Geneva (Switzerland) (AFP) - Dozens of international health and environmental organizations on Tuesday asked the World Health Organization to review decades-old standards on the amount of nitrates considered safe in drinking water.

First modification: 03/11/2026 - 13:05

In an open letter, 85 organisations, including Greenpeace International and the World Organization of Family Physicians (WONCA), asked the UN health agency to include nitrates in the next review of its water quality guidelines.

The toxic effects of nitrates, waste products mainly associated with intensive agriculture, are widely recognized as especially dangerous for children and pregnant women.

However, the current World Health Organization (WHO) limits, which set a maximum concentration of 50 milligrams per liter of nitrate or 11.3 milligrams per liter of nitrogen from nitrates, date back to 1958 and are "obsolete," the organizations warned.

That threshold was set specifically to prevent so-called "blue baby syndrome," a potentially fatal disorder that reduces the blood's ability to carry oxygen.

But the letter maintains that the limit "has not been updated despite strong epidemiological evidence" linking chronic exposure to low levels of nitrates with long-term health risks, particularly "colorectal cancer and adverse pregnancy outcomes."

"Studies now link nitrates in drinking water, even at levels well below the current WHO limit, with bowel cancer and premature births," WONCA president Pratyush Kumar said in a joint statement.

The letter was released to coincide with "One Health" Day, a day promoted by the WHO to highlight the interconnection between human, animal, plant and ecosystem health.

The signatories warned that hundreds of millions of people around the world are exposed to high levels of nitrates.

"Water should give life, not endanger it," said Amanda Larsson, global head of agriculture at Greenpeace.

"We cannot protect human health without protecting the groundwater and rivers that sustain us," he added.

© 2026 AFP

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