PFAS vs Nitrates
EPA limits, health effects, treatment options, and affected U.S. utilities — compared
Quick Answer
Per- and Polyfluoroalkyl Substances (PFAS) carries a higher EPA risk classification (high). PFAS affects 0 utilities in our database vs. 2,174 for Nitrates.
Synthetic Chemicals
PFAS are a group of thousands of man-made chemicals that have been used in industrial and consumer products since the 1940s.
Agricultural Chemicals
Nitrates are colorless, odorless compounds that occur naturally in soil but reach dangerous levels in water primarily from agricultural fertilizer runoff and septic system leakage.
Head-to-Head Comparison
| Metric | PFAS | Nitrates |
|---|---|---|
| Category | Synthetic Chemicals | Agricultural Chemicals |
| Risk Classification | high | moderate |
| EPA MCL | 4 ppt | 10 mg/L |
| Utilities in Violation | 0 | 2,174 |
| Well Water Risk | Yes — test recommended | Yes — test recommended |
| Primary Sources |
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| Recommended Treatments |
Health Effects Compared
PFAS Health Effects
- Increased risk of kidney and testicular cancer
- Thyroid disease and hormonal disruption
- Immune system suppression — reduced vaccine effectiveness
- High cholesterol and cardiovascular effects
- Developmental delays and low birth weight in infants
- Liver damage at high exposure levels
Who is affected: People near military bases (which used PFAS-containing firefighting foam), industrial sites, and communities that have received contaminated biosolid fertilizer face the highest exposure. Infants, pregnant women, and people with compromised immune systems are most vulnerable.
Nitrates Health Effects
- Methemoglobinemia ('blue baby syndrome') in infants under 6 months — potentially fatal without emergency treatment
- Reduced blood oxygen-carrying capacity — causes bluish skin discoloration, rapid heart rate, and in severe cases death
- Colorectal cancer: a 2021 epidemiological study found 17% higher risk at 5–9.9 mg/L nitrate exposure
- Bladder and kidney cancer association with long-term exposure above 5 mg/L (IARC Group 2A)
- Adverse birth outcomes: preterm birth and neural tube defects associated with elevated exposure during pregnancy
- Thyroid disruption: nitrate competes with iodide uptake, potentially impairing thyroid function with chronic exposure
Who is affected: Infants under 6 months face the most acute risk — their digestive systems have higher bacterial activity that converts more nitrate to nitrite, and fetal hemoglobin is more susceptible to methemoglobin formation. Pregnant women are advised to limit exposure because nitrate may affect fetal oxygenation and is associated with adverse birth outcomes at higher levels. People with hereditary methemoglobin reductase deficiency cannot reduce methemoglobin effectively. Rural residents relying on private wells in the Midwest Corn Belt (Iowa, Nebraska, Kansas, Indiana, Illinois), California's Central Valley (Tulare, Fresno, Merced counties), and the Mid-Atlantic are at the highest risk of exceeding the EPA limit.
Filters That Remove Both
These treatment methods are effective against both PFAS and Nitrates: