How Farm Runoff Poisons Our Drinking Water
Imagine not being able to turn on your tap for a drink of water, or being able to shower or boil water for pasta. We’re all familiar with the crisis that has afflicted Flint, Michigan, because of lead poisoning. But nearby Toledo, Ohio, faces the same threat each summer thanks to toxic algae in Lake Erie that thrive on the nutrients in farm runoff. In 2014, the algae was so bad that it shut down the drinking water supply for nearly half a million people. Similar algal blooms afflict communities across the country.
Excess nutrients from farm runoff can feed the explosive growth of algae. Cloudy, soupy, green water makes swimming and other recreation unpleasant to say the least. It can also be fatal. Some forms of algae produce a toxin that poisons the water, irritating the skin and eyes, and causing problems with the intestinal and nervous systems if ingested or through prolonged exposure. Sufficient exposure can kill people as well as their pets and wildlife.
The Gulf of Mexico exemplifies what comes after an algal bloom. As all of that algae dies, its decomposition eats up all of the oxygen in the water, starving other aquatic life of air. This great Gulf “Dead Zone,” stemming from the nutrients washing down the massive Mississippi River watershed, has been a major and growing problem.
This year, the Dead Zone hit record size, encompassing an area the size of New Jersey in which fish and other creatures either had to migrate or perish.
There are tools available for farmers to reduce their impacts on water quality, such as applying nutrients more carefully and in more precise ways, installing wetlands and stream buffers, and using cover crops to take up excess nutrients and hold soil in place during the winter. However, adoption of these practices has so far been insufficient to protect water quality. At the same time, the ethanol mandate has created so much increased demand for corn that water quality problems have grown ever more serious.
In recent years, the nation has made a strong commitment to restore and protect America’s iconic waters and is investing billions of dollars to restore the Great Lakes, Gulf Coast, Chesapeake Bay, and other great waters. The National Wildlife Federation supports common-sense reforms to fix the ethanol mandate so that our federal policies are helping—not undermining—efforts to restore these waters.
This Isn’t Your Grandfather’s Corn Farm
The vast majority of corn in this country is not grown on small farms of the American Gothic model. Commercial farming today is a major industrial enterprise with technology, equipment, and efficiency to maximize the number of crops that can be harvested from every available acre. The corn ethanol mandate only heightened this trend by encouraging farmers not only to bring millions of new acres into production, but also to double down the intensity of farming on their land in ways that can increase pollution to water supplies.
Among the major commercial crops, corn in particular requires lots of nutrients in the form of nitrogen and phosphorous fertilizers. These are applied in chemical form, or spread over fields as livestock manure. Rain and snowmelt carries these nutrients—and often precious topsoil—off the farm field and into streams, rivers, and ultimately our lakes and oceans. This type of water pollution from farm runoff is a major contributor to water bodies all around the country, but particularly in major agricultural watersheds.