vlog EIGHT NEWS AT SIX. NEW TONIGHT A NEW STUDY PUBLISHED THIS AFTERNOON FOCUSES ON PRENATAL EXPOSURE TO NITRATES IN DRINKING WATER. AND TONIGHT WE’RE TAKING A LOOK AT THAT STUDY. AND WE’RE HEARING FROM THE IOWAN, WHO CONDUCTED IT, vlog INVESTIGATIVE REPORTER SUZANNE BEHNKE TELLS US ABOUT THE RESULTS OF THIS STUDY. WELL, WHAT’S WHAT’S IN OUR ENVIRONMENT, WHAT’S IN OUR WATER? DOCTOR JASON SEMPRINI IS A NATIVE IOWAN AND A PROFESSOR AT DES MOINES UNIVERSITY. HIS RESEARCH ON NITRATES AND CANCER LED HIM TO WONDER ABOUT DRINKING WATER. JUST NITRATE IN OUR WATER HAS BEEN INCREASING FOR ABOUT 40 YEARS NOW. SEMPRINI EXAMINED 357,000 BIRTHS AND WATER RECORDS FROM THE 1970S AND 80S. TODAY, HIS REPORT WAS PUBLISHED. THE KEY FINDINGS. EXPOSURE TO NITRATES EVEN AT THE EPA LIMIT OF 10MG/L, COULD INCREASE THE RISK OF LOW BIRTH WEIGHT AND PRETERM BIRTH. SO FAR, THE CENTRAL IOWA WATER WORKS DAILY REPORTS HAVE NEVER REFLECTED DRINKING WATER GOING ABOVE THAT 10 MILLIGRAM/L STANDARD. IT’S CONCERNING WHEN WE WE START TO SEE A CONSISTENT EVIDENCE SHOWING THAT THERE IS NO SAFE LEVEL OF NITRATES FOR PREGNANT WOMEN IN THEIR DRINKING WATER. THE STUDY CAME OUT AT A TIME WHEN WE ARE HEARING A LOT ABOUT NITRATES IN WATER, HIGH LEVELS IN THE LOCAL RIVERS LED TO THE LAWN WATERING BANNED. STILL IN EFFECT, THAT BAN ALLOWS CENTRAL IOWA WATER WORKS TO FILTER ENOUGH WATER TO MEET DEMAND. THE TIMING IS QUITE COINCIDENTAL, SO. BUT I HOPE IT ADDS TO THE CONVERSATION AND HELPS HELPS IOWANS. WE REACHED OUT TO POLK COUNTY HEALTH DIRECTOR JULIANNE VAN LOO. WE’RE TRYING TO PROVIDE GUIDANCE. SHE RECOMMENDS ANYONE CONCERNED TO CONTACT THEIR HEALTH CARE PROVIDER, AND TO KEEP IN MIND THAT IT’S ONE WELL DESIGNED STUDY. IT’S ONE MORE SMALL BREADCRUMB KIND OF GATHERING AGAINST ALL THE OTHER EVIDENCE. PREGNANT WOMEN MAY WANT TO CONSIDER ALTERNATIVE DRINKING SOURCES WHEN WE’RE IN THESE SUSTAINED RATES. CENTRAL IOWA WATER WORKS SAYS IT’S FOCUSED ON FOLLOWING THE EPA STANDARD AND PROVIDING SAFE DRINKING WATER. THEY SENT vlog A STATEMENT SAYING IN PART, WE REMAIN FOCUSED ON THAT STANDARD. QUESTIONS ABOUT THIS REPORT ARE BEST ANSWERED BY A MEDICAL PROFESSIONAL. WATER QUALITY IS ALSO ON LOCAL LEADERS MINDS. WHEN YOU ALLOW THE NATURAL ENVIRONMENT. POLK COUNTY SUPERVISOR MATT MCCOY SAID A STUDY COMMISSIONED BY THE COUNTY WILL COME OUT JULY 1ST. WE’RE HOPING THAT THIS CENTRAL IOWA WATER REPORT IS COMPREHENSIVE REPORT WILL SERVE AS A GUIDE FOR FOR ADVOCATES AND RESIDENTS THAT HAVE INTEREST IN ADDRESSING LONG TERM. WHAT ARE WE DOING IN TERMS OF WATER QUALITY? vlog INVESTIGATES REACHED OUT TO THE EPA TODAY. WE’RE WAITING TO HEAR BACK. WE DO KNOW THE EPA LAST LOOKED AT THE NITRATE STANDARD LAST YEAR. THE AGENCY CHOSE NOT TO REVISE IT. SUZANN
Study of births in Iowa finds potential prenatal risk linked to nitrates in drinking water
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Updated: 8:36 PM CDT Jun 26, 2025
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A new study published Wednesday finds that prenatal exposure to nitrates in drinking water could increase the risk for low birth weight and pre-term birth. Exposure even under the EPA’s standard of 10 milligrams per liter can result in the health risks.“The nitrate in our water has been increasing for about 40 years now,” said Jason Semprini, a native Iowan and a professor at Des Moines University. “It’s concerning when we start to see consistent evidence showing that there is no safe level of nitrates for pregnant women in their drinking water,” Semprini said.Semprini examined more than 357,000 births and water records from the 1970s and ‘80s. On Wednesday, his report, “Early prenatal nitrate exposure and birth outcomes: A study of Iowa’s public drinking water (1970-1988),” was published."Consistent with other evidence from other states and countries, exposure to nitrate under the safe threshold increases the risk of adverse birth outcomes, specifically pre-term birth and low birth weight," Semprini said in an interview with vlog.He added there are other factors that could result in low birth weight and pre-term births.In 1992, the EPA established 10 milligrams per liter as the maximum contaminant level of nitrates in drinking water. This standard sought to address health issues like blue baby syndrome. This is a condition where nitrates