References and Community Resources
Under certain conditions, the body changes nitrate into nitrite. Methemoglobinemia, a form of anemia, can result from the reaction of nitrite with hemoglobin in the blood. When this occurs, the ability of the blood to carry oxygen to the body's tissues is decreased. In infants, this condition is one of the causes of "blue baby" syndrome. Infants are especially susceptible for four reasons: 1) their fluid intake per body weight is greater than that of adults; 2) their stomach acidity can be lower than adults, thus allowing the growth of stomach bacteria that change nitrate into nitrite; 3) they have a form of hemoglobin that is more likely to form methemoglobin; and 4) they are less able to change methemoglobin back into normal hemoglobin. Pregnant women are also more susceptible to nitrate-induced methemoglobinemia since they have higher than normal levels of methemoglobin.
Nitrate can form a variety of N-nitroso compounds by reacting with proteins in the stomach. Some of these compounds have been found to cause cancer in animals. However, according to the USEPA, the data are inadequate to determine whether exposure to nitrate and nitrite in drinking water can result in human cancer.
U.S. EPA's guide to drinking water from household wells:
[https://www.epa.gov/privatewells]