Nitrate is a compound that can naturally occurs and has many human-made sources. Nitrate is in some lakes, rivers, and groundwater including in your tap water. You cannot taste, smell, or see nitrate in water. Consuming too much nitrate can be harmful—especially for babies.
The Australian standard for nitrate in drinking water is 0>50 milligrams of nitrate (measured as nitrogen) per litre of drinking water (mg/L).
Health Effects
Consuming too much nitrate can affect how blood carries oxygen and can cause methemoglobinemia (also known as blue baby syndrome). Bottle-fed babies under six months old are at the highest risk of getting methemoglobinemia. Methemoglobinemia can cause skin to turn a bluish color and can result in serious illness or death. Other symptoms connected to methemoglobinemia include decreased blood pressure, increased heart rate, headaches, stomach cramps, and vomiting.
The following conditions may also put people at higher risk of developing nitrate-induced methemoglobinemia: anemia, cardiovascular disease, lung disease, sepsis, glucose-6-phosphate-dehydrogenase deficiency, and other metabolic problems.
Only recently has scientific evidence emerged to assess the health impacts of drinking water with high nitrate on adults. A growing body of literature indicates potential associations between nitrate/nitrite exposure and other health effects such as increased heart rate, nausea, headaches, and abdominal cramps. Some studies also suggest an increased risk of cancer, especially gastric cancer, associated with dietary nitrate/nitrite exposure, but there is not yet scientific consensus on this question.
Australian Water supplies with high levels of Nitrate.
Based on water quality reports from all over Australia farming, agriculture and mining regions are amonging the many areas and towns with high levels of Nitrates in the water supply. The Australian Drinking Water Guidelines suggest levels of Nitrate of 0>50 mg/l is safe to drink but the study below shows decades of documentation and studies suggesting 10 mg/l or more is unsafe.
Nitrate and Methemoglobinemia
Drinking water with high nitrate can cause a potentially fatal disorder called methemoglobinemia. Methemoglobinemia is a condition in which more than one percent of the hemoglobin in red blood cells take the form of methemoglobin. Hemoglobin carries oxygen in our blood, delivering it from the lungs to the rest of our body. Methemoglobin does not carry oxygen well and, when it replaces hemoglobin, it can cause a gray blueness of the skin (cyanosis). We have a lot of information about how excess nitrate in drinking water behaves in our bodies and leads to methemoglobinemia. Nitrate in water is almost completely absorbed into the blood. Our bodies convert a portion of that nitrate into nitrite. Nitrite reacts with blood to create methemoglobin. The more methemoglobin in the blood, the worse that blood is at carrying oxygen where it is needed. Along with these changes in blood chemistry, a person suffering methemoglobinemia may also experience elevated resting heart rate, weakness, nausea, and in severe cases, death.
Research and case reports
Research and case reports show that nitrate in water above 10 milligrams per liter (mg/L) can cause methemoglobinemia in infants less than six months old. In 1945 the hypothesis that high levels of nitrate in well water caused methemoglobinemia was published. 1 Two years later, an infant near the town of Tyler became the first published case in Minnesota. 2 In the following three years, there were 146 cases voluntarily reported in Minnesota, including 14 deaths. In 1979 and 1980 there were two reported cases of methemoglobinemia in Minnesota. In both cases nitrate concentrations in the water were over 50 mg/L. Once the source of water was changed in the homes, the methemoglobinemia resolved. 3 Most Minnesota cases of methemoglobinemia in infants occurred in the southwestern part of the state, but cases have been reported from the southern border to as far north as Becker County. Some infants developed symptoms after fewer than two days, and other infants were fed formula prepared with well water for up to 60 days before symptoms appeared. It is suspected that many milder cases were resolved by changing the source of the infant’s water and were never reported.2 There were no methemoglobinemia cases reported in breast fed babies. The most recognized symptom of methemoglobinemia is a gray-blue color to the lips that eventually spreads to the whole body. In some cases, the bluish color can be so subtle that it goes unnoticed. 2 This was the case when parents in Columbia County, WI brought their child in for immunizations in 1998. They noticed that their child had been “crabbier than normal” and had been vomiting after feeding since they moved to a new house served by a private drinking water well. Concerned that this may be a case of methemoglobinemia, a home nurse visited the family and took water samples. The concentration of nitrate in their water was 22.9 mg/L. The doctor placed the baby on bottled water and the methemoglobinemia resolved
Other Cases of Methemoglobinemia
Nitrate in water and methemoglobinemia are not unique to the Midwest. It occurs all over the country, as well as around the world. According to the Centers for Disease Control and Prevention, between 1979 and 1996 there were six infant deaths from methemoglobinemia in Texas, South Dakota, Louisiana, Virginia, and Colorado. Additionally, it is a common problem in Eastern Europe, where most methemoglobinemia cases are associated with contaminated water
Infants Are Especially Sensitive to Nitrate in Water
While adults can develop methemoglobinemia due to high levels of nitrate in drinking water, public health actions mainly focus on infants less than six months old because they are an especially sensitive population. Infants fed formula prepared with water high in nitrate are the most highly exposed population. They receive the highest dose of nitrate compared to all other age groups based on body weight.5 In addition to their high exposure, infants have different body chemistries than adults. They convert more nitrate to nitrite, which leads to the creation of methemoglobin, and their bodies are less able to convert methemoglobin back into hemoglobin. This causes methemoglobin to build up in the body of an infant faster than it builds up in the body of an adult.
