Nitrate in Drinking Water: Measures and Data
Why is nitrate a concern?High levels of nitrate can have acute effects on health, limiting the ability for the blood to transport oxygen, especially in infants. Other possible acute effects may include adverse pregnancy outcomes and birth defects. Long-term nitrate exposure has been associated with some cancers, although more research is needed. Adults lacking stomach acids and certain enzymes may experience problems.
How is it tracked?Nitrate levels can vary seasonally. Public water systems are required to test regularly for nitrate under the Safe Drinking Water Act. Water systems must notify customers if even one sample exceeds the MCL of 10 parts per million. There is no federal mandate to test private wells for nitrate, although some counties in Washington require it under certain circumstances.
What can be done about elevated nitrate levels?Infants with an unnaturally brownish-blue skin tone should receive medical treatment. Well owners should test for nitrate frequently. Pregnant women and small children should switch to bottled water if nitrate levels exceed 5 ppm; it does not help to boil water. Protection of wellheads, deeper wells, and siting of wells away from sewage sources will help avoid problems.
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