Nitrate in drinking water

S. Deak, quoted in Health Hazards from Nitrates in Drinking Water, Report on a WHO meeting, Copenhagen, 5-9 Mareh 1984, WHO, Geneva, 1985. 

In 1945, H. H. Comly first estimated the correlation between nitrates in drinking water and the incidence of methemoglobinemia. Research shortly afterwards showed that no cases of methemoglobinemia had been reported in any area of the United States where the water supply contained less than 45 ppm of nitrate ion. This value has become accepted in USA as the upper limit for the nitrate concentration in drinking water. At present the WHO limit is also 45 ppm of nitrate but the value of 22 ppm of nitrate has been set for EC countries. 

Let us consider in brief the nitrate biogeochemical provinces, where a significant growth of cancer incidents has been observed. It is known that the absorption of nitrate and nitrite from water in the intestinal tract is 2 times as much as from food products. This means that the accumulation of nitrate in drinking water sources should be of special concern during consideration of food webs in any relevant biogeochemical province. 

Experiment 23 Determination of Nitrate in Drinking Water by UV Spectrophotometry... 

Barrett JH, Parslow RC, McKinney PA, Law GR, Forman D (1998) Nitrate in drinking water and the incidence of gastric, esophageal, and brain cancer in Yorkshire, England. Cancer Causes Control 9 153-159... 

Steindorf K, Schlehofer B, Becher H, Hornig G, Wahrendorf J (1994) Nitrate in drinking water A case-control study on primary brain tumours with an embedded drinking water survey in Germany. Int J Epidemiol 23 451 57... 

WHO (1985b) Health hazards from nitrates in drinking water. World Health Organization,... 

Nitrate in drinking water above the standard poses an immediate threat to children under three months of age. In some infants, excessive levels of nitrate have been known to react with the hemoglobin in the blood to produce an anemic condition commonly known as blue baby. If the drinking water contains an excessive amount of nitrate, it should not be given to infants under three months of age and should not to be used to prepare formula. The standard allows for 10.0 mg of nitrate (as N) per liter of water. Nitrate can be removed from water by ion exchange, RO, or distillation [48]. 

The potentially harmful effects of exposure to high concentrations of nitrates in drinking water result from reduction to nitrites, which combine with haemoglobin to form methaemoglobin (blue baby disease). Additionally, nitrosamine formation can cause cancer and hypertension. In nature, high levels of nutrients, such as nitrates, lead to eutrophication of water sources, which in, severe cases, lead to the extermination of the other aquatic life due the decreased levels of oxygen and luminosity. 

Many countries have also established specific regulations to protect children from exposure to certain environmental hazards, including toxic chemicals. Examples include banning of heavy metals in toys, strict limit setting for persistent toxic substances in baby foods, and the setting of environmental limit values derived on the basis of infants sensitivities (e.g. nitrates in drinking-water). In the United States, concerns about children s special vulnerabilities... 

There has long been concern expressed over the presence of nitrate in drinking water at concentrations exceeding the EC guideline of 50 mg L because of the risk of methaemoglobinaemia (blue baby syndrome). Here,... 

Connolly, D. and Pauli, B. Rapid detemination of nitrite and nitrate in drinking water samples using ion-interaction chromatography. Anal. Chim. Acta 2001, 441, 53-62. 

Hepatic toxicity was also found several other studies. In one study, Sprague-Dawley rats (15/sex/dose) were exposed to uranium as uranyl nitrate in drinking water (males up to 36.73 mg/kg/day females up to 53.56 mg/kg/day) for 91 days and then sacrificed. Hepatic lesions, which included anisokaryosis. 

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