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CAS Number: 14797-55-8
Contaminant Type: Chemical

Nitrate (NO3-), combined with various organic and inorganic compounds, is a widespread groundwater contaminant and a major water quality concern in drinking water supplies [2267].

Primary sources of organic nitrates include human sewage and livestock manure [2269]. Livestock feedlots, wastewater treatment discharge, and faulty septic systems can result in the release of organic nitrates into the environment [2267]. Fertilizers containing potassium nitrate and ammonium nitrate compounds are the major source of inorganic nitrate [2269]. In 2005, over 291 million pounds of inorganic nitrate compounds associated with fertilizer application were reportedly released [2268].

In natural waters, most nitrogenous materials are converted to nitrate. All sources of combined nitrogen, particularly nitrogen and ammonia, are potential sources of nitrate [2269]. Nitrates are very mobile in soil and have a high potential to migrate to ground water due to weak soil retention and high water solubility [2268]. Nitrates do not volatilize and therefore are likely to remain soluble in water until consumed by plants or other organisms [2268].

Excessive levels of nitrate in drinking water supplies can cause serious illness and possibly death, with infants and children among the highest at risk [2268]. The major health concern associated with nitrate consumption is methemoglobinemia, also known as “blue baby syndrome” [2268]. In infants, nitrate is reduced to nitrite which combines with hemoglobin in the blood to form methemoglobin [2268]. The presence of methemoglobin decreases the oxygen-carrying capacity of the blood resulting in acute symptoms, such as shortness of breath and blue coloration of the skin [2268]. Reduced oxygenation of the tissues can have numerous adverse implications, the most severe of which are coma and death [2268]. 

The maximum contaminant level (MCL) for nitrate is 10 mg per L as nitrogen (N) or 45 mg per L as Nitrate. EPA has identified ion exchange, reverse osmosis, and electrodialysis as the best available technologies for nitrate removal from drinking water.


Date of Literature Search: July 2014

2267 Jensen, V., Darby, J., Seidel, C., and Gorman, G. ; 2014; Nitrate in potable water supplies: alternative management strategies; Envir. Sci. & Tech.; 44:2203
2268 USEPA; 2007; Nitrates and nitrites toxicity and exposure assessment for children’s health chemical summary; http://www.epa.gov/teach/chem_summ/Nitrates_summary.pdf; As posted on November 20, 2014. EPA TEACH databases, Washington, DC.
2269 USEPA; 2014; Technical factsheet on: nitrate/nitrite; http://www.epa.gov/ogwdw/pdfs/factsheets/ioc/tech/nitrates.pdf; As posted on November 20, 2014. EPA Office of Ground Water and Drinking Water, Washington, DC.

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