Amsterdam, Netherlands - Over 80 leading global health, environment, and food advocacy organisations including Greenpeace International, the International Panel of Experts on Sustainable Food Systems and the World Organization of Family Doctors have issued an open letter to the World Health Organization (WHO) urging a review of international drinking water standards for nitrate to protect public health from the growing threat of agricultural pollution.
Amanda Larsson, Global Project Lead for Agriculture at Greenpeace said: "Water should be life-giving, not life-threatening. We cannot protect human health without protecting the groundwater and rivers that sustain us. Governments must take decisive action to curb the growth of intensive livestock farming and actively support producers in transitioning to ecological farming practices – ensuring that clean, safe drinking water isn't a luxury but a guarantee."
Timed to coincide with World One Health Day, marked by the WHO and three other UN bodies to highlight the interdependence between human, animal, and ecosystem health, the coalition is calling on the WHO Secretariat and its Guideline Development Group to formally prioritise nitrate for full evaluation in its upcoming review of global drinking water quality guidelines.[1]
The letter argues that current guidelines are outdated and risk exposing the public to a range of adverse health risks. The existing guideline of 50 mg/L NO₃ (11.3 mg/L NO₃-N) was established in 1958 specifically to prevent infant methemoglobinemia, also known as "blue-baby syndrome". However, a growing body of 21st-century epidemiological research links chronic, low-level exposure to nitrate in drinking water to increased risks of colorectal cancer, preterm birth, and birth defects at concentrations far below the existing threshold.
Dr Pratyush Kumar, Chair of the World Organization of Family Doctors (WONCA) Working Party on Rural Practice said: "Studies now link nitrate in drinking water, at levels well below the current WHO limit, to bowel cancer and premature birth. As a rural family doctor, I support the call to update these limits so that farming families can trust the water they drink. In low-resource areas, that must come with international support, helping communities achieve both chemical and essential microbial safety."
Last year, an international expert panel commissioned by the Danish government concluded that current international standards are insufficient to protect public health, recommending a dramatic reduction of the national nitrate limit to 6 mg/L NO₃ – nearly ten times lower than current WHO benchmark.[2] Following its 2026 election, Denmark committed to revising its national limit in line with this scientific advice. Intensive livestock production and synthetic nitrogen fertilisers are among the primary drivers of nitrate leaching into groundwater and surface water worldwide. Beyond human health risks, excessive nitrogen runoff degrades freshwater ecosystems, accelerates soil degradation, and drives biodiversity loss.
The coalition points to the benefits of source water protection for human and ecosystem health, climate mitigation and nature protection and encourages the WHO to adopt a 'One Health' approach to drinking water nitrate guidelines – one that considers broader ecosystem and long-term public health impacts alongside traditional toxicological limits.
Because national governments generally peg their own drinking water standards to WHO guidelines, the coalition's open letter emphasises that an updated WHO standard is vital for global policy reform.
Olivier De Schutter, co-chair of IPES-Food said:
"Industrial food production is highly dependent on fossil fuels, particularly via synthetic nitrogen fertilisers. This dependence is contributing to climate change, polluting drinking water, harming health, and leaving us vulnerable to volatile energy prices and costly imports. Updating WHO guidelines to reflect the latest science can go hand in hand with a shift towards agroecology - protecting public health, reducing fossil fuel dependence, and building more resilient, self-reliant food systems."
