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Public health

Nitrates impact our health

By Jessica Fargen Walsh

Dr. Don Coulter’s reasoning goes like this. 


If about 85% of Nebraskans get their water from the ground and the groundwater is contaminated with nitrate, a probable carcinogen, then shouldn’t we be studying nitrates and public health more?  


Coulter, a pediatric oncology doctor at the University of Nebraska Medical Center in Omaha, and a group of researchers are working on a public health study in Nebraska to look at cancer rates by watershed, rather than county or city. 


Nebraska has the 7th highest age-adjusted pediatric cancer incidence rate in the country and the highest in the Midwest, according to CDC data from 2003 to 2014. 


Coulter said it’s unclear why the state’s pediatric cancer rate is so high. 


“All we can do is we can guess,” Coulter said. “But while we don’t necessarily know what causes pediatric cancer, we know there has to be an underlying genetic component. It’s not hard to imagine there is an environmental component. That’s why we are focusing on the environment as a possible trigger and looking around and trying what to figure out what‘s different about Nebraska.” 

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Sammy Nahorny of Columbus, pictured here at age 5 at Boston Children's Hospital, was diagnosed at age 4 with stage 4 neuroblastoma, which is a cancer of the adrenal system. He's now 12 and cancer free. Photo courtesy Sammy's Superheroes.

From 2003 to 2014, 1,133 Nebraska kids got cancer, according to CDC data.

One of those kids was Sammy Nahorny of Columbus. 

At age 4, he was diagnosed with stage 4 neuroblastoma, which is a childhood cancer of the adrenal system. He underwent treatment at hospitals in Austin, Texas; Chicago; Seattle and Omaha. He is now 11 and cancer free.  


Since his diagnosis, his mom and dad Erin and Chris Nahorny, have worked to increase pediatric cancer awareness. Erin Nahorny has started thinking about environmental toxins in her life. Last summer, after a water symposium, she called several home water treatment providers to get a whole-house water filtration system installed.

“We don’t know why,” Nahorny said. “The rest of the states around, when you look at a map, we are a big red spot in the middle, you know, why is that?” 


The Nahornys run a nonprofit called Sammy’s Superheroes to raise money for pediatric cancer research and awareness. 

Researchers at the University of Nebraska-Lincoln and UNMC are involved in two studies probing the relationship between agrichemicals including nitrate and atrazine and public health outcomes such as birth defects and cancer. A third study involves collecting and testing water samples from hundreds of private drinking wells. 


Nebraska researchers are studying nitrates in the drinking water.  


Public health and watersheds: A group of researchers is studying the effects of nitrates and atrazine, a herbicide, on incidences of birth defects, Parkinson’s disease and pediatric cancer analyzed by watershed. The study started in fall 2016. The $150,000 project is funded by  the Department of Pediatrics at UNMC, Sammy’s Superheroes and the Edna Ittner Pediatric Research Support Fund. The next step is to analyze three watersheds with high pediatric cancer incidence rates and high levels of atrazine and nitrate in the water, plus three areas with low pediatric cancer incidence and analyze and compare water quality within those areas. 


Citizen scientists: This project, called Well Water, Farm Families and Better Health study, is using citizen scientists to test private well water in Nebraska. It’s estimated about 20% of Nebraskans get water from private wells. So far, 335 citizen scientists from 45 counties collected 338 surface water and 327 well water samples. To date, 20.5% of the wells sampled had nitrate levels at or above the drinking water standard.  It is supported by the National Institute of General Medical Sciences and funded with $100,000. It involves community group GC Resolve, the University of Nebraska-Lincoln, University of Nebraska Medical Center and the University of Nebraska at Omaha.  

Agrichemicals and birth defects: UNL researcher Martha Rhoades is leading a pilot project to assess the feasibility of conducting a population-based study to evaluate relationships between adverse birth outcomes and maternal exposure to nitrate and nitrosatable agrichemicals in drinking water. This past summer, Rhoades, in conjunction with the state Department of Health and Human Services, sent a letter to every woman who gave birth in Nebraska in 2014 and 2015 inviting them to participate in the study. The letter will also seek information about the woman’s drinking water source. The Birth Outcomes and Water project is funded with $150,000 from the NU Foundation.

“We are on a fact finding mission,” said Martha Rhoades, who is a research manager in UNL’s School of Natural Resources.

Rhoades said the percentage of birth defects that have an unknown cause is very high. 

“Most birth defects are unexplained,” she said. 


Past studies have drawn some correlation between nitrates in the drinking water and some cancers. A recent study concluded that there was evidence for a relationship between drinking water with nitrates and colorectal cancer, thyroid disease and neural tube defects, according to the 2018 study published in the International Journal of Environmental Research and Public Health. 

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Nebraska is an agricultural state and one of the most heavily irrigated in the country.

Studies have shown correlations between nitrate leaching and irrigated cropland.


Dan Snow, a professor and director of laboratory services of the University of Nebraska-Lincoln Water Sciences Laboratory, said awareness of the impacts of nitrate contamination is rising because it's becoming more costly to supply drinking water and because more is known about the origins of the problem. 

"We’ve progressed a lot in terms of our knowledge and ability to study the problem," Snow said. "In the past, it was pretty easy just to say well that was something that happened in the 70s and 80s, but now we know it’s something in some areas that is in the past five years. It's definitely having an impact. It’s not something we can blame on the past." 

Nebraska farmers are doing a better job of limiting nitrate use than in the past, he said. 

"The answer, though, is that it’s still not good enough in most cases," he said. "It's not enough to prevent nitrate leaching. 

If we hadn’t changed our practices 20 or 30 years ago, things would be way worse than they are now. I have no doubt about that." 

Signs like this one dot Nebraska's rural landscape. There are more than 400 drinking water protection areas, sometimes called wellhead protection areas, that are aimed are protecting land near drinking water wells.


The red on these maps indicates groundwater samples that were more than 10 parts per million of nitrate. 

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Source:  Exner, M. Hirsh, A. Spalding, R. "Nebraska’s groundwater legacy: Nitrate contamination beneath irrigated cropland," Water Resources Research, 2014.

Unlike cancer-causing substances such as tobacco, there has been no definitive link between nitrates in drinking water and cancer. While overall, pediatric cancer cases make up a small percentage of all cancers, it’s still a concern, said Dr. Eleanor Rogan, a professor in the department of environmental, agricultural and occupational health in the College of Public Health at UNMC. The studies she is involved with will test the hypothesis that nitrate contamination in drinking water is one cause of pediatric cancer.

“There is an increased urgency on the subject of nitrates. This is a big concern,” Rogan said. “I think this is leading to health problems in the state, and it’s something that we really need to figure out how to do something about in a way that is good for everybody, and I share that concern because it’s leading to health problems that we could avoid.”

This lagoon in Hastings holds the equivalent of 660 Olympic-sized swimming pools of nitrate-laden water, a byproduct of the city's water treatment process. 

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