Understanding Nitrate in Drinking Water and Its Impact on Health

Nitrate is a naturally occurring compound that can be found in water, soil, and various foods. While nitrate is essential for a healthy environment, its presence in drinking water at elevated levels can lead to serious health concerns, particularly for infants and people with certain pre-existing health conditions. In this article, we will explore the potential effects of nitrate in drinking water, how it contaminates water sources, and steps you can take to ensure your water remains safe.

What is Nitrate?

Nitrate (NO₃⁻) is a compound that consists of nitrogen and oxygen atoms. It naturally occurs in the environment as a part of the nitrogen cycle, primarily in the soil and water. In low concentrations, nitrate is harmless and can even be beneficial to plants. However, when it enters drinking water sources at high levels, it becomes a health risk.

Nitrate itself has no color, taste, or smell, which makes it difficult to detect without proper testing. For this reason, it is crucial to regularly test water sources to ensure nitrate levels remain within safe limits.

The Dangers of Nitrates in Your Tap Water

Consuming high levels of nitrate in drinking water can be harmful to health, particularly for infants. When nitrate enters the body, it can be reduced to nitrite (NO₂⁻), which interferes with the oxygen-carrying capacity of red blood cells. This can lead to methemoglobinemia, commonly known as blue baby syndrome, a serious condition primarily affecting bottle-fed infants under six months old.

Nitrate in Drinking Water

Blue Baby Syndrome and Methemoglobinemia

Infants under the age of six months are particularly vulnerable to nitrate contamination in drinking water. When babies consume water with high levels of nitrate, their bodies convert the nitrate into nitrite. Nitrite then binds to hemoglobin in the blood, reducing its ability to carry oxygen. This results in a bluish tint to the skin, especially around the lips, eyes, and fingers. Blue baby syndrome is also characterized by: 

• Decreased blood pressure
• Increased heart rate
• Headaches
• Stomach cramps
• Vomiting

In severe cases, methemoglobinemia can lead to organ damage, and without prompt medical intervention, it can even result in death. If you notice your infant’s skin turning blue or if they exhibit other symptoms of methemoglobinemia, seek medical attention immediately.

The Level of Nitrates in Potable Water

To prevent the health risks associated with nitrate contamination, the U.S. A 10-milligram nitrate standard in drinking water has been set by the EPA, which is roughly equivalent to 10 parts per million (ppm). Drinking water with nitrate levels at or below this limit is considered safe for everyone. However, any drinking water with nitrate levels above this threshold is considered unsafe, especially for infants and pregnant individuals.

For those relying on private wells, it’s essential to be aware of nitrate contamination as water from wells may not be routinely tested. If you suspect high nitrate levels in your well water, it’s advisable to have the water tested regularly to avoid potential health risks.

The level of nitrates in potable water

Nitrate Contamination Pathways

Nitrate contamination in drinking water typically comes from several sources. One of the most common contributors is the use of fertilizers in agriculture. Excessive fertilizer application, particularly in areas near water sources, can lead to runoff, which carries nitrate into groundwater and surface water. Other potential contributors to nitrate pollution are:

• Decomposing plant material
• Large-scale livestock manure and waste
• Wastewater discharge
• Septic tanks
• Industrial waste

Nitrate is highly soluble in water, which makes it easy to transport through soil and into water supplies. Once nitrate reaches groundwater or surface water, it becomes challenging to remove, and its presence can continue to affect drinking water for long periods.

Quantifying and Tracking Nitrate Concentrations

To ensure that your drinking water is safe, especially if you rely on private well water, regular testing for nitrate contamination is essential. If your water source comes from a well, you are responsible for testing it at least once a year to monitor nitrate levels. Testing kits are available, and samples can be sent to accredited laboratories for analysis.

Public water systems are typically regulated to ensure that nitrate levels do not exceed the EPA’s safety standards. However, if nitrate contamination has been detected above 25 mg/L in the past, the public water supplier is required to monitor nitrate levels regularly and notify consumers of any potential health risks.

Dealing with High Nitrate Levels in Drinking Water

If testing reveals that the nitrate level in your drinking water exceeds the EPA’s recommended limit of 10 mg/L, immediate action should be taken to reduce the risk of exposure, especially for infants. Follow these steps:

1. Switch to a Safe Water Source: If nitrate levels are too high, consider switching to an alternative safe water source, such as bottled water. Boiling the water is not a safe solution for removing nitrate since boiling water can actually concentrate nitrate levels.
2. Inspect Your Well: A licensed well contractor should inspect your well to ensure that it is functioning properly and that no sources of contamination are present.
3. Identify and Remove Potential Sources of Contamination: Ensure that any potential sources of nitrate, such as fertilizers, septic systems, or animal waste, are located away from your well. You can refer to local resources for guidance on how to protect your well from contamination.
4. Water Treatment Options: If eliminating the contamination source is not feasible, water treatment may be necessary. Point-of-use devices, such as reverse osmosis systems or ion exchange filters, can remove nitrate from water. These systems can reduce nitrate levels by more than 90%, but they can be expensive, so it’s important to assess the long-term costs of using such devices before installation.

Inspect your well to ensure that it is functioning properly

Engineering Solutions for Nitrate Reduction

Several treatment technologies can effectively reduce nitrate levels in drinking water. Among the most common are reverse osmosis and ion exchange systems.

• Reverse Osmosis: This process forces water through a semipermeable membrane, which filters out contaminants, including nitrate. Reverse osmosis is highly effective in removing nitrates but can be costly to install and maintain.
• Ion Exchange: Ion exchange systems use resin to absorb nitrate from the water, providing a similar level of nitrate reduction. These systems are also effective but require regular maintenance and replacement of the resin to maintain efficiency.

Before choosing a treatment system, it’s important to evaluate the long-term costs, as well as the lifespan of the equipment. Regular maintenance is essential to keep the system working effectively.

Proactive Nitrate Contamination Prevention

The best way to avoid the health risks associated with high nitrate levels in drinking water is to take proactive measures to prevent contamination. Here are some steps to reduce the risk of nitrate entering your water supply:

• Properly Construct Your Well: Ensure that your well is built in a safe location, preferably in an area that is less prone to contamination.
• Protect Your Well: Seal and protect your well from contamination by ensuring that it is regularly inspected and well-maintained.
• Minimize Fertilizer Use: Use fertilizers in moderation and avoid applying them too close to water sources to reduce the risk of runoff.
• Proper Waste Disposal: Properly manage animal waste, wastewater, and septic systems to prevent contamination.

Seal and protect your well from contamination

Conclusion

Nitrate contamination in drinking water is a serious health concern, particularly for infants under six months old. It can lead to methemoglobinemia, also known as blue baby syndrome, which interferes with the oxygen-carrying ability of blood. Regular testing, proper water treatment, and preventive measures can significantly reduce the risks associated with high nitrate levels in drinking water. By understanding how nitrate enters water sources and taking steps to protect both your well and your health, you can ensure that your drinking water remains safe for you and your family.

For more information on nitrate in drinking water and how to protect yourself and your loved ones, always consult with water quality experts and local health authorities.