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Analysis of Nitrate in Water

Nitrate is a form of nitrogen found in the soil. It's an essential element for plants, especially in some crops, but too much in drinking water is dangerous.

  1. Nitrate analysis in drinking water

    • A certified lab tests water samples

      Since nitrate cannot be seen or tasted, it's impossible to detect without chemical analysis. Most nitrate contamination is from private water wells, so well water should be tested by a certified laboratory or local health department. Water samples are collected in sterilized plastic containers from the source and the exit point, such as a faucet. If the testing reveals that the water sample contains more than 10 mg per liter of nitrate, treatment is necessary. There could be seasonal variations due to fluctuation in groundwater, so testing throughout the year is recommended.

    Dangers

    • Infants are especially at risk.

      Even though nitrate is important, too much in drinking water can cause blood disease called methemoglobinemia in humans, especially in infants. The acid in a baby's stomach converts the nitrate from the water into nitrite, which moves into the bloodstream, where it changes hemoglobin into methemoglobin. Methemoglobin cannot properly carry oxygen like hemoglobin can. A lack of sufficient oxygen can cause brain damage or death.

    Drinking Water Standards

    • The EPA regulates drinking water standards.

      Analysis of water is done to determine if the water has acceptable levels of nitrate. According to the drinking water standards of the Environmental Protection Agency (EPA), a level of 45 mg per liter of nitrate is the maximum allowed.

    Protection

    • Cattle feedlots contain nitrate waste.

      Nitrate contamination is caused when nitrate-containing substances get into groundwater. Fertilizer is the major cause of nitrate contamination, as well as cattle waste. Thus any wells located too close or downstream to field crops, cattle feed lots, large residential areas where fertilizer is used or fertilizer-manufacturing plants stand a good chance of becoming contaminated. For this reason, groundwater wells should always be positioned upstream and as far from these places as possible. Any abandoned wells must be sealed and capped to prevent pollutants from entering the well. High-nitrate fertilizer should be used sparingly.

    Treating water

    • If analysis detects high nitrate levels in a water supply, some sort of treatment is required. Possible treatment methods include dilution, distillation or reverse osmosis. Distillation will boil off the water, leaving the nitrate behind. Reverse osmosis pushes water through a special membrane that only allows the water molecules to pass through. If possible, diluting a water source could spread out the nitrates into allowable levels, however, this method would be very difficult.

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