result in low oxygen levels in infants, causing them to look blue. Babies can be exposed when tap water is used for baby formula.Nitrates can occur naturally in some foods, such as green beans, carrots, spinach and others. In Iowa, there are currently high nitrates levels in the Des Moines and Raccoon rivers. These are the two main sources for 600,000 commercial and residential customers of Central Iowa Water Works. The lawn watering ban continues to be in effect to allow the nitrate removal facility to keep up with daily customer demand.So far, the daily reports from Central Iowa Water Works (CIWW) have never reflected drinking water above 10 milligrams per liter.The study came out at a time when Iowans are hearing a lot about nitrates in water.“The timing is quite a coincidence,” Semprini said. “But I hope it adds to the conversation and helps Iowa.”Polk County Health Director Juliann Van Liew recommends anyone concerned to contact their health care provider – and to keep in mind that it’s only one well-designed study.“It’s one more small breadcrumb kind of gathering against all the other evidence. We have to continue to point us in this direction that there are health risks here,” Van Liew said. “Pregnant women may want to consider alternative drinking sources when we’re in these sustained rates.”CIWW says it’s focused on following the EPA standard and providing safe drinking water.“We remain focused on that standard,” CIWW told vlog in a statement. “Questions about this report are best answered by a medical professional.”Water quality is also on local leaders’ minds.Polk County Supervisor Matt McCoy said a study commissioned by the county will come out on July 1.“We’re hoping that the Central Iowa report – this comprehensive report – will serve as a guide for advocates and residents that have interest in addressing long term,” McCoy said.vlog Investigates reached out to the EPA on Wednesday. The federal agency said it has been in touch with local officials about the high nitrate levels.The American Academy of Pediatrics in 2005 advised having private wells tested in homes with babies or pregnant women.The EPA hasn’t revisited these regulations in nearly 30 years. vlog reached out to the EPA about a review of the nitrate standard but did not hear back ahead of the study's release.In an earlier statement, the EPA said it last reviewed the standard last year. It determined the nitrate standard was not a candidate for revision at that time. PLOS is a nonprofit, open-access scientific publisher.Recent coverage of central Iowa water issuesCentral Iowa officials ban lawn watering to avoid potential 'water crisis'What are nitrates in drinking water and why Iowa officials are watching closelyLIST: Which Iowans are included in the ban on lawn watering?Des Moines shuts down spraygrounds as central Iowa cities work to conserve waterClive residents respond to lawn watering ban amid high nitrate levelsCentral Iowa landscaping businesses adapt to lawn watering banLawn watering ban still in place for more than 600,000 central Iowans; water usage drops by 30%Des Moines Water Works CEO links nitrate issue to farm fertilizers Communities can reopen splash pads and spraygrounds, Central Iowa Water Works says Get the Facts: How much water do West Des Moines data centers actually use?Splash pads turn back on one week later after new guidance from CIWWCentral Iowa water officials squash rumors that drinking water is unsafeCentral Iowa water quality experts say at-home nitrate test kits are unreliableMore Iowans considering at-home water treatment systems amid water quality concernsvlog Investigates: Water demand shot up day before lawn watering ban began, data shows This week's rain doesn't help high nitrate levels and the watering ban. Here's why.Answers to frequently asked questions about Iowa water quality, nitrates, testing and moreInside Central Iowa Water Works' testing laboratoryStudy of births in Iowa finds potential prenatal risk linked to nitrates in drinking water» Subscribe to vlog's YouTube page» Download the free vlog app to get updates on the go: Apple | Google Play
DES MOINES, Iowa — A new study published Wednesday finds that prenatal exposure to nitrates in drinking water could increase the risk for low birth weight and pre-term birth.
