Types of Freshwater Pollution and Effective Legal Challenges

In high-income countries and many emerging economies, agriculture is the main source of water degradation as it causes eutrophication. Eutrophication happens when nitrogen and phosphorus, commonly from fertiliser runoff, enter water, which leads to algal blooms, murky water, and a lack of oxygen to support life in freshwater. The expansion and intensification of agricultural systems, in particular with regard to increasing production of animal feed and livestock, have led not only to land clearing, but also to the unsustainable overuse and misuse of agrochemicals such as nitrogen and phosphorous fertilisers and pesticides, and drugs such as antibiotics used to accelerate growth of livestock. These have increased the pollution loads in freshwater. Livestock production accounts for 70% of all agricultural land and 30% of the land surface of the planet. The livestock sector is one of the top three contributors to the most serious environmental problems, including water-quality degradation, at every scale from local to global.

Agricultural runoff is the excess water from farms that carries pollutants from industrial agriculture such as pesticides, fertilisers, phosphate, nitrogen, ammonia (air emissions) chemicals, waste and soil into water sources. It can have negative impacts on the environment and health. 

These include:

1. Polluting surface water with harmful substances that affect aquatic life and drinking water supplies, leading to algal blooms and dead zones. 
2. Degrading groundwater that many people and animals depend on for clean drinking water
3. Damaging wetland habitats that are vital for certain plants and wildlife.  

Examples

1. In Galicia, Spain, the proliferation of over 300 intensive animal farms in the region since 2011, led to severe odours and water contamination, making life “unviable” for citizens. Seven citizens, alongside NGOs ClientEarth and Friends of the Earth Spain, brought a case against the authorities. They argued that residents faced serious health risks as pollution levels rose in the local reservoir and had to endure unbearable odours that left them unwilling to open their windows in the summer. The lawsuit drew on scientific evidence revealing the presence of antibiotic-resistant superbugs in the water – listed by the World Health Organisation (WHO) as one of the top ten threats to humanity – and “an extremely high level of nitrates”, a risk factor for several cancers, as well as non-Hodgkins lymphoma and methemoglobinemia.

In the 2025 landmark decision, the High Court of Galicia ordered the authorities to restore the environment, stating:

“Human rights and environmental protection are interdependent. A sustainable environment is necessary for the full enjoyment of human rights, including the rights to life, to an adequate standard of living, to drinking water and sanitation, to housing, to participation in cultural life and to development.

“Residents of the village of As Conchas who live in the affected area are found to be in a serious situation concerning their enjoyment of daily life. This includes the presence of foul odours, the risk of aerosol exposure, contamination of private wells to levels that render them unusable, loss of property value, and a severe potential health risk… the court finds that they are undeniably experiencing ongoing moral harm.”

The court recognised that allowing years of environmental pollution, including, water, air and environmental pollution caused by more than 300 intensive livestock facilities can amount to a violation of fundamental rights. 

Specifically, the High Court of Justice of Galicia ruled that administrative inaction violated:

• The right to life and prohibition on degrading treatment (Articles 15 of the Spanish Constitution and 2 and 3 of the ECHR);
• The right to private and family life (Articles 18 of the Spanish Constitution and 8 of the ECHR);
• The right to property (Article 33.1 of the Spanish Constitution and Article 1 of Protocol 1 of the ECHR);
• The right to enjoy a healthy environment (Art 45 Spanish Constitution) 

The court ordered both remedial action to clean up the pollution and compensation to be paid to claimants.

1. In the UK, the Environment Agency prosecuted a North Devon company that caused a pollution incident leading to a devastating fish kill on the River Mole near South Molton. The company was fined £2,000 and ordered to pay £9,836 in costs. An employee negligently spread digestate on a field when rain was forecast, and the digestate washed into the river, killing approximately 15,600 fish. The company and employee pleaded guilty to causing the discharge.

1. In the UK, the Herefordshire Council, a local government body, created a new policy that required industrial livestock units to demonstrate that the waste produced would be managed in a way that would not pollute rivers and protected nature areas. This was done because the River Wye catchment had very poor water quality due to the enormous number of factory chicken farms in the region. The National Farmers Union (NFU) brought a legal challenge against the policy, which failed. The high court held in NFU v Herefordshire Council [2025] EWHC 536 that chicken manure can be considered a toxic waste, and that the local planning authorities are not obliged to assume that environmental regulations (in this case, the ‘Farming Rules for Water’) will effectively protect the environment, when the evidence shows otherwise. This was an example of using regional policy tools to prevent future pollution.

1. In the UK in 2024, River Action (an NGO) brought a legal complaint against the Environment Agency due to the pollution of the River Wye with agricultural runoff. The Complaint notes that phosphorus pollution from the explosion of intensive poultry units has damaged the river’s ability to support unique plant and animal life by causing large algal blooming events. 

1. Legal challenges against intensive animal farm developments can be used preventatively to stop factory farming pollution from taking hold. This is much less expensive than trying to clean up pollution after it’s started, or trying to stop a pollution development after it’s been built. For example, in the UK, Communities Against Factory Farming (CAFF) successfully overturned three approval decisions for intensive chicken farms 2025-26.  Two cases settled ahead of any hearing, with the councils agreeing to consent to have their decisions overturned by the high court. In one case, the applicant (the developer) planned to build an intensive chicken farm next to an existing intensive dairy farm. CAFF argued that the Environmental Impact Assessment screening unlawfully overlooked cumulative odour, pollution, nuisance, and water-abstraction impacts when assessed alongside the neighbouring intensive dairy unit. 

