Experts warn Denmark’s proposed nitrate limit still leaves cancer risk in drinking water

Danish researchers say the government’s planned nitrate limit of 6 mg/L in drinking water will still expose citizens to cancer risks, with data showing a stricter threshold could prevent four times as many colorectal cancer cases, DR reports.

Environment Minister Magnus Heunicke (Social Democrats) has proposed lowering the current nitrate limit from 50 mg/L to 6 mg/L, arguing the change would ensure “drinking water does not cause cancer.” But calculations from the ministry’s own expert group reveal the new limit would only prevent an estimated 57 colorectal cancer cases annually—far fewer than a tighter restriction.

Amalie Timmermann, a member of the expert panel and associate professor at the University of Southern Denmark, confirmed that reducing the limit further—such as to 1.3 mg/L—could spare around 213 cancer cases per year. “The lower the threshold, the more cases we can prevent,” she said, though she noted greater uncertainty at very low levels.

Lea Sletting Jakobsen, a senior researcher at DTU Food Institute, called the 6 mg/L proposal insufficient for full protection: “Health-wise, this limit still means we’ll see cancer cases linked to nitrate in drinking water.” She described the decision as a political trade-off between cost and public health, adding, “It’s a fair balancing act, but one that must be acknowledged.”

Heunicke, who declined an interview, told DR in writing that he followed the expert group’s advice but is awaiting further input from the Danish Health Authority. He acknowledged the “scientific debate” over the precise limit but did not address why he chose 6 mg/L despite data showing stricter thresholds could save more lives.

The issue has been central to Denmark’s election campaign, with water quality emerging as a key concern. Heunicke previously stated in a March radio interview that the 6 mg/L limit would eliminate cancer risks from tap water—a claim experts now contradict.