Even small amounts of nitrate in drinking water — far below current federal limits — were linked to a higher risk of premature and underweight births in a large study of Iowa children.
Pamela Ferdinand reports for U.S. Right to Know.
In short:
- A study of 350,000 Iowa birth records from 1970 to 1988 found that nitrate levels as low as 0.1 mg/L in drinking water were linked to increased rates of preterm and low birth weight births.
- More than 80% of babies in the study were exposed to nitrate during gestation, with exposure early in pregnancy proving the most harmful.
- The current U.S. Environmental Protection Agency nitrate limit of 10 mg/L was designed to prevent blue baby syndrome but does not account for risks like premature birth, prompting calls for revised standards.
Key quote:
“The stakes are clear. No level of nitrate in drinking water appears safe during pregnancy.”
— Jason Semprini, assistant professor of public health economics at Des Moines University and study lead author
Why this matters:
Nitrate contamination is one of the most widespread forms of drinking water pollution in the United States, especially in rural and agricultural regions where fertilizer runoff and animal waste seep into groundwater. While the current EPA limit is meant to protect infants from acute conditions like blue baby syndrome, new research suggests that much lower levels — previously considered safe — may interfere with fetal development. This matters because preterm birth and low birth weight are among the leading causes of infant death and long-term disability. They also increase the risk of chronic illnesses later in life.
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