The second in our series about emerging groundwater contaminants, nitrates are a class of compounds which occur both naturally in the environment and as a product of human activities. Nitrates infiltrate water sources in a variety of ways such as industrial processes, runoff from fertilizers, improperly disposed sewage, leaking septic systems, industrial waste, or manure.
When nitrates are present in water in concentrations exceeding in 10mg/L (10 ppm) both humans and the environment can be harmed. Nitrates contribute to the algal blooms seen the Great Lakes which dissolve oxygen in the water and potentially kill fish and other plants which depend on the oxygen to survive. In humans, consumption of nitrate contaminated water can lead to a severe blood disorder called methemoglobinemia which usually affects infants and pregnant women, as well as other problems still under scientific investigation. (More on methemoglobinemia from the Minnesota Department of Health).
What can I do?
Private well and septic owners should take steps to prevent nitrate contamination and of course, regularly test your water. If you have a septic system, have it inspected yearly by a professional and pumped out to ensure it is not overloaded and at risk of failure. Leaking septic systems can release nitrate to private wells nearby.
In other cases where you may not have control of a nitrate source, take steps to prevent excess nitrates from entering your well. Have your well checked – is it properly constructed to prevent surface water from entering? Have you constructed adequate diversion ditches to keep runoff from the well? New wells should be located uphill and at least 100 feet away from potential contaminant sources like feedlots, septic systems, barnyards and chemical storage facilities.
If you believe your water is contaminated, the best option is to have your well tested. If you do need to treat nitrates in your water supply, contact a water professional as boiling, filtering, chemical disinfection, and water softeners are not effective in removing nitrates from water supplies.
The Marion County Health Department offers free well testing through their Private Well Program for nitrates and a variety of other water contaminants. Call 317-221-2147 to schedule your test or learn more at http://marionhealth.org/private-well-program/.
For more information on nitrates, view these helpful resources:
https://storymaps.arcgis.com/stories/e7e6ec676acb4cc58d3d35e914efc207
https://extension.psu.edu/nitrates-in-drinking-water
