Nitrate in drinking water
Learn more about nitrate in drinking water — and a groundbreaking strategy to improve water and air quality while strengthening rural economies.
Nitrate is essential to plant growth and animal health, but excess nitrate in our drinking water can pose risks to human health.
To protect us from health hazards, the EPA set a maximum contaminant level (MCL) for nitrate10 parts per million (10 mg/L). Public helath officials are concerned about nitrates and ‘blue-baby syndrome’ (infant methemoglobinemia). Additional potential health concerns that the State of Minnesota considers worthy of additional research include thyroid issues, adverse pregnancy outcomes, and cancers (particularly colorectal cancer).
Read on to learn more about nitrate in drinking water, and explore a strategy to reduce it at one of its major sources.
Are you attending the SAF Conference in Minneapolis, September 22-24?
Don't miss the breakout session "Balancing Land, Climate and Biodiversity in SAF Feedstock Development." FMR Water Program Director Trevor Russell presents on SAF Strategy for Broader Biodiversity Outcomes on Wednesday, September 24, 8:30 a.m.
Nitrate in drinking water: An overview
Nitrate (NO₃⁻) is a compound of nitrogen and oxygen that occurs naturally and is produced from human activities. It is highly soluble in water and often used in fertilizers for crops and lawns, but that also makes it a common groundwater contaminant. Nitrate contamination most often affects people in small towns who rely on community water systems or private wells. You cannot taste, smell or see nitrate in water.
Once a water source becomes contaminated, protecting people from nitrate exposure can be costly. Conventional drinking water treatment processes do not remove nitrate, so additional — and often expensive — treatment systems are required.
Nitrate in drinking water: Potential health impacts
Consuming too much nitrate can interfere with the blood’s ability to carry oxygen and may cause ‘blue-baby syndrome’ (infant methemoglobinemia), which can lead to serious illness or death. Beyond ‘blue-baby syndrome’, the harmful health effects of nitrate in drinking water are still being studied, including potential connections to colorectal cancer, thyroid disease, and neural tube defects (birth defects of the brain and spine).
The impacts of excessive nitrate also go beyond potential health concerns. Elevated nitrate levels can harm fish and aquatic life in our lakes and streams.
This is why EPA is involved in areas especially prone to nitrate pollution, like southeastern Minnesota. And some state agencies, like the Minnesota Department of Agriculture and Minnesota Pollution Control Agency, have been ordered to work together to reduce nitrates in drinking water.
To learn more about public health concerns, see the Minnesota Department of Health’s information sheet Nitrate and Methemoglobinemia (PDF) and this article on Safe Drinking Water for Your Baby.
Entrepreneurial farmers are growing winter-hardy camelina, an oilseed. (Photo by Dodd Demas for FMR)
Winter-hardy oilseeds: A groundbreaking strategy to cut excess nitrate in drinking water
Winter-hardy oilseeds such as winter camelina and pennycress could help reduce nitrate runoff from agriculture — a significant source of excess nitrate in water.
In Minnesota, more than 70% of nitrate loads in monitored watersheds come from cropland. Nitrate in drinking water is a widespread issue in Minnesota, particularly in the southwest, west-central, and southeast regions. In Minnesota’s southeast karst region, the EPA indicated action was needed to protect public health in 2023. According to a 2020 report, one in eight Minnesotans relies on groundwater with elevated nitrate levels.
Winter oilseeds and other Continuous Living Cover (CLC) keep living roots in the ground through the “brown months” between late fall and spring when Minnesota’s croplands lie bare.
According to a 2023 report, a realistic statewide rollout of Continuous Living Cover in Minnesota could lead to a 23% reduction in nitrogen runoff.
Because winter oilseeds can be used in Sustainable Aviation Fuel (SAF), they can also provide a new revenue stream for farmers without replacing summer crops.
"Some new lower-carbon jet fuel options — purportedly 'sustainable' ones — could further contaminate our waters. Other lower-carbon jet fuel options could actually improve water quality."
— Trevor Russell, Friends of the Mississippi River Water Program Director
A win-win solution: Winter-hardy oilseeds support rural economies and help address nitrate in drinking water
Planting winter oilseeds between cash crops addresses nitrate pollution at its primary source — safeguarding communities while opening new income streams for farmers.