NitratNitrogen

NitratNitrogen, commonly referred to as nitrate-nitrogen (NO3-N), denotes the portion of nitrate that contains nitrogen in chemical analyses. It is a standard metric in water quality, soil science, and environmental chemistry because nitrate is an essential nutrient for plants and a major indicator of nutrient pollution.

Concentrations are usually reported as milligrams per liter as NO3-N (mg/L NO3-N) or as milligrams per liter as NO3- (mg/L NO3-). To convert, multiply NO3-N by about 4.43 to obtain NO3-, or divide NO3- by 4.43 to obtain NO3-N.

Sources include natural nitrification of ammonium in soils; agricultural fertilizers and manure; septic systems and wastewater; and some industrial effluents. In aquatic systems, elevated NitratNitrogen can fuel algal blooms and lead to lower dissolved oxygen, harming aquatic life. In drinking water, high nitrate levels pose health concerns, especially for infants, due to methemoglobinemia.

Regulatory guidance varies by country, but a common standard in many jurisdictions is an upper limit of 10 mg/L NO3-N in drinking water (equivalent to 45 mg/L NO3-). Agencies also monitor nitrate as part of nutrient management and groundwater protection.

Analytical methods include colorimetric assays for NO3-N, ion-selective electrode measurements for NO3-, and spectrophotometric or chromatographic techniques. Samples require appropriate preservation and consideration of interferences during measurement.

Management approaches to reduce NitratNitrogen in water include best management practices in agriculture, buffer strips to reduce runoff, controlled fertilizer application, and treatment processes such as denitrification in wastewater facilities.