NZ Study Links Nitrates in Drinking Water to Premature Births

A national study in New Zealand has found a significant association between nitrate-contaminated drinking water and premature births. Researchers at the universities of Canterbury, Otago and Massey estimated that, if the relationship is causal, nitrate exposure could account for about 120 premature births a year – 4% of pregnancies ending between 20 and 37 weeks.

The increased risk was observed even at levels far below New Zealand’s legal limit of 11.3 milligrams per liter for nitrates in drinking water. The association grew stronger as nitrate concentrations rose, particularly for more severe outcomes.

Nitrate pollution is largely attributed to intensive agriculture, particularly the use of synthetic nitrogen fertilizer and run-off from livestock manure. New Zealand’s dairy sector is the country’s largest export earner and is expected to generate a record NZ$28.6bn ($16.56bn) in revenue in the year to June 2026.

Greenpeace has called for tighter regulation of the dairy industry and limits on the amount of synthetic nitrogen fertilizer applied to farmland.

Industry body DairyNZ said questions concerning public health and drinking-water standards were matters for health and regulatory agencies responsible for assessing the scientific evidence.

The study, which is due to be published in the peer-reviewed journal Environmental Research in September, analyzed more than 735,000 births between 2008 and 2021.

(Reuters, Max)