Nitrite and Nitrate in Water

Nitrate in Water

Question #1: What are nitrite and nitrate in Water?

Both nitrite and nitrate are compounds of nitrogen. They are colorless, odorless and tasteless. It is nitrate which is more commonly found in water than nitrite. They are found naturally in soil, water, plants and food. When microorganisms break down organic materials such as plants, animal manure and human sewage, nitrite and nitrate are formed.

Nitrate is found in chemical fertilizers and as such is extensively used on farms, golf courses and residential lawns and gardens. Nitrite is also used to cure meat.

Question #2: How do nitrite and nitrate get into our drinking water?

Since nitrogen in its various forms is such an essential part of all living things, it's easy to see how it can be washed into rivers, streams, lakes and reservoirs. And when rain and snow seep into the ground, it's easy to see how it becomes a part of groundwater and eventually appears in wells.

Nitrite rapidly converts to nitrate. Nitrate is a compound of nitrogen and oxygen. Not only is it a nutrient that is applied in great quantities to the growth of plants whether on farms or lawns, but it is formed when organic materials are broken down by microorganisms. You can see that runoffs from farms, golf courses and residential gardens and lawns will have nitrate in it. And you can see how landfills, animal feed lots and faulty septic systems are a source of nitrate in water.

Wells that are improperly constructed or that are dug too close to landfills, animal farms or septic systems can have high levels of nitrate.

Question #3: How can nitrite and nitrate in water effect my health?

They probably won't have much affect on your health unless you are pregnant or elderly or an infant under one year of age, in which case you wouldn't be reading this! The body changes nitrate into nitrite which in turn decreases the ability of the blood to carry oxygen throughout the body in babies particularly. The result is a condition called methemoglobinemia or "blue baby" syndrome. The blood robbed of it's oxygen gives a blue look.

A pregnant mother's susceptibility to methemoglobinemia peaks at week 30 of her pregnancy and then returns to normal by birth. Older people with impaired enzyme systems may have the same risk of methemoglobinemia.

Question #4: How big a problem are nitrite and nitrate in our drinking water?

High levels of nitrite or nitrate in water is not likely in most areas. The U.S. Geological Survey found that, between 1970 and 1992, only 9% of the private wells that were tested had levels of nitrate that were higher than the safety limit. However, if you have members of your family that are particularly vulnerable to methemoglobinemia, it's important to know if and how much nitrate you have in your water.

Question #5: How can I know if nitrite or nitrate is in my drinking water?

If you get your tap water from a public water company, they are required by law to send you annually a Consumer Confidence Report (CCR). If you don't have a copy you can get one from your city hall. Look to see if there is either nitrite or nitrate in your water and how much. They cite the "Level Found" and the "MCL" (Maximum Contaminant Level). For nitrite, the standard set by the EPA is 1 mg/L (milligrams per liter). For nitrate the standard set is 10 mg/L. Any water which has more than this amount of nitrite or nitrate is not safe. The water company is required to state in the CCR that nitrite or nitrate is over the MCL limit and what they are doing to correct this. They are also required to inform the public through newspapers and television that the level of nitrite or nitrate is over the level of safety.

If you get your tap water from a private well, it is recommended that you have it tested for nitrite, nitrate and other pollutants that may make it unsafe to drink as is. You can order a water testing kit and test it yourself or hire a water testing laboratory in your area to do it for you.

Question #6: How would I go about removing nitrite or nitrate from my drinking water?

There are two kinds of filters that can remove nitrite from your tap water: Distillation and Reverse Osmosis. There are three kinds of filters that can remove nitrate from your tap water: Distillation, Reverse Osmosis, and Filtration (granular/carbon). However, you need to check the individual filter that you are considering to not only see if they claim to reduce nitrite or nitrate, but also to see if this has been certified by the NSF International as a filter that does indeed effectively reduce nitrite or nitrate.

SUMMARY TABLE

For further information on the best filters in the categories of Distillation, Reverse Osmosis and Filtration go to "Best Water Filters". Or for a broader discussion of the multiple considerations you need to keep in mind in selecting a filter go to "How to Choose a Water Filter".

For more information about Nitrite, Nitrate and other toxic contaminants, go to "Nitrite and Nitrate in Water".