Mississippi River conservation groups are among a broad coalition urging the federal government to take action against nitrate contamination in drinking water, which they say has reached “crisis levels” and is a public health emergency.
Nitrate, which forms when nitrogen-rich sources combine with oxygen, has long been found in the country’s surface waters and groundwater, where it can end up in people’s drinking water. Consuming water with elevated levels of nitrate is linked to birth defects, thyroid problems and some cancers.
Agricultural fertilizer and manure are the most common sources of nitrogen to groundwater, with septic systems and lawn fertilizers also contributing. An April analysis from the Environmental Working Group found that about 18% of the U.S. population from 2021 to 2023 used drinking water from community systems with 3 milligrams per liter (mg/L) or more of nitrate, the threshold at which the Environmental Protection Agency says indicates contamination.
Related: Minnesota asks the public if groundwater rule is enough to curb nitrate pollution, following lawsuit
Advocates say nitrate contamination has struggled to capture public attention but is costly and hazardous to those it affects.
The May 5 letter to the Department of Health and Human Services and the EPA was signed by 80-plus groups, about a third of which are located in or focused on the Mississippi River basin. It calls on the agencies to “immediately identify and eliminate sources of nitrate pollution in drinking water and provide funds to communities to reduce nitrate to safe levels.”
The letter cites a recent report from the Iowa Environmental Council and the Harkin Institute at Drake University in Des Moines that found high nitrate levels in drinking water, as well as the presence of pesticides and forever chemicals, are linked to rising cancer rates in Iowa. Intensive farming across the state, including corn, soy and hogs, is the dominant source of nitrate pollution, the report notes.
“We understand these are long-term problems,” said Tyler Lobdell, senior attorney at Food & Water Watch, which spearheaded the letter. “The longer we wait to address root causes, the more difficult, and more expensive [it is], and the more harm is caused in the long run.”
The Department of Health and Human Services did not respond to a request for comment on the letter. A spokesperson for the EPA said it is beginning the next round of review of national drinking water regulations, which was last published in 2024.
Too much nitrogen taints drinking water, hurts river ecosystem
Nitrate contamination is a widespread problem across the country, especially in the Corn Belt, but actions to address it have been slow-going.
Groups in multiple states, including Wisconsin, Minnesota and Iowa, have previously petitioned the EPA to take emergency action on nitrate problems in specific regions. Lobdell said the agency has either ignored or given an insufficient response to those petitions, dating back several years and multiple presidential administrations.
Under former President Joe Biden, the EPA restarted an assessment — which had been suspended during the first Trump administration — of the impacts of nitrate on human health. Environmental advocates had hoped that it could lead to an adjustment of the national standard for nitrate in drinking water, which currently sits at 10 mg/L, because some research shows impacts to human health below that level. Little progress has been made on the assessment.
Beyond human health impacts, too much nitrogen in surface water can drive excessive algae growth, causing harm to fish and other aquatic life. It’s one culprit, in addition to phosphorus, in the creation of the Gulf of Mexico’s “dead zone,” an area of low oxygen that spans thousands of square miles from the mouth of the Mississippi River.
Kelly McGinnis, executive director of the environmental advocacy organization One Mississippi, a signatory on the letter, said humans aren’t separate from the environment and that addressing nitrate contamination would have positive impacts on both.
Related: Let’s face up to the risks associated with groundwater nitrates in southeastern Minnesota
She said she hopes the letter catches the attention of Health and Human Services Secretary Robert F. Kennedy Jr., who has pledged to “Make America Healthy Again” and has shown interest in reducing toxins in people’s diets.
“We felt the urgency right now to take advantage of the new research [from Iowa] to say, ‘Hey, this is something you guys need to be addressing,’” McGinnis said.
The spokesperson for the EPA said the agency is “committed to Making America Healthy Again by taking real, tangible steps to evaluate risks of nitrates in drinking water while following the law and gold standard science.”
This story is a product of the Mississippi River Basin Ag & Water Desk, an independent reporting network based at the University of Missouri in partnership with Report for America, with major funding from the Walton Family Foundation.
Basin-state signatories
Alabama: Black Warrior Riverkeeper
Illinois: Climate Action Evanston; Committee on the Middle Fork Vermilion River; Illinois Stewardship Alliance; League of Women Voters of Illinois
Indiana: Wabash Riverkeeper Network
Iowa: Iowa Citizens for Community Improvement; Iowa Environmental Council; LWV of Iowa; UNI’s Center for Energy & Environmental Education
Kentucky: Kentucky Waterways Alliance
Minnesota: League of Women Voters of Minnesota (LWVMN); Minnesota Center for Environmental Advocacy
Mississippi: MS Communities United for Prosperity (MCUP)
New York: Chuatuauqa-Conewango Consortium, Inc.
Ohio: Ohio Environmental Council
Pennsylvania: Three Rivers Waterkeeper
Tennessee: Harpeth Conservancy
Texas: Bayou City Waterkeeper
Wisconsin: League of Women Voters of WI; Midwest Environmental Advocates; Milwaukee Riverkeeper
Regional/Multi-State Focus: Environmental Law & Policy Center (active in IL, IA, MN, and WI); Izaak Walton League of America; League of Women Voters Upper Mississippi River Region ILO; Mississippi River Collaborative; Ohio River Foundation; One Mississippi; Sierra Club; Waterkeeper Alliance
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