This article was written by Lower Loup NRD Information & Education Coordinator Alan Bartels for the Loup Lines Column.

LOUP LINES
Lower Loup Natural Resources District
Volume 46, No. 9 (September 2025)

Hard Facts About Nitrate Pollution and Responsibility
Nitrates can’t be seen, smelled, or tasted, but thousands of Nebraskans unknowingly consume the pollutant – through contaminated drinking water – every day. Municipal wells are required by law to be tested periodically. When high nitrate levels are found, communities are faced with difficult, expensive decisions. Unfortunately, for Nebraskans who get their water from private domestic wells, there is no requirement for testing of any kind.

How do nitrates get into Nebraska’s water?
Nitrates occur naturally, but it is human activity that typically elevates the compound to harmful levels. Nitrates enter water supplies when sewage systems, lagoons, and septic tanks overflow, from accidental releases from wastewater treatment plants, in runoff from feedlots and other livestock operations, from industrial waste, and as a byproduct of food processing. High precipitation events and overapplication of irrigation water can lead to fertilizer runoff from golf courses, park areas, and lawns. With that said, most of the nitrates in our drinking water comes from fertilizer applied to farm fields.

In January 2020, when the Lower Loup NRD (LLNRD) created a new water quality management area north of Columbus after nitrate readings in wells there soared to as high as 48 parts per million, the blame game erupted during a public meeting. Feedlot owners were in attendance. So were farmers who apply commercial fertilizer. They boisterously blamed each other for elevated nitrate levels in groundwater.

From Finger Pointing to Fingerprinting
There is a scientific way to get to the truth. At the Nebraska Water Center’s Water Sciences Laboratory, which is part of the University of Nebraska’s Daugherty Water for Food Global Institute, researchers have developed a method of measuring nitrates and can determine if it originated from organic sources like manure, or from commercial fertilizer. This method is called isotropic fingerprinting.

Extensive data collection has revealed that nitrogen in commercial fertilizers has a specific isotope composition. Comparatively, nitrogen from manure tends to be enriched by a heavier isotope. These constant variables allow researchers studying nitrate-laced water to determine the source of contamination.

“Based on stable isotope testing in the Water Sciences Laboratory, the majority of nitrate in Nebraska groundwater with elevated concentrations originates from commercial nitrogen fertilizer,” said Daniel Snow, director of laboratory services at the University of Nebraska’s Water Sciences Laboratory. “There are places, for example in the Lower Loup NRD, where we see evidence for organic nitrogen (manure, wastewater, etc.) sources which contributes to high groundwater nitrate. Overapplication of any nitrogen source (fertilizer or manure) in excess of plant needs will over time result in nitrate accumulation, leaching and eventually contaminate local groundwater.”

FACTS

• The statewide median nitrate level in Nebraska doubled between 1978 and 2019.
• The Nebraska Water Center has stated that approximately one-third of nitrogen applied to corn in Nebraska is lost to leaching.
• Overapplication of commercial and organic fertilizer puts our water, and the health of our residents, at risk.
• Over-irrigation wastes our precious water resources, contaminates streams and groundwater, and puts the health of residents at risk.
• Nebraska has one of the highest nitrate levels in the US, and the highest pediatric cancer rate west of Pennsylvania.
• High nitrate exposure is also linked to brain cancer, colorectal cancer, thyroid cancer, leukemia, and lymphoma.
• Pregnant women should not drink high nitrate water.
• The Environmental Protection Agency’s (EPA) maximum contaminant level for nitrates in drinking water is 10 parts per million (ppm).
• Approximately 10% of Nebraska’s community water systems have exceeded the EPA’s maximum contaminant level for nitrates at least one time since 2010.
• A University of Nebraska Medical Center expert has stated that the EPA’s maximum contaminant level of 10 ppm is too high.

