Nitrate Exposure & Blue Baby Syndrome

Nitrate (N03) is a common groundwater contaminant which also occurs naturally in our environment and is important in natural processes such as decomposition and plant growth. Natural levels of nitrate in roundwater are rarely high enough to be dangerous to humans who drink the water. However, when it becomes highly concentrated in groundwater, nitrate can be toxic.

• Significant sources of nitrate contamination include fertilizers, animal wastes, and human sewage.

• Nitrate may contaminate a private drinking water well if the well is shallow, poorly maintained, old, and/or near a source of contamination.

• These situations also favor contamination by disease-causing bacteria. Disease-causing bacteria such as fecal coliform, or E. coli, may worsen the health effects of nitrate if ingested.

• Infants under six months of age are at the most danger from elevated levels of nitrates in drinking water. A baby fed water high in nitrates (or fed formula made with high-nitrate water) may develop a condition called “methemeglobinemi” or blue baby syndrome.” In this condition, the baby’s blood is unable to properly carry oxygen. As a result, the baby’s skin turns a blue color, particularly around the eyes, nose, and mouth. Death may follow, if oxygen deprivation is severe and lengthy enough. Susceptibility to blue baby syndrome increases if fecal coliform bacteria are also present in the baby’s drinking water. Fecal coliform bacteria cause diarrhea and interfere with digestion, intensifying nitrate’s effects on the body.

• Any water nitrate-nitrogen level over 10 mg/L is considered too high for safe drinking by babies under six months of age. This 10 mg/L nitrate-nitrogen limit is the Maximum Contaminant Level set up by the U.S. Environmental Protection Agency. Almost all adults may drink water with nitrate-nitrogen levels higher than 10 mg/L. However, some hereditary disorders render a few adults susceptible to methemeglobinemia. Also, women who are pregnant should not drink water high in nitrates.