Nitrate-nitrogen converter.

Nitrate-N to Nitrate Converter: how it works

Nitrate as nitrogen (NO3-N) times 4.43 gives nitrate as NO3, and nitrite as nitrogen times 3.28 gives nitrite as NO2. The factors are the ion's molecular weight divided by nitrogen's atomic weight: 62.005 / 14.007 for nitrate and 46.006 / 14.007 for nitrite (nitrogen as N2 is 28.014 g/mol, so N is half).

Worked example. A lab reports 10 mg/L nitrate-N, the US EPA limit for nitrate measured as nitrogen. 10 x 4.427 = 44.27 mg/L as nitrate, which matches Health Canada's 45 mg/L as nitrate (10 mg/L as nitrate-nitrogen) once rounded. Another report says 30 mg/L nitrate: 30 / 4.427 = 6.78 mg/L as N, within both limits.

Limits. The US EPA primary standard is 10 mg/L for nitrate and 1 mg/L for nitrite, both measured as nitrogen, because infants under six months who drink water above the limit can become seriously ill (blue-baby syndrome). Health Canada's maximum acceptable concentrations are 45 mg/L as nitrate and 3 mg/L as nitrite (10 and 1 as nitrogen).