The federal nitrate standard was set three decades ago to protect infants from a disease called blue baby syndrome. Now there are new worries. Recent studies in the United States and Denmark on nitrate exposure indicate a higher risk of preterm birth, low birth weight, birth defects, and infant brain tumors. In adults, there is a higher risk of colorectal cancer and some associations with thyroid disease. These associations are present when nitrate is above and, in some cases, below the federal drinking water standard.
“There seems to be quite a growing literature that suggests that the standard that was really based on blue baby syndrome is not sufficiently stringent to protect children from other adverse birth outcomes,” Leslie Stayner, a professor emeritus of epidemiology at the University of Illinois at Chicago, School of Public Health, told Circle of Blue. Stayner currently lives in Denmark, where he is using that country’s meticulous data registries to investigate the health damage from nitrate.
Researchers who specialize in the health effects of nitrate say that more work needs to be done to establish cause-and-effect relationships. In the field of epidemiology, and especially in drinking water assessments, no single study is ever definitive.
“Taken together these studies add to the evidence for adverse health effects related to nitrate ingestion at levels below the current regulatory standards in the U.S. and E.U.,” said Mary Ward, a senior investigator at the National Cancer Institute. “However, the number of studies is still too few to draw conclusions about risk.”
If the U.S. Environmental Protection Agency were to lower the nitrate standard — something the agency rejected in 2016, in its last review of federal drinking water regulations — the consequences would be enormous. The risk of disease would likely decrease. But more communities would violate the standard and would be required to upgrade their treatment works or find new water sources with lower levels of nitrate. That is a difficult proposition in farm country, where a town may be surrounded by high-nitrate groundwater. In deciding whether to lower the standard, the EPA would weigh the reduction in health risks against these community financial liabilities.
Soybean harvest in late October.
Nitrate is already one of the most violated federal drinking water standards, with EPA data showing 458 systems in violation in the fourth quarter of 2021. Yet, it remains overlooked. Spurred by public outrage after high-profile health crises in the last decade, other drinking water contaminants have taken center stage in the federal response to dirty water.
The $1.2 trillion infrastructure package that President Joe Biden signed into law in November included $15 billion to remove lead pipes and $10 billion for dealing with toxic PFAS chemicals. But there was no specific earmark for utilities to address nitrate.
Chad Seidel, who works on drinking water treatment and policy, says he is frustrated with the lack of attention to such a deeply rooted, widespread problem. “If we were addressing nitrate with the fervor we’re currently addressing PFAS, we would have solved the problem a decade ago,” said Seidel, president of Corona Environmental Consulting. “But we haven’t. We’ve accepted the fact that hundreds and hundreds of water systems across the U.S. can be out of compliance. And we’re okay with it.”
