Global Health Groups Urge WHO to Tighten Nitrate Limits in Drinking Water

Keypoints:

• Over 80 global organisations are urging the WHO to review its drinking water standards for nitrate pollution.
• Long-term nitrate exposure has been linked to colorectal cancer, premature births, and birth defects.
• The current WHO limit of 50 mg/L was established in 1958 to prevent blue-baby syndrome.
• A Danish expert panel has recommended lowering its national nitrate limit to 6 mg/L.
• The coalition says stricter standards are needed to address agricultural pollution and protect public health.

More than 80 international organisations are calling on the World Health Organization (WHO) to tighten its drinking water standards, warning that nitrate pollution from agricultural activities could pose growing risks to public health.

The coalition includes Greenpeace International, the International Panel of Experts on Sustainable Food Systems (IPES-Food), and the World Organization of Family Doctors (WONCA). In an open letter, the organisations have urged the WHO to prioritise nitrate for a comprehensive scientific review in its upcoming drinking water guidelines update.

The concern centres on the WHO's existing nitrate limit of 50 milligrams per litre (mg/L), which was established in 1958 primarily to prevent infant methemoglobinemia, commonly known as blue-baby syndrome. However, the coalition argues that this standard does not reflect more recent research linking long-term nitrate exposure to other health conditions.

Studies have associated nitrate in drinking water with increased risks of colorectal cancer, premature births, and birth defects, including at concentrations below the current WHO threshold. The organisations believe these findings warrant a fresh assessment of how much nitrate drinking water can safely contain.

Agricultural activities are among the main sources of the pollution. Intensive livestock farming and the widespread use of synthetic nitrogen fertilisers contribute to nitrate entering groundwater and surface water. Communities that rely heavily on these sources for drinking water could face greater exposure if contamination remains unaddressed.

Amanda Larsson, Global Project Lead for Agriculture at Greenpeace, said governments must address the problem by reducing intensive livestock production and supporting farmers transitioning to ecological farming practices. She argued that protecting drinking water requires action to safeguard the natural water sources that communities depend on.

Denmark has also become part of the growing discussion around stricter nitrate standards. An international expert panel commissioned by the Danish government concluded in November 2025 that existing international limits were insufficient to protect public health. It recommended reducing Denmark's national nitrate limit to 6 mg/L, nearly nine times lower than the current WHO guideline.

Following its 2026 election, Denmark committed to revising its national standard in line with the scientific recommendations. The decision adds momentum to calls for stronger international regulations.

The effects of nitrate pollution extend beyond drinking water safety. Excessive nitrogen runoff can damage freshwater ecosystems, contribute to soil degradation, and accelerate biodiversity loss. The coalition argues that agricultural pollution should therefore be addressed as both a public health and environmental concern.

The campaign was launched around World One Health Day, supported by the WHO and three other UN organisations. The annual observance promotes the idea that human, animal, and environmental health are closely connected. The coalition wants this approach reflected in the WHO's updated drinking water guidelines, with greater attention to long-term health and environmental impacts.

Dr Pratyush Kumar, Chair of WONCA's Working Party on Rural Practice, said updated standards are particularly important for rural communities. He also stressed that countries with limited resources need international support to ensure drinking water is protected against both chemical and microbial contamination.

A revised WHO guideline could have implications for countries worldwide. Many national governments use WHO recommendations as a reference when setting their own drinking water standards. A stricter international limit could encourage governments to strengthen water quality regulations, improve monitoring, and take further action against agricultural contamination.

The organisations also see an opportunity to address the issue through changes in food production. Olivier De Schutter, co-chair of IPES-Food, pointed to the agricultural sector's dependence on fossil fuels, particularly in the production of synthetic nitrogen fertilisers. He argued that shifting towards agroecological farming could reduce water pollution while helping build more resilient food systems.

The coalition's immediate demand is for the WHO to formally prioritise nitrate in its upcoming review. Its decision could shape future drinking water regulations and influence how countries protect public health from agricultural pollution.