Global groups press WHO to update old water nitrate limits

UPDATE - follow-up to WHO urged to review drinking water standards amid nitrate health fears: Dozens of global health and environmental organisations urged the World Health Organization on Tuesday to revise decades-old standards for nitrate levels in drinking water. In an open letter, 85 groups including Greenpeace International and the World Organization of Family Doctors asked the UN agency to include nitrate in an upcoming drinking water guideline review.

Current Standards

The current WHO guidelines set the maximum acceptable nitrate level at 50 milligrammes per litre as nitrate or 11.3 milligrammes per litre as nitrate-nitrogen. These rules date back to 1958 and were set to prevent blue-baby syndrome, a deadly blood disorder that reduces the body's oxygen-carrying capacity. However, the letter argues these limits are outdated and fail to reflect recent evidence linking chronic, low-level nitrate exposure to colorectal cancer and adverse birth outcomes.

Evidence and Demands

Studies now connect nitrate in drinking water at levels well below the current limit to bowel cancer and premature birth. Surface water models show that hundreds of millions of people worldwide face exposure to elevated nitrate levels. Amanda Larsson from Greenpeace stated that governments must curb intensive livestock farming and support a shift to ecological farming. An expert panel commissioned by the Danish government last year recommended lowering the limit to 6.0 mg/L, and Denmark committed to this change earlier this year. Most national governments follow WHO standards, making an update vital for global policy reform.

Context

Nitrates in water mostly come from intensive farming and runoff from heavy fertilizer use and livestock waste. Because many countries rely directly on international health rules to set their domestic laws, any change by the UN health agency typically triggers widespread policy reviews globally.