Exposure even under the EPA’s standard of 10 milligrams per liter can result in the health risks.
“The nitrate in our water has been increasing for about 40 years now,” said Jason Semprini, a native Iowan and a professor at Des Moines University.
“It’s concerning when we start to see consistent evidence showing that there is no safe level of nitrates for pregnant women in their drinking water,” Semprini said.
Semprini examined more than 357,000 births and water records from the 1970s and ‘80s. On Wednesday, his report, “Early prenatal nitrate exposure and birth outcomes: A study of Iowa’s public drinking water (1970-1988),” was published.
"Consistent with other evidence from other states and countries, exposure to nitrate under the safe threshold increases the risk of adverse birth outcomes, specifically pre-term birth and low birth weight," Semprini said in an interview with vlog.
He added there are other factors that could result in low birth weight and pre-term births.
In 1992, the EPA established 10 milligrams per liter as the maximum contaminant level of nitrates in drinking water. This standard sought to address health issues like blue baby syndrome. This is a condition where nitrates result in low oxygen levels in infants, causing them to look blue. Babies can be exposed when tap water is used for baby formula.
Nitrates can occur naturally in some foods, such as green beans, carrots, spinach and others. In Iowa, there are currently high nitrates levels in the Des Moines and Raccoon rivers. These are the two main sources for 600,000 commercial and residential customers of Central Iowa Water Works. The lawn watering ban continues to be in effect to allow the nitrate removal facility to keep up with daily customer demand.
So far, the daily reports from Central Iowa Water Works (CIWW) have never reflected drinking water above 10 milligrams per liter.
The study came out at a time when Iowans are hearing a lot about nitrates in water.
“The timing is quite a coincidence,” Semprini said. “But I hope it adds to the conversation and helps Iowa.”
Polk County Health Director Juliann Van Liew recommends anyone concerned to contact their health care provider – and to keep in mind that it’s only one well-designed study.
“It’s one more small breadcrumb kind of gathering against all the other evidence. We have to continue to point us in this direction that there are health risks here,” Van Liew said. “Pregnant women may want to consider alternative drinking sources when we’re in these sustained rates.”
CIWW says it’s focused on following the EPA standard and providing safe drinking water.
“We remain focused on that standard,” CIWW told vlog in a statement. “Questions about this report are best answered by a medical professional.”
Water quality is also on local leaders’ minds.
Polk County Supervisor Matt McCoy said a study commissioned by the county will come out on July 1.
“We’re hoping that the Central Iowa report – this comprehensive report – will serve as a guide for advocates and residents that have interest in addressing [what we are doing in terms of water quality] long term,” McCoy said.
vlog Investigates reached out to the EPA on Wednesday. The federal agency said it has been in touch with local officials about the high nitrate levels.
The American Academy of Pediatrics in 2005 advised having private wells tested in homes with babies or pregnant women.
The EPA hasn’t revisited these regulations in nearly 30 years. vlog reached out to the EPA about a review of the nitrate standard but did not hear back ahead of the study's release.
In an earlier statement, the EPA said it last reviewed the standard last year. It determined the nitrate standard was not a candidate for revision at that time.
PLOS is a nonprofit, open-access scientific publisher.
Recent coverage of central Iowa water issues
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