Nitrate Water Testing Information

What is Nitrate-N?

Nitrogen is an essential part of every living thing.  Nitrate-N is formed when nitrogen combines with oxygen or ozone.  However, nitrate-N easily dissolves in water and does not adhere to soil which allows it to be easily carried into groundwater, making it one of the most common groundwater pollutants in Juneau County and across the state of Wisconsin.

Where does Nitrate-N come from?
Low levels of nitrate-N (below 1 mg/L) can occur naturally in groundwater.  However, elevated levels of nitrate-N are indicative of impacts from human land use.  The WGCC (Wisconsin Groundwater Coordinating Council) report cites work by Dr. Byron Shaw that states approximately 90% of all nitrate-N inputs to groundwater originate from agricultural sources, 9% from septic systems, and 1% from lawns or other sources.  While nitrate-N contamination of drinking water can be found throughout the state, there are certain areas that are more susceptible due to naturally occurring geology and human land uses. 
To learn more about the Nitrate-N in drinking water you can visit the following resources:

• Wisconsin Coordinating Council Report on Groundwater-Nitrate Section
• Wisconsin Department of Health Services-Nitrate
• Wisconsin Department of Natural Resources-Nitrate in Drinking Water

Natural nitrate-N levels in central Wisconsin, absent of all pollution sources, are less than 1 parts per million or 1 mg/L. The health-based drinking water standard and maximum contaminant level (mcl) for nitrate-N is 10 parts per million (as nitrate-N) or 10 mg/L. Nitrate-N above the drinking water standard can affect anyone. Small children and infants, women who are pregnant or who are of childbearing age should absolutely not consume water over the drinking water standard of 10 mg/L. No one should consume drinking water long term with nitrate-N over the drinking water Standard of 10 mg/L.

• Blue Baby Syndrome (methemoglobinemia)Nitrate-N can affect how our blood carries oxygen. Nitrate-N can turn hemoglobin (the protein in blood that carries oxygen) into methemoglobin. High levels can turn skin to a bluish or gray color and cause more serious health effects like weakness, excess heart rate, fatigue, and dizziness. Nitrate-N can affect babies more seriously because their bodies interact with nitrate-N differently.  When nitrate-N levels are high, water should not be given to babies less than 6 months old or used to make infant formula.

• Birth DefectsHigh levels of nitrate-N in drinking water may cause neural tube defects (a type of birth defect). The neural tube turns into the brain and spine in an unborn baby. Neural tube defects can occur very early in pregnancy.  When nitrate-N levels are high, women who are or may become pregnant should immediately stop using the water for drinking and preparing foods that use a lot of water.

• Thyroid DiseaseHigh levels of nitrate-N in drinking water may increase the risk of thyroid disease. Nitrate-N can affect how the thyroid functions by blocking the uptake of iodine. The thyroid needs iodine to make hormones. Low levels of thyroid hormone levels can cause fatigue, weight gain, dry skin, hair loss, and goiters (enlarged thyroid).  When nitrate-N levels are high, everyone should avoid long-term use of the water for drinking and preparing foods that use a lot of water.

• Colon CancerHigh levels of nitrate-N in drinking water may increase the risk of colon cancer. Nitrate-N may enhance the cancer potential of other compounds or may turn into cancer-causing chemicals like the body. Nitrate-N in drinking water has not been shown to increase the risk of other kinds of cancer.  When nitrate-N levels are high, everyone should avoid long-term use of the water for drinking and preparing foods that use a lot of water.