Nitrate Typical river water nitrate (NO₃^-) values range form 0 to 0.2 mg N per liter of sample (or ppm N). Concentrations greater than 1 ppm N are usually the result of stormwater runoff associated with sewage or fertilizers. The degradation of sewage generates dissolved nitrogen as nitrate and fertilizers contain nitrogen as nitrate. High nitrate levels can stimulate algal growth and lead to eutrophication. Ammonium and nitrite are the other products of the nitrification. The simplest way to denote nitrification would be as follows: Dissolved organic matter nitrogen ==> Ammonium ==> Nitrite ==> Nitrate. Nitrite is the most unstable as compared to the other forms of nitrogen and therefore, reads zero in almost all of our field measurements.