Freshwater pollution caused by mining activities can take many forms and occur at various stages in the mining process. Most commonly, pollution can occur when mining and storing polluting metals, such as lead, gold, and silver. Mining activities may also cause pollution via secondary processes which take place after the initial process of mining. This could include the extraction of minerals from ore using chemicals such as mercury or acids, or via the failure of storage methods such as dams and waste heaps. Chemicals and toxic minerals can spill into rivers and streams and, in turn, this can cause contamination of water used for human consumption, washing, agriculture and fishing. This may subsequently cause problems for communities who may  experience serious health issues and even death. 

Examples

1. In the landmark Colombian Constitutional Court case Sentencia T06/25 (mercury pollution from mining in Amazonian Indigenous territories), a group of 30 indigenous peoples brought a constitutional claim (‘tutela action’) to address the mercury pollution from illegal gold mining. According to a 2024 report, illegal mining activity exists in 29 of Colombia’s 32 departments. Mercury, commonly used to separate precious metals from worthless sediments, had been detected in these regions in natural environments. The claimants argued not only that the mercury pollution was poisoning the water and contaminating fish, a food source, but also that the pollution in the indigenous territory negatively impacted the traditional medicine cycle, food sovereignty, and cultural identity.

The court found that many fundamental rights had been violated by the mercury pollution, including:

1. The right to a healthy environment;
2. The right to self-determination of Indigenous Peoples and administrative due process;
3. The right to health of indigenous communities;
4. The right to food security and indigenous food systems;
5. The right to water;

The court also found breaches of :

1. Environmental protection laws for the Amazonian region;
2. The precautionary principle in environmental law;
3. Breaches of due diligence and due process laws. 

This case demonstrates how domestic and international laws protecting the environment and fundamental human rights can be used together to compel the courts to order the state to make changes. The International Court of Justice (ICJ) also confirmed the linkage between environmental law and human rights in international law in its 2025 advisory opinion on the obligations of states in respect of climate change, concluding ‘under international law, the human right to a clean, healthy and sustainable environment is essential for the enjoyment of other human rights.’

The Colombian Constitutional Court made several declarations and orders to various regional and national government agencies designed to remedy the damage caused by mining pollution and prevent it in future. It declared that the identity, health, survival, and food security of the Yuruparí Affinity People was at risk. The court ordered the creation of a dialogue group with different entities and communities to discuss environmental and mining issues, along with the following orders:

1. Implementation of a comprehensive health care strategy (order no 22b).
2. Suspension of new gold mine licenses (order no 6).
3. Promotion of legislative actions for environmental conservation and remediation in the amazon (order no 26).
4. Conduct a baseline study on water pollution in the macro-territory (order no 7).
5. Design a programme to decontaminate water sources (order no 8).
6. Create a training programme to investigate environmental crimes (order no 11).
7. Create an opportunity for intercultural and interinstitutional dialogue on identity and territory (order no 13).

1. In Zambia, an acid spill from a mine left the local water yellow and unfit for consumption. In 2015, a group of 1826 Zambian villagers filed a lawsuit against Vedanta Resources in the UK court over water pollution caused by its subsidiary’s copper mining operations (Konkola Copper Mines). They claimed that the water pollution from the Nchanga Copper Mine damaged their lands and livelihoods. On 19 January 2021, the parties agreed to settle the claims without Vedanta’s admission of liability and the case is now closed.

Oil pollution is often caused by the spillage of oil from extraction and transportation processes into surrounding lakes, rivers and streams. This can occur directly or indirectly for various reasons including negligence in maintenance, industrial accidents and criminal damage, all of which can cause freshwater pollution and have devastating effects on the natural environment and human health. 

Examples 

1. In the Nigerian case of Gbemre v. Shell Petroleum Development Company of Nigeria Ltd. and Others (2005), the Niger Delta Iwherekan community brought a case against the government for failing to stop pollution from Shell. Among other things, the court found that flaring of gas in the course of oil production caused acid rain which in turn acidified the community’s lakes and streams and damaged vegetation. The judge found that gas flaring was in breach of the citizen’s right to a healthy environment and ordered steps be taken to stop the gas flaring immediately, but made no award of damages or costs.

1. The more recent and large-scale litigation against Shell for pollution of water and waterways in Nigeria is addressed in more detail below under Claims Against Polluters in Foreign Jurisdictions.

1. Over three decades of oil drilling in the Ecuadorian Amazon, Chevron dumped more than 16 billion gallons of toxic wastewater, and millions of litres of oil, into the rainforest, leaving local people suffering a wave of cancers, miscarriages, and birth defects. Despite numerous litigation efforts over 30 years, no redress has yet been obtained. The case began in 1993 when a human rights lawyer filed a class action suit against Texaco in New York on behalf of the affected people in Ecuador, Aguinda v Texaco. The American court ruled that the case should be tried in Ecuador. The Ecuadorian Supreme Court found in favour of the indigenous people in 2011 and ordered Chevron (who had bought Texaco) to pay USD 9.5 billion in damages, however US courts blocked the claimants from collecting the payment. Chevron  i) refused to pay, ii) took a number of actions against the lawyer representing the indigenous people and brought what was widely perceived as a SLAPP (Strategic Litigation Against Public Participation) suit against him, and iii) brought arbitration proceedings against Ecuador under the US-Ecuadorian Bilateral Investment Treaty. US courts, the arbitration tribunal, and Dutch courts found in favour of Chevron, finding that the Ecuadorian judgment was procured by fraud and corruption.  

Cases of this type are very unusual but illustrate some of the difficulties in holding corporations to account for water (or other) pollution.