Source of NitriteNitrites are not usually found in drinking water supplies at concentrations above 1 or 2 mg/i (ppm). Nitrates are reduced to nitrites in the saliva of the mouth and upper GI tract. This occurs to a much greater degree in infants than in adults, because of the higher alkaline conditions in their GI tract. The nitrite then oxidizes hemoglobin in the blood stream to methemoglobin, thus limiting the ability of the blood to carry oxygen throughout the body. Anoxia (an insufficiency of oxygen) and death can occur. The US EPA has established the MCL (maximum contaminant level) for nitrite at 1 mg/l.
Treatment of NitriteNitrites are removed in the same manner as nitrates; reverse osmosis, anion exchange, or distillation. See Nitrate - Treatment.