Nitrate is a chemical found in most fertilizers, manure, and liquid waste discharged from septic tanks, Natural bacteria in soil can also convert nitrogen into nitrate, Rain or irrigation water can carry nitrates down through the soil into groundwater. If a well draws from this groundwater, the drinking water may contain nitrates. Washington’s drinking water quality standard for nitrate is 10 milligrams per liter (mg/L), or 10 parts per million (ppm).

Nitrates reduced the ability of red blood cells to carry oxygen by binding to hemoglobin. In most adults and children these red blood cells rapidly return to normal, although there are some health conditions which make people more susceptible to nitrates. In infants it can take much longer for the blood cells to return to normal. Infants who drink water with high levels of nitrate (or eat foods make with nitrate-contaminated water) may develop a serious health condition due to the lack of oxygen and, if untreated, may die. This condition is called methemoglobinemia or blue baby syndrome. Additionally7, studies have also found an increased risk of spontaneous abortion or certain birth defects if the mother drank water high in nitrate. Finally, adults with reduced stomach acidity or deficient in the enzyme that changes red blood cells back to normal, are also susceptible to methemoglobinemia.

In January of 2010, the United States Environmental Protection Agency (EPA) issued a finding stating that groundwater in the Lower Yakima Valley was an underground source of drinking water which was contaminated, and that this contamination may present an imminent and substantial endangerment to human health.

For more information, see the following resources below:

Washington State Department of Health Information regarding Nitrate and Lower Yakima Valley:

DOH Nitrate in Drinking Water (Link to

DOH Lower Yakima Valley Nitrate Health Assessment Fact Sheet (Link to

DOH Evaluation of Risk from Exposure to Nitrate Contamination in the Groundwater of the Lower Yakima Valley Health Assessment (Link to