Recent articles in the Des Moines Register and the Iowa Farm Bureau Spokesman regarding the Des Moines Water Works potentially filing a law suit against northwest Iowa counties for high nitrate levels on the Raccoon River made me think of what part do each of us have in increasing the nitrate levels in our communities or counties. In addition to being a Muscatine County Master Gardener, I am also on the Muscatine County Board of Health, which works with staff in Muscatine County to see that all water wells are tested for safe water drinking standards. It is no secret that sellers of fertilizers promote the use of nitrates. Here are some facts from common department of natural resources literature:
What is nitrate?
Nitrate (NO3) is a naturally-occurring chemical made of nitrogen and oxygen. It is found in air, soil, water, and plants. Much of the nitrate in our environment comes from decomposition of plants and animal wastes. People also add nitrate to the environment in the form of fertilizers.
How does nitrate get into well water?
Natural levels of nitrate in Iowa groundwater are usually quite low (less than 1 milligram per liter [mg/L] of nitrate-nitrogen). However, where sources of nitrate such as fertilizers, animal wastes, or human sewage are concentrated near the ground surface, nitrate may seep down and contaminate the groundwater. Elevated nitrate levels in groundwater are often caused by run-off from barnyards or feedlots, excessive use of fertilizers, or septic systems. Wells most vulnerable to nitrate contamination include shallow wells, dug wells with casing which is not watertight, and wells with damaged, leaking casing or fittings. Nitrate contamination of a well is often regarded as a first sign of deteriorating groundwater quality.
When you apply a fertilizer, either liquid or granular to your lawn, a portion of the fertilizer will either runoff or infiltrate into the groundwater system. Usually the purpose for fertilizing your lawn is to make it look very green or increase turf density, but where fertilizer and weed management are in the same bag, there is an additional increase in the hazards to human, pet, and fish health? Studies have shown that the fish flesh maintains the pesticides and herbicides from such mixes for a period of years.
Health risks to infants
Too much nitrate in drinking water poses a risk to infants less than six months of age. If an infant is fed water or formula made with water that is high in nitrate, a condition called "blue baby syndrome" can develop. Bacteria which are present in an infant's stomach can convert nitrate to nitrite (NO2), a chemical which can interfere with the ability of the infant's blood to carry oxygen. As the condition worsens, the baby's skin turns a bluish color, particularly around the eyes and mouth. If nitrate levels in the water are high enough and prompt medical attention is not received, death can result.
Let’s do our part
Now that we've reviewed that information, let's talk about what we can do.
Before application of fertilizer or weed management control, have your yard checked for amount needed. A simple test can be performed, and you can get the forms at the Extension Office. The results will tell you how deficient your turf is in minerals. Weed control many times can be accomplished by a dense turf. Manual removal of weeds in the lawn may require more labor on your part, but you are doing your part in helping the environment by not using chemicals. If you live in an area not served by a municipal water supply, have your water tested as you may find unwanted chemicals and high levels of bacteria, lead, arsenic, or other unwanteds in your water. Consider the buildup in the soil profile and eventually the groundwater of yearly application of fertilizer and chemicals. As we are more intensively using the shallow groundwater for irrigation, we are going to see more concentrations of unwanted, unhealthy items in the water supply. Consider yourself, your children, and your grandchildren and their health. Use the knowledge we have gained and improve the environment, by Doing Our Part!
A postscript on turf care: Consider modifying your landscape to include plant species that take up nitrogen from the soil. In many communities, the new subdivision designs require water that is running off from rooftops and overland to be maintained on each lot for some defined number of minutes. Others ask that no, or minimal, water be allowed to enter the gutter system, by using plants that take up water. This can be done by slightly elevated areas near the curb, and plants that take up water and nitrogen placed in those locations. This reduces the chemical runoff to the streets, gutters, and eventually the streams. These plants are readily available at most garden stores, and very much help beautify the landscape as well as protect our water supplies.