Scientific Support for 10 Milligrams per Litre
The evidence supporting the 10 mg/L US EPA Maximum Contaminant Level (MCL) for nitrate in drinking water and the Minnesota Health Risk Limit (HRL; which is the adopted MCL) is strong. Because exposure to nitrate and resulting illness has been observed in humans rather than just laboratory animals, values derived to protect people do not have to be adjusted to account for differences in animals and humans. Additionally, the six Minnesota cases of methemoglobinemia in infants described by Rosenfield and Huston occurred in water with nitrate levels above 10 mg/L. 2 A nationwide survey performed by the American Public Health Association in 1949 showed this was a national trend. The survey collected details of 278 methemoglobinemia cases, of which 214 included information about drinking water sources. All 214 cases were associated with drinking water that had a concentration of nitrate above 10 mg/L
Factors That May Reduce Cases of Methemoglobinemia
Much of what is known about the health risks of nitrate is from reports, surveys, and other work done in the mid-1900s. Physicians and scientists quickly concluded that water with nitrate above 10 mg/L is potentially lethal to infants less than six months old. Since that time, there have been several changes that may have reduced the real or perceived number of methemoglobinemia cases in Minnesota. • The high number of cases of methemoglobinemia in 1947-1949 lead to a familiarity with the illness in infants and how to treat it (switch water sources). There has been a gradual drop off in the number of cases voluntarily reported by physicians following this awareness. Additionally, new mothers are more aware of their water source and may opt to feed their babies formula reconstituted with bottled water. • The condition may not be easily recognized by health care providers, particularly in mild cases with symptoms like irritability, lethargy, and/or a blue skin color that may fade and return. • Methemoglobinemia is not a reportable illness in Minnesota and there is no mechanism in place for a provider to report cases to the state health department. This limits our ability to know how many infants are treated for this condition each year. In a recent review of hospital discharge data and emergency department records in Minnesota from 2000-2016, there were 10 cases of methemoglobinemia in infants greater than one day old and less than one year old. The majority of the case records lacked supporting information needed to definitively rule out nitrate in drinking water as a cause or contributor to the diagnosis.
Emerging Health Risks for Adults from Nitrate in Water
In sum, the evidence remains compelling that high levels of nitrate in water cause methemoglobinemia. While methemoglobinemia in infants may be less common today, it has not disappeared, and remains an important public health concern. Only recently has scientific evidence emerged to assess the health impacts of drinking water with high nitrate on adults. A growing body of literature indicates potential associations between nitrate/nitrite exposure and other health effects such as increased heart rate, nausea, headaches, and abdominal cramps. Some studies also suggest an increased risk of cancer, especially gastric cancer, associated with dietary nitrate/nitrite exposure.
Solutions to solving the growing problem of contaminated drinking water in Australia.
Whole home water filtration has become a growing trend in Australia, as more people are aware of the chemicals and contaminants now displayed in our tap water. Nitrate is just one of the hundreds even thousands of chemicals and contaminants Australians now deal with on a daily basis.
The solution to reducing your daily chemical exposure is a POE (point of entry) Water filter system like the Vortex-Pro from waterfilter.direct or the Whirlpool-Pro range. The Whirlpool-RO system successfully removes 99.99% of chemicals like fluoride, chlorine and chlorine just to name a few including Nitrates.
Chemical free living starts with chemical free water, find out how you can reduce your daily chemical exposure for you and your family and book a free consultation today.
References 1. Comly, H.H., MD. (1945). “Cyanosis in Infants Caused by Nitrates in Well Water.” JAMA 129: 112-116. 2. Rosenfield, A.B. and R. Huston (1950). “Infant methemoglobinemia in Minnesota due to nitrates in well water.” Minn Med 33(8): 789-796. 3. Convery, M. (2013). Infant methemoglobinemia in Minnesota due to nitrate in well water. Personal communication. 4. Knobeloch, L., et al. (2000). “Blue babies and nitrate contaminated well water. Environ Health Perspect 108 (7): 675- 678. 5. U.S. Environmental Protection Agency (USEPA). (2011). “Exposure Factors Handbook.” Retrieved from Exposure Factors Handbook, 2011 Edition (Final Report): https://cfpub.epa.gov/ncea/risk/recordisplay.cfm?deid=236252. 6. Walton, G. (1951). “Survey of literature relating to infant methemoglobinemia due to nitrate-contaminated water.” Am J Public Health Nations Health 41 (8 Pt 1): 986-996. 7. Agency for Toxic Substances and Disease Registry (ATSDR). (2017). Toxicological Profile for Nitrate and Nitite. https://www.atsdr.cdc.gov/toxprofiles/tp204.pdf 8. USEPA (2017). IRIS Assessment Plan for Nitrate and Nitrite (Scoping and Problem Formulation Materials). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-17/331, 2017.
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