Can Well Water Contain Sodium Nitrites or Nitrates?

Sources

• Wells are often contaminated with sodium nitrates and nitrites when infilitrated by water carrying nitrogen-rich substances. Excess applications of inorganic nitrogen-based fertilizers, as well as manures from farmland, can spread the substances to well water. Rainstorms tend to create the problem by spreading contaminants through storm water runoff. Nitrogen-rich waste from human and animal feces can oxidize into nitrites, which readily form nitrates. Certain bacteria called Nitrosomonas can form nitrites in stagnant, oxygen-poor water containing nitrate.

Concentration

• Most surface and ground water, including many wells, contain some amount of nitrates. According to the World Health Organization, most such water sources contain less than 4 mg per liter, but 3 percent of surface waters and 6 percent of groundwater sources contain more than 20 mg per liter. The 1986 studies also took samples finding even more extreme levels, with 44 mg of nitrate per liter measured in hundreds of ground and surface water sources.

  In one case reported by the Centers for Disease Control and Prevention, an infant living in a rural home near acres of farmland became afflicted with Methemoglobinemia, otherwise known as blue baby syndrome. This disease occurs when a baby, usually under 6 months of age, is poisoned by high levels of nitrates or nitrites, reducing his blood's ability to carry oxygen. The well water samples at the house were found to contain 58 mg of nitrate per liter.

Increased Contamination

• A number of causes are to blame for the high rate of nitrate contamination in wells and other water sources. Excessive fertilization in farmland, inappropriate waste disposal from barns, runoff from septic tanks and industrial wastes can increase nitrate levels. Furthermore, contaminated aquifers can remain contaminated for many years, despite attempted reductions of runoff.

Preventing Contamination

• Test well water for nitrate concentration, and avoid using water if levels exceed 10 mg per liter. For levels of 5 mg or below, consider treatment options to remove the contaminant. Options include reverse osmosis and anion exchange. If levels are particularly high, use a new water source or consider blending the two waters to dilute nitrate levels. Always test water for bacterial contamination as well, particularly if nitrate sources are related to manure or sewage contamination.