Lower Loup NRD Research
The LLNRD is working on an innovative study to monitor the movement of nitrates year-round from the soil surface, through the root zone, and beyond. The study involves soil probing fields where manure is applied as a nutrient, and also fields where commercial fertilizer is applied. The fields being probed in the study include soil types ranging from sandy to heavy clay.

Producers can perform their own soil tests. Soil testing allows producers to determine how much residual nitrogen remains in the root zone, which in turn allows them to precisely determine how much to apply to get a crop through to harvest. Considering the price of fertilizer, the cost of soil sampling is money well spent, and the Lower Loup NRD is even offering a cost-share program as an incentive.

The purpose of the Lower Loup NRD’s Advanced Soil Sampling Cost-Share program is to encourage landowners to adopt advanced soil sampling analysis with the intent of reducing nutrient input and improving soil health across the entire Lower Loup NRD. Water quality also will benefit.

To qualify, landowners must have certified irrigated acres and use an approved soil testing method. The Lower Loup NRD would then cost share up to $55 per soil sample, up to eight soil samples per year, for four years. Participants would be required to conduct 36-inch-deep soil nitrate tests, the cost of which will be covered by the Lower Loup NRD up to $15 per soil sample. Funding is available now. Landowners with property within the Lower Loup NRD can sign up at their local NRCS office. 

Similarly, producers should consider the nitrates in their irrigation water when planning their fertilizer regimen. Failure to do so can lead to over-application of fertilizer, which is expensive, and increases the possibility of leaching.

What can you do? Test your well.
Approximately 85% of Nebraskans rely on groundwater sources for their drinking water. This comes from wells drilled into aquifers. Except for public water systems, which are required by law to be tested for contaminants, less than 4% of Nebraska’s 180,000 registered wells are tested annually. And this does not include the many unregistered wells across the state.

Residents who rely on domestic wells ultimately bear the responsibility for ensuring the safety of their drinking water for themselves and their families. Far too many Nebraskans turn a blind eye to the threat of contamination.

At a recent Test Your Water event, several people told LLNRD staff that they’d wondered about nitrates in their water for years. A simple water test put their minds at ease, even for one rural Merrick County man who learned that the nitrate level in his private domestic well is twice what the EPA’s safe drinking standard would allow for a municipal well.

There are Nebraska labs that sells nitrate/nitrite testing kits for less than $10 each. They arrive with sample bottles, instructions, packing material, and a return label for shipping the sample back to the lab. Other labs, including the Department of Health and Human Services Public Health Environmental Lab in Lincoln, offer similar services for nitrates testing and water analysis for other contaminants and mineral composition.

Installation of a reverse osmosis system can help bring contamination down to safe levels for some households. Depending on contaminant levels, others may need to drill a new well, rely on bottled water, or find another solution. Boiling water will not decrease nitrate levels.    

Here are a few more facts:

• Sandy, irrigated soils are highly susceptible to nitrate leaching.
• Center pivot irrigation is much more efficient than gravity irrigation, and far less likely to cause nutrients to leach into water resources.
• Buffer strips can reduce polluted runoff from reaching waterways. Cost-share is available.
• Algal blooms that impact recreation and starve lakes and fish of oxygen are fueled by nutrients including nitrates.
• “Doing things how we’ve always done them,” is not necessarily the right, safe, or responsible way of doing things today.
• Animals are also susceptible to nitrate exposure. In cattle and dogs this exposure can lead to the loss of young and reduced milk production. Hogs exposed to high nitrate water can lose entire litters.

More is not better. The technology exists for the precise application of fertilizer, other agricultural chemicals, and irrigation water. Considering the known health effects of nitrate exposure, is there a reason to ever apply more than the crop can use?

A few final facts:

• Landowners, land managers, farmers, ranchers, feedlot owners, homeowners, businessowners, and land users must practice appropriate nutrient management and work to decrease nitrate loss.
• Nebraska’s groundwater and surface water belong to all the people of this state.
• Water is a finite resource.
• Irrigating is expensive. Fertilizer is expensive.
• Good health – yours, mine, our children’s, and their children’s – is priceless.