MCL: 10 ppm
Source: Occurs naturally in minerals and is found in fertilizers. Runoff of these fertilizers can contaminate natural water sources. Sewage waste may also produce nitrate.
Summary: Nitrate is the conjugate base of nitric acid and forms when ntiric acid loses a proton. It may occur as an environmental contaminant through its use in fertilizers. Leaks in septic tanks and discharge from sewage may also cause nitrate to occur as an environmental contaminant. Nitrate also occurs naturally and erosion may cause discharge into water sources. Nitrate is measured in water by the total concentration of nitrogen present. Excess amounts of nitrogen in water is used by algae and plants. Algae blooms are common occurrences resulting from excess nitrogen uptake in plants and algae. This process also depletes the dissolved oxygen levels in the water and may lead to fish kills. Nitrate may be used as a surfactant in industrial applications. When reacted with organic materials it may oxidize rapidly and explosively.