Overview

• The PLOS Water study analyzed 357,741 Iowa birth records from 1970 to 1988 and found nitrate levels rose roughly 8% per year.
• Early prenatal exposure above 0.1 mg/L—just 1% of the EPA’s 10 mg/L limit—was associated with a 0.66 percentage point increase in preterm births.
• Prenatal nitrate exposure exceeding 5 mg/L correlated with a 0.33 percentage point rise in low birthweight infants.
• Researchers estimate prenatal nitrate harm equals about 15% of the damage caused by maternal smoking.
• The EPA’s maximum contaminant level for nitrates has not been updated since 1992 despite mounting evidence of risks at much lower concentrations.