia Commons

Industrial waste

• Many industries such as cloth manufacturers and tanneries dispose of waste directly into the river; these include heavy metals and toxins

• Mining waste is washed into the river and its tributaries by rain

Agricultural waste

• Pesticides and fertilisers used on agricultural land are washed into the river

Impacts of pollution in the Nairobi River

Impacts of pollution in the Nairobi River

• The Nairobi River is the only source of water for many people living in Nairobi

• It is used for cleaning, bathing, washing and watering

• People are consuming the river water, which leads to a range of health issues

  • Bacteria from sewage can lead to diseases such as typhoid, cholera and dysentery

  • Heavy metals and toxins lead to an increase in rates of cancer, damage to human and animal nervous systems and birth defects

• The polluted water is used to irrigate the market gardens, which also increases the risk of diseases

• Fertilisers have increased eutrophication and the growth of water hyacinth

  • Water hyacinth grows very rapidly and can clog the waterways and harm both plant and animal life in the river

  • The oxygen levels in the water are reduced

• The water has a foul smell and bubbles due to the presence of methane gas and hydrogen sulphide

• Aquatic life and habitats are destroyed and damaged by the presence of pollutants in the water

Strategies to manage pollution in the Nairobi River

Strategies to manage pollution in the Nairobi River

• Past efforts to clean the Nairobi River have failed due to a lack of:

  • funding

  • education regarding the impacts of polluting the water

  • enforcement

  • data regarding the levels of pollution

  • effective waste management

• There is also corruption within local and national government

• In February 2023, the Nairobi Rivers Commission was launched

• The commission will:

  • Employ over 12,000 people to clean the river and plant trees

  • Introduce a plastic tax to help reduce plastic pollution

  • Involve and educate local people so they have an understanding of the impact their waste has on the river

• Increased industrial regulation through the National Environment Management Authority (NEMA)

  • This requires industries to remove waste before discharging into the rivers

  • Monitoring and fines have helped reduce toxic waste levels

• Community based clean up programmes such as Clean up Kenya which:

  • Organises regular river cleaning activities

  • Educates residents about proper waste disposal practices

• The Nairobi River Regeneration and Engineering Works Programme was introduced in March 2025

  • This aims to build sewage pipes and treatment plants to prevent untreated wastewater entering the river

• There is also work underway to improve the city's sewerage system with sewage treatment plants such as the Ruai sewage treatment works