What are they?

Nitrates are chemical compounds that can be found in drinking water supplies. While harmless in small amounts, high levels of nitrates can affect humans and animals negatively. This is especially true for infants and pregnant women.

Nitrates infiltrate drinking water through several sources. Runoff from fertilizers is the most common source of nitrates, but they may also come from improperly disposed sewage, leaking septic systems, industrial waste, food processing waste, and erosion of natural deposits.

Why are they a problem?

High levels of nitrate in the body can cause methemoglobinemia, also known as blue baby syndrome. This sickness is extremely rare, but it is important to be aware of the risks. The most common symptom of methemoglobinemia is a bluish color of the skin, headache, dizziness, weakness or trouble breathing. Infants under six months of age, pregnant women, adults with low amounts of stomach acidity, or adults deficient in the methemoglobin reductase enzyme (which converts methemoglobin to hemoglobin) are especially susceptible.

The maximum contaminant level for nitrates in drinking water as issued by the EPA is 10mg/L or 10 ppm (parts per million). This level has been set based on the best available science to prevent potential health problems.

What can I do?

The construction and location of drinking water wells often have the most to do with the amount of nitrates in your drinking water. New wells should be located uphill and at least 100 feet away from potential contaminant sources like feedlots, septic systems, barnyards and chemical storage facilities. This simple act of prevention can be invaluable to preventing nitrates from entering your drinking water.

If you believe your groundwater is contaminated, the best option is to have your well tested by your local health department or water system. Several methods have been proven to remove nitrates, including:

  • distillation
  • reverse osmosis
  • ion exchange
  • electrodialysis

Boiling, filtering, chemical disinfection such as chlorination, and water softeners are not effective in removing nitrates from water supplies.