Nitrates

Nitrate (NO3) is a naturally-occuring compound made up of nitrogen and oxygen that is an essential nutrient for plants. It forms when ammonia or other sources of nitrogen combine with oxygen in water. Nitrate is found in plants, soil, animal manure, septic systems, sewage, fertilizers, and airborne components from industry that are deposited through precipitation or dry particles.

Nitrate is highly soluble in water and does not easily bind with other compounds, making it more likely to remain in the water cycle and thus move large distances and remain in solution in rivers, streams, or groundwater for long periods of time. This means that one could find nitrate in high concentrations miles from the original source, and years after the original source was gone.

Infants under 6 months are susceptible to methemoglobinemia, where the nitrates are converted to nitrites in their stomachs (due to bacteria in their stomachs) which then enter the bloodstream and subsequently interferes with the body's ability to carry oxygen to tissues. In children and adults, nitrates may be linked to birth defects and certain types of cancer.

So what does this mean? Long-term exposure to high levels of nitrate poses a health hazard, and therefore well owners should regularly test their groundwater for levels of nitrate above the MCL (maximum contaminant level), which is 10 mg/L for both Montana and California.

Image: American Falls at Idaho Falls, ID (July 2008)