Jenna Ladd | October 4, 2016

A recent review of dozens of health studies by the Iowa Environmental Council suggests that elevated nitrate levels in drinking water are more dangerous to human health than previously thought.

As a part of the Safe Drinking Water Act of 1962, the U.S. Environmental Protection Agency set the nitrate limit for drinking water at 10 milligrams per liter in order to prevent blue baby syndrome, which was a prevalent at the time. While the last known case of blue baby syndrome in Iowa was in the 1970’s, recent studies suggest that nitrates’ health impacts extend beyond this condition. The council’s report “Nitrate in Drinking Water: A Public Health Concern for All Iowans” provided an overview of several studies that linked high nitrate levels in drinking water with birth defects, cancers and thyroid problems.

The report said, “While most of the associations have been found when nitrate levels are higher than the drinking water standard, some research suggests that nitrate concentrations even lower than the drinking water standard may be harmful.”

Historically, some communities in Iowa have had trouble remaining in compliance with current drinking water nitrate limits. Based on a state drinking water compliance report, eleven public drinking water supplies exceeded the 10 milligrams per liter limit in 2015. Iowans that get their drinking water from private wells are at an increased risk. According to a Des Moines Register report, 15 percent of private wells that were voluntarily tested between 2006 to 2015 had nitrate levels that exceeded federal standards.

Concerns about nitrates from agricultural drainage tiles, rural and urban fertilizers, and water treatment systems seeping into water ways have been on the rise in Iowa. The Environmental Council is among many groups in the state that seek to bolster the Nutrient Reduction Strategy, which aims to curb nitrogen and phosphorous that enters into Iowa’s streams and rivers by 45 percent. The group also supports a movement for an additional three-eighths of 1 cent sales tax to fund the Natural Resources and Outdoor Recreation Trust Fund. Sixty-three percent of Iowans voted to approve this amendment in 2010, but state legislators did not approve funding for the measure.

Peter Weyer is interim director of the Center for Health Effects of Environmental Contamination at the University of Iowa and has studied the relationship between long-term exposure to low-level nitrates in water and cancer in women. He said, “Based on our research and elsewhere in the U.S. and abroad, it looks like nitrates are problematic for other health effects.”