Nitrates and nitrites are nitrogen-oxygen chemical units which combine with various organic and inorganic compounds. Nitrate is a compound that is formed naturally when nitrogen combines with oxygen or ozone. Nitrogen itself is essential for all living things, but high levels of nitrate in drinking water can be dangerous to human health, especially for infants and pregnant women.
Nitrates are made in large amounts by plants and animals, and are released in industrial smoke and automotive exhaust. The greatest use of nitrates is as a fertilizer. It is often difficult to pinpoint sources of nitrates because there are so many possibilities. Major sources of nitrate contamination in drinking water may include runoff or seepage from fertilized agricultural lands, municipal and industrial waste water, refuse dumps, animal feedlots, septic tanks and private sewage disposal systems, urban drainage and decaying plant debris. High levels of nitrate in well water often result from improper well construction, well location, overuse of chemical fertilizers, or improper disposal of human and animal waste. Wells may be more vulnerable to such contamination after flooding.
Once taken into the body, nitrates are converted to nitrites. Fetuses and newborn children are particularly sensitive to nitrates and nitrites. High levels may result in a dangerous condition known as “Blue Baby Syndrome.” Its technical name is methemoglobinemia, a lack of oxygen in the blood. This can lead to coma, and can be fatal, though the condition is reversible if treated immediately. Nursing mothers who consume water with elevated nitrate levels can find that their breast milk is affected. Adults with heart or lung problems may also suffer ill effects from nitrates.
Although methemoglobinemia is the most immediate life-threatening effect of nitrate exposure, there is evidence to suggest a number of equally serious longer-term impacts. In numerous studies, exposure to high nitrate drinking water has been linked to a variety of effects, ranging from an enlarged thyroid to fifteen different types of cancer to two kinds of birth defects–and even to hypertension. For many years, public health professionals have known that nitrate has the potential to form carcinogenic compounds when it reacts with naturally occurring materials. Despite this known link, there has been uncertainty over the carcinogenic risk posed by nitrate in water, largely because we consume much more nitrate in our food than we do in our drinking water. Over the past two decades, however, numerous human epidemiology and physiology studies as well as animal studies have shown a potential link between nitrate intake in water and increased risk of cancer.
The most effective way to reduce nitrates in your drinking water supply is with a reverse osmosis system.