Who is at risk from high nitrates in drinking water?
The Environmental Protection Agency (EPA) has set the Maximum Contaminant Level (MCL) of nitrate as nitrogen (NO3-N) at 10 mg/L (or 10 parts per million) for the safety of drinking water. Nitrate levels at or above this level have been known to cause a potentially fatal blood disorder in infants under six months of age called methemoglobinemia or “blue-baby” syndrome; in which there is a reduction in the oxygen-carrying capacity of blood. The symptoms of blue-baby syndrome can be subtle and often confused with other illnesses. An infant with mild to moderate blue-baby syndrome may have diarrhea, vomiting, and/or be lethargic. In more serious cases, infants will start to show obvious symptoms of cyanosis: the skin, lips or nailbeds may develop a slate-gray or bluish color and the infant could have trouble breathing. A sample of the infants blood can easily confirm a diagnosis of blue-baby syndrome. It is difficult to determine the true incidence of blue-baby syndrome in Washington State
